Late Quaternary Activity Along the Lone Pine Fault, Eastern California

Late Quaternary activity along the Lone Pine fault, eastern California

LESTER K.C. LUBETKIN U.S. Forest Service, Eldorado National Forest, Placerville, California 95667 MALCOLM M. CLARK U.S. Geological Survey, Menlo Park, California 94025

ABSTRACT

The Lone Pine fault is a north-trending secondary break of the Owens Valley fault zone, 1.4 km west of Lone Pine, California. This fault forms an east-facing scarp as much as 6.5 m high across an abandoned outwash fan of the Tioga (latest Pleistocene) glaciation. The fault experienced large right-lateral and smaller vertical displacement during the 1872 Owens Valley earthquake. Knowledge of the character and amount of slip at this site in and before 1872 is necessary for evaluations of earthquake hazard near Owens Valley and may help us to understand earthquakes along other parts of the eastern front of the Sierra Nevada and in the Great Basin. Scarp profiles indicate a 1- to 2-m component of dip slip in 1872; thus three 1872-type earthquakes could have created the scarp. This number of events is also indicated by desert-varnish patterns on boulders in the fault scarp, by scarp morphology, and by sediments near the fault. Horizontal offset of a relict channel on the fan is 12 to 18 m (3 earthquakes). Horizontal offset of a younger debris flow is 10 to 12 m (apparently 2 earthquakes). Average horizontal offset for each earthquake, including that of 1872, is 4 to 6 m. The age of the fan surface is bracketed by a 21 ka shoreline of former Lake Owens and by the time of abandonment of the fan, about 10 ka. An average recurrence interval for 3 earthquakes is 5,000 to 10,500 yr. The average recurrence interval, combined with the average oblique offset for each event of 4.3 to 6.3 m, gives an average late Quaternary slip rate of 0.4 to 1.3 mm/yr for the Lone Pine fault. If we add the average horizontal-slip component for the Lone Pine fault to the 1872 horizontal slip reported for the adjacent main Owens Valley trace of 2.7 to 4.9 m, the combined 1872 horizontal-slip component for the Owens Valley fault zone is approximately between 7 and 11 m, a large value. The associated horizontal-slip rate for the Owens Valley fault zone is 0.7 to 2.2 mm/yr.

INTRODUCTION

The great earthquake of March 26, 1872, in Owens Valley was one of the three largest historic shocks in California. The earthquake was associated with extensive strike-slip and oblique-slip surface faulting along Figure 1. Location of Owens Valley fault zone, Lone Pine fault, the Owens Valley fault zone in eastern California (Fig. 1) and caused and other faults that comprise the Owens Valley fault zone near Lone strong ground shaking throughout a vast region (Oakeshott and others, Pine. Ball on downthrown side of fault scarps; faults dashed where 1972). Little has been published about the surface ruptures of 1872 and approximately located. Star identifies 14C sample site (USGS 609). previous late Quaternary faulting in this region, however. Several geolo- gists made limited observations of the surface rupture during the 35 yr after Valley fault zone south of Big Pine (Martel, 1984; Martel and others, the earthquake (Whitney, 1872; Gilbert, 1884; Hobbs, 1910). More recent 1987). No earlier investigations, however, have concentrated on either investigations classified patterns of 1872 and earlier faulting in Owens total 1872 displacement or horizontal displacement from earlier earth- Valley (Slemmons and Cluff, 1968; Carver and others, 1969), verified quakes along the Owens Valley fault zone. In 1985-1986, Sarah Beanland reported 1872 right slip of about 4 m (Bateman, 1961; Bonilla,1968), and completed a comprehensive field study of the entire 1872 rupture and the analyzed 1872 and earlier normal faulting on a branch of the Owens Owens Valley fault zone (Zoback and Beanland, 1986; Beanland and

Geological Society of America Bulletin, v. 100, p. 755-766,12 figs., 2 tables, May 1988.

