A Paleoseismic Transect Across the Northwestern Basin and Range Province, Northwestern Nevada and Northeastern California, USA GEOSPHERE; V

Research Paper

GEOSPHERE A paleoseismic transect across the northwestern Basin and Range Province, northwestern Nevada and northeastern California, USA GEOSPHERE; v. 13, no. 3 Stephen F. Personius1, Richard W. Briggs1, J. Zebulon Maharrey1,2, Stephen J. Angster1,3, and Shannon A. Mahan4 1Geologic Hazards Science Center, U.S. Geological Survey, MS 966, PO Box 25046, Denver, Colorado 80225, USA doi:10.1130/GES01380.1 2Department of Geology and Geophysics, University of Alaska, Fairbanks, 900 Yukon Drive, PO Box 755780, Fairbanks, Alaska 99775, USA 3Center for Neotectonic Studies, University of Nevada, Reno, MS 174, 1664 N. Virginia Street, Reno, Nevada 89557, USA 13 figures; 3 tables; 12 supplemental files 4Crustal Geophysics and Geochemistry Science Center, U.S. Geological Survey, MS 974, PO Box 25046, Denver, Colorado 80225, USA

CORRESPONDENCE: personius@usgs.gov ABSTRACT 1971, 1978; Wallace, 1984, 1987). A total of ~150 km of extension across the CITATION: Personius, S.F., Briggs, R.W., Maharrey, 700–800-km-wide province is thought to be related to a combination of buoy- J.Z., Angster, S.J., and Mahan, S.A., 2017, A Paleo‑ seismic transect across the northwestern Basin and We use new and existing data to compile a record of ~18 latest Quaternary ancy changes in the crust and mantle and accommodation of right-lateral Range Province, northwestern Nevada and north‑ large-magnitude surface-rupturing earthquakes on 7 fault zones in the north- transform motion across the Pacific–North American plate boundary since eastern California, USA: Geosphere, v. 13, no. 3, western Basin and Range Province of northwestern Nevada and northeastern inception of the San Andreas fault system (Wernicke, 1992; Jones et al., p. 782–810, doi:10.1130/GES01380.1. California. The most recent earthquake on all faults postdates the ca. 18–15 ka 1996; Sonder and Jones, 1999). Approximately 20%–25% of the ~50 mm/yr of last glacial highstand of pluvial Lake Lahontan and other pluvial lakes in the right-lateral deformation across the plate boundary is distributed east of the Received 18 June 2016 Revision received 13 January 2017 region. These lacustrine data provide a window in which we calculate latest Sierra Nevada, and most of that deformation is taken up by strike-slip faulting Accepted 27 March 2017 Quaternary vertical slip rates and compare them with rates of modern defor- in the Walker Lane and normal faulting along the eastern and western mar- Published online 10 May 2017 mation in a global positioning system (GPS) transect spanning the region. gins of the province (Dixon et al., 1995; Bennett et al., 1998, 2003; DeMets and Average vertical slip rates on these fault zones range from 0.1 to 0.8 mm/yr Dixon, 1999; Thatcher et al., 1999; Thatcher, 2003; Hammond and Thatcher, and total ~2 mm/yr across a 265-km-wide transect from near Paradise Val- 2004; Bormann et al., 2016). The remainder is taken up by normal faulting ley, Nevada, to the Warner Mountains in California. We converted vertical along isolated ranges in the interior of the province. slip rates to horizontal extension rates using fault dips of 30°–60°, and then The Neogene tectonic and magmatic history of the northwestern Basin and compared the extension rates to GPS-derived rates of modern (last 7–9 yr) Range Province (NWBR) differs from the better studied parts of the province in deformation. Our preferred fault dip values (45°–55°) yield estimated long- central Nevada. The latest phase of extension in the NWBR is thought to have term extension rates (1.3–1.9 mm/yr) that underestimate our modern rate initiated later (≤12 Ma versus ≤30 Ma) and accumulated less strain (≤20% ver- (2.4 mm/yr) by ~21%–46%. The most likely sources of this underestimate are sus 50%–100% extension) than the central part of the province (Colgan et al., geologically unrecognizable deformation from moderate-sized earthquakes 2006b; Lerch et al., 2008; Egger and Miller, 2011). With the exception of the and unaccounted-for coseismic off-fault deformation from large surface-rup- Warner Range on the western margin of the NWBR, the area was covered with turing earthquakes. However, fault dip values of ≤40° yield long-term rates voluminous middle Miocene (ca. 16 Ma) Columbia River basalts (Noble et al., comparable to or greater than modern rates, so an alternative explanation is 1970; Hart and Carlson, 1985) and nearly coeval rhyolites associated with cal- that fault dips are closer to 40° than our preferred values. We speculate that deras related to initial impingement of the Yellowstone hotspot (Coble and OLD G the large component of right-lateral shear apparent in the GPS signal is parti- Mahood, 2016). The deposition of extensive middle Miocene volcanic rocks tioned on faults with primary strike-slip displacement, such as the Long Valley largely predates the onset of the latest phase of extension (Colgan et al., 2004, fault zone, and as not easily detected oblique slip on favorably oriented normal 2006a, 2006b) in the NWBR. faults in the region. Two recent paleoseismic transects determined late Quaternary slip histo- OPEN ACCESS ries at lat 40°–41°N (Wesnousky et al., 2005) and 38.5°–40°N (Koehler and Wes- nousky, 2011) across Basin and Range structures in central and north-central INTRODUCTION Nevada. Both studies compared cumulative slip on late Quaternary structures to geodetic networks at the same latitudes. The transect at 40°–41°N pro- The Basin and Range Province is a large region of extensional tectonics in duced a much slower cumulative extension rate on faults over the past 20 k.y. the intermountain region of western North America. The province is character- (~0.65 mm/yr) than the geodetically measured extension rate of ~2 mm/yr. In This paper is published under the terms of the ized by numerous north-trending ranges and internally drained basins formed contrast, the transect farther south at 38.5°–40°N resulted in a cumulative ex- CC‑BY license. primarily by normal faulting in the Neogene and Quaternary (e.g., Stewart, tension rate on faults over the past 20 k.y. (~1 mm/yr) that was consistent with

geodetic rates across the region. Such mixed results are common in other rate (Surprise Valley fault zone), permanent global positioning system (GPS) sta-

121.0° 42.0° 120.0° Figure S1A. Map of NWBR transect region in northwestern Nevada and northeastern California, showing Quaternary faults from USGS Quaternary Fault and Fold database (U.S. Geological 119.0° Survey, 2015) and modifications from current study. 118.0° 117.25° y s e 42.0° ne tn ll zo Denio a M V Sheldon EQ swarm t lo (November 2014-2017?) ul lo a b f b e Goose u e uue ne EXPLANATION ey P l P o Lake l a z e Fault Ages V ) n t o l Latest Pleistocene o n u an z o to Holocene i a u t t f comparison studies (e.g., Friedrich et al., 2003, 2004; Bell et al., 2004; Gold tions that span the region, and a lack of historical surface ruptures that can l G y c (<15 ka) u e e a l e f l s g a Late Pleistocene s

V er n an (<130 ka) t e v o R

te Ri HoH Middle Pleistocene a S Steens East Bog Hot n vs=1.1 m s (<750 ka) g n Steens Bog Hot o Valley profile site ui B vs=13.8 m Ro Valley trench site Pleistocene y vs=1.9 m Q (m-lp) ( vs=22.2 m (<2 Ma) e a l vs=4.4 m t l Denio EQ swarm (e-mp) a Mahogany s (February-April 1973) M an GPS Stations n VaV Mountain i o S B PBO a n t i y l t MAGNET n k a e eey u ll n one s Campaign o i a o z G C a V ran pr ite M t r l C e P r ee e Seismicity ur k e M

au V i g S ne k t M 2-2.95 r f y ng n n e a ongo lt K s a M M 3-3.95 u L f R rn i ey a a n l f F tn a u g M 4-4.95 k or l al t s e e s Northwest Nevada plateau W vs=13.4 m

a V e n r es z s o et al., 2014) in the Basin and Range. Possible disparities between the geologic create transient signals associated with post-seismic relaxation (e.g., Hetland Shor (m-lp) M 5-5.95

o C z R t o e

n t C r r s eek i e e R t v i l Site Location d l e d R u pr r A a an f r an D t tephra site Big Creek a ur s t Vertical separation V e e o k n S ge a g a u measurement L a i n l l b a -in post-18 ka deposits al e S lk l vs=1.0 m A R y e Area of vs=2.5 m t -in pre-18 ka deposits Fig. 11d s Lo H e (early to late Pleistocene) vs=1.0 m r y o n e F e l

vs=12.1 m g l Mo 010 e a km Vya vs=0.7 m n

Cooks Canyon Va i Lo V u d P trench n n a l r r nng le t t vs= a e s g vs=13.5 m y Quinn River e i v k n 0.5 m a OR L s f Ri Crossing e Orovada e a il n ) V u Cedarville m k y o t l c n n C r al t Alturas d z o n o A NV Fo n i i l e a R t eey r t t z n u l s k c Santa Rosa-Orovada e y o on c e u Q e n r z k eeg a g l l trench site a o a io s nan f L a z e a B Su l l ex / n

a te s e r n o and geodetic deformation data are important because previous seismic haz- and Hager, 2003) in the modern strain field. Such perturbations can complicate t t si i o n e l n n s g r e e u g n vs=5.2 m n p S C e Quinn River a Area of d t e n f i a r re t WWa c is ur d S ti x on Lakes a vs= n Fig. 11a vs=0.6 m R e = e 1 a e p a 0 R g r 0/ vs=0.3 m t 2 0.5 m 8 a r ri n 0 s ° e ne s V s a e g tephra a e k o a R s n r Area of a

ll R n L a Steamboat Canyon exposure o

e r o Fig. 11b,c V R e R fault exposure y a y

d t n l MoM Sand Canyon ne u n a a Area of a ou f o o t a a l C fault & tephra a B u l Fig. 3 z ey n u s s S nt exposures ( y a PBO-P013 lt t o

a vs=3.7 m

a S R ul H i z n vs=15.1 m vs=1.4 m a o f s ne a PBO P013 to P145 tta y PBO P145 to P731 n Deer Creek e PBO Transect l a Total Vdiff= 1.2 ± 0.1 mm/yr Total Vdiff= 2.6 ± 0.1 mm/yr fault exposure PBO P013 to P731 al S e y PBO-731 Extension Vdiff= 1.6 ± 0.1 mm/yr vs>1-1.5 m V Extension Vdiff= 0.8 ± 0.1 mm/yr n PBO-P145 Total Vdiff= 3.8 ± 0.1 mm/yr o t lle z vs=4.6 m a er Extension Vdiff= 2.4 ± 0.1 mm/yr t (lp) V l es u t r a D f e s s s ards maps of the region were based primarily on historical seismicity and long versus short-term rate comparisons (Wesnousky et al., 2005). Hobo Canyon e n n i t shoreline complex D B a M l y vs=5.1 m aca nt Area of e e c l k u vs=7.5 m Fig. 6 S n l n o a l u z RRo o V Mo m s t o k l y c b u k n c a o e e a le f s l s J r is R i al k s n l ddi c l B a i VaV g nng a l H ra o

g J a e n o e Gabica t u d P H

King Lear Peak R a y t Butte i l y shoreline complex l SSt s d King Lear R vs=2.5 m o

o t l u r vs=6.0 m Peak er B e n v lv s Corbeal B Area of iil B e vs=2.0 m la Fig. 8 S H l D Butte a c i c l k l k k s vs=1.0 m Area of c R g o Fig. 2 R r o a R b o c e

c k n paleoseismic data from mapped Quaternary faults (e.g., Frankel et al., 2005), We chose to focus our paleoseismic transect on faults that have been ac- k vs=0.5 m k f c a a Mormon Dan lla D u vs=0.9 m l B e t Butte

e z r o t n e

41.0° Jungo Hills

Base is a DEM from USGS NED (10-m) elevation data, overlain by Alturas, Cedarville, Denio, High Rock Canyon, Jackson Mountains, Osgood Mountains, and Quinn River Valley USGS 100,000-scale topographic maps. Coordinate system: NAD 27, UTM zone 11N. 41.0° but the latest maps include geodetic data in hazards calculations (Petersen tive in the latest Pleistocene and Holocene because these structures probably

1Supplemental Figure S1. (A) Map of transect region et al., 2014a, 2014b). Disparities between geologic and geodetic deformation are responsible for ongoing deformation in the region and thus may be the in northwestern Nevada and northeastern Califor- rates add to uncertainties in such calculations. most likely sites of future surface-rupturing earthquakes. Fortuitously, all of the nia, showing Quaternary faults from the U.S. Geo- In this study we characterize the history of surface-rupturing earthquakes Holocene-active faults in the transect were covered in whole or part either by logical Survey Quaternary Fault and Fold Database (U.S. Geological Survey, 2015) and modifications in latest Quaternary time (past 15–18 k.y.) across a transect at lat 41°–42°N in the last (Sehoo) pluvial cycle of Lake Lahontan or by other closed-basin pluvial from current study; (B) KMZ files of Quaternary fault the NWBR of northwestern Nevada and northeastern California (Fig. 1; also lakes of equivalent age. The Sehoo lake cycle began ca. 35 ka, and culminated layers shown in Fig. 1A. Please visit http://doi .org refers to the larger scale, more detailed version; see Supplemental Fig. S11). at its highstand elevation (~1330–1340 m) ~13,000 14C yr ago (Thompson et al., /10.1130/GES01380 .S1 or the full-text article on www We chose to study this region for several reasons, including the excellent pres- 1986; Benson et al., 1995; Adams and Wesnousky, 1998, 1999). We use the lat- .gsapubs.org to view Supplemental Figure S1. ervation of faulted features, the well-defined western margin of the province ter age and an uncertainty value of ±200 yr to determine a calibrated age of

121.0° 120.0° 119.0° 42.0° 118.0° 117.25° Sheldon EQ swarm (2014–17?) Denio Fault ages FZ <18–15 ka

QRs Guano Denio EQ <2 Ma Valley Steens FZ swarm (1973) PBO GPS ST1 station

Vya FZ Seismicity Long V Valley M 2–2.95 Northwest Nevada plateau M 3–3.95

Surprise Valley FZ LV3 M 4–4.95 regional extension fault Alder Ck M 5–5.95 Vya alley FZ Quinn River Warner Mountains Hays Canyon Range FZ Site location Pine Forest SV1 Range FZ Crossing Orovada Alturas direction = 100/280° Fig. location Santa Rosa Range FZ Cedarville SRRs 01km 0 SRR1 Quinn River 5 SV2 LV1 JM1b Quinn River LV2 PBO Transect JM1 P013 P145 JM4 731 alley

lley FZ Valley Black Rock FZ JM2 OR JM3 DV1

a DV2 CA

Desert Va Paradise V NV Jackson Mountains FZ

Bloody Run Hills FZ

Nevada

41.0° Californi Black Rock Desert

Figure 1. Simplified map of transect region in northwestern Nevada and northeastern California, showing Quaternary faults (from U.S. Geological Survey, 2015) and modifications from current study. Base map is from 100,000-scale topographic maps and 10-m-elevation National Elevation Data set (NED) data of the U.S. Geological Survey (http://ned .usgs.gov/). Most seismicity data are from the ANSS (Advanced National Seismic System; http://www .ncedc.org /anss/) Composite Catalog, 1898–present (accessed 28 January 2015); data from the 1973 Denio swarm are from Richins (1974), and data from 2014–2015 Sheldon swarm are from the University of Nevada-Reno Seismological Laboratory and National Earthquake Information Center (see Supplemental Fig. S1 [footnote 1] for larger scale, more detailed version of this figure). SRRs—Santa Rosa Range section; QRs—Quinn River section; EQ—earthquake; FZ—fault zone; PBO—Plate Boundary Observatory (www.unavco.org); GPS—global positioning system.

15.6 ± 0.3 ka (unless otherwise noted, all ages are presented with 1s uncer- a scale of 1:100,000 for inclusion in Supplemental Figure S1 (see footnote 1), tainties) for the Sehoo highstand in the Lahontan basin. Highstands of some and later simplified for inclusion in Figure 1. We assumed that faults in this part isolated pluvial lakes such as Lake Surprise and Lake Alvord may be slightly of the Basin and Range undergo primarily normal displacement, so we used older (~18 ka) than the Lahontan highstand shoreline, so herein we use an age the vertical separation of correlative geomorphic surfaces as proxies for fault range of 18–15 ka for these datums. The widespread sediments and landforms slip (Supplemental Fig. S22). These values were obtained primarily from field associated with Lake Lahontan and other pluvial lakes provide important data measurements of topographic profiles using high-resolution GPS (RTK, real for assessing the recency of surface faulting, and allow us to calculate rates of time kinematic) surveying equipment, supplemented with a few profiles mea- deformation over a uniform time period that we then compare to the modern sured across larger scarps using 10 m NED (National Elevation Dataset; http:// strain field as determined by space geodesy. ned.usgs .gov/) digital elevation models. Where multiple measurements of slip After a discussion of methods, we briefly describe (from east to west) what were available, we primarily chose the maximum slip values to compensate is currently known about the paleoseismology of seven fault systems that off- for possible underestimation of slip at depth (i.e., shallow slip deficit). In addi set Sehoo and younger deposits in our transect region of northwestern Nevada tion to published data, we derived additional timing information using opti and northeastern California (Fig. 1). Four of these faults (Santa Rosa Range, cally stimulated luminescence (OSL; Supplemental Table S13) and uranium- southern Steens, Surprise Valley, and Black Rock fault zones) have been the series (Supplemental Table S24) dating techniques, supplemented by chemical subject of extensive investigations, including fault trenching. The other three fingerprinting and correlation of several tephra samples (Supplemental Table faults (Desert Valley, Jackson Mountains, and Long Valley fault zones) have not S35) and regional correlations of pluvial lake shoreline sequences related to been the subject of previous detailed investigations, so we concentrate our the Sehoo cycle of pluvial Lake Lahontan. Unless otherwise described, all ages discussion on the results of our efforts on these structures. are assumed to be equivalent to calendar ages before present (in ka) with 1s uncertainties. One unavoidable consequence of our focus on latest Pleistocene and METHODS younger deformation is that given the typical recurrence intervals of many Basin and Range faults, our selected time interval (<18–15 ka) for calculating

Figure S2. Plots of topographic profiles measured across fault scarps in this study. Profiles are labeled by fault zone, and organized from north to south. Most profiles were measured in the field with high precision RTK receivers; Sixprofiles (JM_5_01_2014-1 and JM_5_01_2014-8 on JMFZ; PFR 3_11_2015-1b and PFR 3_11_2015-3bb on PFRFZ; LVB-1 and LVB-2 on LVFZ) were measured from 10 m DEM (NED) data from USGS, and two (SRR_AM_3-3 and SRR_AM_9-10) were measured in the field with a total station by A.M. Michetti (written commun., 2001). Santa Rosa Range Scarp Profiles Desert Valley Scarp Profiles We applied a variety of methods to map surface ruptures and determine slip rates is too short for some faults to contain a complete seismic cycle (two 3 3 3 ) ) profile SRR_AM_3-3 profile SRR_AM_9-10 )

2 2 2 profile ) 2 vertical vertical vertical DV 4_26_2010-2D profile vertical separation separation separation Height (m DV 4_26_2010-3A separation Height (m 1 1 1 1 =0.5 m =0.5 m Height (m =2.5 m =0.3 m

VE=17X VE=17X VE=17X Height (m VE=17X 0 0 0 0 050 100 150 050 100 150 050 100 150 050 100 150 200 Distance (m) Distance (m) Distance (m) Distance (m) deformation rates on faults in our transect. Where detailed mapping was not earthquakes). The time interval contains the elapse times that predate and 10 Jackson Mountains Scarp Profiles

profile JM 9_24_2014-1 6.0 profile 4.0 ) upper scarp JM 6_02_2013-T1 profile JM 6_02_2013-T3 vertical ) 4.0 5 separation ) vertical vertical

Height (m lower scarp total vertical =0.5 m 2.0 separation 2.0 separation vertical separation available, we mapped most of the latest Quaternary fault traces in the region postdate the event, but the uncertainties associated with calculating slip rates 0.4 m =0.4 m separation =5.2 m Height (m =4.7 m 0 Height (m VE=6X VE=4X VE=4X 0 0 050 100 150 200 02550 02550 Distance (m) Distance (m) Distance (m) 6.0

4.0 at a nominal scale of 1:24,000 through analysis of aerial photographs and are likely higher than for faults that show evidence of multiple earthquakes profile JM 6_02_2013-T8 profile JM 4_25_2010-4F profile JM 4_25_2010-4E 4.0 fluvial terrace 4.0 ) backedge ) ) 2.0 vertical separation vertical Height (m 2.0 Height (m =2.3 m 2.0 separation vertical

Height (m =2.1 m separation =1.7 m 0 high-resolution, 1 m NAIP (National Agriculture Imagery Program; https://www in the latest Quaternary. Three of our structures (Santa Rosa Range, Desert VE=4X VE=4X VE=4X 0 0 02550 02550 0255075 Distance (m)Distance (m) Distance (m) 6.0 10 profile JM 9_24_2014-2 profile JM 9_24_2014-3A 4.0 profile JM 4_25_2010-4C 4.0 .fsa.usda.gov/programs-and-services/aerial-photography/imagery-programs/) Valley, and Long Valley fault zones) show evidence of a single earthquake and 4.0 ) profile JM 4_25_2010-4D ) ) ) vertical vertical separation 5 separation =4.9 m Height (m vertical 2.0 2.0 Height (m =3.7 m vertical 2.0

Height (m separation

Height (m separation = 1.4 m =2.0 m VE=4X VE=4X VE=6X VE=4X 0 0 0 0 imagery, and limited field checking. The fault traces were then compiled at yield low slip rates with small uncertainties (<0.2 ± 0.03 mm/yr). The calculated 02550 02550 050 100 02550 Distance (m) Distance (m) Distance (m) Distance (m)

10 20 30 profile JM 4_24_2010-4A

profile JM_5_01_2014-1 profile JM 8_29_2011-4 ) ) vertical ) 20 separation 5 =4.6 m 10 Height (m Height (m Height (m 10 vertical vertical separation separation = 7.4 m =3.2 m VE=6X VE=1.5X VE=1X 0 0 0 050 100 0255075 100 125 0255075 100 Distance (m) Distance (m)

30 20

profile JM 8_29_2011-5 profile JM_5_01_2014-8 )

) 20

10 Height (m

Height (m vertical vertical 10 separation separation =10.1 m = 2.4 m VE=1X VE=1.5X 0 0 0255075 100 0255075 100 125 Distance (m) Distance (m) SUPPLEMENTAL TABLE S1. OPTICALLY-STIMULATED LUMINESCENCE (OSL) DATA AND AGES FROM 30 SUPPLEMENTAL TABLE S3. GEOCHEMICAL FINGERPRINTING OF TEPHRA SAMPLES FROM NWBR TRANSECT

) 2.0 2.0 THE JACKSON MOUNTAINS, NORTHWESTERN NEVADA 20 vertical Sample H2O Corr §

profile JM 6_1_2013-S2 separation ) ParameterSiO2Al2O3 Fe2O3MgO MnO CaO TiO2 Na2O K2OCl∑ Wt% Comments and Correlations ) profile JM 4_23_2010-4D SC =3.9 m profile JM 4_24_2010-2B name Diff Factor Height (m § # 1.0 1.0 % Water 10 total vertical vertical Sample K (%)† U (ppm)† Th (ppm)† Cosmic dose Total Dose Equivalent N Age** vertical vertical Height (m Jackson Mountains tephra bed, NW Nevada† Height (m separation separation separation =7.5 m separation =0.9 m Mount Mazama tephra; averageof 46 =3.6 m VE=2X =0.5 m VE=8.5X VE=8.5X name content* additions (Gy/ka) Rate (Gy/ka) Dose (Gy) (ka) 230 NV ave* Average: 72.5 14.7 2.22 0.45 0.05 1.61 0.43 5.22.7 0.16 ———1.000 0 0 0 SUPPLEMENTAL TABLE S2. U̺TH CONCENTRATIONS, ISOTOPIC COMPOSITIONS, AND CALCULATED TH/U # 050 100 150 200 0255075 025 50 samples from northern Nevada Distance (m) Distance (m) 234 238 n=46 1σ SD:0.2 0.10.050.020.010.050.020.1 0.10.02— —— Distance (m) AGES AND INITIAL U/ U ACTIVITY RATIOS FOR SAMPLES OF LAKE LAHONTAN TUFA FROM THE JACKSON Pine Forest Range Scarp Profiles JM-1 1 (23) 1.15 ± 0.03 1.35 ± 0.09 3.65 ± 0.15 0.28 ± 0.02 1.93 ± 0.07 32.3 ± 1.07 24 (25) 16.8 ± 0.83 30 30 ## MOUNTAINS, NORTHWESTERN NEVADA 2.64 ± 0.10†† 47.3 ± 4.02†† N.A. 17.9 ± 1.45†† JM-T1Average: — 100.00 Th 234 238 72.7414.62 2.15 0.48 1.69 0.48 4.92 2.74 0.18 0.68 1.01 Sand canyon ash exposure (this study) ) ) 20 20 Sample nameSample U Th 230 /U Age Initial U/ U Measured activity ratios Detritus-corrected activity ratios n = 25 1σ SD: — 0.00 profile PFR 3_11_2015-3bb profile PFR 3_11_2015-1b § § 0.37 0.27 0.12 0.02 0.05 0.15 0.34 0.08 0.06 1.34 0.01 vertical weight (μ/g) (μ/g) (± 2σ, ka) AR (± 2σ) vertical separation 232 238 230 238 234 238 230 232 230 238 234 238 § =13.4 m Th/ U AR Th/ U AR U/ U AR Th/ U AR Th/ UAR† U/ U AR† ρ48-08 0.88 Correlated w/ Mount Mazama tephra

Height (m * * * Height (m (g) * 10 separation 10 JM-2 8 (40) 1.90 ± 0.03 2.72 ± 0.08 8.51 ± 0.32 0.27 ± 0.02 3.16 ± 0.08 13.0 ± 0.27 17 (20) 4.10 ± 0.14 SC 0.9970.995 0.9670.937 —0.951 0.8980.946 0.984 ———0.973 =13.8 m (± 2σ) (± 2σ) (± 2σ) (± 2σ) (± 2σ) 9

VE=2X VE=2X Upper tephra bed, Long Valley, NW Nevada† 0 0 050 100 150 200 050 100 150 200 250 JM䇲 U䇲 2C1 0.0864 1.10 0.3990.1200 ± 0.00060.361 ± 0.009 1.477 ± 0.0053.0 0.284 ± 0.0511.532 ± 0.032 0.78 22.0 ± 4.7 1.566 ± 0.028 Distance (m) Distance (m) LT-2 Average: 75.2514.04 1.60 0.21 0.07 1.02 0.24 4.28 3.29 —100.00— —1.000 Trego Hot Springs tephra; Black Rock JM-3 5 (25) 1.72 ± 0.04 2.03 ± 0.09 5.76 ± 0.3240.27 ± 0.02 2.70 ± 0.11 30.6 ± 0.24 17 (20) 11.0 ± 0.41 # Long Valley Scarp Profiles Desert, Nevada (type locality) 1.0 1.0 profile LV 4_22_2010-1B 1.0 profile LV 4_22_2010-1E profile LV 4_22_2010-1A ) ) ) JM䇲 U䇲 3A10.0430 1.50 0.4830.1064 ± 0.00040.335 ± 0.002 1.418 ± 0.0073.2 0.266 ± 0.0441.460 ± 0.026 0.77 21.6 ± 4.3 1.489 ± 0.023 animal vertical T-1U Average: 75.5313.55 1.63 0.22 —1.050.234.353.310.14100.002.481.03 burrow separation JM-4 3 (24) 1.38 ± 0.05 2.17 ± 0.08 4.49 ± 0.29 0.26 ± 0.02 2.42 ± 0.09 28.5 ±0.8316 (20) 11.8 ± 0.56 Long Valley ash exposure (this study) vertical = 0.6 m vertical Height (m Height (m Height (m separation separation n = 23 1σ SD:0.180.220.100.03—0.06 0.11 0.18 0.15 0.05 0.00 0.72 0.01 = 0.3 m = 0.3 m VE=40X VE=40X VE=40X § 0 0 0 JM䇲 U3A2 0.0658 1.75 0.6960.1315 ± 0.00040.372 ± 0.003 1.403 ± 0.0042.8 0.289 ± 0.0551.455 ± 0.031 0.79 23.8 ± 5.5 1.487 ± 0.028 SC 0.9960.965 0.9840.977 —0.974 0.9640.983 0.994— 0.983 050 100 150 050 100 150 050 100 150 200 Correlated w/ Trego Hot Springs tephra Distance (m) JM-5 1 (21) 2.78 ± 0.04 2.49 ± 0.14 10.3 ± 0.35 0.18 ± 0.01 4.10 ± 0.11 15.4 ± 0.42 20 (24) 3.75 ± 0.13 Distance (m) Distance (m)

profile LV 9_23_2014-100 *Field moisture, with figures in parentheses indicating the complete sample saturation %. Ages calculatedusing approximately 25% of saturation values. Lowertephra bed, Long Valley, NW Nevada† 1.0 1.0 1.0 JM䇲 U䇲 3A30.0460 1.54 0.5100.1090 ± 0.00050.375 ± 0.002 1.418 ± 0.0103.4 0.307 ± 0.0441.461 ± 0.028 0.72 25.3 ± 4.4 1.496 ± 0.025 profile LV 4_22_2010-2A )

) Wono tephra; Agency Bridge, ) vertical profile LV 9_23_2014-5 vertical †Analyses obtained using in-situ low-resolution gamma spectrometry (NaI detector) and checked with high-resolution lab gamma spectrometry LD-30Average:74.10 14.032.110.300.061.380.324.533.17—100.00 ——1.000 separation separation # = 0.7 m vertical = 0.8 m 234 238 Nevada (type locality) separation (Ge detector). Analyses by S.A. Mahan at USGS Luminescence Dating Laboratory, Denver, CO. Measured isotope ratios corrected for mass fractionation, spike contributions, procedural blank and normalized relative tostanda a rd value for NIST SRM 4321b U/ U=0.0000529;

Height (m * Height (m Height (m = 0.7 m § all analyses conducted by James B. Paces at the USGS Denver Radiogenic Isotope Laboratory, April, 2012. VE=40X VE=40X VE=40X Cosmic doses and attenuation with depth were calculated using the methodsof Prescott and Hutton (1994). 0 0 0 232 238 234 238 230 238 T-1L Average: 74.0913.95 2.20 0.30 —1.370.344.503.120.13100.002.051.02 050 100 150 200 02550 0255075 100 䇲 Long Valley ash exposure (this study) Distance (m) Distance (m) Distance (m) # †Assumed Th bearing detrital component has an atomic Th/U of 4 with the following activity ratios and 2s errors:Th / U=1.276 ± 0.64; U/ U=1.0 ± 0.1; and Th/ U=1.0 ± 0.25. Number of replicated equivalent dose (De) estimates used to calculate the equivalent dose. Figures in parenthesesindicate total number of measurements § n = 28 1σ SD:0.310.160.150.02—0.07 0.20 0.23 0.10 0.06 0.00 1.26 0.01 60 60 230Th/U age, initial 234U/238U ratio and associated errors calculated using detritus䇲 corrected activity ratios. § included in calculatingthe represented equivalent dose and age using the minimum age model (MAM).Excluded aliquots failed methodology tests or had SC 1.0000.994 0.9610.993 —0.991 0.9510.994 0.986— 0.988 Correlated w/ Wono tephra 40 profile LVB-1 40 profile LVB-2 (Miocene basalt) (Miocene basalt) large dispersion. vertical separation vertical Height (m ) Height (m ) Dose rate and age for fine-grained 250-90 microns quartz (except JM-5 at 250-180 microns). Exponential fit used on equivalent dose; errors to 1σ. *Mazama ash geochemistry is average of 46 identified samples from Nevada (Davis, 1985). 20 =43.0 m 20 separation ** =40.0 m VE=2X VE=2X ††Feldspar fine-grains 4-11 micron polymineral silt. Exponential fit used for equivalent dose, multiple aliqotu additive dose; errors to 1σ. Fade tests indicate †Values represent an average of 20 analyses of individual glass shards from each sample (in oxide weight percentage). 0 0 § 0 100 200 300 400 500 600 0 100 200 300 400 500 600 6.05 g/decade correction. Similarity Coefficient (SC) averages calculated using Si, Al, Fe, Ca, Na, K oxides;chem ical analyses and correlation by J.Z. Maharrey and J.E. Begét at Alaska Center for Distance (m) Distance (m) 4 ## Tephrochronology (ACT), University of Alaska, Fairbanks, AK. 60 60 Supplemental Table S2. U/Th concentrations, iso # N.A.—Not applicable. References: Wono andTrego Hot Springs tephras—Benson et al. (1997); Mazama ash—Davis (1985). 40 profile LV NF-1 40 profile LV NF-2 (Miocene basalt) (Miocene basalt) vertical vertical 230 Height (m ) Height (m ) 20 separation 20 separation REFERENCES CITED =44.0 m =48.0 m topic compositions, and calculated Th/U ages and VE=2X VE=2X REFERENCES CITED Benson, L.V. Smoot, J.P., Kashgarian, M., Sarna-Wojcicki, A, and Burdett, J.W., 1997,Radiocarbon ages and environments of deposition of the Wono and Trego 0 0 0 100 200 300 400 500 600 0 100 200 300 400 500 600 Hot Springs tephra layers in the Pyramid Lake subbasin, Nevada: Quaternary Research, v. 47, p. 25-2160. Distance (m) Prescott, J.R. and Hutton, J.T., 1994, Cosmic ray contributions to dose rates for luminescence and ESR dating: large Distance (m) 234 238 depths and long-term time variations: Radiation Measurements, v. 23, no. 2, p. 497-500. initial U/ U activity ratios for samples of Lake Davis, J.O., 1985, Correlation of late Quaternary tephra layers in a long pluvial sequence near Summer Lake, Oregon:Quaternary Research, v. 23, no. 1, p. 38-53. Lahontan tufa from the Jackson Mountains, north- 2Supplemental Figure S2. Plots of topographic pro- 3Supplemental Table S1. Optically stimulated lumines- western Nevada. Please visit http://doi .org /10 .1130 5Supplemental Table S3. Geochemical fingerprinting files measured across fault scarps in this study. cence (OSL) data and ages from the Jackson Moun- /GES01380.S4 or the full-text article on www.gsapubs of tephra samples from Jackson Mountains and Long Please visit http://doi.org/10.1130/GES01380.S2 or tains, northwestern Nevada. Please visit http://doi .org .org to view Supplemental Table S2. Valley, northwestern Nevada. Please visit http://doi the full-text article on www.gsapubs.org to view Sup- /10.1130/GES01380 .S3 or the full-text article on www .org/10 .1130/GES01380 .S5 or the full-text article on plemental Figure S2. .gsapubs.org to view Supplemental Table S1. www.gsapubs.org to view Supplemental Table S3.

errors probably underestimate the actual uncertainties, so we used compari- Michetti and Wesnousky (1993), Narwold and Pezzopane (1997), and Nar- sons with other faults in the region to assign a probable 1s estimate of ±0.1 wold (2001) conducted geologic mapping, soils studies, and topographic scarp

Figure S3. Summary figures of paleoseismology of Santa Rosa Range fault zone. A) Scarp profile and logs from a trench across A EAST SCARP PROFILE WEST the Santa Rosa Range fault zone at a site ~5 km southeast of Orovada, NV (modified from Figs. 3 and 4 of Personius and Mahan, 20 2005). B) New OxCal model of chronological data from Personius and Mahan (2005). soil pit outline scarp height: 8.5 m OxCal v4.2.4 Bronk Ramsey (2009); Bronk Ramsey and Lee (2013); r:5 IntCal13 atmospheric curve (Reimer and others, 2013) 10 meter s mm/yr to slip rates for these three faults. This value is consistent with a maxi profiling along the Quinn River section of the SRRFZ. In the transect area (Fig. 1) surface offset: 7.0 m B Paleoseismic Parameters fault scarp parameters Sequence Santa Rosa Range Chronology scarp height: 8.5 ± 1.7 m trench outline 0 surface offset: 7.0 ± 1.5 m fault Paleoearthquake timing (2σ) max. scarp slope angle: 15° no vertical exaggeration Historic constraint (1850 AD) zone same datum as trench logs EQ P2005* this study SR1 13.5 ± 2.5 ka 13.4 ± 2.6 ka 100 50 0 -30 ORNT5 (IRSL; 5.7 ± 0.3 ka) meters SR2 99 ± 9 ka 97.6 ± 5.2 ka mum estimate of 0.25 mm/yr based on the rates of two faults in our transect the Quinn River section consists of a piedmont trace (Hot Spring Hills fault of 10 ORNT6 (IRSL; 8.5 ± 0.7 ka) SR3 140 ± 15 ka 137.6 ± 10.2 ka

EAST WEST 2 meters ORNT10 (IRSL; 11.3 ± 0.9 ka) Recurrence Intervals (2σ) area of inset 5 Interval P2005* this study boulder 7 k 7 Earthquake SR1 (13.4 ± 2.6 ka) SR1-0 13.5 ± 2.5 kyr 13.4 ± 2.6 kyr south wall 1 5 SR1-SR2 85.5 ± 11.5 kyr 84.1 ± 5.9 kyr k 3 4 (Black Rock and Steens fault zones) that record more than one post-Sehoo Narwold, 2001) marked by fault scarps with surface offsets of 16–22 m in early 6 SR2 SR1 Lahontan highstand (15.6 ± 0.6 ka) SR3 0 SR2-SR3 41 ± 14 kyr 40.0 ± 11.4 kyr 45 40 35 30 25 20 15 10 5 0 meters ORNT9 (IRSL; 66.0 ± 5.0 ka) EXPLANATION Vertical Displacements (1σ) trench units fault zone inset ORNT8 (TL+IRSL; 101.0 ± 7.0; 96.0 ± 5.3 ka) SR1 2.0 ± 0.5 m (incl. +0.5 m basin fault) 7 Silty, grusy colluvium from SR1 ORNT-10 ORNT-8 11.3 ± 0.9 ka SR2 2.1 ± 0.7 m 6 fault comminution zone 101 ± 7 ka ORNT-5 5 2 7 5.7 ± 0.3 ka ORNT-6 Earthquake SR2 97.6 ± 5.2 ka) SR3 1.5 ± 0.5 m earthquake. This rate would be reasonable estimate of maximum slip rate if to middle Pleistocene deposits and 1–3 m in latest Pleistocene to Holocene(?) 5 Silty, stony colluvium from SR2 8.5 ± 0.7 ka k Total 5.6 ± 0.7 m

4 Silty, sandy colluvium from SR3 7 meters 5 ORNT7 (TL; 97.0 ± 7.0; 99.5 ± 4.9 ka) 3 Sandy, gravelly colluvium from SR4 1 2 younger fan alluvium 4 Slip Rate (1σ) 6 k ORNT4 (IRSL; 98.0 ± 9.0; 102.7 ± 6.1 ka) 1 older fan alluvium Average (latest Quaternary): 0.13 ± 0.03 mm/yr N5W 3 ORNT-9 soil pit units 80W 66 ± 5 ka (2.0 ± 0.5 m/15.6 ± 0.30 kyr) ORNT-1 ORNT-4 ORNT3 (IRSL; 128.0 ± 11.0; 125.5 ± 8.8 ka) up3 younger loess ORNT-3 ORNT-2 98 ± 9 ka ORNT-7 0 141 ± 14 ka 128 ± 11 ka 133 ± 8 ka 97 ± 7 ka the three single-event faults underwent a second surface rupture in the near deposits. Narwold (2001) used soil development and scarp profiles to calculate up2 older loess ORNT2 (TL+IRSL; 133.0 ± 8.0 ka; 20 15 10 Average (Interval SR1-SR3): 0.03 ± 0.01 mm/yr up1 older fan alluvium meters 132.1 ± 6.8 ka) soil pit exposure (3.6 ± 0.7 m/124.2 ± 5.25 kyr) ORNT-11 15 11.6 ± 0.7 ka 15

meter s Earthquake SR3 (137.6 ± 10.2 ka) symbols modeled earthquake pdf up3 contact; dashed where gradational luminescence age (years) Average (pre SR3-present): 0.04 ± 0.01 mm/yr ORNT-9 up2 ORNT1 (TL; 141.0 ± 14.0 ka; posterior pdf 66 ± 9 ka up1 (post-model) prior pdf (5.6 ± 0.7 m/143.2 ± 5.5 kyr) fault ORNT-14 143.2 ± 10.9 ka) (pre-model) ORNT-13 128 ± 13 ka eroded fault-scarp free face krotovina (burrowed zone) 403 ± 30 ka future. A minimum slip rate of 0.05 mm/yr is consistent with longer term rates minimum vertical slip rates of 0.01–0.15 mm/yr, and concluded that the most k 10 10 mean 2σ range earthquake horizon Sequence start SR1 stones 100 95 90 (*--Personius and Mahan, 2005) meters

250,000 200,000 150,000 100,000 50,000 0 Modeled age (cal yr BP) 6 Summary The paleoseismology of the Santa Rosa Range section (SRRS) of the Santa Rosa Range fault zone (SRRFZ) has been described in detail by Personius et al. (2004) and Personius and Mahan (2005). Here the SRRFZ consists of two primary strands: a range front strand that forms the from trench data on the Santa Rosa Range fault zone (Supplemental Fig. S3 ; recent earthquake (MRE) on the Quinn River section occurred ca. 10 ka and steep western margin of the Santa Rosa Range, and a sympathetic strand with considerably less total throw that offsets the basin floor 4-6 km west of the range front trace. We include both primary strands in the SRRFZ because the trace of the basin floor strand mimics the strike and overall length (35-40 km) of the range front strand and both probably ruptured at the same time during the most-recent surface-rupturing earthquake. Data from a trench on a splay of the range front trace about 5 km southeast of Orovada, Nevada yielded evidence for four surfaceruptur- ing earthquakes, the last three of which occurred since 141 ± 14 ka (Fig. A; modified from Figs. 3 and 4 of Personius and Mahan (2005). Based on the cross-sectional area of the colluvial wedges, the oldest and youngest dated surface ruptures (SR3 and SR1) had surface offsets of 1.5 ± 0.5 m, and the middle rupture (SR2) had a surface offset of 2.1 ± 0.7 m. The basin-floor strand is marked by a ~0.5-m-high scarp in sediments related to the highstand of Lake Lahontan. Personius and Mahan (2005) used luminescence dating to estimate the following times of the past three surface-rupturing earthquakes: the most recent earthquake (SR1) occurred 13.5 ± 2.5 ka, the penultimate earthquake (SR2) occurred 99 ± 9 ka, and the next older earthquake (SR3) occurred 140 ± 15 ka; a fourth earthquake is poorly constrained at >141 ± 14 ka and <403 ± 30 ka. Herein we present an OxCal model of the chronological data from Personius and Mahan (2005) that produces similar earthquake ages (Fig. B). We combine the surface offset estimate of earthquake SR3 from the Orovada trench (1.5 ± 0.5 m) and the surface offset of the basin floor trace (0.5 m), and use the regional age of the Lahontan highstand (15.6 ± 0.3 ka) to calculate an average latest Quaternary slip rate of 0.13 ± 0.03 mm/yr. However, this rate is substantially higher than late Quaternary interval and average rates based on the long (tens of thousands of years) recurrence intervals between the past three dated earthquakes at the Orovada trench site (Personius and Mahan, 2005). modified from Personius and Mahan, 2005, Figs. 3 and 4 therein). We also averaged 0.6 ± 0.3 m of vertical displacement. Michetti and Wesnousky (1993) References Cited Bronk Ramsey, C., 2009, Bayesian analysis of radiocarbon dates: Radiocarbon, v. 51, no. 1, p. 337–360. Bronk Ramsey, C., and Lee, S., 2013, Recent and planned developments of the program OxCal: Radiocarbon, v. 55, no. 2–3, p.720-730. Personius, S.F., Anderson, R.E., Okumura, K., Mahan, S.A., and Hancock, D.A., 2004, Logs and data from an investigation of the Orovada trench site, Santa Rosa Range fault zone, Humboldt County, Nevada: U.S. Geological Survey Scientific Investigations Map 2815. Available at: http://pubs.usgs.gov/sim/2004/2815/. Personius, S.F., and Mahan, S.A., 2005, Unusually low rates of slip on the Santa Rosa Range fault zone, northern Nevada: Bulletin of the Seismological Society of America, v. 95, no. 1, p. 319–334, doi:10.1785/0120040001. Reimer, P.J., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Ramsey, C.B., Buck, C.E., Cheng, H., Edwards, R.L., Friedrich, M. and Grootes, P.M., 2013, IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP: Radiocarbon, v. 55, no. 4, p.1869-1887.Per- increased uncertainties on the other faults in the transect to ±0.1 if their calcu- noted that the MREs on the Quinn River and Santa Rosa Range sections ap- sonius, S.F., and Mahan, S.A., 2005, Unusually low rates of slip on the Santa Rosa Range fault zone, northern Nevada: Bulletin of the Seismological Society of America, v. 95, no. 1, p. 319–334, doi:10.1785/0120040001. lated rates were below this value. peared to have similar early Holocene ages, but could not determine whether 6Supplemental Figure S3. Summary figures of paleo seismology of Santa Rosa Range fault zone. Please We calculated regional GPS velocity differences across the transect using the youngest ruptures on the two sections occurred during the same or differ- visit http://doi .org /10 .1130/GES01380 .S6 or the full- northing and easting data (in the UNAVCO North America 2008, NAM08, ent earthquakes. The large gap (11–12 km) between the 2 sections, and their text article on www.gsapubs.org to view Supplemen- reference frame) downloaded from UNAVCO PBO (Plate Boundary Observa- combined length (>90 km) versus event displacement estimates of ≤2 m, lead tal Figure S3. tory) Velocity files (www.unavco.org), and calculated differential extension us to infer that the 2 sections ruptured independently during separate latest components using a regional extension direction (100°/280°) estimated from Pleistocene and/or early Holocene earthquakes on this part of the SRRFZ. strikes of Holocene faults in the transect. We used our mapped surface rupture The Santa Rosa Range section of the fault zone consists of two primary lengths and offset measurements to estimate paleoearthquake magnitudes strands: a range-front strand that forms the steep western margin of the range,

(moment magnitude, Mw) using a weighted average of magnitude scaling re- and a synthetic strand with considerably less total throw that offsets the basin lationships of Hanks and Kanamori (1979), Wells and Coppersmith (1994), and floor 4–6 km west of the range-front trace. The synthetic strand may be the Hemphill-Haley and Weldon (1999). northern extension of the Bloody Run Hills fault zone, although the latter structure was not reactivated during the youngest rupture on the SRRFZ. In addition, a short (6 km long) normal fault appears to have connected the range- PALEOSEISMOLOGY front trace of the SRRFZ and the northern end of the Bloody Run Hills fault zone during one or more pre-Holocene surface ruptures (Fig. 1). We include Santa Rosa Range Fault Zone both strands in the Santa Rosa Range section because the trace of the basin floor strand mimics the strike and overall length of the range-front strand and The Santa Rosa Range fault zone (SRRFZ) forms piedmont and range-front both probably ruptured at the same time during the most recent surface-rup- fault scarps along the eastern margin of the Quinn River Valley and the west- turing earthquake. Data from a trench on a splay of the range-front trace ~5 km ern flank of the Santa Rosa Range in the northeast corner of the transect area southeast of Orovada, Nevada (site SRR1 in Fig. 1), yielded evidence for 4 sur- (Fig. 1). The range is underlain by Triassic metasedimentary rocks intruded face-rupturing earthquakes, the last 3 of which occurred since 141 ± 14 ka and by Cretaceous granitic rocks, which in turn are unconformably overlain by caused surface offsets of ~1.5–2.0 ± 0.5 m each (see Supplemental Fig. S3 [see Miocene volcanic rocks (Colgan et al., 2004, 2006b; Breuseke et al., 2008). footnote 6]; modified from Personius and Mahan, 2005, Figs. 3 and 4 therein). Thermochronologic studies indicate unroofing and initial extension in the The basin-floor strand is marked by an ~0.5-m-high scarp in sediments related region ca. 12 Ma (Colgan et al., 2006b), and recent analysis of the tectonic to the highstand of Lake Lahontan (e.g., Michetti and Wesnousky, 1993; A.M. geomorphology of the Santa Rosa Range indicates renewed uplift 5 Ma to Michetti, 2001, written commun.). Here we present an OxCal (https://c14 .arch 0.1 Ma (Ellis et al., 2014). Quaternary activity along the SRRFZ was described .ox.ac .uk/) model of the chronological data (from Personius and Mahan, 2005) in Michetti and Wesnousky (1993), Narwold and Pezzopane (1997), Narwold to better quantify earthquake ages (Supplemental Fig. S3B [footnote 6]). Lumi- (2001), Personius et al. (2004), and Personius and Mahan (2005). In the tran- nescence ages indicate that the youngest surface rupture on the Santa Rosa sect area, the SRRFZ consists of 2 primary sections or segments; a northern, Range section occurred 13.5 ± 2.5 ka. 50-km-long Quinn River section that extends into the upper Quinn River valley We combine the surface offset estimate of the youngest rupture in the Oro in southern Oregon, and a southern, 42-km-long Santa Rosa Range section in vada trench (1.5 ± 0.5 m) and the surface offset of the basin floor trace (0.5 m), the lower Quinn River Valley (U.S. Geological Survey Quaternary Fault and and use the regional age of the Lahontan highstand (15.6 ± 0.3 ka) to calculate Fold Database of the United States; U.S. Geological Survey, 2015). The two a latest Quaternary slip rate (rounded to nearest 0.05 mm) of 0.15 ± 0.05 mm/yr sections are separated by an 11–12-km-wide right-stepping gap in latest Qua- (Table 1). This rate is similar to the estimated rates of slip on the Quinn River ternary fault scarps. section of the SRRFZ (<0.2 mm/yr; Narwold, 2001), but are higher than late

TABLE 1. PALEOSEISMIC PARAMETERS OF FAULTS IN NORTHWESTERN BASIN AND RANGE PROVINCE TRANSECT Rupture Average Estimated* Vertical Vertical† Strike Dip length Number of EQ timing recurrence magnitudes Time datum separation slip rate

Fault zone (°) direction (km) paleo-EQs (ka) (yr) (Mw, ± 0.1) (ka) (m) (mm/yr)Comments Santa Rosa Range 005 W 42 (SRRs) 1 13.5 ± 2.5 n.a. 7.1 15.6 ± 0.32.0 ± 0.5 <0.15 ± 0.1 Data from Narwold (2001), Personius et al. 50 (QRs) 1 10 ± 5 7.2 2.0 ± 0.5 (2004), Personius and Mahan (2005) Desert Valley 005 W 65 1 <15.6 ± 0.3 n.a. 7.115.6 ± 0.32.4 ± 0.2<0.15 ± 0.1 Data from this study; slip from profiles near Gabica Butte Jackson Mountains 022 W 57 2–3 <15.6 ± 0.3 7650 (2 eqs) 7.2 (2 eqs) 15.6 ± 0.37.5 ± 0.50.5 ± 0.1 Data from this study; slip from offset of Sehoo 5100 (3 eqs) 7.1 (3 eqs) shoreline at Hobo Canyon Steens 025 E 42 3 4.0 ± 0.2 60007.1 18.0 ± 1.14.4 ± 0.20.25 ± 0.1 Data from Personius et al. (2006, 2007b) 6.1 ± 0.3 12.7 ± 2.6 Black Rock 008° W 57 3 0.6 ± 0.5 85007.1 33.7 8 ± 1.0 0.25 ± 0.1 Data from Dodge (1982); not used in rates 3 ± 2 comparison 18 ± 13 Long Valley 008 NW, SE, 40 1 <15.6 ± 0.3 n.a. 7.015.6 ± 0.32.5 ± 0.5<0.15 ± 0.1 Data from this study; slip from profiles on vertical? Alkali Lake and Boulder Lake strands. Surprise Valley 344 E 75 5 1.2 ± 0.1 37007.3 18.4 ± 1.615.0 ± 1.00.8 ± 0.1 Data from Personius et al. (2007a, 2009) 5.8 ± 1.5 8.5 ± 0.5 10.9 ± 3.2 18.2 ± 2.6 Note: SRRs—Santa Rosa Range section; QRs—Quinn River section; EQs, eqs—earthquakes; n.a.—not applicable.

*Magnitude (moment magnitude, Mw) estimates are weighted average of four regression relations: surface rupture length (all faults), and rupture area (all faults) or maximum displacement (all faults)—Wells and Coppersmith (1994); average displacement (all faults)—Hemphill-Haley and Weldon (1999), and seismic moment equation with seismogenic depth = 12 km, and shear modulus = 3 × 1011 dyne-cm—Hanks and Kanamori (1979). †Slip rates on faults with only one documented earthquake rupture (i.e., time window does not contain a complete seismic cycle—herein the Santa Rosa Range, Desert Valley, Long Valley fault zones) are considered maximum rates. All slip rates were assigned a minimum uncertainty of 0.1 mm/yr (see text).

Quaternary interval and average rates based on the long (tens of thousands Desert Valley Fault Zone of years) recurrence intervals between the past three dated earthquakes at the Orovada trench site (0.03–0.05 mm/yr; Personius and Mahan, 2005). Thus we Little information is available on the paleoseismology of the Desert Val- consider our latest Quaternary rate to be a maximum for the limited time win- ley fault zone (DVFZ). The fault was previously mapped by Dohrenwend and dow used in this study, and increase the uncertainty accordingly (i.e., ≤0.15 ± Moring (1991a, scale 1:250,000; U.S. Geological Survey, 2015). We mapped 0.1 mm/yr). the fault zone from Mormon Dan Butte northward to Quinn River Lakes on A comparison between longer term (hundreds of thousands to millions the Quinn River for this study (scale of 1:24,000; summarized in Supplemental of years) measures of slip rate and the rates from Narwold (2001), Per Fig. S1 [see footnote 1]), and although we identified additional fault strands, sonius and Mahan (2005), and those presented herein leads us to infer that the basic form of the fault zone is similar to that shown in the U.S. Geological slip rates on the SSRFZ declined significantly in the late Quaternary. Longer Survey (2015) database. The ~65-km-long fault zone extends from the sub- term rate estimates include post–12 Ma exhumation rates of 0.3–0.5 mm/yr dued western margin of the southern Slumbering Hills northward to the vicin based on thermochronology (Colgan et al., 2006b), slip rate estimates of ity of Gabica Butte, and then across the floor of northern Desert Valley and 0.3–0.9 mm/yr based on the heights of faceted spurs along the footwall of southern Kings River Valley. Other than the small scarps that mark the trace the SRRFZ (dePolo, 1998), and a post–0.5 Ma period of increased slip on the in latest Quaternary surficial deposits, the fault zone shows little topographic SRRFZ inferred from analysis of rates of knickpoint retreat in the Santa Rosa expression indicative of repeated Quaternary activity. However, limited drill Range (Ellis et al., 2014). The long recurrence intervals (~17–65 k.y., deter- hole and gravity data indicate that the fault scarps are coincident with the mined by Personius and Mahan, 2005) also support low rates of slip in the steep eastern margin of Paleogene–Neogene basin-fill deposits that reach late Quaternary. We use vertical displacements of 2 m and probable fault thicknesses of 1.2 km beneath the valley floor directly west of the southern

rupture lengths of 42–50 km to estimate magnitudes (Mw) of 7.1–7.2 (Table 1) end of our mapped trace (Sinclair, 1962; Willden, 1964; Berger, 1995; Ponce for surface-rupturing earthquakes on the Santa Rosa Range or Quinn River and Plouff, 2001). Basin-fill sediments thin across a bedrock high that extends sections of the SRRFZ. across the valley from the Jungo Hills to Mormon Dan Butte, and subdivides

118.13° 118.11° The surface expression of the DVFZ is characterized by single (Fig. 2A) and 41.18° multiple small (~0.5–2.5-m-high), primarily down-to-the-west, fault scarps in A B DV02C Corbeal deposits of the Sehoo cycle of pluvial Lake Lahontan and eolian and alluvial Vs = 2.0 m Butte deposits that postdate the ca. 15.6 ka age of the Sehoo highstand (Figs. 1 and 2A). The consistent down-to-the-west aspect and formation of a continuous graben (Fig. 2B) that extends for at least 5 km between Corbeal Butte and Mormon Dan Butte indicate primarily normal displacement along the DVFZ. We also measured scarp topographic profiles in the field primarily along the 1280 reach of the fault between Gabica Butte and Corbeal Butte where the young-

1270 m est deformation is confined to a single trace (Figs. 1 and 2). Scarps along this m section have consistent vertical separations (surface offsets) of 2–2.5 m; scarps

Desert apparently decrease in size to the north and south, but multiple fault traces to DV02B the north, and the presence of the extensive graben (site DV2 in Figs. 1 and Vs = 1.0 m 2) and burial of the fault with several meters of windblown sand to the south Valley fault zone (net) make accurate determination of vertical separation difficult in these areas (Fig. graben 2C; Supplemental Fig. S2 [footnote 2]). We found no evidence indicative of multiple latest Quaternary displacements, so we infer that the faults scarps on the DVFZ were formed during a single large surface-rupturing earthquake that postdated final retreat of the waters of Lake Lahontan below an elevation of ~1280 m in Desert Valley. Our largest vertical separation value, from a limited number of scarp profiles (2.4 ± 0.5 m, site DV1 in Fig. 1), and the age of the 0 500 m Sehoo highstand (15.6 ± 0.3 ka) yield a latest Quaternary slip rate of 0.15 ± contour interval = 2 m 0.03 mm/yr. Given our assumption that the scarps are the result of a single 41.15° event and the lack of preexisting fault topography, we consider this value to be a maximum slip rate, and increase the uncertainty to ±0.1 mm/yr. The fault length of 65 km (U.S. Geological Survey, 2015) and a vertical displacement of

4 2.4 m indicate an estimated magnitude of Mw 7.2 for this event (Table 1). profile DV02C C Vs (surface offset) 3 = 2.0 m Jackson Mountains Fault Zone profile DV02B 2 net Vs (surface offset) Little information is available on the paleoseismology of the Jackson meters = 1.0 m 1 Mountains fault zone (JMFZ). The footwall consists of Paleozoic and Meso- zoic metasedimentary and metavolcanic rocks intruded by Triassic and Juras- VE = 12× sic plutons and overlain by Cretaceous sediments and Paleogene–Neogene 0 020406080100 120140 160180 volcanic rocks (Maher, 1989; Quinn et al., 1997). Thermochronologic studies meters indicate unroofing and initial extension in the region ca. 12 Ma (Colgan et al., 2006b), and recent analysis of the tectonic geomorphology of the Jackson Figure 2. Fault map and profiles of southern part of Desert Valley fault zone (see Fig. 1 for location); background is from 1:12,000-scale digital orthoquadrangle data of U.S. Geological Survey. (A) Annotated fault map showing single and graben scarps and locations of Mountains indicates renewed uplift from 5 Ma to 0.1 Ma (Ellis et al., 2014). scarp profiles. (B) Unannotated image of same area as A. (C) Representative scarp profiles across single and graben scarps. Parts of the fault are included in reconnaissance mapping by Dohrenwend and Moring (1991b, scale 1:250,000) and despite significant topographic relief (1– 1.5 km) and a very steep range front, the fault is only classified as Quaternary in the basin fill into two depocenters; the southern subbasin is filled with at least compilations (dePolo, 2008; U.S. Geological Survey, 2015). To better define the 2 km of basin-fill deposits. The restriction of scarps in surficial deposits to the Quaternary history of the fault zone, we mapped it from Quinn River Crossing northern subbasin indicates that the bedrock high probably controlled earth- southward ~57 km to the latitude of Rattlesnake Canyon (Supplemental Fig. quake rupture extent in the MRE, and probably has done so for much of the S1 [see footnote 1]). We also conducted reconnaissance field studies to check history of the fault. our mapping, obtained detailed topographic data on fault scarps and lacus-

trine shoreline features, examined natural and soil pit exposures, and collected thinner colluvium appears to be in depositional contact with an eroded fault samples for chronological analysis. scarp free face. The upper part of the hanging wall is covered by the same Our mapping revealed abundant evidence for multiple latest Pleistocene poorly exposed eolian sand, alluvium, and colluvium as the footwall. Several and Holocene surface ruptures along most of the western margin of the Jack- correlative stratigraphic contacts indicate total vertical displacement of 1.5 m son Mountains. Youthful scarps that postdate the Sehoo cycle of pluvial Lake since formation of the beachrock, but determination of the number of earth- Lahontan are well expressed where all or part of the fault diverges from the quakes responsible for this displacement is complicated by incomplete expo- range front onto piedmont slopes underlain by lacustrine and post-lake alluvial sure of the upper 2–3 m of the sequence, the obliquity of the fault with the deposits. In contrast, scarps along the steep range front are difficult to recog- canyon wall (~30°), and probable cutting and filling during terrace formation. nize on high-resolution imagery and in the field. The latter scarps are poorly However, projection of the fault to the southern flank of the canyon places the expressed for the following reasons: (1) the range-front traces commonly are fault trace on a 40-cm-high scarp in the t2 terrace surface (Fig. 3B); the faulting located on steep slopes at the bedrock-colluvial contact; (2) much of the moun- event that formed this scarp cannot account for the 1.5 m of total displacement tain front consists of cliff-forming, very resistant rock types (basalt, dense lime- we measured in the exposure and thus indicates at least two post-Sehoo sur- stone); (3) the long fetch across the Black Rock Desert exposed the range front face ruptures on this strand. This interpretation is supported by the presence to extensive erosion during highstands of Lake Lahontan; and (4) Lahontan of the two fault-scarp colluvial deposits in the hanging wall. shorelines are commonly parallel to and occupy the same elevations as the The second, eastern fault exposure in the south wall at an elevation of fault trace. These factors result in poor conditions for preservation of fault 1310 m revealed a sequence of fan gravels in the footwall, faulted against scarps along the range-front trace, and thus likely account for the failure of one or two deposits of probable fault-scarp colluvium and an intervening 1- previous investigations to recognize the recency of faulting along the western to 2-m-thick sequence of very crudely bedded silty and sandy alluvium in the flank of the Jackson Mountains. hanging wall (Fig. 4B). We interpret the latter deposit, which is not present in We conducted detailed field studies at three sites (Fig. 1; Supplemental Fig. the footwall, as a fill deposit related to enhanced fluvial erosion and deposition S1 [see footnote 1]): (1) a deeply incised canyon at the mouth of an unnamed along a preexisting fault scarp. Measurement of total vertical offset across this drainage (herein Sand canyon) on the northern part of the fault zone (site JM1); fault splay is problematic. The apparent vertical offset of the t2 terrace surface (2) a Lahontan shoreline complex at the mouth of Hobo Canyon on the central across the fault scarp west of the exposure is 1.7 m, but our interpretation of part of the fault zone (site JM2); and (3) an extensive shoreline complex at the extensive cutting and filling prior to the MRE complicates measurement of total mouth of a major unnamed canyon system draining the western flank of King throw across this strand. We conclude that the presence of two ~1-m-thick col- Lear Peak on the southern part of the fault zone (site JM3). luvial wedges and the absence in the hanging wall of sediments correlative to the fan deposits in the footwall are consistent with an estimated minimum vertical displacement of >1.5 m to as much as 4 m, if we use double the thickness of Sand Canyon Site the colluvial wedges as an estimate of slip (e.g., McCalpin, 2009) on this strand. Taken together, fault-scarp profile data and our interpretations of exposures of Detailed surficial geologic mapping and topographic profiling helped us the two known fault strands in the walls of Sand canyon yield evidence for at document extensive Sehoo lake cycle sedimentation and subsequent post– least two surface-rupturing earthquakes and an estimated minimum vertical Sehoo highstand incision that created a suite of terraces and exposed two displacement of >3–5.5 m since retreat of Lake Lahontan ca. 15.6 ka. fault traces near the mouth of an unnamed canyon on the northern part of the We used three sources of chronological data to refine the ages of the earth- JMFZ (site JM1 in Fig. 1). As is common elsewhere, the JMFZ at this location quakes identified at the Sand canyon site. (1) The Lake Lahontan hydrograph is characterized by piedmont and range-front strands (Fig. 3). Unfortunately, (Fig. 5) indicates that at the elevations of the fault exposures (1310–1315 m),

A B the range-front trace is coincident with and thus obscured by the highstand of shoreline features date to within a few hundred years of the age of the Se- possible t2 terrac e backedg Lake Lahontan, but the piedmont strand is exposed in two places in the walls hoo highstand (ca. 15.6 ± 0.3 ka). (2) A >1-m-thick deposit of volcanic ash that sampled e outcrop geology pick for scale of Sand canyon. The western fault exposure in the north wall (Fig. 4A) revealed chemically correlates with the Mazama ash (7.63 ± 0.15 ka; Zdanowicz et al., location of sample JM-T1 a footwall sequence of fan alluvium capped by a tufa-cemented boulder gravel 1999; Supplemental Table S3 [footnote 5]) is preserved in the south wall of that likely formed as beachrock at an elevation of ~1310 m during the rapid rise Sand canyon a few hundred meters upstream of our fault exposures (Fig. 3C; to or fall from the Lahontan highstand (elevation ~1333 m). The upper part of Supplemental Fig. S47). The elevation of this fluvially reworked deposit above 7Supplemental Figure S4. Photographs (A, B) of thick the footwall is covered by several meters of poorly exposed eolian sand, allu- the modern channel is similar to a remnant of terrace t2 cut in the north wall (>1 m) outcrop of Mazama ash on south flank of Sand vium, and colluvium. The base of the hanging wall consists of the same alluvial directly across the modern channel. The fact that the deposit is very thick, but canyon, Jackson Mountains fault zone. Please visit stratigraphy and beachrock as the footwall. Overlying the faulted beachrock in is currently cropping out from a steep canyon wall exposure, leads us to in- http://doi.org/10.1130/GES01380.S7 or the full-text article on www.gsapubs.org to view Supplemental the hanging wall are a thin eolian sand and two deposits of poorly sorted fault- terpret that the ash was probably deposited during or shortly after formation Figure S4. scarp colluvium. The lower, thicker colluvium is faulted, whereas the upper, of a t2 terrace remnant now largely eroded from the south wall of the canyon.

SC1 1300 m 0

lac 1250 m e lac opographic profile (Fig. 3C g olcanic ash exposur western fault spla profil m SC3 contour interval = 5 lac 0.2 m 5.0 ± exposure of eHPa EXPLAN AT lac e 2.3 m

06 e t2 100 profil m 0.4 m 0.4 m 1.9 ± SC2 t2 m mHa profile SC3 e ION Distance along profile (m y 4.9 m t3 e ash outcro p

Mazama downstream lHa m 04

1.4 m ) mHa 0.2 m 4.2 ± Mazama as h 1.7 m profile SC t3 2.1 m 500 eHPa exposur profile SC2 1300 m 0.2 m 1.9 ±

t2 t2 0.5 m 4.1 ±

1.5 m (Fig. 4A ) t2

t1 ~1–4 m (Fig. 4B ) e 0.3 m 4.8 ± la c t2 0 1 lH a eHPa eHPa lH a eHPa 0.2 m 3.8 ± la c tilted? t1 back- ) t2 Section B t3 lHa t2 mH a 0.4 m (Fig. 4B ) la c ~1–4 m 2.3 m eHPa t1 t2 t1 0.2 m 5.7 ± 1.7 m 0.2 m 6.6 ± (Fig. 4A ) t2 la c 20 es 1.5 m t1 0.4 m 10.3 ± Mazama as h eHPa Sout h es ? phsa exposur eHPa eHPa eHPa eHPa 0.5 m ~10 ± la c la c t3 eHPa t2 ? phsa ? phsa 0 e 1350 m

1300 1305 1310 1315 1320 1325 1330 1350 m 11 bd k bd k

phsa m 1400 1400 8.47° Elevation (amsl, m) (amsl, Elevation above mean sea level. 3B) across Sand canyon; amsl—altitude 3 topographic profiles (green lines in Fig. probable correlations of fluvial terraces on >1-m-thick outcrop of Mazama ash and yon geology. (C) Geomorphic setting of imagery. (B) Enlarged view of Sand can - /aerial -photography /imagery .fsa .usda .gov /programs -and -services Imagery Program (NAIP; https:// m National Agriculture background is 1 mental Fig. S1 [footnote 1] for location); Mountains fault zone (Fig. 1; see Supple - cinity of Sand canyon, northern Jackson Figure 3. (A) Surficial geologic map in vi - -programs/) www

GEOSPHERE | Volume 13 | Number 3 Personius et al. | Paleoseismic transect across northwestern Basin and Range 789 Research Paper

A B

eolian sand (es)

mixed eolian sand, fan alluvium alluvium, and colluvium OSL JM-5 3.75 ± 0.13 ka tufa-cemented boulder gravel fault scarpm e colluviu uncemented cobbl & boulder gravel

Figure 4. Sand canyon fault exposures. muddy debris flow (A) View looking north of western expo- eolian sand sure of Jackson Mountains fault zone in tufa-cemented north wall of Sand canyon; note that the boulder gravel fault strikes ~30°oblique fault strikes 30° oblique to canyon wall. to exposure Stratigraphic separation of lower gravel shovel sequence across the fault is 1.5 m; note the uncemented cobble & boulder gravel 1-m-long shovel for scale. OSL—optically muddy debris flow stimulated luminescence. (B) Unannotated image of same area as A. (C) View looking south of eastern fault exposure in south wall of canyon; note that the fault strikes C D 40° oblique to canyon wall. Note presence scarp strikes ~40° oblique to exposure of at least two probable wedges of scarp coarse colluvium, separated by weakly bedded fan alluvium (t2) (blue dashed lines) terrace alluvium. MRE— most recent earthquake. (D) Unannotated image of same area as C. MRE colluvium fine fan alluvium

terrace alluvium coarse fan alluvium

fine fan alluvium P2 ? colluvium COV ERED COVERED

~1 m

A similarly thick deposit of ash incorporated into fluvial sediments at about overlies the tufa-cemented boulder gravel in the footwall of the western ex- the same height above the modern channel is present a few hundred meters posure. Given its position overlying a Lahontan beach deposit and underly- upstream of the mouth of an unnamed canyon ~3.5 km north of Sand canyon ing several meters of fan alluvium that appears to predate the formation of (Fig.1, site JM1b). (3) We obtained an OSL age of 3.75 ± 0.13 ka (Supplemen- the ca. 8–7 ka t2 terrace, we suspect the OSL age is anomalously young by tal Table S1 [see footnote 3]) on a deposit of what we interpreted to be eolian several thousand years (the sample may have contained burrowed sediment, sand that underlies the older wedge of fault scarp colluvium and directly rather than intact eolian sand).

offset multiple shorelines of the Sehoo lake cycle and alluvial sediments that 1350 Prominent Lahontan shorelines postdate retreat of the lake (Fig. 6). The middle strand is well exposed in a gully in vicinity of Jackson Mountains 4400 Hydrograph source Sehoo highstand SL as a well-defined gouge and shear zone in Jurassic basaltic andesite (Maher, Bills et al., 2007, model B (1333 m; ca.16–15 ka) 1989) with a strike of N40°E, dip of 56°W. Two exposures of the western strand Reheis et al., 2014 Faulted beachrock at Sand in basaltic andesite have similar attitudes (N10W, 63°W; N5E, 59°W; Fig. 6). Benson et al., 2013 4300 Canyon (1310 m) Field studies at the site included detailed mapping and topographic profil- 1300 5–6 intermediate SLs (ca.18–15 ka) ing. Results include the following: (1) fault scarps with vertical offsets of 10 m Stansbury-equivalent SL? or more are present in pre–Sehoo highstand alluvium on the eastern strand (1280 m; ca. 28–27 ka) 4200

) north of Hobo Canyon; (2) vertical offset of the shoreline complex is ~7.6 m

Darwin Pass threshold SL? Elevation (ft) Trego HS tephra (1268 m; ca. 22–19 ka) as summed across the western (3.7 m) and middle fault strands (3.9 m); and 29.9 ka 1250 DP SL (3) comparison of multiple topographic profiles and the presence or absence (1250 m; ca.18–14.5 ka) 4100 of well-rounded lacustrine clasts indicate apparent vertical offset 7.5 ± 1 m of Wono tephra Tufa SL Elevation (m 33.7 ka (1238 m; ca.19–14.5 ka) the Sehoo highstand across the middle fault strand (Fig. 7). These two ver- Younger Dryas SL? tical separation estimates represent the highest slip values we measured in (1222–1224 m; ca.13–12 ka) 4000 Sehoo-aged deposits along the entire length of the JMFZ, and may indicate the 1200 apex of post-Sehoo displacement along the JMFZ. Mazama ash 3900 7.6 ka King Lear Peak Site

? 3800 Extensive deposits of Lake Lahontan (herein referred to as the King Lear 1150 ? Peak shoreline complex, KLP) are preserved at the mouth of a major unnamed 40 30 20 10 0 canyon system draining the western flank of KLP on the southern part of the Age (ka) JMFZ (site JM3 in Fig. 1). The range-front fault trace trends southeast in a Figure 5. Composite hydrograph of Sehoo cycle of pluvial Lake Lahontan (gray shaded area) in the western Great Basin. 2–3-km-wide left step that creates a large embayment in the range front at the Three sources used in compilation (Bills et al., 2007; Benson et al., 2013; Reheis et al., 2014) are shown with different latitude of the KLP shoreline complex (Fig. 8). We found only sparse evidence line types. Tephra ages are from Zdanowicz et al. (1999) and Benson et al. (2013). Elevation ranges of prominent shorelines in vicinity of Jackson Mountains are shown as blue-gray bands on right side of figure. Elevation range of faulted of young faulting along the range front southeast of this step, but our mapping beachrock exposure in Sand canyon is shown as red band. DP—Desert Pavement; HS—Hot Springs; SL—shoreline. indicates that latest Quaternary faulting steps onto a piedmont fault zone that cuts the shoreline complex and extends southwestward for at least 15 km. The piedmont strand cuts a suite of Sehoo lake cycle shoreline platforms, two of From this limited data set, we infer the following at the Sand canyon site. which we correlate across the fault trace. These two platforms, herein infor- (1) A minimum of 2 earthquakes caused total vertical offset of at least 3–5.5 m mally named the Tufa shoreline and Desert Pavement (DP) shoreline, are both sometime after 15.6 ± 0.3 ka on the piedmont strand of the JMFZ. (2) The lower vertically displaced ~5–6 m (Fig. 9). The Tufa shoreline occupies an elevation colluvial wedge in the western fault exposure in places directly overlies tufa- range of ~1234 m (hanging wall) to ~1242 m (footwall), and is characterized by cemented beachrock, suggesting that this earthquake occurred shortly after a broad platform and abundant cementation of carbonate tufa deposits that the final retreat of Lake Lahontan. (3) Deposition of the P2(?) colluvium in the may be unique in this part of the Black Rock Desert. The DP terrace occupies an eastern fault exposure predates erosion and deposition of fluvial sediments elevation range of 1247 m (hanging wall) to 1253 m (footwall) and is character- that may be correlative with the Mazama ash–bearing terrace t2, and thus may ized by a well-developed desert pavement. correlate with the older (pre-t2) earthquake in the western exposure 1. The We used OSL and uranium-series methods to determine the ages of sedi- MRE in the western and eastern exposures formed 0.4-m-high and 1.5-m-high ments underlying these data (Fig. 10; Supplemental Tables S1 [footnote 3] and scarps, respectively, in the t2 terrace surface, and thus likely postdates the age S2 [footnote 4]). OSL samples from a well-sorted sand deposited near the top of the Mazama ash (younger than 7.6 ka). of the lacustrine sequence underlying the Tufa terrace yield ages of 18–17 ka (Fig. 10A). Uranium-series ages of ca. 22 ka on tufa formed in the upper part of Hobo Canyon Site the sequence indicate a somewhat older age, but the presence of substantial amounts of detrital Th yielded broad uncertainties that overlap with the OSL A well-preserved suite of Lake Lahontan shorelines is present in an em- ages at 2s (Fig. 10B). We prefer the much lower uncertainties of the OSL ages, bayment coincident with a prominent right step in the JMFZ at the mouth of and infer from the Lahontan hydrograph (Fig. 5) that the sediments underlying Hobo Canyon (site JM2 in Fig. 1). The fault zone consists of three strands that the Tufa terrace were deposited during the rapid rise of Lake Lahontan to the

118.56° 118.53° 41.30° N10°W 63°W bdk fault exposure mHPa Vs = 3.2 m lHa mHPa mHPa lac N05°E 59°W phsa Vs = 7.4 m bdk fault exposure 1300 m bdk lac lHa phsa Vs = 10.1 m mHPa lHa 1250 m phsa mHPa lac Figure 6. Surficial geologic map in vicin m bdk Vs = 2.4 m ity of Hobo Canyon, central Jackson Mountains fault zone (Fig. 1; see Supple- N40°E 56°W 1350 m 1400 mental Fig. S1 [footnote 1] for location); bdk fault exposure phsa lHa background is 1 m National Agriculture Vs = 3.9 m Imagery Program (NAIP; https://www bdk .fsa.usda.gov/programs-and-services /aerial-photography/imagery-programs/) 1500 m Vs = 7.5 m imagery. Note locations of topographic Vs = 3.7 m lac profiles in footwall (light green lines) and Hobo hanging wall (dark green lines) used in Fig- EXPLANATION ure 7 to demonstrate 7.5 m of vertical sep- Canyon m lHa -Late Holocene alluvium aration (Vs) of Sehoo highstand shoreline lac across fault zone. mHPa mHPa -Latest Pleistocene to middle Holocene 1350 m alluvium m lac -Lacustrine sediments of Lahontan Sehoo lake cycle e 1300 rod m ed free fa bdk 150 canal spoil phsa -Pre-Sehoo alluvium, mid-late Pleistocene

ce Av soil horizon 1400 Bk (stg II-III) bdk -Mesozoic-Paleozoic bedrock soil horizon Bw soil horizon cemented fault zone PE1 colluvium 100 -Shoreline platform remnants of Sehoo pre-Sehoo fan alluvium lake cycle buried soil (A+B) on PE2 colluvium

centimeters -Approximate location of Sehoo PE2 colluvium 50 highstand backedge lHa Covered m -Fault scarp profile w/ vertical separation

0 (Vs, m) 50 centimeters 100 lac 0 500 Figure S5. About 4 km south of Sand canyon near the mouth of Deer Creek Canyon, erosion from a blown out drainage canal exposed the contour interval = 5 m -Topographic profiles (Fig. 7) upper 2 m of the range front strand of the Jackson Mountains fault zone in pre-Sehoo alluvial-fan sediments (see figure). The footwall consists of poorly sorted silty, sandy, cobbly alluvium with moderately well developed 25-cm-thick stage II+ Bk and 15-cm-thick Bk soil horizons. Both the degree of soil development and the fact that the Lahontan highstand shoreline is etched into the surface of the fan 600-700 m downslope of the Deer Creek exposure are consistent with a late Pleistocene age for these sediments. Two deposits of very poorly sorted silty, sandy, cobbly fault-scarp colluvium in the hanging wall are juxtaposed against the fan sediments across a 41.28° west-dipping fault zone that in places is cemented with calcium carbonate. The lower, faulted scarp colluvium is capped by a 20-cm- thick buried soil that consists of A and incipient Bw soil horizons. Exposed thickness of the lower colluvium is about 50 cm. The upper colluvium consists of similar sediments and is capped with weakly developed Av and Bw soil horizons. The lower half of the upper colluvial wedge is in depositional contact with the carbonate-cemented fault zone, but the upper half lies on an inclined erosional remnant of the fault scarp free face. We interpret this exposure as evidence of a younger surface-rupturing earthquake with vertical separation of 1-1.5 m. The weakly developed soils bracketing the younger colluvium are consistent with a middle to late Holocene age for this earthquake. Lack of exposure of the base of the lower colluvium hinders estimation of the age of formation of this deposit, but the weak soil formed between the two colluviums suggests to us that the older earthquake may be latest Pleistocene or early Holocene in age. The fault scarp at the site was disturbed by the canal blowout, but we measured 4.6 m Sehoo highstand. We were unable to obtain a sufficient sample of appropriate Other Sites along the JMFZ of vertical separation across a better-preserved compound scarp formed on similar pre-Sehoo fan deposits a few hundred meters south of Deer Creek (Fig. S1, S2). Our estimate of 1-1.5 m of vertical separation during the MRE suggests that the larger scarps likely record a total of 3 or 4 surface ruptures along this part of the range front trace in the late Quaternary. grain size from the lacustrine sediment underlying the DP terrace, but samples Measurement of total slip near Deer Creek is complicated because about 1.5 km to the southwest, a prominent fault trace splits away from the range front and extends northward for about 6 km before rejoining the range front just north of Sand canyon. At the latitude of the Deer Creek exposure, the piedmont trace is marked by a small (vertical separation of 1.4 m) scarp in middle(?) Holocene from a weakly developed soil formed on the lacustrine sequence and an over- In addition to our three primary study areas, we found evidence of latest alluvium, and larger (vertical separation of 3.7 m) scarps in Sehoo-aged lacustrine sediments. We interpret that the smaller scarp formed during the MRE and thus its size likely indicates the larger scarps along the piedmont trace are the result of 2 or 3 surface- rupturing earthquakes of similar size. We conclude from this evidence that total post-Sehoo vertical slip across the JMFZ at the lying eolian deposit yield OSL ages of 12–11 ka (Fig. 10C). We interpret these Quaternary earthquakes at several other sites along the JMFZ. Approximately latitude of Deer Creek is 5-7 m. ages as indicating that the DP terrace may have formed during the rapid retreat 4 km south of Sand canyon near the mouth of Deer Creek Canyon (site JM4 in 8Supplemental Figure S5. Exposure log and discus- from the Sehoo highstand. We interpret the consistent vertical displacements Fig. 1), erosion from a blown out drainage canal exposed the upper 2 m of the sion of faulting at Deer Creek Canyon site, northern of ~6 m of these 2 latest Pleistocene data as evidence of at least 2 and perhaps range-front fault in pre-Sehoo alluvial-fan sediments (see Supplemental Fig. Jackson Mountains fault zone. Please visit http://doi 8 .org/10 .1130/GES0 1380.S8 or the full-text article on 3 or more surface-rupturing earthquakes on the southern strand of the JMFZ S5 for detailed description of this exposure). We mapped two colluvial wedges www.gsapubs.org to view Supplemental Figure S5. since retreat from the Sehoo highstand. separated by a weak buried soil in this exposure, and interpreted two events:

Sehoo highstand average Figure 7. Hobo Canyon shoreline plots. elevation in footwall Comparison of Sehoo highstand shoreline 1340 hanging-wall profiles elevations derived from multiple RTK (real 1332.5 ± 0.2 m footwall profiles

time kinematic) topographic profiles (see ) Fig. 6) in the footwall and hanging wall of 1330 Apparent vertical the Jackson Mountains fault zone (JMFZ) separation 7.5 ± 1.0 m at the Hobo Canyon site. Elevations (amsl—altitude above mean sea level) are averages of shoreline backedges (stars) 1320 located during field surveying. Apparent Sehoo highstand average vertical separation value (7.5 ± 1.0 m) is es- backedge elevation in hanging wall sentially identical to sum of surface offsets Elevation (m, amsl elevation 1325.0 ± 0.9 m from topographic profiles across the west- VE = 2.6× ern (3.7 m) and middle strands (3.9 m) of 1310 the fault zone. VE—vertical exaggeration. 050100 150 200 250 Distance (m)

118.63° 118.60° 41.20°

1250 m

500 m lac 1400 m lac lac 1 bdk lac lac Figure 8. Surficial geologic map in vicinity lHPa lac of shoreline complex west of unnamed Se SL m lac canyon draining the western flank of 1300 King Lear Peak (KLP), southern Jackson phsa Mountains fault zone (Fig. 1; see Supple- profile mental Fig. S1 [footnote 1] for location); background is 1 m National Agriculture 2011-1 lHPa SL Imagery Program (NAIP; https://www lHPa DPt SL lac DP .fsa.usda.gov/programs-and-services JM-U3 Tufa SL 1400 Vs = 6.1 m lac phsa /aerial-photography/imagery-programs/) m imagery. Note that late Quaternary activ- JM-OSL3,4 ity appears to jump from range front onto lac Vs = 6.0 m 0 westernmost piedmont strand, where profile phsa lHPa multiple scarp profiles (Fig. 9) demon- 2011-2 EXPLANATION strate ~6 m of vertical separation of Sehoo

JM-OSL1 Tufa SL SL lHPa -Post-Sehoo alluvium, shoreline platforms across the fault zone. latest Pleistocene-late Holocene DP Sample types: OSL—optically stimu- lHPa phsa -Pre-Sehoo alluvium, lac lated luminescence; U—Uranium series. early-late Pleistocene Shorelines (SL): DP—Desert Pavement; lHPa lac -Lacustrine sediments of Sehoo cycle

DPt DPt—Darwin Pass threshhold; Se—Stans- JM-OSL2 bdk -Neogene-Paleozoic bedrock -Shoreline platform remnants of bury-equivalent. SL JM-U2 1350 m Sehoo lake cycle lHPa 1300 m -Trace of Jackson Mtns fault zone -Approximate location of Sehoo highstand backedge fa SL 6m -Fault scarp profile w/ vertical lac Tu m separation (Vs, m) lac -Topographic profiles (Fig. 9) 0 500 contour interval = 5 m -Sample location 1250 m 41.19°

Figure 9. Topographic profiles across (in boxes) and parallel to prominent fault scarp cutting 1260 Sehoo shoreline platforms in King Lear Peak (KLP) shoreline complex (see Fig. 8 for locations). Similar values of vertical separation determined from direct scarp measurements (6.0 and 6.1 m) fault scarp across and differences in shoreline platform elevation (4.6 and 5.0 m) indicate that most of the late 1255 Tufa terrace DP shoreline Quaternary offset on the southern Jackson Mountains fault zone (JMFZ) has transferred to this Vs = 6.0 m strand. DP—Desert Pavement; amsl—altitude above mean sea level. 1250 Vs = 5.0 m 1245 (1) a younger (middle to late Holocene) surface-rupturing earthquake (MRE) Tufa shoreline with a vertical separation of 1–1.5 m, and (2) a penultimate earthquake rupture of unknown size that may be latest Pleistocene or early Holocene in age. 1240 Our estimate of 1–1.5 m of vertical separation during the MRE suggests that e Vs = 4.6 m the 4–5-m-high scarps in these pre-Sehoo fan sediments record a total of 1235 footwall profil 2011–2 Vs = 6.1 m

3 or 4 surface ruptures along this part of the range-front trace in the late Elevation (amsl, m) Quaternary. 1230 hanging-wall profile fault scarp across Measurement of total slip near Deer Creek is complicated because ~1.5 km 2011-1 DP terrace to the southwest, a prominent fault trace splits away from the range front and 1225 extends northward for ~6 km before rejoining the range front just north of Sand canyon. At the latitude of the Deer Creek exposure, the piedmont trace 1220 is marked by a small (vertical separation of 1.4 m) scarp in middle(?) Holocene 0 20 40 60 80 100 120 140 160 alluvium, and larger (vertical separation of 3.7 m) scarps in Sehoo-aged lacus- Distance (m) trine sediments. We interpret that the smaller scarp formed during the MRE and thus its size likely indicates that the larger scarps along the piedmont trace are the result of two or three surface-rupturing earthquakes of similar size. We ~15 k.y. (Table 1). Our largest post-Sehoo offset measurements (7.5 m at Hobo conclude from this evidence that total post-Sehoo vertical slip across the JMFZ Canyon) and the age of the Sehoo highstand (15.6 ± 0.3 ka) yield a latest Qua- at the latitude of Deer Creek is 5–7 m. ternary slip rate of 0.50 ± 0.1 mm/yr.

Paleoseismic Summary of the JMFZ Steens–Black Rock Fault System

Our investigations consistently show evidence of multiple post-Lahon- The three easternmost faults in our transect (SRRFZ, DVFZ, and JMFZ) are tan surface rupturing earthquakes along the 57-km-long JMFZ. Multiple fault spaced ~30 km apart; such spacing is typical of many parts of the Basin and traces and poor preservation of faulted surficial deposits along the steep range Range (Stewart, 1971, 1978; Fletcher and Hallet, 1983). In contrast, a gap nearly front complicate measurement of total post-Sehoo vertical slip, but we mea- 3–4 times as wide exists between the JMFZ and the Long Valley fault zone at sured total slip of 5–7.5 m by a variety of methods from the KLP shoreline the latitude of our PBO transect. However, evidence of multiple latest Quater- complex in the south to a site ~9 km north of Sand canyon near the northern nary paleoearthquakes on the southern Steens (SFZ; Pueblo Mountains fault end of the fault zone at Quinn River Crossing. At the southern end, total slip of dePolo, 1998) and the northern Black Rock (BRFZ) fault zones suggests to us is partitioned on two splays: the eastern splay offsets the Lahontan highstand that latest Quaternary extension occurred 30–40 km west of the JMFZ in the shoreline ~1 m, and the western splay offsets post-Lahontan, middle to late(?) gap between these two fault zones (Fig. 1; Supplemental Fig. S1 [footnote 1]). Holocene fan deposits ~0.5 m (Fig. 1; Supplemental Fig. S2 [footnote 2]). The Evidence for such deformation includes numerous north-northeast–striking number of surface-rupturing earthquakes necessary to cause vertical separa- normal faults that offset Paleogene–Neogene bedrock (Stewart and Carlson, tions of 5–7.5 m is difficult to quantify, but the fault exposures at Sand canyon 1978; Stewart, 1980; Colgan et al., 2006b; Lerch et al., 2008) and in a few places (Fig. 4) and Deer Creek (Supplemental Fig. S5 [footnote 8]) indicate a minimum offset Quaternary deposits (Dohrenwend and Moring, 1991b; dePolo and Dee, of 2 earthquakes that likely postdate the Lahontan lake cycle. The size of indi- 2015; U.S. Geological Survey, 2015). In Personius et al. (2007b) it was inferred vidual surface displacements is complicated by the presence of piedmont and that the SFZ is kinematically linked to the north-northeast–striking Alder Creek range-front fault traces, but individual strands probably have displacements of fault of Colgan et al. (2006a), which would extend the SFZ an additional 32 km 1–2 m and collectively 2–3 m per event. We conclude that the JMFZ has under- to the southwest. We infer that the latest Quaternary deformation from the gone at least 2 and perhaps 3 surface rupturing earthquakes with estimated SFZ and the northern BRFZ likely influences the modern stress field across our

magnitudes of Mw 7.1 (3 event scenario) to Mw 7.2 (2 event scenario) in the past transect, so we include these fault zones in our analysis.

coarse sand “T “DP” shoreline station JM1 very coarse at base medium-coarse at top to coarsens downward from well sorted coarse sand ufa” shoreline station JM1 coarse sand well-sorted 1-28 coarse sand coarse sandy sil e

11 JM-OSL 4 11 JM-OSL 3 pebble grave pebble 23.8 ± 5.5 ka .8 ± 0.6 ka .0 ± 0.4 ka 21.6 ± 4.3 ka IRSL: 17.9 ± 1.4 ka OSL: 16.8 ± 0.8 ka JM-OSL 1 tufa sample JM-U 3

; l eolian sand ventifacts an d post-lacustrine 1-29 1-25 loes s post-lacustrine lacustrine sand and eolian mixed loes lacustrine post- lacustrine soil incipient 25.3 ± 4.4 ka s ? ? ? 4.1 ± 0.1 ka JM-OSL 2 cobbles tufa-cemented “T D ufa” shoreline station JM1 station JM 11 “T sandy pebble gravel ufa” shorelin coarse pebbly sand silt -2 7 e tufa sample JM-U2 1-26 22.0 ± 4.7 ka lacustrine loes s lacustrine post - shoreline OSL site JM-29. soil pit exposure of Desert Pavement (DP) (E) Interpreted and unannotated views of U-series site JM11-27 and hand (C) Tufa shoreline U-series site JM11–28 annotated image of same area as A. OSL sites JM11–25 and preted arroyo exposures of Tufa shoreline D are numerated in centimeters. (A) Inter - ated in decimeters; clear scales in C and scales shown in A–B and E–F are numer infrared stimulated luminescence. Tape S2 [footnote 4] for analytical data). IRSL— Supplemental Tables S1 [footnote 3] and study (see Fig. 9 for sample locations; see uranium-series samples dated in this cally stimulated luminescence (OSL) and Figure 10. Stratigraphic settings of opti sample. (D) Tufa shoreline and hand sample. JM11-26.- (B) Un -

GEOSPHERE | Volume 13 | Number 3 Personius et al. | Paleoseismic transect across northwestern Basin and Range 795 Research Paper

Paleoseismology of the Southern Steens fault zone

OxCal v4.2.4 Bronk Ramsey (2009); Bronk Ramsey and Lee (2013); r:5 IntCal13 atmospheric curve (Reimer and others, 2013) 10 Figure S6. Summary figures of paleoseismology A EAST scarp profileWEST B of southern Steens fault zone. A) Scarp profile and Steens Fault Zone et al., 2014) yields a slightly longer (8500 yr) average recurrence estimate. Sequence Steens-Bog Hot Valley Chronology 5 fault-scarp parameters logs from a trench across the Steens fault zone at a trench outline scarp height: 4.3 m surface offset: 4.3 m Historic constraint (1850 AD) site ~15m southwest of Denio, NV (modified from meters 0 soil pit outline fault max. slope angle: 15.5° Fig. 4 of Personius et al., 2007). B) New OxCal zone no vertical exaggeration R04 (3,430 ± 35 14C yr BP; 3,580-3,830 cal yr BP) model of chronological data from Personius et al. same datum as trench log (2007). -20-10 01020304050 meters R02 (3,680 ± 9014C yr BP; 3,720-4,300 cal yr BP) None of the Dodge (1982) trenches exposed evidence of all four earthquakes, Paleoseismic Parameters EAST WEST BT03 (TL-IRSL; 3,690 ± 360 yr; 3.9 ± 0.2 ka) stratigraphic vertical separation: 4.4 ± 0.2 m 4 Paleoearthquake timing 3 3 Earthquake ST1 (3,950 ± 200 yr) EQ P2007* this study 5 area of inset 2 8 ST1 4.6 ± 0.5 ka 3.95 ± 0.2 ka 1 BT01 BT06 (TL-IRSL; 3,930 ± 270 yr; 4.0 ± 0.2 ka) ST2 6.1 ± 0.5 ka 6.05 ± 0.28 ka

meters The paleoseismology of the southern SFZ was described in detail in Per indicating either that not all earthquakes ruptured the entire fault trace, or 7 6 4 south wall ST3 11.5 ± 2.0 ka 12.74 ± 2.64 ka 4 4 5 3 BT08 (TL-IRSL; 6,050 ± 260 yr; 5.9 ± 0.2 ka) 3 4 modeled earthquake pdf 0 F3 F2 F1 Recurrence Intervals 0 5 10 15 meters 20 25 30 35 posterior pdf Earthquake ST2 (6,050 ± 280 yr) (post-model) prior pdf Interval P2007* this study (pre-model) EXPLANATION ST1-0 4.6 ± 1.0 kyr 4.0 ± 0.20 kyr BT06 mean 2σ range fault zone inset R04 3,930 ± 270 8 slope-wash colluvium BT07 (TL-IRSL; 6,140 ± 310 yr; 6.2 ± 0.3 ka) ST1-ST2 1.5 ± 1.1 kyr 2.1 ± 0.34 kyr sonius et al. (2006, 2007b). Data from a trench across a single 4–5-m-high east- erosion during the Lahontan lake cycle in places completely removed existing 5 3,580-3,830 R02 post-lake 7 fault-scarp colluvium from rupture ST1 ST2-ST3 5.4 ± 2.1 kyr 6.7 ± 2.65 kyr R01 3,720-4,300 R03 2 colluvium 6 fault-scarp colluvium from rupture ST2 BT09 (TL-IRSL; 11,130 ± 360 yr; 11.0 ± 0.4 ka) 4,240-4,430 BT03 4,240-4,530 3,690 ± 360 lacustrine 5 fault-scarp colluvium from rupture ST3 Vertical Displacements E1 8 deposits 1 of pluvial 4 lacustrine silt Earthquake ST3 (12,740 ± 2,640 yr) ST1 1.1 ± 0.5 m 7 Lake Alvord 3 fluvial(?) sand and gravel UBL ST2 1.1 ± 0.5 m

meters pre- and LBL 6 2 lacustrine sandy silt, sand, and gravel Zero boundary 1 4 interlake ST3 2.2 ± 0.5 m facing scarp at the Bog Hot Valley site (site ST1 in Fig. 1) yielded evidence fault scarps. Other features of interest exposed in the Black Rock trenches BT04 ST1 fluvial(?) 1 fluvial(?) gravel and sand 4 4 5 deposits Total 4.4 ± 0.2 m ST2 Phase Lake Alvord 1295 m barrier bar 3 contact; dashed where gradational 3 4 ST3 F3 BT09 fault PT01 (OSL; 17,360 ± 4,120 yr; F2 F1 F1 Slip Rate 0 BT08 11,130 ± 360 17.6 ± 1.6 ka) BT05 eroded fault-scarp free face 6,050 ± 260 BT07 Average (latest Quat.): 0.25 ± 0.02 mm/yr 4,790 ± 830 BT02 6,140 ± 310 17,870 ± 1,140 BT02 (TL-IRSL; 17,870 ± 1,140 yr; 17.7 ± 1.0 ka) ST1 earthquake horizon (4.40 ± 0.20 m/17.87 ± 1.14 kyr) 6 10 meters 15 EAST WEST UBL charcoal bed; upper (UBL) and lower for three surface-rupturing earthquakes since ca. 18 ka (Supplemental Fig. include evidence of liquefaction, and the presence of slickensides in at least 4 (LBL) burn layers soil pit Regional lacustrine age estimate (18.0 ± 2.2 ka) Average (Miocene): 0.20 ± 0.10 mm/yr BT03 luminescence age (years) 2 4 3,690 ± 360 meters 3 R04 Sequence start radiocarbon age (calibrated years B.P.) (*--Personius et al. 2007) 3,580-3,830 -24 -20-16 9 40,000 30,000 20,000 10,000 0 Modeled age (cal yr BP) S6 ). An additional 9-km-long zone of west-facing, 0.5–2-m-high fault scarps one trench that indicate primarily normal displacement. Summary The paleoseismology of the southern Steens fault zone is described in detailed by Personius et al. (2006, 2007). Data from a trench at the Bog Hot Valley site yielded evidence for 3 surface-rupturing earthquakes since ~18 ka (Fig. A; modified from Fig 4 of Personius et al. 2007). The vertical offset of distinctive facies of the faulted lacustrine complex at the site is 4.4 ± 0.2 m (estimated 2σ uncertainties). A 9-km-long zone of west-facing, 0.5- to 2-m-high fault scarps is present along the southeastern margin of the Bog Hot Valley, but their short length, position adjacent to the mapped trace of the Steens fault zone, and scarp morphology indicate they likely represent triggered slip on a buried fault antithetic to the southern Steens fault zone. Based on the cross-sectional area of the colluvial wedges, the two older surface ruptures (ST3 and ST2) had surface offsets of ~1.1 m, and the youngest rupture (ST1) had a surface offset of ~2.2 m. Personius et al. (2007) used radiocarbon and luminescence dating to estimate the following times of the past three surface-rupturing earthquakes: the most recent earthquake (ST1) occurred 4.6 ± 1.0 ka, the penultimate earthquake (ST2) occurred 6.1 ± 0.5 ka, and the oldest earthquake (ST3) occurred 11.5 ± 2.0 ka. Herein we present a new OxCal model of the chronological data from Personius et al. (2007) that produces similar earthquake ages (Fig. B). Based on the stratigraphic offset from the Bog Hot Valley trench (4.4 ± 0.2 m) and similar surface offsets from scarp profiles along the southern 10-15 km of the fault (Personius et al. 2006), we use the luminescence age from near the top of the lacustrine sequence in the trench (BT02--17,870 ± 1,140 yr) to calculate an average latest Quaternary slip rate of ~0.25 mm/yr. This rate is consistent with latest Quaternary interval rates is present along the southeastern margin of the Bog Hot Valley, but their short Dodge (1982) did not calculate slip rates for the Black Rock fault zone. based on the past three dated earthquakes at the Bog Hot Valley site, as well as from offset of Miocene bedrock at the northern end of the valley (Personius et al. 2007). References Cited Bronk Ramsey, C., 2009, Bayesian analysis of radiocarbon dates: Radiocarbon, v. 51, no. 1, p. 337–360. Bronk Ramsey, C., and Lee, S., 2013, Recent and planned developments of the program OxCal: Radiocarbon, v. 55, no. 2–3, p.720-730. Personius, S.F., Crone, A.J., Machette, M.N., Kyung, J.B., Cisneros, H., Lidke, D.J., and Mahan, S.A., 2006, Trench logs and scarp data from an investigation of the Steens fault zone, Bog Hot Valley and Pueblo Valley, Humboldt County, Nevada: U.S. Geological Survey Scientific Investigations Map 2952. Available at http://pubs.usgs.gov/sim/2006/2952/. Personius, S.F., Crone, A.J., Machette, M.N., Mahan, S.A., Kyung, J.B., Cisneros, H., and Lidke, D.J., 2007b, Late Quaternary paleoseismology of the southern Steens fault zone, northern Nevada: Bulletin of the Seismological Society of America, v. 97, p. 1662–1678, doi:10.1785/0120060202. length, position adjacent to the mapped trace of the SFZ, and scarp morphol- Calculations of average slip rates are complicated by lack of exposure of a Reimer, P.J., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Ramsey, C.B., Buck, C.E., Cheng, H., Edwards, R.L., Friedrich, M. and Grootes, P.M., 2013, IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP: Radiocarbon, v. 55, no. 4, p.1869-1887. ogy indicate that they likely represent triggered slip on a buried fault antithetic complete, four-event stratigraphic record in any of the Black Rock trenches. 9Supplemental Figure S6. Summary figures of paleo- to the SFZ. Radiocarbon and luminescence dating were used to estimate the Measurements of individual earthquake displacements are sparse: 4 measure- seismology of southern Steens fault zone. Please visit following times of the past three surface-rupturing earthquakes (Personius ments of MRE (PE1) ranged from 1 to 3.5 m of vertical offset, and a single mea- http://doi.org/10.1130/GES01380.S9 or the full-text article on www.gsapubs.org to view Supplemental et al., 2007b): the MRE (ST1) occurred 4.6 ± 1.0 ka, the penultimate earthquake surement of PE2 was 1.8 m. Total cumulative offset for the last 4 earthquakes Figure S6. (ST2) occurred 6.1 ± 0.5 ka, and the oldest earthquake (ST3) occurred 11.5 ± is unknown, but we use two measures to estimate this value: (1) the largest 2.0 ka; a new OxCal model (Supplemental Fig. S6B [footnote 9]) of the chrono- surface offset of a compound (multievent) scarp measured by Dodge (1982) is logical data (from Personius et al., 2007b) yields similar ages of 4.1 ± 0.2, 6.1 ± 8.3 m, and (2) an assumed average offset of 2 m for each of the 4 documented 0.3, and 12.7 ± 2.6 ka, respectively, for these same earthquakes (Table 1). Total earthquakes yields an estimated total cumulative offset of 8 m. We used these vertical offset of the lacustrine sequence exposed in the Bog Hot Valley trench 2 offset values to calculate an estimated latest Quaternary (post–34 ka) slip (4.4 ± 0.2 m) and similar surface offsets from scarp profiles along the southern rate of ~0.25 mm/yr. Average displacements of ~2 m and the complete length

10–15 km of the fault (Personius et al., 2006) yield an average vertical offset of Holocene surface rupture (57 km) yield magnitude estimates of Mw 7.1 for of ~1.5 m for the last 3 surface ruptures. Vertical offsets of 1.5 m and a likely the last 4 surface-rupturing earthquakes on the Black Rock fault zone. The re-

fault rupture length of 42 km yield a magnitude estimate of Mw 7.0 (Table 1) for sults of existing studies of the SFZ and the BRFZ produce essentially identical these earthquakes. We use an average stratigraphic offset of 4.5 ± 0.2 m and post-Sehoo slip rates of 0.25 mm/yr, so we project this value across our tran- a composite luminescence age from near the top of the lacustrine sequence sect 30–50 km west of the JMFZ (Fig. 1). in the area (18.0 ± 1.1 ka; Personius et al., 2007b) to calculate an average latest Quaternary slip rate of ~0.25 mm/yr. This rate is consistent with latest Quater- nary interval rates based on the past three dated earthquakes at the Bog Hot Long Valley Fault Zone Valley site, as well as from offset of Miocene bedrock at the northern end of the valley (Personius et al., 2007b). The only significant topographic expression of post-Miocene faulting between the Steens–Black Rock extensional zone and Surprise Valley in northeastern California is Long Valley, a basin controlled by north-, northeast-, and Black Rock Fault Zone northwest-striking normal faults mapped as Quaternary (younger than 1.6 Ma) in U.S. Geological Survey (2015). None of these faults offset pluvial lake sedi- The paleoseismology of the BRFZ was the subject of a doctoral thesis ments and landforms along the margins of Long Valley. However, numerous by Dodge (1982), whose work was summarized in U.S. Geological Survey northeast-striking fault strands were mapped across the floor of Long Valley (2015). The fault therein is mapped on the basis of mapping of Dodge (1982, (Fig. 1; Supplemental Fig. S1 [see footnote 1]) by Dohrenwend and Moring scale 1:24,000) and 1:250,000-scale mapping of Dohrenwend et al. (1991) (1991b). These faults are herein informally named the Long Valley fault zone and Dohrenwend and Moring (1991b). Dodge (1982) mapped and described (LVFZ). Little information is available on the paleoseismology of this structure. a broadly arcuate, 55-km-long fault zone consisting of numerous right- and The fault was previously mapped by Dohrenwend and Moring (1991b, scale left-stepping fault scarps in late Pleistocene lacustrine (Lake Lahontan) 1:250,000; U.S. Geological Survey, 2015). We mapped the fault at a scale of deposits and post-lacustrine alluvial sediments of Holocene age. Extensive 1:24,000 for this study; although additional strands have been identified, the scarp topographic profiling and the results from seven trench investiga- basic form of the fault zone (Supplemental Fig. S1 [footnote 1]) is similar to tions were used to determine that the fault zone had undergone at least four that shown in the U.S. Geological Survey (2015) database. The fault zone con- surface-rupturing earthquakes since deposition of the Wono tephra. Dodge sists of four en echelon, left-stepping, and northeast-striking fault strands or (1982) used the 4 identified earthquakes and an age of 25 ka of the Wono arrays of small (generally <1 m high) northwest- and southeast-facing scarps tephra to calculate an average recurrence interval of 6250 yr; a revised, better (Fig. 1; Supplemental Fig. S1 [footnote 1]). The two northern strands (Alkali constrained age of the Wona tephra (ca. 34 ka; Benson et al., 2013; Reheis Lake and Fortymile Lake) are confined to the floor of central Long Valley, but

the two southern strands (Central Lake and Boulder Lake) extend from the floor during which the level of Lake Lahontan rose ~60 m in the time period 13–11 ka of southern Long Valley southward across a series of unnamed basalt-cored (Fig. 5). Lakes in the western Great Basin regressed from this intermediate hills that form the southern margin of the Long Valley basin. highstand to current elevations ca. 10 ka (Benson et al., 2013; Reheis et al., Although assumed to be a normal fault, the left-stepping pattern and in 2014), so we infer that the youngest surface rupturing earthquake on the LVFZ many cases very linear fault traces are suggestive of strike-slip faulting such occurred after 10 ka. as the 1932 Cedar Mountain earthquake sequence in central Nevada (Bell et al., To help quantify slip along the LVFZ, we measured scarp topographic pro- 1999). Given the strong northwest strikes of faults composing the right-lateral files in the field across three of the four primary strands (Fig. 1; Supplemental Walker Lane west of Long Valley, the sense of slip of the northeast-striking Fig. S2 [footnote 2]). Most individual scarps are small (<1 m), as expected in Long Valley fault would likely be left lateral. We searched for geomorphic in- a distributed fault zone with a significant strike-slip component. The northern dicators of lateral slip in surficial deposits, but found no dominant patterns of (Alkali) strand, which consists of curvilinear fault traces perhaps indicative of offset channels or other features. One possible indicator of left-lateral slip is a a more normal sense of slip, yielded a composite vertical separation of ~2.5 m series of right steps and bends in the very linear Boulder Lake strand north of (north side down) across the three scarps that compose the northernmost part State Road 34 (Figs. 11A, 11B). The scarps increase in height at each of these of the strand (Figs. 11E, 11F). Scarps along the Boulder Lake strand have much bends; at the bend ~500 m north of State Road 34 (site LV1 in Fig. 1), the verti- smaller vertical separations (~0.3 m), but the lateral component, although un- cal separation doubles, from an average of 0.3 m to 0.6 m. We infer that such known, is probably larger. If the long-term horizontal:vertical slip ratio we mea- features are pushups in zones of compression in right-stepping (constraining) sured in Miocene bedrock is still characteristic of slip in the Quaternary, then bends of a left-lateral fault zone. A much longer term sense of slip is evident we estimate that lateral offset along this strand is ~2.4 ± 0.5 m. We use these where the Boulder Lake strand cuts Miocene (16–15 Ma) basalt flows south of 2 offset values to determine a slip value of 2.5 ± 0.5 m as our best estimate of the southern margin of Long Valley (site LV2 in Fig. 1). Here, the fault offsets the total post-highstand slip on the LVFZ, and the age of the Lahontan (Sehoo) a northwest-striking normal fault zone in bedrock in a left-lateral sense ~340 ± highstand (15.6 ± 0.3 ka) to calculate a slip rate of 0.15 ± 0.05 mm/yr. Given our 50 m, and in a down-to-the-east normal sense 40–45 m (Figs. 11C, 11D). These assumption that the scarps are the result of a single event and the lack of pre- offset estimates yield a horizontal:vertical ratio of ~8 ± 1.5:1. existing fault topography in Quaternary deposits, we consider this value to be The Long Valley basin was occupied by pluvial Lake Meinzer during the late a maximum slip rate, and increase the uncertainty to ±0.1 mm/yr. Our vertical 80 A Interpreted Stratigraphy Sandy, silty soil formed on Pleistocene (Snyder et al., 1964; Mifflin and Wheat, 1979; Reheis, 1999). Little slip value and a rupture length of 40 km yields a magnitude estimate of Mw 7. 0 70 silty lacustrine and sandy eolian sediment Silty lacustrine sediment is known about the history of this lake, which reached a highstand at 1768 m, for the Long Valley earthquake (Table 1). 60 Trego Hot Springs tephra; sample LVT-1U sharp upper & lower contacts filling the basin to a depth of ~90 m. The only available chronological data per- 50 Silty lacustrine sediment tinent to the history of Lake Meinzer are chemical correlations of two tephra we Surprise Valley Fault Zone 40 Fine to coarse fluvial sand; fines upward to gradational upper contact observed in a stream cut in the valley floor located within the Alkali Lake set 30 Wono tephra

Approximate Height (cm) sample LVT-1L Turf-like buried soil of faults (site LV3 in Fig. 1) at an elevation (1685 m) only 3 m above the current The prominent east-dipping normal Surprise Valley fault zone (SVFZ) forms 20

Cross-bedded, medium to low point in the Lake Meinzer basin (Figs. 11E, 11F). The two tephra were posi the western margin of the Basin and Range in northeastern California (Fig. 10 coarse fluvial sand tively identified as the Wono and Trego Hot Springs tephras (Supplemental 1). The fault separates Eocene to Pliocene volcanic, volcaniclastic, and sedi- 0

B Table S3 [footnote 5]), dated elsewhere as ca. 34 ka and 30 ka, respectively mentary rocks in the Warner Mountains from 1–2-km-thick basin-fill sediments (Benson et al., 2013). Our interpretation of the stratigraphy at the Alkali Lake beneath Surprise Valley with a total dip-slip displacement of 7–8 km (Colgan tephra site (Supplemental Fig. S710) is consistent with the depositional settings et al., 2006b; Egger and Miller, 2011). Hedel (1980, 1984) mapped and docu- Wono tephra Buried soil of other Wono and Trego Hot Springs localities in the Lahontan basin (Fig. 5; mented evidence of Quaternary faults in Surprise Valley. Bryant (1990) reeval- Adams, 2010). We infer from this agreement that Lake Meinzer likely has a uated and modified the mapping of Hedel (1980, 1984), and attributed some hydrograph similar to Lake Lahontan and nearby isolated lakes such as Lake of Hedel’s faults to nontectonic origins (i.e., lacustrine shorelines). The paleo- Surprise and Lake Alvord, and thus reached its highstand at about the same seismology of the SVFZ was first described in detail in Personius et al. (2007a, time (ca. 18–15 ka). 2009). Ongoing studies are focused on utilizing newly acquired lidar (light de-

Figure S7. Annotated photographs of Wono and Trego Hot Springs tephras in Long Valley, 6 km Numerous fault scarps along the LVFZ are preserved in silty lacustrine sedi tection and ranging) data for detailed mapping and paleoseismic analysis (e.g., northeast of Vya, NV; A) Photograph and stratigraphic interpretation of stream cut in fluvial and lacustrine sediment containing Wono and Trego Hot Springs tephras. B) Closeup of Wono tephra showing sharp lower contact between ash and underlying thin, turf-like, ments on the floor of Long Valley and some also cut the highstand shoreline, Egger, 2014). organic-rich buried soil. See Fig. 11D for location. thus indicating that the fault ruptures date to <18–15 ka. In addition, the ma- Surprise Valley was occupied by pluvial Lake Surprise, which reached an 10Supplemental Figure S7. Photographs and strati- jority of fault scarps are at low elevations (1685–1695 m) relative to the 1768 m elevation of 1530–1545 m (Hedel, 1980, 1984; Irwin and Zimbelman, 2012; graphic interpretations of Wono and Trego Hot elevation of the Lake Meinzer highstand. We found no obvious evidence of Ibarra et al., 2014) at its latest Pleistocene highstand (15.2 ± 0.2 ka; Ibarra Springs tephra outcrops in Long Valley, 6 km north- reworking of these scarps by lacustrine shoreline processes, which leads us et al., 2014). Data from a trench and borehole at the Cooks Canyon site (ele east of Vya, Nevada. Please visit http://doi .org /10 .1130/GES01380 .S10 or the full-text article on www to infer that the timing of the earthquake responsible for the LVFZ scarps also vation 1470–1478; site SV1 in Fig. 1) and from a natural exposure at the .gsapubs.org to view Supplemental Figure S7. postdates the age of the last major transgression (Younger Dryas–Gilbert) Steamboat Canyon site (elevation 1493 m; site SV2 in Fig. 1) yielded evidence

GEOSPHERE | Volume 13 | Number 3 Personius et al. | Paleoseismic transect across northwestern Basin and Range Downloaded from https://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/13/3/782/2542672/782.pdf 797 by guest on 18 December 2018 on 18 December 2018 by guest Downloaded from https://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/13/3/782/2542672/782.pdf Research Paper ainl giutr Iaey rga (AP https:// www (NAIP; Program Imagery Agriculture National Figure 11. Fault maps of selected areas along Long Valley fault zone (LVFZ; Fig. 1; see Supplemental Fig. S1 [footnote 1] for locations); backgrounds are 1 m to Lake Lahontan. (F) Unannotated image of same area as E. profiles across the three northern strands, and location of tephra site (Supplemental Fig. S7 [footnote 10]) that helps correlate the pluvial record in Long Valley we estimate a horizontal to vertical ratio of ~8 ± 1.5:1. (E) Map of northern end of Alkali Lake scarps; note complex fault pattern, locations of topographic a northwest-striking normal fault indicates ~340 ± 50 m of left-lateral offset on the LVFZ. Combined with vertical separations of 40–45 m across the fault trace, retrodeformation of central part of Boulder Lake strand of LVFZ in Miocene (16–15 Ma) basalt. Reconstruction of topography and general trend (green lines) of fault trace as possible evidence of left-lateral strike-slip movement on the LVFZ. (B) Unannotated image of same area as A. (C) Fault map and (D) Interpreted preted map of northern end of Boulder Lake scarp; we interpret the linear fault trace and apparent compressional pushups related to right steps and bends in 41.485 41.60° 41.65° 41.46° 11 41.425 41.445 9.78 °1

11 °

e Rout State

9.87 °

A 11 EF 1697 m t faul a Vy a faul a Vy

9.82 ° 34 ° t 1700 m 1695 m C Vs = 43.0 m L VB-1 1800 m

1690 m 0 pushup contour interval = 1 Vs = 44.5 m LV Vs = 0.3 m NF-1 1850 m pushup 1696 m ? 0.6 m Vs = m 01

Alkali Lake strand contour interval = 10 ? pushup ? Vs = 40.0 m L 0 VB-2 contour interval = 5 1690 m 1000 340 ± 50 m left-lateral = m Vs = 0.3 m m ?

Boulder Lake strand 0.8 m m km 1685 Vs = 1800 m 1850 m ? tephra m sit e 00 0 stepovers and bends in fault trac may be related to compressional Area of higher topography that measurements (Vs, m) Profile site, with vertical separation fault; green line is average strike Older (pre-Quaternary?) normal Active trace of LV

.fsa .usda .gov /programs -and -services /aerial -photography /imagery m

Vs = 48.0 m LV 1696 m m 2 1690 NF-2 To

1.1 m

Vs =

m 1800 1800 1750 m

2.5 m

tal Vs = m 1700 11 0.7 m Vs =

9.79 ° 1697 m 19.75° 11 FZ 9.79° B e D porm/ iaey () Inter - (A) imagery. -programs/)

GEOSPHERE | Volume 13 | Number 3 Personius et al. | Paleoseismic transect across northwestern Basin and Range 798 Research Paper

Figure S8. Summary figures of paleoseismology of Surprise Valley fault zone. A) Logs from a trench and borehole at the Cooks Canyon site OxCal v4.2.4 Bronk Ramsey (2009); Bronk Ramsey and Lee (2013); r:5 IntCal13 atmospheric curve (Reimer and others, 2013) and from a natural exposure at the Steamboat Canyon site (modified from Fig 4 of Personius et al., 2009). B) OxCal model ofchronological data (modified from Fig. 6 of Personius et al., 2009). B modeled earthquake pdf Sequence Surprise Valley Chronology posterior pdf (post-model) prior pdf A (pre-model) for five surface-rupturing earthquakes since deposition of a Lake Surprise 3.7 k.y. on the margin-bounding SVFZ to 8.5 k.y. on the BRFZ; recurrence in- Historic constraint (1850 AD ± 5) mean 2σ range DEPOSITS SV-R03 (1,350 ± 45 14C yr B.P.; 1,170-1,350 cal yr B.P.) 15 SOUTH WALL, COOKS CANYON TRENCH 1 Slope-wash colluvium 5 Earthquake SV1 (1,200 ± 100 yr) Fault-scarp colluvium k 2 1 7 11 from SV1 rupture k Phase (buried soil on P2 colluvial wedge) 2006 drill hole SV–L08 3 Fluvial sand and silt 13,380 ± 2,640 yr 14 deltaic complex that dates to ca. 18 ka (Supplemental Fig. S8 ; Personius tervals on faults with only a single post-Sehoo earthquake are unknown, but (4 m south of trench wall) 7 k k SV-R05 (1,240 ± 140 C yr B.P.; 900-1,410 cal yr B.P. ) 10 Fault-scarp colluvium 9–1 (13.4 ± 2.2 ka) 4 k 14 from SV2 rupture SV–L06 SVSC-R01 (1,300 ± 35 C yr B.P.; 1,170-1,300 cal yr B.P.) SV-R03 8 9–2 18,400 ± 3,170 yr 5 Debris flow (1,170–1,350 cal yr B.P.) 9bk (19.6 ± 2.5 ka) SV-L01 (1,110 ± 630 yr; 1.5 ± 0.3 ka) 2 Fault-scarp colluvium 4 6-1 SV-R04 (1,960 ± 180 14C yr B.P.; 1,520-2,350 cal yr B.P.) from SV3 rupture 3 9–3 5 Fluvial sand and gravel 5 SV-L03 (4,670 ± 400 yr; 4.6 ± 0.4 ka) et al., 2009; Ibarra et al., 2014). Vertical stratigraphic offset of distinctive facies likely exceed the length of our time window (>15 k.y.). The entire region (Fig. 1) 6-2 interbeds in unit 6-1 SV–L01 9–4 1,110 ± 630 yr 6–1 Fault-scarp colluvium Earthquake SV2 (5,800 ± 1,500 yr) c4? (1.5 ± 0.3 ka) from SV4 rupture Mazama ash 6–2 SV-L04 (8,260 ± 2,850 yr); 6.9 ± 1.1 ka

meters Post-lacustrine eolian 6–1 STEAMBOAT CANYON EXPOSURE p 68° 7 Mazama ash (7,630 ± 150 cal yr B.P.) 0 sand c4? buried ed di Sub-lacustrine fault- vertical offset 7 t SVSC–R01 14 soil? SV-R02 (7,050 ± 55 C yr B.P.; 7,740-7,980 cal yr B.P.) of the faulted deltaic sediment in the trench is 13.5 ± 2 m (estimated 2s un- has on average one such event per thousand years. 8 scarp colluvium from (stratigraphic throw) 8 5 (1,170–1,300 cal yr B.P.) SV5 rupture k =13.5 ± 2 m projec Earthquake SV3 (8.5 ± 0.5 ka)* Pluvial deltaic topset 1 9-1 sediment 9–1 Earthquake SV4 (10,900 ± 3,200 yr) Pluvial deltaic forset -5 9-2 SYMBOLS SV-L08 (13,380 ± 2,640 yr); 13.4 ± 2.2 ka sediment meters 9–3 Pluvial deltaic Fault; arrows show 9–2 Lahontan highstand (13,000 ± 200 14C yr B.P.; 9-3 2 bottomset sediment relative motion 14,800-16,100 cal yr B.P.) certainties). Additional slip of ~1.5 m on synthetic fault scarps on the val- Pluvial barrier-bar 9-4 Fault-scarp free face SV-L05 (17,590 ± 4,640 yr); 16.8 ± 2.1 ka sediment 9–3 buried 4 Earthquake SV5 (18,200 ± 2,600 yr) -10 k Krotovina Luminescence age (yr) 9–4 soil (OxCal-model age, ka) Pebbles & cobbles 0 SV-L06 (18,400 ± 3,170 yr); 19.6 ± 2.5 ka Radiocarbon age; in 0 5 calibrated years B.P. Buried soil (drill hole) meters SV-L07 (28,080 ± 4,440 yr; 23.8 ± 4.6 ka) ley floor (Hedel, 1984; Bryant, 1990) yields a combined vertical slip of 15 ± 40,000 30,000 20,000 10,000 0 0 51015202530354045 Modeled age (cal yr B.P.) meters Summary The paleoseismology of the Surprise Valley fault is described in detail by Personius et al. (2007, 2009). Data from a trench and borehole at the Cooks Canyon site and from a natural exposure at the Steamboat Canyon site yielded evidence for 5 surface-rupturing earthquakes since ~18 ka (Fig. A; modified from Fig 4 of Personius et al., 2009). The vertical stratigraphic offset of distinctive facies of the faulted deltaic complex at Cooks Canyon is 13.5 ± 2 m (estimated 2σ uncertainties) dated to ~18 ka (Personius 3 m since deposition of the deltaic complex; topographic profiles on scarps et al., 2009; Ibarra et al., 2014); additional slip of ~1.5 m on synthetic fault scarps on the Valley floor (Hedel , 1980, 1984; Bryant, 1990) yields a combined vertical slip of 15 ± 2 m since deposition of the deltaic complex; topographic profiles on scarps across COMPARISON WITH GEODESY similar-aged deposits indicate slip of similar magnitude at several other locations along the fault zone (Personius et al., 2007). If the paleoseismic record from the Cooks canyon trench is complete, then the five dated surface ruptures averaged ~2.7 m per earthquake. The timing of these earthquakes is constrained by radiocarbon, luminescence, and correlated tephra ages, with the most-recent earthquake well constrained at both the Cooks Canyon and Steamboat Canyon sites at ~1.2 ± 0.1 ka (Fig. B; modified from Figure 6 of Personius et al., 2009). References Cited Bronk Ramsey, C., 2009, Bayesian analysis of radiocarbon dates: Radiocarbon, v. 51, no. 1, p. 337–360. Bronk Ramsey, C., and Lee, S., 2013, Recent and planned developments of the program OxCal: Radiocarbon, v. 55, no. 2–3, p.720-730. Bryant, W.A., 1990, Surprise Valley and related faults, Lassen and Modoc counties, in California Division of Mines and Geology Fault Evaluation Report, v. 217, 17 p. across similar-aged deposits indicate slip of similar magnitude at several Hedel, C.W., 1980, Late Quaternary faulting in western Surprise Valley, Modoc County, California [Master’s thesis]: San Jose, California, San Jose State University, 113 p. Hedel, C.W., 1984, Maps showing geomorphic and geologic evidence for late Quaternary displacement along the Surprise Valley and associated faults, Modoc County, California: U.S. Geological Survey Miscellaneous Field Studies Map MF-1429. Personius, S.F., Crone, A.J., Machette, M.N., Lidke, D.J., Bradley, L.-A., and Mahan, S.A., (2007b), Logs and scarp data from a paleoseismic investigation of the Surprise Valley fault zone, Modoc County, California: U.S. Geological Survey Scientific Investigations Map 2983. Available at http://pubs.usgs.gov/sim/2983/. Personius, S.F., Crone, A.J., Machette, M.N., Mahan, S.A., and Lidke, D.J., 2009, Moderate rates of late Quaternary slip along the northwestern margin of the Basin and Range Province, Surprise Valley fault, northeastern California: Journal of Geophysical Research, v. 114, 17 p., doi:10.1029/2008jb006164. Reimer, P.J., Bard, E., Bayliss, A., Beck, J.W., Blackwell, P.G., Ramsey, C.B., Buck, C.E., Cheng, H., Edwards, R.L., Friedrich, M. and Grootes, P.M., 2013, IntCal13 and Marine13 radiocarbon age calibration curves 0–50,000 years cal BP: Radiocarbon, v. other locations along the fault zone (Fig. 1; Hedel, 1980, 1984; Personius 55, no. 4, p.1869-1887. Modern Deformation Rates et al., 2007a). If the paleoseismic record from the Cooks Canyon trench is 11 Supplemental Figure S8. Summary figures of paleoseismology of Surprise Valley fault zone. Please visit complete, then the 5 dated surface ruptures averaged ~2.7 m per earthquake. We chose the longest continuous geodetic records available (the PBO net- http://doi .org /10 .1130/GES01380 .S11 or the full-text We use a vertical displacement of 2.5 m and a fault rupture length of 75 km work) to calculate rates of horizontal deformation across the transect region. article on www.gsapubs.org to view Supplemental to calculate estimated magnitudes of Mw 7.3 for earthquakes that rupture the From east to west, we chose PBO stations P013, P145, and P731, because File S8. entire length of the SVFZ. The timing of these earthquakes is constrained by they are permanent, robust installations with long (~7–9 yr) records of con- radiocarbon, luminescence, and correlated tephra ages; the MRE is well continuous operation (Fig. 1). We first calculated the total values of differential strained at both the Cooks Canyon and Steamboat Canyon sites as ca. 1.2 ± velocity (Vd) and direction between these stations (3.8 ± 0.1 mm/yr at 331°, 0.1 ka (Supplemental Fig. S8B [footnote 11]). Our total offset estimate (15 ± NAM08 reference frame), and then calculated the extension-only component 3 m) and a luminescence age on the youngest lacustrine deposits exposed (2.4 ± 0.1 mm/yr at 280°) using an estimate of the regional extension direction in the Cooks Canyon trench (18.4 ± 1.6 ka) yield a latest Quaternary slip rate (100°/280°) based on the strikes of the seven Holocene-active faults in the tran- of 0.80 ± 0.1 mm/yr. sect area (Tables 1 and 2). Our estimated regional extension direction is very Our rate is slightly lower than a recently determined rate of ~1.1 mm/yr similar to those derived from analysis of regional GPS (e.g., 104°/284°; Payne from the central part of the SVFZ, based on detailed shoreline and fault scarp et al., 2012) and fault strike data and is also consistent with the few published mapping on recently obtained lidar imagery (Marion, 2016). In addition, Mar- earthquake focal mechanisms in the region (Patton and Zandt, 1991; Pezzopane ion (2016) also determined lower slip rates on the southern (~0.4 mm/yr) and and Weldon, 1993). northern (0.3 mm/yr) parts of the fault zone. Taken together, our rate of 0.8 ± The ~50° more northward orientation of the total Vd vectors with respect 0.1 mm/yr may be a reasonable average estimate of slip along the total length to the regional extension direction (Table 2) indicates a substantial compo- Text File S1

EXCLUDED STRUCTURES of the SVFZ. nent (~3 mm/yr) of dextral shear across the transect, but the shear component likely decreases eastward away from active strike-slip faulting in the Walker Pine Forest Range fault zone Lane (Hammond and Thatcher, 2005, 2007; Payne et al., 2012). So how might Excluded Structures this shear be expressed on faults in the transect? We suspect that either shear Little information is available on the paleoseismology of the Pine Forest Range fault zone

(PFRFZ), which forms the steep eastern flank of the prominent, north-trending Pine Forest is partitioned on primarily strike-slip faults (e.g., 1932 Cedar Mountain earth- Range. The footwall consists of Paleozoic and Mesozoic metasedimentary and metavolcanic Our focus on faults that have undergone at least one post-Sehoo sur- quake; Bell et al., 1999) or is distributed as an oblique-slip component during rocks intruded by Jurassic to Cretaceous plutons and overlain by Tertiary volcanic and face-rupturing earthquake excludes several faults in the transect inferred to earthquakes on some of the active normal faults in the region (e.g., 1954 Rain- sedimentary rocks (Smith, 1973; Wyld, 1996; Colgan et al., 2006a). Thermochronologic studies have been active in the Quaternary. These include the Pine Forest Range fault bow Mountain–Stillwater sequence; Caskey et al., 2004). A likely example of indicate unroofing and initial extension in the region 11-12 Ma (Colgan et al., 2006a, 2006b) and

likely continued to near-present time (<1 Ma) at rates of 0.3-0.8 mm/yr (40-70° fault dip range). zone, numerous faults in Miocene volcanic rocks in the northwest Nevada pla- partitioned slip is the Long Valley fault system, where our field reconnaissance Recent analysis of the tectonic geomorphology of the Pine Forest Range suggest a pattern of teau (Sheldon Plateau of Lerch et al., 2007), and the Hays Canyon Range fault revealed evidence of strike-slip faulting during a Holocene surface-rupturing renewed uplift 5 Ma to 0.1 Ma, although the knickpoint retreat data from the PFR is less zone in Surprise Valley (Fig. 1). None of these structures has demonstrated earthquake. Other candidates might include some of the numerous favorably convincing than similar data from the Jackson Mountains fault zone (JMFZ; Ellis et al., 2014).

The fault is included in 1:250,000 scale reconnaissance mapping by Dohrenwend and Moring evidence of faulting in latest Quaternary deposits. A more detailed discussion oriented northeast- or northwest-striking faults on the northwest Nevada pla- 12 (1991) and Quaternary activity is supported by significant post-Miocene slip (>7-9 km, Colgan et of these features is presented in Supplemental Text File S1 . teau, or pre-Sehoo strike-slip faults that may be present unrecognized beneath al., 2006a, 2006b), a steep range front, rapid knickpoint migration (Ellis et al., 2014), and lacustrine, eolian, and alluvial deposits in some of the broad valleys in the historical seismicity. The latter was manifest as an earthquake swarm during February-April transect, such as the northeastern arm of the Black Rock Desert adjacent to 1973,beneath the west flank of the Bilk Creek Mountains that likely occurred on the northern

part of the PFRFZ. This swarm consisted of numerous M4+ events and thousands of smaller PALEOSEISMIC SUMMARY the JMFZ. Egger et al. (2010) suggested that some of the more steeply dipping faults underlying Surprise Valley may be partitioning strike-slip displacement, 12Supplemental Text File S1. Discussion of other Our compilation of new and existing paleoseismic data identifies a total because a corrugated geometry probably prevents significant oblique slip on Quaternary(?) faults in the transect region exclud- of 18 probable latest Quaternary, large magnitude (M ≥ 7) surface-rupturing the main trace of the SVFZ. Oblique slip on some of the active normal faults ed from our analysis. Please visit http://doi.org /10 w .1130/GES01380 .S12 or the full-text article on www earthquakes in the NWBR transect region (Table 1; Fig. 12). Recurrence inter- in the transect is also likely but very difficult to quantify, because in our expe- .gsapubs.org to view the Supplemental Text File S1. vals on individual faults with multiple post–18–15 ka earthquakes range from rience, clear evidence of lateral displacement is rarely observed along most

20 A SV5 30 ka Lake Lahontan Sehoo highstand 15 SRR1 ST3 JM3 BR3 SV4 10 QRS1? Figure 12. (A) Time-space diagram showing me (ka ) JM2? number and ages of large-magnitude (mo-

Ti SV3 Mazama ash ment magnitude, Mw > 6.8), surface-rup- DV1 turing earthquakes in northwestern Basin SV2 LV1 ST2 and Range Province (NWBR) transect 5 region. Black squares and vertical black ST1 JM1 lines are weighted means and 2σ calibrated BR2 age ranges from OxCal models of well- dated sequences (for OxCal models from SV1 BR1 Santa Rosa Range, see Supplemental Fig. 0 S3 [footnote 6]), Steens (Supplemental Surprise Long Black Steens Jackson Desert Santa Rosa Fig. S6 [footnote 9]), and Surprise Valley Valley FZ Valley FZ Rock FZ FZ Mtns FZ Valley FZ Range FZ (Supplemental Fig. S8 [footnote 11]) fault zones (FZ); light red boxes and vertical gray 42.0° lines are estimates of most likely 2σ age ranges of surface-rupturing earthquakes

a B Denio QR on remaining fault zones based on field evidence discussed in text, with exception S

Long of Black Rock fault zone (earthquake times

Nevada are from Dodge, 1982). Earthquakes are Californi Steens FZ Surprise V Quinn River OR queried where uncertain. (B) Index map at Vya Valley FZ Crossing Orovada approximately same horizontal scale as A. Cedarville NV PBO—Plate Boundary Observatory (www CA .unavco.org); SRRS—Santa Rosa Range Alturas section; QRS—Quinn River section. alley FZ

PBO Transect Santa Rosa Range FZ SRRS

Black Rock alley FZ = = P013 731 = P145 = 0 mm/yr 2.4 mm/yr 1.6 mm/yr FZ

10 km Desert V

41.0° Jackson Mountains FZ 121.0° 120.0° 119.0° 118.0° 117.25°

late Quaternary normal faults in the region. With the exception of the LVFZ, we U-series) data, as well as data from published studies, to estimate deformation observed no unequivocal evidence of a significant lateral-slip component on rates on the seven fault zones that postdate the latest Pleistocene Sehoo high- any of the prominent normal faults in the current study. stand shoreline of pluvial Lake Lahontan in the transect area (Fig. 1). This widespread datum provides a uniform time window for calculation of slip rates, and definitively identifies those faults responsible for most of the strain release Latest Quaternary Deformation Rates during the last 15–18 k.y. We calculated vertical slip rates using what we infer are average to maximum values of slip over this time period (Table 1), and We used the results of our field mapping, investigations of natural and then convert these vertical rates to horizontal extension rates using a range of manmade exposures, scarp profiling, limited new chronological (OSL and possible fault dips (Table 3).

TABLE 2. GLOBAL POSITIONING SYSTEM VELOCITY DATA FOR NORTHWESTERN BASIN AND RANGE PROVINCE PALEOSEISMIC TRANSECT Extension-only† vN vE Velocity Direction Epoch Total velocity difference Direction velocity difference Direction Station pair* (mm/yr) (mm/yr) (mm/yr) (°) (yr) (mm/yr) (°) (mm/yr) (°) PBO P013 1.02 ± 0.02 –2.70 ± 0.03 2.9 ± 0.1 2917.5 3.8 ± 0.1331 2.4 ± 0.1280 PBO P731 4.40 ± 0.03 –4.54 ± 0.08 6.2 ± 0.1 3147.1

PBO P013 1.02 ± 0.02 –2.70 ± 0.03 2.9 ± 0.1 2917.5 2.6 ± 0.1332 1.6 ± 0.1280 PBO P145 3.35 ± 0.02 –3.92 ± 0.04 5.2 ± 0.1 3118.9

PBO P145 3.35 ± 0.02 –3.92 ± 0.04 5.2 ± 0.1 3118.9 1.2 ± 0.1329 0.8 ± 0.1280 PBO P731 4.40 ± 0.03 –4.54 ± 0.08 6.2 ± 0.1 3147.1 *Northing velocity (vN) and Easting velocity (vE) data downloaded from PBO (Plate Boundary Observatory) Velocity files (UNAVCO; www.unavco.o rg), 01 August 2015, in North America 2008 (NAM08; UNAVCO) reference frame. †Global positioning system differential extension components calculated using regional extension direction (100°/280°) estimated from strikes of Holocene faults in transect.

Comparison of Modern and Latest Quaternary Rates that are 46%–79% of the modern extension rate across the transect (Fig. 13A; Table 3). Unfortunately, actual values of fault dip are rarely known, so estima- As previously recognized (Friedrich et al., 2003; Wesnousky et al., 2005; tion of fault dip is a large source of uncertainty in our comparisons of long- Koehler and Wesnousky, 2011), our calculated extension rates are strongly term and modern rates of deformation. In addition to fault dip uncertainties, dependent on the values of fault dip used in the conversions (Table 3). Our other possible sources of our apparent geologic-geodetic discrepancy include results appear to show that the sum total extension rate of the seven latest the following: (1) underestimated slip rate uncertainties; some of our slip rates Quaternary faults in the transect is nearly equal to modern (geodetic) rates have large uncertainties because the chosen time period (last 15–18 k.y.) only of extension only if the faults dip ≤40° to seismogenic depths (Fig. 13A). If contains a single earthquake and thus does not cover a complete seismic cycle; the range-bounding faults in the transect dip at steeper angles of 45°–60° to (2) not all potential seismic sources are included in our assessment; (3) un- seismogenic depths, then our vertical slip rates yield estimated extension rates recognized off-fault coseismic deformation associated with large-magnitude,

TABLE 3. ESTIMATED DIP-DEPENDENT EXTENSION RATES ON FAULTS IN NORTHWESTERN BASIN AND RANGE PROVINCE TRANSECT Extension at Extension rate Extension rate Extension rate Extension rate Extension rate Extension rate Extension* 280° strike† at 60° dip at 55° dip at 50° dip at 45° dip at 40° dip at 30° dip Fault zone (m) (m) (mm/yr) (mm/yr) (mm/yr) (mm/yr) (mm/yr) (mm/yr) Santa Rosa Range 1.2 1.1 0.10.1 0.10.1 0.10.2 Desert Valley 1.4 1.4 0.10.1 0.10.2 0.20.3 Jackson Mountains 4.3 4.3 0.30.3 0.40.5 0.60.8 Steens–Black Rock 2.5 2.5 0.10.2 0.20.2 0.30.4 Long Valley 1.4 1.4 0.10.1 0.10.2 0.20.3 Surprise Valley 8.7 8.2 0.40.5 0.70.8 0.91.3 Fault transect totals 19.5 19.0 1.11.3 1.61.9 2.33.3

For comparison: Global positioning system (GPS) total transect velocity difference† (P013 to P731) = 3.8 ± 0.1 mm/yr at 331° GPS extension-only velocity difference§ (P013 to P731) = 2.4 ± 0.1 mm/yr at 280° 90% of GPS extension-only velocity difference** (P013 to P731) = 2.2 ± 0.1 mm/yr at 280° 75% of GPS extension-only velocity difference** (P013 to P731) = 1. 8 ± 0.1 mm/yr at 280° *Extension (E) calculated using vertical separation (Vs) values in equation: E = Vs/tan 60°, using a fault dip of 60° (Koehler and Wesnousky, 2011). †Extension values normalized to regional extension direction (100°/280°) estimated from strikes of Holocene faults in transect. §GPS differential extension components calculated using regional extension direction (100°/280°). **Extension-only velocity difference reduced by 10% and 25% based on analyses of Pancha et al. (2006; see text).

West East surface-rupturing earthquakes on faults included in our analysis; and (4) un- PBO Surprise Va recognized deformation from localized earthquake swarms or moderate-sized P731 A Long Va faul t earthquakes too small to cause surface rupture. All of these possible sources faul t 4 are discussed in the following. Steens/Black Rock fault lley lle y Horizontal Extension rate (mm/yr

PBO Jackson Mountains faul Possible Sources of Slip Rate Uncertainties GPS total velocity = 3.8 ± 0.1 P145 3 Fault Dip

GPS extension only = 2.4 ± 0.1 mm/y s Traditional estimates of normal fault dips of ~60° are based on Ander Desert Va 1.9 ± 0.2 Santa Rosa Range faul sonian concepts of Mohr-Coulomb fault theory and rock mechanics (e.g., at 45° m 90% GPS m/yr 2 Anderson, 1951; Jaeger and Cook, 1979), but the discovery of low-angle shear t zones in deeply exhumed extensional terrains (Wernicke, 1995; Axen, 2004) lley faul 75% GPS 30° dip fostered a growing recognition of the possibility of large earthquakes gen- ) 2.2 ± 0.1 mm/y erated on less steeply dipping normal faults. Most western United States ex- r 1.3 ± 0.2 t 1.8 ± 0.1 mm/y amples of such faults are located in the eastern California shear zone and at 55° r 40° dip 1 Death Valley (e.g., Cichanski, 2000; Hayman et al., 2004; Numelin et al., 2007), r t 50° dip PBO and include surface rupture on a low-angle (~20°) detachment fault during the P013 60° dip 2010 primarily right-lateral strike-slip El Mayor–Cucapah earthquake (Fletcher et al., 2014). Examples in the Basin and Range include the Ruby–East Hum- 0 boldt Range fault (Smith et al., 1989; Wernicke, 1995; Wesnousky and Wil- 250 200 150 100 50 0 loughby, 2003) and parts of the 1954 Dixie Valley earthquake rupture (Abbott Distance along Transect (km) et al., 2001). Within our transect, recent seismic reflection and refraction sur- veys in Surprise Valley identified a strong planar reflector thought to be the 80 B SVFZ dipping at a shallow (~30°) angle beneath the valley floor (Lerch et al., 70 2010). Lerch et al. (2010) inferred that the SVFZ initiated at a dip of ~50°–60°, 60 and rotated into its present position (e.g., Buck, 1988) over the past 12 m.y. 50 Other studies of post-Miocene uplift and exhumation of most of the fault- bound mountain ranges in the region assume current fault dips of ~40° based 40 mean = 49° ± 7.5° on similar models (Colgan et al., 2006b). The question of whether the Qua- Dip (° ) 30 ternary-active range-front trace of the SVFZ and possibly other fault zones 20 sole into the shallowly dipping reflector, or instead have shifted to a more 10 favorably oriented, more steeply dipping throughgoing structure (e.g., Egger 0 et al., 2010), remains unknown because the part of the seismic section be- 1915 1954 1954 1959 1983 neath the range-front fault trace is devoid of coherent reflectors (Lerch et al., Pleasant Fairview Dixie Hebgen Borah Valley Peak Valley Lake Peak 2010). This situation is consistent with other studies that indicate that steeply dipping range-front faults in the Basin and Range are commonly obscured by Figure 13. (A) Cumulative plot of horizontal extension rates of Holocene-active faults in northwestern Basin and Range Province (NWBR) transect calculated using assumed fault dips of 30°, seismically opaque wedges of alluvial-fan sediments (Anderson et al., 1983; 40°, 50°, and 60°, plotted against 4 measures of extension from velocity differences between 3 Okaya and Thompson, 1985). permanent global positioning system stations in UNAVCO Plate Boundary Observatory (PBO; We prefer somewhat steeper dip values (45°–55°), because steeper fault www.unavco.org) network: upper dashed line is calculated total velocity, which includes a large dips are supported by seismological and geodetic studies of several of the (~3 mm/yr) dextral shear component; middle orange line is calculated extension-only component of total velocity; lower two lines are calculated 75 and 90 percentiles of extension-only historic surface-rupturing earthquakes in the region. These include the 1915 velocity based on analysis of Pancha et al. (2006). Values of our preferred dip range (45°–55°) are Pleasant Valley (36°–52°), 1954 Fairview Peak (50°–75°), and Dixie Valley (45°– plotted along the left axis. See discussion in text. GPS—global positioning system. (B) Plot of 50°), Nevada, earthquakes (Romney, 1957; Slemmons; 1957; Doser, 1986, 1988; published estimates of fault dip to seismogenic depth of five major Basin and Range historical earthquakes. Vertical lines are range of dip values discussed in text. Horizontal line and shading Caskey et al., 1996; Hodgkinson et al., 1996), the 1959 Hebgen Lake, Montana, are mean and 1 standard deviation of the mean. earthquake (45°–50°; Barrientos et al., 1987), and the 1983 Borah Peak, Idaho,

earthquake (42°–49°; Doser and Smith, 1985; Stein and Barrientos, 1985; Potential Tectonic Effects of Pluvial Lakes Richins et al., 1987; Payne et al., 2004). The dip range estimates from these 5 earthquakes yield a mean dip of 49° ± 7.5° (Fig. 13B). Similar dips are also We know from modern seismicity records that rapid filling of reservoirs be-

typical of some of the swarms of Mw 4–5 earthquakes in the region (Smith hind natural or artificial dams can induce earthquakes (e.g., Gupta, 2002), and and Lindh, 1978; Patton and Zandt, 1991; Pezzopane and Weldon, 1993). Global some studies suggest that the rise and fall of pluvial lakes in the western U.S. analyses of large historical normal-faulting earthquakes indicate that most oc- may have enhanced or inhibited earthquake recurrence (Hetzel and Hampel, cur on faults dipping 30°–70° (Jackson and White, 1989), 40°–50° (Thatcher and 2005; Hampel and Hetzel, 2006; Karow and Hampel, 2010). Hill, 1991), and 30°–65° (Collettini and Sibson, 2001), with all 3 studies consis- Marion (2016) correlated a cluster of three earthquakes on the Surprise tent with peak occurrence at ~45°. Analysis of regional subsets of the global Valley fault (earthquakes P2, P3, and P4 of Personius et al., 2009; earthquakes catalog with the best seismological and geological data (e.g., Doser and Smith, SV2, SV3, and SV4 in Supplemental Fig. S8 [footnote 11]) with the post–11 ka 1989; Thatcher and Hill, 1991) support relatively steep dips (45°–65°). Geologic desiccation stage of pluvial Lake Surprise. However, directly relating the evidence supporting steeper dips in the transect region includes numerous paleoseismic history of the SVFZ to fluctuations in lake level is not well sup- examples of bedrock exposures of the active range-front fault traces with dips ported given a near-complete lack of dated shoreline features in this time of 55°–70° on the SVFZ (Hedel, 1980, 1984; Egger and Miller, 2011) and 56°–63° range (ca. 11–1 ka) and the large constraints on the ages of these earthquakes on the JMFZ (this study; Fig. 6). (2s ranges of 0.5–3.2 k.y.). Thus we conclude that the effects of pluvial lake fluctuations on the slip histories of the SVFZ and other faults in the NWBR remain largely unknown and are an additional source of uncertainty in our Length of Time Window slip rate calculations.

Slip rates are best constrained with knowledge of precise timing of several paleoearthquakes and accurate estimates of fault slip during these events. Exclusion of Potential Earthquake Sources However, obtaining the necessary data to calculate such interval slip rates is dependent on detailed and expensive trench studies, which are difficult to jus- We cannot exclude the possibility that other potential sources of significant tify in remote areas with low population densities such as the transect region. deformation, such as the Pine Forest Range fault zone, exist in the transect re- However, average slip rates can be determined with data as simple as topo- gion. However, only one of the historic surface ruptures in the central Nevada graphic profiling and regional correlation of faulted surfaces and deposits. We seismic belt (1954 Fairview Peak earthquake) occurred on a fault without a justify our inclusion of several average fault slip rates based on a probable record of at least one prior Holocene rupture (Bell et al., 2004), so we infer single earthquake (e.g., SRRFZ, DVFZ, LVFZ) because (1) the chosen time in- that most of the ongoing deformation in the transect region is associated with terval includes elapsed time before and after the earthquake; and (2) a single faults that have been active in the past 15 k.y. However, the lack of a post–15 ka earthquake in the last 15–18 k.y. is a good indicator of long recurrence and earthquake indicates that most or all of the excluded faults have slip rates of low rates of fault activity. We consider our slip rates for the three faults with <0.1 mm/yr and thus would have little impact in reducing the apparent fault- single ruptures as maximum rates and conclude that the absence of a second slip deficit. earthquake in these records does not have a significant effect on our rate discrepancy. Evidence of temporal variations in slip rate, such as those observed on the SRRFZ (Personius and Mahan, 2005), indicates another source of slip Off-Fault Coseismic Deformation and Shallow Slip Deficit rate uncertainty. However, the wide aperture of our transect area and number of recently active faults included in the analysis probably average out faults Some studies of coseismic ruptures associated with recent large-magni- with accelerating and decelerating earthquake recurrence and thus should not tude earthquakes indicate that fault slip measured at the surface underesti- have a significant effect on our cumulative slip rate across the region. Our mates the amount of slip at several kilometers depth calculated from geodetic 15–18 k.y. time window is also supported by results from the previous tran- and seismologic data, a phenomenon commonly referred to as shallow slip sects in the region, which determined only slightly lower extension rates over deficit (e.g., Simons et al., 2002, Fialko et al., 2005). Coseismic deformation longer time windows. Wesnousky et al. (2005) determined extension rates of that occurs off the main rupture traces has long been recognized as a likely 0.42 mm/yr since 45 ka and 0.65 mm/yr since 20 ka; Koehler and Wesnousky source of this deficit (Rockwell et al., 2002; Shelef and Oskin, 2010; Rockwell (2011) determined extension rates of 0.8 mm/yr since 60 ka and 1.0 mm/yr since and Klinger, 2013), but other controls such as fault maturity have also been 20 ka. Such slight differences are likely related in part to incomplete paleo proposed (Dolan and Haravitch, 2014). A recent study of off-fault deformation

seismic records (Wesnousky et al., 2005) and less precise age estimates of along the length of the 200-km-long rupture associated with the 2013 Mw 7. 7 older earthquakes. Balochistan earthquake (Gold et al., 2015) documented that on-fault deforma-

tion averaged ~72% of total offset along the entire rupture. Gold et al. (2015) and Range (Grauch and Hudson, 2007; Stephenson et al., 2012; Athens et al., showed that the percentage of off-fault deformation is highly variable (0 to 2016). Although larger (>0.5 m high) scarps on such structures (i.e., SRRFZ >50%) along strike, and cautioned against using a single value for estimating and DVFZ; Fig. 1) can be readily observed, smaller scarps may be obscured off-fault contributions to offset estimates used in hazards calculations. by post-earthquake erosion, deposition, and human disturbance, and thus are Regrettably, most studies of off-fault deformation are focused on strike- a likely source of unrecognized off-fault deformation. We conclude that our

slip earthquakes, but a recent study of the Mw 7.0, 2006 Mozambique normal displacement estimates are more likely to underestimate, rather than overesti fault earthquake indicates that deformation measured across fault scarps at mate, total displacement, and thus undocumented off-fault deformation is a the surface (~1–2 m; Fenton and Bommer, 2006) was only 50% of the 3–4 m probable source of some of the geology–geodesy rate discrepancy. of slip at 10 km depth modeled by Copley et al. (2012). In addition, a study of off-fault deformation using three-dimensional ground-penetrating radar in Deformation Unaccompanied by Surface Rupture the Taupo rift of New Zealand showed that undocumented drag folding and block rotation accounted for 41% of total slip across a trenched normal fault Coseismic deformation from localized earthquake swarms or moderate- (McClymont et al., 2009). However, differences in crustal structure and rheol- sized earthquakes below the magnitude threshold of surface rupture is gener- ogy of the Mozambique and New Zealand locations and the steep dip (~75°) ally small and localized, but over the time period used to calculate our fault slip of the Mozambique rupture plane suggest to us that these off-fault deforma- rates may be a source of unidentified long-term deformation. Several earth- tion estimates may not be directly applicable to normal faulting in the NWBR. quake swarms in the NWBR in the past several decades indicate that such seis- For example, inversions of geodetic (Stein and Barrientos, 1985; Ward and mic events may be very common, and unfortunately nearly impossible to iden- Barrientos, 1986; Du et al., 1992) and seismologic (Doser and Smith, 1985; Men- tify in the geologic record. Examples include the previously discussed Denio doza and Hartzell, 1988) data from the 1983 Borah Peak earthquake yield similar swarm on the Pine Forest Range fault zone, the currently ongoing Sheldon calculated values of slip at depth with slip measured at the surface (Crone and swarm on the southern end of the Guano Valley fault zone northeast of Long Machette, 1984; Crone et al., 1987), although the slip distribution patterns vary Valley (Fig. 1; Supplemental Fig. S1 [footnote 1]; Ruhl et al., 2015), and a third from model to model. The conclusion of Dolan and Haravitch (2014) that ma- swarm that occurred ~40 km northwest of the Sheldon swarm near Adel, Ore- ture strike-slip fault systems produce surface ruptures that exhibit only minor gon, in May–July 1968 (Couch and Johnson, 1986). The latter presumably oc- (5%–15%) underestimates of slip at depth, if applicable to normal faults, may curred along one or more normal faults bounding the Warner Valley in southern

indicate that surface measurements on the mature faults in our transect (Sur- Oregon. At least 14 earthquakes of Mw 4–4.7 occurred during this swarm, most prise Valley, Steens–Black Rock, Jackson Mountains, Santa Rosa Range) are of which occurred beneath the floor of Warner Valley. A composite focal mecha- reasonable estimates of overall slip. nism by Schaff (1976; see also Smith and Lindh, 1978) shows left-lateral oblique The effect of off-fault deformation on our slip rate estimates is difficult to movement on a fault plane striking N04°E and dipping 80°E (presumably the quantify, given that historic surface ruptures in the Basin and Range exhibit a west Warner Valley fault zone), and moment tensor analysis of a surface wave

range of fault complexity, from relatively simple, narrow fault traces (e.g., parts magnitude, Ms 5.1 earthquake in the sequence yielded a solution with a dip of of the 1983 Borah Peak earthquake; Crone et al., 1987) to several-kilometer- 70°E and strike of 01°N (Patton and Zandt, 1991; Pezzopane and Weldon, 1993). wide fault zones with multiple fault traces (e.g., 1932 Cedar Mountain and 1954 None of the faults associated with these swarms show evidence of latest Qua- Fairview Peak earthquakes; dePolo et al., 1989; Wesnousky, 2008). The pas- ternary surface displacement (U.S. Geological Survey, 2015). sage of time compounds the difficulty of determining offsets across complex A second potential source of unidentified long-term deformation is asso- prehistoric fault ruptures in the NWBR, particularly in dynamic landscapes af- ciated with moderate-sized earthquakes at or below the magnitude threshold

fected by such processes as pluvial lake-level fluctuations, eolian deflation and of surface rupture. Recent examples are 2 Mw ~6 earthquakes near Klamath deposition, and alternating episodes of fluvial erosion and deposition. Scarp Falls, Oregon, on 20 September 1993 (Braunmiller et al., 1995; Dreger et al.,

preservation can be especially poor where ruptures are localized on steep 1995), and the Mw 6.0 earthquake sequence near Wells, Nevada, on 21 Feb- slopes at the alluvial-colluvial and bedrock contact. These range-tight rup- ruary 2008 (Smith et al., 2011). Although no surface rupture was reported for tures characterize much of the trace of the Lost River fault zone after the 1983 either the Klamath Falls or Wells earthquakes, Mendoza and Hartzell (2009) Borah Peak earthquake, and many prehistoric ruptures elsewhere in the Basin modeled subsurface vertical deformation of as much as 88 cm on a 6.5 km by and Range. Our challenges with mapping complex ruptures along the JMFZ 4 km fault patch during the Wells earthquake, and radar interferograms indi- serve as a good example of these difficulties: offset along the range-tight trace cate 15–20 cm of vertical surface deformation associated with the event (Bell, can only be measured in a few fortuitous locations, and complete documen- 2011a, 2011b). Even if these moderately sized earthquakes rupture the surface

tation of displacement on complex piedmont ruptures is unlikely, given the (e.g., Mw 6.5 2009 L’Aquila, Italy, earthquake), fault scarps are small and dis- erosional and depositional processes active in the region. Intrabasin faults are continuous and may be difficult to identify a few thousand years in the future. commonly imaged in geophysical studies beneath valley floors in the Basin Although earthquakes of this size are uncommon along large active normal

faults such as the Wasatch fault zone (e.g., Arabasz et al., 1992), they may be 2005) and 38.5°–40°N (Koehler and Wesnousky, 2011). The closest transect, at more characteristic of deformation on smaller faults such as those thought 40°–41°N, resulted in a basin-wide extension rate of ~0.65 mm/yr (60° assumed to be responsible for the Klamath Falls and Wells earthquakes. In addition to fault dip), and the transect at 38.5°–40°N resulted in a basin-wide extension major normal faults that do not offset latest Quaternary deposits (e.g., Pine rate of ~1 mm/yr (also 60° assumed fault dip). These rates were both consid- Forest Range and Hays Canyon Range fault zones), there are dozens of shorter ered minimums, and thus probably are not significantly different than our 60° faults in the NWBR that may have undergone repeated earthquake swarms or dip extension rate estimate of 1.1 mm/yr (Table 3). The similar results indicate

moderate-sized (Mw ~ 6.5) earthquakes during the 15–18 k.y. duration of our that late Quaternary extension may be nearly constant across the Great Basin paleoseismic record. from ~42°N south to at least 38.5°N, although our transect is much shorter, Dike intrusion commonly accompanies normal faulting in active volcanic so deformation appears to be compressed into the northwestern part of the centers such as the Snake River Plain (Kuntz et al., 2002; Holmes et al., 2008), Basin and Range north of 41°. This difference is reflected in the distribution of but may be a possible source of unrecognized deformation if the intrusion late Quaternary faulting in southeastern Oregon, and is expressed in the tec- does not reach the surface. An example of this phenomenon is a mafic dike tonic geomorphology of northeastern Nevada and northwestern Utah east of intruded into an intrabasin fault zone identified with magnetic, gravity, and our transect; most of this region is characterized by broad, undeformed table- seismic reflection data 60 m beneath the floor of Surprise Valley (Athens et al., lands (e.g., Owyhee Plateau) and subdued normal-fault–controlled basins and 2016). This feature is thought to have been intruded ca. 2 Ma and did not reach ranges with little evidence of post-Sehoo deformation (Hecker, 1993; dePolo, the ground surface (Athens et al., 2016). However, given the lack of latest Qua- 2008; U.S. Geological Survey, 2015). ternary volcanic activity in the region (Stewart and Carlson, 1978; Stewart, 1980), diking is probably not a significant source of unrecognized deformation in the transect area. CONCLUSIONS How much of our apparent geologic rate deficit might be attributable to the many possible sources of geologically undetectable deformation? In a In this study we use new and existing paleoseismic data to compile a comparison of seismic, geodetic, and geologic moment rates, Pancha et al. record of ~18 large-magnitude surface-rupturing earthquakes in the past 15– (2006) determined that modern moment rates determined from seismicity and 18 k.y. on 7 fault zones in the NWBR of northwestern Nevada and northeastern geodesy were similar across the Great Basin, but their calculated geologic mo- California. We use the size of surface ruptures and this latest Quaternary time ment rates based on slip rate estimates from inputs to the 1986 and 2002 na- window to estimate vertical slip rates on these fault zones and compared them tional seismic hazard maps (Frankel et al., 1996, 2002; Haller et al., 2002) were to GPS-derived rates of modern extension across the region. The horizontal 37%–65% of geodetic rates of the same region. One possible explanation is extension rates derived from our fault slip rates are particularly sensitive to as- that the fault catalog used in the 1986 and 2002 hazard maps was incomplete, sumed fault dip (Fig. 13A). For example, our preferred fault dip values (45°–55°) as suggested by differences in the catalog used in the 2014 iteration (Petersen yield estimated long-term extension rates (1.3–1.9 mm/yr) that are 54%–79% of et al., 2014a). A second explanation may be related to the Pancha et al. (2006) our extension only modern rate, but fault dip values of 40° or less yield long- determination that 76% of the moment release in the 150 yr history of seis term rates comparable to or greater than our preferred modern rate. These

micity in the region was attributable to 10 large-magnitude (Mw ≥ 6.8) surface- relations may simply mean that actual fault dips are closer to 40° rather than rupturing earthquakes, and 90% of the moment release was attributable to our preferred values. However, we continue to favor steeper fault dips, so we

just 38 earthquakes with magnitudes Mw ≥ 6.1. If these ratios are applicable to conclude that our long-term rate underestimates of ~21%–46% probably are longer time periods (thousands of years), then perhaps 10%–25% of the total attributable to some combination of (1) geologically unrecognizable defor

moment release across our transect may be attributed to geologically unde- mation from moderate-sized (Mw 6.0–6.8) earthquakes; and (2) unobserved

tectable deformation associated with smaller, non-surface-rupturing (Mw < 6.8) off-fault deformation from larger (>Mw 6.8), surface-rupturing earthquakes. earthquakes. Such calculations would nearly eliminate (within 1s uncertain- The observation of Pancha et al. (2006) of a ~25% difference between the mo- ties) the apparent discrepancy between the geodetic and geologic deformation ment released during 10 surface-rupturing earthquakes and total moment in rates for fault dips of 45°–55° (75% and 90% GPS lines in Fig. 13A). the seismic record of the Basin and Range indicate that both of these factors contribute to the differences observed in our analysis. In addition to fault dip uncertainties, remaining questions include the appropriate length of the time DISCUSSION window used to determine representative long-term (paleoseismic) extension rates, and the potential effects of crustal loading and unloading from pluvial Despite some differences in methodology (primarily the length of time win- lake fluctuations. Definitive answers will remain elusive until denser GPS net- dow considered) our paleoseismic transect at lat 41°–42°N appears to yield works are established, and well-constrained earthquake histories and better results similar to those of previous transects at lat 40°–41° (Wesnousky et al., estimates of dip on all faults in our transect are available.

ACKNOWLEDGMENTS Bennett, R.A., Wernicke, B.P., Niemi, N.A., Friedrich, A.M., and Davis, J.L., 2003, Contemporary This research was supported by the Earthquake Hazards Reduction Program of the U.S. Geological strain rates in the northern Basin and Range Province from GPS data: Tectonics, v. 22, 1008, Survey (USGS). We acknowledge the cooperation of the Winnemucca office of the Bureau of Land doi:10.1029/2001TC001355. Management in facilitating research on lands under their jurisdiction in northwestern Nevada. Benson, L., Kashgarian, M., and Rubin, M., 1995, Carbonate deposition, Pyramid Lake subbasin, We also appreciated the cooperation of Surprise Valley, California, landowners Denise and Jim Nevada 2—Lake levels and polar jet stream positions reconstructed from radiocarbon ages Harrower and Bill Duncan for access to their properties. The efforts of many colleagues during and elevations of carbonates (tufas) deposited in the Lahontan basin: Palaeogeography, field and office work (Lee-Ann Bradley, Ernie Anderson, Koji Okumura, Dean Hancock, Michael Palaeoclimatology, Palaeoecology, v. 117, p. 1–30, doi:10.1016/0031-0182(94)00103-F. Machette, Tony Crone, David Lidke, Jai Bok Kyung, Hector Cisneros, Ryan Gold) and discussions Benson, L.V., Smoot, J.P., Lund, S.P., Mensing, S.A., Foit, F.F., Jr., and Rye, R.O., 2013, Insights with Bill Hammond and Craig dePolo are greatly appreciated. The manuscript was improved by from a synthesis of old and new climate-proxy data from the Pyramid and Winnemucca lake USGS reviewers Ryan Gold and Chris DuRoss, Geosphere reviewers Anne Egger and Anka Fried- basins for the period 48 to 11.5 cal ka: Quaternary International, v. 310, p. 62–82, doi:10.1016 rich, and Geosphere Associate Editor Colin Amos. /j.quaint.2012.02.040. Berger, D.L., 1995, Ground-water conditions and effects of mine dewatering in Desert Valley, Humboldt and Pershing Counties, northwestern Nevada, 1962–91: U.S. Geological Survey REFERENCES CITED Water-Resources Investigations Report 95-4119, 94 p. Bills, B.G., Adams, K.D., and Wesnousky, S.G., 2007, Viscosity structure of the crust and upper Abbott, R.E., Louie, J.N., Caskey, S.J., and Pullammanappallil, S., 2001, Geophysical confirma- tion of low-angle normal slip on the historically active Dixie Valley fault, Nevada: Journal of mantle in western Nevada from isostatic rebound patterns of the late Pleistocene Lake Geophysical Research, v. 106, no. B3, p. 4169–4181, doi:10 .1029/2000JB900385. Lahontan high shoreline: Journal of Geophysical Research, v. 112, B06405, doi:10.1029 Adams, K.D., 2010, Lake levels and sedimentary environments during deposition of the Trego /2005JB003941. Hot Springs and Wono tephras in the Lake Lahontan basin, Nevada, USA: Quaternary Re- Bormann, J.M., Hammond, W.C., Kreemer, C., and Blewitt, G., 2016, Accommodation of missing search, v. 73, p. 118–129, doi:10.1016/j.yqres.2009.08.001. shear strain in the Central Walker Lane, western North America: Constraints from dense Adams, K.D., and Wesnousky, S.G., 1998, Shoreline processes and the age of the Lake Lahontan GPS measurements: Earth and Planetary Science Letters, v. 440, p. 169–177, doi:10 .1016/j highstand in the Jessup embayment, Nevada: Geological Society of America Bulletin, v. 110, .epsl.2016.01.015. p. 1318–1332, doi:10.1130/0016-7606(1998)110<1318:SPATAO>2.3.CO;2. Braunmiller, J., Nabelek, J., Leitner, B., and Qamar, W., 1995, The 1993 Klamath Falls, Oregon, Adams, K.D., and Wesnousky, S.G., 1999, The Lake Lahontan highstand: Age, surficial char- earthquake sequence—Source mechanisms from regional data: Geophysical Research Let- acteristics, soil development, and regional shoreline correlation: Geomorphology, v. 30, ters, v. 22, p. 105–108, doi:10.1029/94GL02844. p. 357–392, doi:10.1016/S0169-555X(99) 00031–8. Breuseke, M., Hart, W., and Heizler, M., 2008, Diverse mid-Miocene silicic volcanism associated Anderson, E.M., 1951, The Dynamics of Faulting and Dyke Formation with Applications to Brittan with the Yellowstone–Newberry thermal anomaly: Bulletin of Volcanology, v. 70, p. 343–360, (second edition): Edinburgh, Oliver and Boyd, 206 p. doi:10.1007/s00445-007-0142-5. Anderson, R.E., Zoback, M.L., and Thompson, G.A., 1983, Implications of selected subsurface Bryant, W.A., 1990, Surprise Valley and related faults, Lassen and Modoc Counties: California data on the structural form and evolution of some basins in the northern Basin and Range Division of Mines and Geology Fault Evaluation Report 217, 17 p. province, Nevada and Utah: Geological Society of America Bulletin, v. 94, p. 1055–1072, doi: Buck, W.R., 1988, Flexural rotation of normal faults: Tectonics, v. 7, p. 959–973, doi:10.1029 10.1130/0016-7606(1983)94<1055:IOSSDO>2.0.CO;2. /TC007i005p00959. Arabasz, W.J., Pechmann, J.C., and Brown, E.D., 1992, Observational seismology and the evalu- Caskey, S.J., Wesnousky, S.G., Zhang, P., and Slemmons, D.B., 1996, Surface faulting of the 1954 ation of earthquake hazards and risk in the Wasatch Front area, Utah, in Gori, P.L., and Hays, Fairview Peak (MS 7.2) and Dixie Valley (MS 6.8) earthquakes, central Nevada: Bulletin of the W.W., eds., Assessment of regional earthquake hazards and risk along the Wasatch Front, Seismological Society of America, v. 86, p. 761–787. Utah: U.S. Geological Survey Professional Paper 1500-D, 36 p. Caskey, S.J., Bell, J.W., Ramelli, A.R., and Wesnousky, S.G., 2004, Historic surface faulting and Athens, N.D., Glen, J.M.G., Klemperer, S.L., Egger, A.E., and Fontiveros, V.C., 2016, Hidden intra paleoseismicity in the area of the 1954 Rainbow Mountain–Stillwater earthquake sequence, basin extension: Evidence for dike-fault interaction from magnetic, gravity, and seismic re- central Nevada: Bulletin of the Seismological Society of America, v. 94, p. 1255–1275, doi: flection data in Surprise Valley, northeastern California: Geosphere, v. 12, p. 15–25, doi:10 10.1785/012003012. .1130/GES01173. Cichanski, M., 2000, Low-angle, range-flank faults in the Panamint, Inyo, and Slate ranges, Cali Axen, G.J., 2004, Mechanics of low-angle normal faults, in Karner, G., et al., eds., Rheology fornia: Implications for recent tectonics of the Death Valley region: Geological Society of and Deformation in the Lithosphere at Continental Margins: New York, Columbia University America Bulletin, v. 112, p. 871–883, doi:10.1130/0016-7606 (2000)112<871:LRFITP>2.0.CO;2. Press, p. 46–91, doi:10.7312/karn12738-004. Coble, M.A., and Mahood, G.A., 2016, Geology of the High Rock caldera complex, northwest Barrientos, S.E., Stein, R.S., and Ward, S.N., 1987, Comparison of the 1959 Hebgen Lake, Mon- Nevada, and implications for intense rhyolitic volcanism associated with flood basalt mag- tana and the 1983 Borah Peak, Idaho, earthquakes from geodetic observations: Bulletin of matism and the initiation of the Snake River Plain–Yellowstone trend: Geosphere, v. 12, the Seismological Society of America, v. 77, p. 784–808. p. 58–113, doi:10.1130/GES01162.1. Bell, J.W., 2011a, InSAR reveals new insights into the behavior of seismically active faults in the Colgan, J.P., Dumitru, T.A., and Miller, E.L., 2004, Diachroneity of Basin and Range extension and western Basin and Range: Nevada Water Resources Association Journal, v. 6, p. 241–252. Yellowstone hotspot volcanism in northwestern Nevada: Geology, v. 32, p. 121–124, doi:10 Bell, J.W., 2011b, Interferometric synthetic aperture radar map of the 2008 Wells earthquake, in .1130/G20037.1. dePolo, C.M., and LaPointe, D.D., eds., The 21 February 2008 Mw 6.0 Wells, Nevada Earth- Colgan, J.P., Dumitru, T.A., McWilliams, M., and Miller, E.L., 2006a, Timing of Cenozoic volcanism quake: Nevada Bureau of Mines and Geology Special Publication 36, 521 p. and Basin and Range extension in northwestern Nevada—New constraints from the north- Bell, J.W., dePolo, C.M., Ramelli, A.R., Sarna-Wojcicki, A.M., and Meyer, C.E., 1999, Surface ern Pine Forest Range: Geological Society of America Bulletin, v. 118, p. 126–139, doi:10 faulting and paleoseismic history of the 1932 Cedar Mountain earthquake area, west-central .1130/B25681.1. Nevada, and implications for modern tectonics of the Walker Lane: Geological Society of Colgan, J.P., Dumitru, T.A., Reiners, P.W., Wooden, J.L., and Miller, E.L., 2006b, Cenozoic tectonic America Bulletin, v. 111, p. 791–807, doi:10.1130/0016-7606(1999)111<0791:SFAPHO>2.3.CO;2. evolution of the Basin and Range province in northwestern Nevada: American Journal of Bell, J.W., Caskey, S.J., Ramelli, A.R., and Guerrieri, L., 2004, Pattern and rates of faulting in the Science, v. 306, p. 616–654, doi:10.2475/08.2006.02. central Nevada seismic belt, and paleoseismic evidence for prior beltlike behavior: Bulletin Collettini, C., and Sibson, R.H., 2001, Normal faults, normal friction?: Geology, v. 29, p. 927–930, of the Seismological Society of America, v. 94, p. 1229–1254, doi:10.1785/012003226. doi:10.1130/0091-7613(2001)029<0927:NFNF>2.0.CO;2. Bennett, R.A., Wernicke, B.P., and Davis, J.L., 1998, Continuous GPS measurements of contem- Copley, A., Hollingsworth, J., and Bergman, E., 2012, Constraints on fault and lithosphere rheol- porary deformation across the northern Basin and Range Province: Geophysical Research ogy from the coseismic slip and postseismic afterslip of the 2006 Mw7.0 Mozambique earth- Letters, v. 25, p. 563–566, doi:10.1029/98GL00128. quake: Journal of Geophysical Research, v. 117, B03404, doi:10.1029/2011JB008580.

Couch, R., and Johnson, S., 1986, The Warner Valley earthquake sequence: May and June, 1968: Egger, A.E., and Miller, E.L., 2011, Evolution of the northwestern margin of the Basin and Range: The Ore Bin, v. 30, p. 191–204. The geology and extensional history of the Warner Range and environs, northeastern Cali- Crone, A.J., and Machette, M.N., 1984, Surface faulting accompanying the Borah Peak earth- fornia: Geosphere, v. 7, p. 756–773, doi:10.1130/GES00620.1. quake, central Idaho: Geology, v. 12, p. 664–667, doi:10.1130/0091-7613(1984)12<664: Egger, A.E., Glen, J.M., and Ponce, D.A., 2010, The northwestern margin of the Basin and Range SFATBP>2.0.CO;2. province: Part 2: Structural setting of a developing basin from seismic and potential field Crone, A.J., Machette, M.N., Bonilla, M.G., Lienkaemper, J.J., Pierce, K.L., Scott, W.E., and Buck- data: Tectonophysics, v. 488, p. 150–161, doi:10.1016/j.tecto.2009.05.029. nam, R.C., 1987, Surface faulting accompanying the Borah Peak earthquake and segmenta- Ellis, M.A., Barnes, J.B., and Colgan, J.P., 2014, Geomorphic evidence for enhanced Pliocene– tion of the Lost River fault, central Idaho: Bulletin of the Seismological Society of America, Quaternary faulting in the northwestern Basin and Range: Lithosphere, v. 7, p. 59–72, doi: v. 77, p. 739–770. 10.1130/L401.1.

DeMets, C., and Dixon, T.H., 1999, New kinematic models for Pacific–North America motion from Fenton, C.H., and Bommer, J.J., 2006, The Mw7 Machaze, Mozambique, earthquake of 23 Febru- 3 Ma to present: I. Evidence for steady motion and biases in the NUVEL-1A model: Geophys- ary 2006: Seismological Research Letters, v. 77, p. 426–439, doi:10.1785/gssrl.77.4.426. ical Research Letters, v. 26, p. 1921–1924, doi:10.1029/1999GL900405. Fialko, Y., Sandwell, D., Simons, M., and Rosen, P., 2005, Three-dimensional deformation caused dePolo, C.M., 1998, A reconnaissance technique for estimating the slip rate of normal-slip faults by the Bam, Iran, earthquake and the origin of shallow slip deficit: Nature, v. 435, p. 295–299, in the Great Basin, and application to faults in Nevada, U.S.A. [Ph.D. thesis]: Reno, Univer- doi:10.1038/nature03425. sity of Nevada-Reno, 199 p. Fletcher, J.M., et al., 2014, Assembly of a large earthquake from a complex fault system: Surface dePolo, C.M., 2008, Quaternary faults in Nevada: Nevada Bureau of Mines and Geology Map rupture kinematics of the 4 April 2010 El Mayor–Cucapah (Mexico) Mw 7.2 earthquake: Geo- 167, scale 1:1,000,000. sphere, v. 10, p. 797–827, doi:10.1130/GES00933.1. dePolo, C.M., and Dee, S.M., 2015, Preliminary Quaternary fault and seismicity map of the Vya Fletcher, R.C., and Hallet, B., 1983, Unstable extension of the lithosphere: A mechanical model 1 × 2 degree quadrangle, Nevada: Nevada Bureau of Mines and Geology Open-File Report for basin-and-range structure: Journal of Geophysical Research, v. 88, no. B9, p. 7457–7466, 15-11A, scale 1:250,000. doi:10.1029/JB088iB09p07457. dePolo, C.M., Clark, D.G., Slemmons, D.B., and Aymard, W.H., 1989, Historical Basin and Range Frankel, A., Mueller, C., Barnhard, T., Perkins, D., Leyendecker, E., Dickman, N., Hanson, S., and province surface faulting and fault segmentation, in Schwartz, D.P., and Sibson, R.H., eds., Hopper, M., 1996, National seismic-hazard maps: Documentation June 1996: U.S. Geological Fault Segmentation and Controls of Rupture Initiation and Termination, Proceedings of Survey Open-File Report 96-532, 110 p. Workshop XLV: U.S. Geological Survey Open-File Report 89-315, p. 131–162. Frankel, A.D., et al., 2002, Documentation for the 2002 update of the national seismic hazard Dixon, T.H., Robaudo, S., Lee, J., and Reheis, M.C., 1995, Constraints on present-day Basin and maps: U.S. Geological Survey Open-File Report 2002-420, 33 p. Range deformation from space geodesy: Tectonics, v. 14, p. 755–772, doi:10.1029/95TC00931. Frankel, A.D., et al., 2005, Seismic-hazards maps for the conterminous United States: U.S. Geo- Dodge, R.L., 1982, Seismic and geomorphic history of the Black Rock fault zone, northwest logical Survey Scientific Investigations Map 2883, 5 p., 6 sheets. Nevada [Ph.D. thesis]: Golden, Colorado School of Mines T-2593, 271 p. Friedrich, A.M., Wernicke, B.P., Niemi, N.A., Bennett, R.A., and Davis, J.L., 2003, Comparison of Dohrenwend, J.C., and Moring, B.C., 1991a, Reconnaissance photogeologic map of young faults geodetic and geologic data from the Wasatch region, Utah, and implications for the spectral in the McDermitt 1° by 2° quadrangle, Nevada, Oregon, and Idaho: U.S. Geological Survey character of Earth deformation at periods of 10 to 10 million years: Journal of Geophysical Miscellaneous Field Studies Map MF-2177, scale 1:250,000. Research, v. 108, no. B4, 2199, doi:10.1029/2001JB000682. Dohrenwend, J.C., and Moring, B.C., 1991b, Reconnaissance photogeologic map of young faults Friedrich, A.M., Lee, J., Wernicke, B.P., and Sieh, K., 2004, Geologic context of geodetic data in the Vya 1° by 2° quadrangle, Nevada, Oregon, and California: U.S. Geological Survey across a Basin and Range normal fault, Crescent Valley, Nevada: Tectonics, v. 23, TC2015, Miscellaneous Field Studies Map MF-2174, 1 sheet, scale 1:250,000. doi:10.1029/2003TC001528. Dohrenwend, J.C., McKittrick, M.A., and Moring, B.C., 1991, Reconnaissance photogeologic map Gold, R.D., Briggs, R.W., Personius, S.F., Crone, A.J., Mahan, S.A., and Angster, S.J., 2014, Latest of young faults in the Lovelock 1° by 2° quadrangle, Nevada and California: U.S. Geological Quaternary paleoseismology and evidence of distributed dextral shear along the Mohawk Survey Miscellaneous Field Studies Map MF-2178, scale 1:250,000. Valley fault zone, northern Walker Lane, California: Journal of Geophysical Research, v. 119, Dolan, J.F., and Haravitch, B.D., 2014, How well do surface slip measurements track slip at depth p. 5014–5032, doi:10.1002/2014JB010987. in large strike-slip earthquakes? The importance of fault structural maturity in controlling Gold, R.D., Reitman, N.G., Briggs, R.W., Barnhart, W.D., Hayes, G.P., and Wilson, E., 2015, On- and on-fault slip versus off-fault surface deformation: Earth and Planetary Science Letters, v. 388, off-fault deformation associated with the September 2013 Mw 7.7 Balochistan earthquake: p. 38–47, doi:10.1016/j.epsl.2013.11.043. Implications for geologic slip rate measurements: Tectonophysics, v. 660, p. 65–78, doi:10 Doser, D.I., 1986, Earthquake processes in the Rainbow Mountain–Fairview Peak–Dixie Valley, .1016/j.tecto.2015.08.019. Nevada region, 1954–1959: Journal of Geophysical Research, v. 91, no. B12, p. 12,572– Grauch, V.J.S., and Hudson, M.R., 2007, Guides to understanding the aeromagnetic expression 12,586, doi:10.1029/JB091iB12p12572. of faults in sedimentary basins: Lessons learned from the central Rio Grande rift, New Mex- Doser, D.I., 1988, Source mechanisms of earthquakes in the Nevada seismic zone (1915–1943): Jour- ico: Geosphere, v. 3, p. 596–623, doi:10.1130/GES00128.1. nal of Geophysical Research, v. 93, no. B12, p. 15,001–15,015, doi:10 .1029 /JB093iB12p15001 . Gupta, H.K., 2002, A review of recent studies of triggered earthquakes by artificial water reser- Doser, D.I., and Smith, R.B., 1985, Source parameters of the 28 October 1983 Borah Peak, Idaho, voirs with special emphasis on earthquakes in Koyna, India: Earth-Science Reviews, v. 58, earthquake from body wave analysis: Bulletin of the Seismological Society of America, v. 75, p. 279–310, doi:10.1016/S0012-8252(02)00063-6. p. 1041–1051. Haller, K.M., Wheeler, R.L., and Rukstales, K.S., 2002, Documentation of changes in fault param Doser, D.I., and Smith, R.B., 1989, An assessment of source parameters of earthquakes in the eters for the 2002 National seismic hazard maps–conterminous United States except Cali- Cordillera of the western United States: Bulletin of the Seismological Society of America, fornia: U.S. Geological Survey Open-File Report 2002-467, 32 p. v. 79, no. 5, p. 1383–1409. Hammond, W.C., and Thatcher, W., 2004, Contemporary tectonic deformation of the Basin Dreger, D., Ritsema, J., and Pasyanos, M., 1995, Broadband analysis of the 21 September, 1993 and Range province, western United States: 10 years of observation with the Global Klamath Falls earthquake sequence: Geophysical Research Letters, v. 22, p. 997–1000, doi: Positioning System: Journal of Geophysical Research, v. 109, B08403, doi:10 .1029 10.1029/95GL00566. /2003JB002746. Du, Y., Aydin, A., and Segall, P., 1992, Comparison of various inversion techniques as applied to Hammond, W.C., and Thatcher, W., 2005, Northwest Basin and Range tectonic deformation ob- the determination of a geophysical deformation model for the 1983 Borah Peak earthquake: served with the Global Positioning System, 1999–2003: Journal of Geophysical Research, Bulletin of the Seismological Society of America, v. 82, p. 1840–1866. v. 110, B10405, doi:10.1029/2005JB003678. Egger, A.E., 2014, Paleoearthquake magnitudes derived from lidar-based mapping of fault scarps Hammond, W.C., and Thatcher, W., 2007, Crustal deformation across the Sierra Nevada, north- in the northwestern Basin and Range: Geological Society of America Abstracts with Pro- ern Walker Lane, Basin and Range transition, western United States measured with GPS, grams, v. 46, no. 6, p. 777. 2000–2004: Journal of Geophysical Research, v. 112, B05411, doi:10.1029/2006JB004625.

Hampel, A., and Hetzel, R., 2006, Response of normal faults to glacial-interglacial fluctuations of volcanic plateaus: Geochemistry, Geophysics, Geosystems, v. 8, Q02011, doi:10.1029 ice and water masses on Earth’s surface: Journal of Geophysical Research, v. 111, B06406, /2006GC001429. doi:10.1029/2005JB004124. Lerch, D.W., Miller, E., McWilliams, M., and Colgan, J., 2008, Tectonic and magmatic evolution Hanks, T.C., and Kanamori, H., 1979, A moment magnitude scale: Journal of Geophysical Re- of the northwestern Basin and Range and its transition to unextended volcanic plateaus: search, v. 84, no. B5, p. 2348–2350, doi:10.1029/JB084iB05p02348. Black Rock Range, Nevada: Geological Society of America Bulletin, v. 120, p. 300–311, doi: Hart, W.K., and Carlson, R.W., 1985, Distribution and geochronology of Steens Mountain–type 10.1130/B26151.1. basalts from the northwestern Great Basin: Isochron-West, v. 43, p. 5–10. Lerch, D.W., Klemperer, S.L., Egger, A.E., Colgan, J.P., and Miller, E.L., 2010, The northwestern Hayman, N.W., Knott, J.R., Cowan, D.S., Nemser, E., and Sarna-Wojcicki, A.M., 2004, Quaternary margin of the Basin-and-Range Province, part 1: Reflection profiling of the moderate-angle low-angle slip on detachment faults in Death Valley, California: Geology, v. 31, p. 343–346, (~30°): Surprise Valley fault: Tectonophysics, v. 488, p. 143–149, doi:10.1016/j .tecto.2009.05 doi:10.1130/0091-7613(2003)031<0343:QLASOD>2.0.CO;2. .028. Hecker, S., 1993, Quaternary tectonics of Utah with emphasis on earthquake-hazard characteriza- Maher, K.A., 1989, Geology of the Jackson Mountains, northwest Nevada [Ph.D. thesis]: Pasa- tion: Utah Geological Survey Bulletin 127, 157 p., 6 plates, scale 1:500,000. dena, California Institute of Technology, 491 p. Hedel, C.W., 1980, Late Quaternary faulting in western Surprise Valley, Modoc County, California Marion, B.N., 2016, Spatiotemporal slip rate variations along Surprise Valley fault in relation [M.S. thesis]: San Jose, California, San Jose State University, 113 p. to Pleistocene pluvial lakes [M.S. thesis]: Ellensburg, Central Washington University, 59 p. Hedel, C.W., 1984, Maps showing geomorphic and geologic evidence for late Quaternary dis- McCalpin, J.P., 2009, Paleoseismology (second edition): International Geophysics Volume 95: placement along the Surprise Valley and associated faults, Modoc County, California: U.S. Oxford, Elsevier, 613 p., doi:10.1016/B978-0-12-374266-7.09984-4. Geological Survey Miscellaneous Field Studies Map MF-1429, scale 1:62,500. McClymont, A.F., Villamor, P., and Green, A.G., 2009, Assessing the contribution of off-fault defor Hemphill-Haley, M.A., and Weldon, R.J., II, 1999, Estimating prehistoric earthquake magnitude mation to slip-rate estimates within the Taupo Rift, New Zealand, using 3-D ground-pene- from point measurements of surface rupture: Bulletin of the Seismological Society of Amer- trating radar surveying and trenching: Terra Nova, v. 21, p. 446–451, doi:10 .1111/j.1365-3121 ica, v. 89, p. 1264–1279. .2009.00901.x. Hetland, E.A., and Hager, B.H., 2003, Postseismic relaxation across the central Nevada seismic Mendoza, C., and Hartzell, S., 2009, Source analysis using regional empirical Green’s functions: belt: Journal of Geophysical Research, v. 108, no. B8, 2394, doi:10.1029/2002JB002257. The 2008 Wells, Nevada, earthquake: Geophysical Research Letters, v. 36, L11302, doi:10 Hetzel, R., and Hampel, A., 2005, Slip rate variations on normal faults during glacial-interglacial .1029/2009GL038073. changes in surface loads: Nature, v. 435, p. 81–84, doi:10.1038/nature03562. Mendoza, C., and Hartzell, S.H., 1988, Inversion for slip distribution using teleseismic P wave- Hodgkinson, K.M., Stein, R.S., and King, G.C., 1996, The 1954 Rainbow Mountain–Fairview Peak– forms: North Palm Springs, Borah Peak, and Michoacan earthquakes: Bulletin of the Seismo- Dixie Valley earthquakes: A triggered normal faulting sequence: Journal of Geophysical Re- logical Society of America, v. 78, no. 3, p. 1092–1111. search, v. 101, no. B11, p. 25,459–25,471, doi:10.1029/96JB01302. Michetti, A.M., and Wesnousky, S.G., 1993, Holocene surface faulting along the west flank of Holmes, A.A.J., Rodgers, D.W., and Hughes, S.S., 2008, Kinematic analysis of fractures in the the Santa Rosa Range (Nevada-Oregon) and the possible northern extension of the central Great Rift, Idaho: Implications for subsurface dike geometry, crustal extension, and magma Nevada seismic belt: Geological Society of America Abstracts with Programs, v. 25, no. 5, dynamics: Journal of Geophysical Research, v. 113, B04202, doi:10.1029/2006JB004782. p. 120–121. Ibarra, D.E., Egger, A.E., Weaver, K.L., Harris, C.R., and Maher, K., 2014, Rise and fall of late Mifflin, M.D., and Wheat, M.M., 1979, Pluvial lakes and estimated pluvial climates of Nevada: Pleistocene pluvial lakes in response to reduced evaporation and precipitation: Evidence Nevada Bureau of Mines and Geology Bulletin 94, 57 p. from Lake Surprise, California: Geological Society of America Bulletin, v. 126, p. 1387–1415, Narwold, C.F., 2001, Late Quaternary soils and faulting along the Quinn River fault zone, northern doi:10.1130/B31014.1. Nevada, southeastern Oregon [M.S. thesis]: Arcata, California, Humboldt State University, Irwin, R.P., III, and Zimbelman, J.R., 2012, Morphometry of Great Basin pluvial shore landforms— 76 p. Implications for paleolake basins on Mars: Journal of Geophysical Research, v. 117, E07004, Narwold, C.F., and Pezzopane, S.K., 1997, Preliminary analysis of late Quaternary faulting along doi:10.1029/2012JE004046. the Quinn River fault zone, northern Nevada–southeastern Oregon: Geological Society of Jackson, J.A., and White, N.J., 1989, Normal faulting in the upper continental crust—Observa- America Abstracts with Programs, v. 29, no. 6, p. A-323. tions from regions of active extension: Journal of Structural Geology, v. 11, p. 15–36, doi:10 Noble, D.C., McKee, E.H., Smith, J.G., and Korringa, M.K., 1970, Stratigraphy and geochronology .1016/0191-8141(89)90033-3. of Miocene volcanic rocks in northwestern Nevada, in Geological Survey Research 1979: Jaeger, J.G., and Cook, N.G.W., 1979, Fundamentals of Rock Mechanics (third edition): London, U.S. Geological Survey Professional Paper 700-D, p. D23–D32. Chapman and Hall, 585 p. Numelin, T., Kirby, E., Walker, J.D., and Didericksen, B., 2007, Late Pleistocene slip on a low-angle Jones, C.H., Unruh, J.R., and Sonder, L.J., 1996, The role of gravitational potential energy in normal fault, Searles Valley, California: Geosphere, v. 3, p. 163–176, doi:10 .1130/GES00052.1. active deformation in the southwestern United States: Nature, v. 381, p. 37–41, doi:10 .1038 Okaya, D.A., and Thompson, G.A., 1985, Geometry of Cenozoic extensional faulting—Dixie Val- /381037a0. ley, Nevada: Tectonics, v. 4, p. 107–125, doi:10.1029/TC004i001p00107. Karow, T., and Hampel, A., 2010, Slip rate variations on faults in the Basin and Range province Pancha, A., Anderson, J.G., and Kreemer, C., 2006, Comparison of seismic and geodetic scalar caused by regression of late Pleistocene Lake Bonneville and Lake Lahontan: International moment rates across the Basin and Range province: Bulletin of the Seismological Society of Journal of Earth Sciences, v. 99, p. 1941–1953, doi:10.1007/s00531-009-0496-3. America, v. 96, p. 11–32, doi:10.1785/0120040166. Koehler, R.D., and Wesnousky, S.G., 2011, Late Pleistocene regional extension rate derived from Patton, H.J., and Zandt, G., 1991, Seismic moment tensors of western U.S. earthquakes and earthquake geology of late Quaternary faults across the Great Basin, Nevada, between 38.5 implications for the tectonic stress field: Journal of Geophysical Research, v. 96, no. B11, N and 40 N latitude: Geological Society of America Bulletin, v. 123, p. 631–650, doi:10.1130 p. 18,245–18,259, doi:10.1029/91JB01838. /B30111.1. Payne, S.J., Zollweg, J.E., and Rodgers, D.W., 2004, Stress triggering of conjugate normal fault- Kuntz, M.A., Anderson, S.R., Champion, D.E., Lanphere, M.A., and Grunwald, D.J., 2002, Tension ing—Late aftershocks of the 1983 Ms 7.3 Borah Peak, Idaho, earthquake: Bulletin of the Seis- cracks, eruptive fissures, dike, and faults related to late Pleistocene–Holocene basaltic vol- mological Society of America, v. 94, p. 828–844, doi:10.1785/0120030122. canism and implications for the distribution of hydraulic conductivity in the eastern Snake Payne, S.J., McCaffrey, R., King, R.W., and Kattenhorn, S.A., 2012, A new interpretation of defor River Plain, Idaho, in Link, P.K., and Mink, L.L., eds., Geology, Hydrogeology, and Environ- mation rates in the Snake River Plain and adjacent basin and range regions based on GPS mental Remediation: Idaho National Engineering and Environmental Laboratory, Eastern measurements: Geophysical Journal International, v. 189, p. 101–122, doi:10 .1111/j.1365 Snake River Plain, Idaho: Geological Society of America Special Paper 353, p. 111–133, doi: -246X.2012.05370.x. 10.1130/0-8137-2353-1.111. Personius, S.F., and Mahan, S.A., 2005, Unusually low rates of slip on the Santa Rosa Range fault Lerch, D.W., Klemperer, S.L., Glen, J.M.G., Ponce, D.A., Miller, E., and Colgan, J., 2007, Crustal zone, northern Nevada: Bulletin of the Seismological Society of America, v. 95, p. 319–333, structure of the northwestern Basin and Range Province and its transition to unextended doi:10.1785/0120040001.

Personius, S.F., Anderson, R.E., Okumura, K., Mahan, S.A., and Hancock, D.A., 2004, Logs and Data Simons, M., Fialko, Y., and Rivera, L., 2002, Coseismic deformation from the 1999 Mw 7.1 Hector from an Investigation of the Orovada Trench Site, Santa Rosa Range Fault Zone, Humboldt Mine, California, earthquake as inferred from InSAR and GPS observations: Bulletin of the County, Nevada: U.S. Geological Survey Scientific Investigations Map 2815, scale 1:500,000. Seismological Society of America, v. 92, p. 1390–1402, doi:10.1785/0120000933. Personius, S.F., Crone, A.J., Machette, M.N., Kyung, J.B., Cisneros, H., Lidke, D.J., and Mahan, Sinclair, W.C., 1962, Ground-Water Resources of Desert Valley, Humboldt and Pershing Counties, S.A., 2006, Trench Logs and Scarp Data from an Investigation of the Steens Fault Zone, Bog Nevada: Nevada Division of Water Resources, Ground-Water Resources Reconnaissance Hot Valley and Pueblo Valley, Humboldt County, Nevada: U.S. Geological Survey Scientific Report 7, 23 p. Investigations Map 2952, http://pubs.usgs.gov/sim/2006/2952/. Slemmons, D.B., 1957, Geological effects of the Dixie Valley–Fairview Peak, Nevada, earth- Personius, S.F., Crone, A.J., Machette, M.N., Lidke, D.J., Bradley, L.-A., and Mahan, S.A., 2007a, quakes of December 16, 1954: Bulletin of the Seismological Society of America, v. 47, Logs and Scarp Data from a Paleoseismic Investigation of the Surprise Valley Fault Zone, p. 353–375. Modoc County, California: U.S. Geological Survey Scientific Investigations Map 2983, http:// Smith, K., Pechmann, J., Meremonte, M., and Pankow, K., 2011, Preliminary analysis of the Mw pubs.usgs.gov/sim/2983/. 6.0 Wells, Nevada, earthquake sequence, in dePolo, C.M., and LaPointe, D.D., eds., The 21 Personius, S.F., Crone, A.J., Machette, M.N., Mahan, S.A., Kyung, J.B., Cisneros, H., and Lidke, D.J., February 2008 Mw 6.0 Wells, Nevada Earthquake: A Compendium of Earthquake-Related 2007b, Late Quaternary paleoseismology of the southern Steens fault zone, northern Nevada: Investigations Prepared by the University of Nevada, Reno: Nevada Bureau of Mines and Bulletin of the Seismological Society of America, v. 97, p. 1662–1678, doi:10 .1785 /0120060202 . Geology Special Publication 36, p. 127–145. Personius, S.F., Crone, A.J., Machette, M.N., Mahan, S.A., and Lidke, D.J., 2009, Moderate rates Smith, R.B., and Lindh, A.G., 1978, Fault-plane solutions of the Western United States—A compi- of late Quaternary slip along the northwestern margin of the Basin and Range province, Sur- lation, in Smith, R.B., and Eaton, G.P., eds., Cenozoic Tectonics and Regional Geophysics of prise Valley fault, northeastern California: Journal of Geophysical Research, v. 114, B09405, the Western Cordillera: Geological Society of America Memoir 152, p. 107–110, doi:10 .1130 doi:10.1029/2008jb006164. /MEM152-p107. Petersen, M.D., et al., 2014a, The 2014 U.S. National Seismic Hazard Maps: A Summary of Smith, R.B., Nagy, W.C., Julander, K.A., Viveireos, J.J., Barker, C.A., and Gants, D.G., 1989, Geo- Changes to Seismic Source and Ground Motion Models: Proceedings of the 10th National physical and tectonic framework of the eastern Basin and Range: Colorado Plateau–Rocky Conference in Earthquake Engineering: Anchorage, Alaska, Earthquake Engineering Re- Mountain transition, in Pakiser, L.C., and Mooney, W.D., eds., Geophysical Framework of the search Institute, 11 p. Continental United States: Geological Society of America Memoir 172 , p. 205–234, doi:10 Petersen, M.D., Zeng, Y., Haller, K.M., McCaffrey, R., Hammond, W.C., Bird, P., Moschetti, M., and .1130/MEM172-p205. Thatcher, W., 2014b, Geodesy- and Geology-Based Slip-Rate Models for the Western United Snyder, C.T., Hardman, G., and Zdenek, F.F., 1964, Pleistocene Lakes in the Great Basin: U.S. Geo- States (Excluding California) National Seismic Hazard Maps: U.S. Geological Survey Open- logical Survey Miscellaneous Geologic Investigations Map I-416, scale 1:1,000,000. File Report 2013-1293, 80 p., doi:10.3133/ofr20131293. Sonder, L.J., and Jones, C.H., 1999, Western United States extension: How the west was wid- Pezzopane, S.K., and Weldon, R.J., 1993, Tectonic role of active faulting in central Oregon: Tec- ened: Annual Review of Earth and Planetary Sciences, v. 27, p. 417–462, doi:10.1146/annurev tonics, v. 12, p. 1140–1169, doi:10.1029/92TC02950. .earth.27.1.417. Ponce, D.A., and Plouff, D., 2001, Bouguer Gravity Map of Nevada: Vya Sheet: Nevada Bureau of Stein, R.S., and Barrientos, S.E., 1985, Planar high-angle faulting in the Basin and Range—Geo- Mines and Geology Geologic Map 128, scale 1:250,000. detic analysis of the 1983 Borah Peak, Idaho, earthquake: Journal of Geophysical Research, Quinn, M.J., Wright, J.E., and Wyld, S.J., 1997, Happy Creek igneous complex and tectonic evo- v. 90, no. B13, p. 11,355–11,366, doi:10.1029/JB090iB13p11355. lution of the early Mesozoic arc in the Jackson Mountains, northwest Nevada: Geological Stephenson, W.J., Odum, J.K., Williams, R.A., McBride, J.H., and Tomlinson, I., 2012, Charac- Society of America Bulletin, v. 109, no. 4, p. 461–482, doi:10.1130/0016-7606(1997)109<0461: terization of intrabasin faulting and deformation for earthquake hazards in southern Utah HCICAT>2.3.CO;2. Valley, Utah, from high-resolution seismic imaging: Bulletin of the Seismological Society of Reheis, M., 1999, Extent of Pleistocene Lakes in the Western Great Basin: U.S. Geological Survey America, v. 102, p. 524–540, doi:10.1785/0120110053. Miscellaneous Field Investigations Map MF-2323, scale 1:800,000. Stewart, J.H., 1971, Basin and Range structure: A system of horsts and grabens produced by Reheis, M.C., Adams, K.A., Oviatt, C.G., and Bacon, S.N., 2014, Pluvial lakes in the Great Basin deep-seated extension: Geological Society of America Bulletin, v. 82, p. 1019–1044, doi:10 of the western United States—A view from the outcrop: Quaternary Science Reviews, v. 97, .1130/0016-7606(1971)82[1019:BARSAS]2.0.CO;2. p. 33–57, doi:10.1016/j.quascirev.2014.04.012. Stewart, J.H., 1978, Basin-range structure in western North America—A review, in Smith, R.B., Richins, W.D., 1974, Earthquake swarm near Denio, Nevada, February to April, 1973 [M.S. thesis]: and Eaton, G.P., eds., Cenozoic Tectonics and Regional Geophysics of the Western Cordillera: Reno, University of Nevada–Reno, 57 p. Geological Society of America Memoir 152, p. 1–32, doi:10.1130/MEM152-p1. Richins, W.D., Pechmann, J.C., Smith, R.B., Langer, C.J., Goter, S.K., Zollweg, J.E., and King, J.J., Stewart, J.H., 1980, The Geology of Nevada: Nevada Bureau of Mines and Geology Special Pub- 1987, The 1983 Borah Peak, Idaho, earthquake and its aftershocks: Bulletin of the Seismologi lication 4, 136 p. cal Society of America, v. 77, p. 694–723. Stewart, J.H., and Carlson, J.E., compilers, 1978, Geologic Map of Nevada: U.S. Geological Sur- Rockwell, T.K., and Klinger, Y., 2013, Surface rupture and slip distribution of the 1940 Imperial vey, scale 1:500,000. Valley earthquake, Imperial Fault, Southern California; implications for rupture segmenta- Thatcher, W., 2003, GPS constraints on the kinematics of continental deformation: International tion and dynamics: Bulletin of the Seismological Society of America, v. 103, p. 629–640, doi: Geology Review, v. 45, p. 191–212, doi:10.2747/0020-6814.45.3.191. 10.1785/0120120192. Thatcher, W., and Hill, D.P., 1991, Fault orientations in extensional and conjugate strike-slip Rockwell, T.K., Lindvall, S., Dawson, T., Langridge, R., Lettis, W., and Klinger, Y., 2002, Lateral offsets environments and their implications: Geology, v. 19, p. 1116–1120, doi:10 .1130/0091-7613 on surveyed cultural features resulting from the 1999 Izmit and Duzce earthquakes, Turkey: (1991)019<1116:FOIEAC>2.3.CO;2. Bulletin of the Seismological Society of America, v. 92, p. 79–94, doi:10 .1785 /0120000809 . Thatcher, W., Foulger, G.R., Julian, B.R., Svarc, J., Quity, E., and Bawden, G.W., 1999, Present day Romney, C., 1957, Seismic waves from the Dixie Valley–Fairview Peak earthquakes: Bulletin of the deformation across the Basin and Range province, western United States: Science, v. 283, Seismological Society of America, v. 47, p. 301–319. p. 1714–1718, doi:10.1126/science.283.5408.1714. Ruhl, C.J., Smith, K.D., Kent, G.M., and Rennie, T., 2015, Persistent seismicity at Sheldon National Thompson, R.S., Benson, L., and Hattori, E.M., 1986, A revised chronology for the last Pleisto- Wildlife Refuge, northwest Nevada [abs.]: Seismological Research Letters, v. 86, p. 655, doi: cene lake cycle in the central Lahontan Basin: Quaternary Research, v. 25, p. 1–9, doi:10.1016 10.1785/0220150017. /0033-5894(86)90039-6. Schaff, S.C., 1976, The 1968 Adel, Oregon, earthquake swarm [M.S. thesis]: Reno, University of U.S. Geological Survey, 2015, Quaternary Fault and Fold Database of the United States: http:// Nevada–Reno, 63 p. earthquake.usgs.gov/hazards/qfaults/ (accessed June 2015). Shelef, E., and Oskin, M., 2010, Deformation processes adjacent to active faults: Examples Wallace, R.E., 1984, Patterns and timing of late Quaternary faulting in the Great Basin province from eastern California: Journal of Geophysical Research, v. 115, B05308, doi:10 .1029 and relation to some regional tectonic features: Journal of Geophysical Research, v. 89, /2009JB006289. p. 5763–5769, doi:10.1029/JB089iB07p05763.

Wallace, R.E., 1987, Grouping and migration of surface faulting and variations in slip rates on Wesnousky, S.G., 2008, Displacement and geometrical characteristics of earthquake surface faults in the Great Basin province: Bulletin of the Seismological Society of America, v. 77, ruptures: Issues and implications for seismic hazard analysis and the process of earthquake p. 868–876. rupture: Bulletin of the Seismological Society of America, v. 98, p. 1609–1632, doi:10.1785 Ward, S.N., and Barrientos, S.E., 1986, An inversion for slip distribution and fault shape from /0120070111. geodetic observations of the 1983, Borah Peak, Idaho, earthquake: Journal of Geophysical Wesnousky, S.G., and Willoughby, C.H., 2003, Neotectonic note: The Ruby–East Humboldt Research, v. 91, no. B5, p. 4909–4919, doi:10.1029/JB091iB05p04909. Range, northeastern Nevada: Bulletin of the Seismological Society of America, v. 93, Wells, D.L., and Coppersmith, K.J., 1994, New empirical relationships among magnitude, rupture p. 1345–1354, doi:10.1785/0120020032. length, rupture width, rupture area and surface displacement: Bulletin of the Seismological Wesnousky, S.G., Barron, A.D., Briggs, R.W., Caskey, S.J., Kumar, S., and Owen, L., 2005, Paleo Society of America, v. 84, p. 974–1002. seismic transect across the northern Great Basin: Journal of Geophysical Research, v. 110, Wernicke, B., 1995, Low-angle normal faults and seismicity: A review: Journal of Geophysical B05408, doi:10.1029/2004JB003283. Research, v. 100, p. 20,159–20,174, doi:10.1029/95JB01911. Willden, R., 1964, Geology and Mineral Deposits of Humboldt County, Nevada: Nevada Bureau Wernicke, B.P., 1992, Cenozoic extensional tectonics of the Cordillera, U.S., in Burchfiel, B., of Mines and Geology Bulletin 59, 154 p. et al., eds., The Cordilleran Orogen: Conterminous U.S.: Boulder, Colorado, Geological Zdanowicz, C.M., Zielinski, G.A., and Germani, M.S., 1999, Mount Mazama eruption: Calendrical Society of America, The Geology of North America, v. G-3, p. 553–582, doi:10.1130/DNAG age verified and atmospheric impact assessed: Geology, v. 27, p. 621–624, doi:10 .1130/0091 -GNA-G3.553. -7613(1999)027<0621:MMECAV>2.3.CO;2.