755 756 LUBETKIN AND CLARK

Clark, 1987). Indeed, the prominent scarp that is the subject of our report the age of the fan, we determine average earthquake recurrence intervals of was widely and incorrectly identified to be the result of displacement 5,000 to 10,500 yr and slip rates of 0.4 to 1.3 mm/yr for this part of the solely in 1872 (for example, Hobbs, 1910; Townley and Allen, 1939; Lone Pine fault, and estimate a horizontal slip rate of 0.7 to 2.2 mm/yr for Richter, 1958, p. 502), although its origin from at least three earthquakes the Owens Valley fault zone near Lone Pine. was later noted by D. B. Slemmons and his students (Oakeshott and The Owens Valley fault zone near the town of Lone Pine consists of a others, 1972, p. 56). Furthermore, earlier emphasis on the dip-slip compo- main trace and many branch and secondary traces (Fig. 1). The main fault nent along this scarp has obscured the fact of dominant strike slip along trace, called the "Owens Valley fault" in this report, extends across the this scarp, the 1872 rupture, and the Owens Valley fault zone. Knowl- western part of Lone Pine and forms the east side of Diaz Lake to the edge of the character and amount of slip in 1872 and during earlier south. Prominent secondary traces lie as much as 1.4 km west of the main earthquakes is necessary for evaluation of seismic hazard near Owens trace at Lone Pine and extend discontinuously to Diaz Lake. Lubetkin Valley and also may be of value in assessing slip rates and recurrence (1980) informally named the most westerly of these prominent secondary intervals for other faults along the eastern front of the Sierra Nevada and faults the "Lone Pine fault." elsewhere in the Great Basin. Scarps of the Lone Pine fault across the surface of the abandoned fan This study focuses on late Quaternary activity along the Lone Pine of Lone Pine Creek (Fig. 2) locally reach as high as 6.5 m. The most fault, a major strand of the Owens Valley fault zone. We investigated the conspicuous scarp forms the west side of a 100-m-wide graben across the prominent scarp of this fault across an abandoned fan of Lone Pine Creek. lower part of the fan. Other scarps, facing both east and west, cross higher This scarp and fan surface preserve some of the clearest evidence in the parts of the fan. Owens Valley fault zone of 1872 and earlier oblique displacement. Our Two large former channels of Lone Pine Creek (LPC 2 and 3, Fig. 2) analysis starts with estimates of the 1872 dip-slip component of displace- incise the fan and are cut by the conspicuous scarp at the west side of the ment, which we then compare to the total dip-slip component recorded by graben. LPC 2 is the younger. It cuts across the head of LPC 3 and was the scarp to determine that three 1872-sized earthquakes formed the scarp. active until abandonment of the fan. The fan surface is now inactive except We determine the larger horizontal component of offset from a channel for minor local runoff in the old channels, on-going encroachment of and a debris flow that are offset at the scarp. Finally, from our estimate of locally derived colluvium along the western and northwestern margins,

EXPLANATION Figure 2. Geologic map showing scarp of Lone Pine I Alluvium (Holocene) - Predominantly derived fault across abandoned fan of Lone Pine Creek. LPC 2 and tÜÜJ from Sierra Nevada LPC 3 are former channels of Lone Pine Creek. Location « • .1 Alluvium and colluvium (Holocene) - Derived U-iJ from Alabama Hills shown on Figure 1. __ Alluvial fan (Pleistocene) - Composed fcfol predominantly of glacial outwash from Sierra Nevada Metavolcanic rocks (Triassic) contact, dashed where \ approximately located

terrace, dashed line at crest of channel band, hachures point downslope Abandoned channel of Lone Pine Creek

w 1)! îî?®)! : ; ; If?:1: : : :??pa i W^ Figure 3. Idealized profile of fault scarp; modified from Wallace (1977). LATE QUATERNARY ACTIVITY, LONE PINE FAULT, CALIFORNIA 757 and infrequent debris flows derived from the hills of metamorphic rock portion is the modified scarp remnant from one or more older slip events. north of LPC 2 (Fig. 2). The lower concave portion is a sedimentary apron that conceals the origi- The channel of LPC 2 was active after at least one event of faulting. It nal fault scarp and consists of colluvium from the upper part of the scarp is more deeply incised than the other relict channels and has deposited a and wash deposits derived from the scarp and colluvium. fan in the northern part of the graben in response to faulting. This fan in The fault scarp is the modified surface expression of the fault plane. the graben and the channel of LPC 2 are now partly covered with a veneer The originally exposed fault surface is no longer completely preserved, of post-abandonment metamorphic debris. hence the position and dip of the fault plane cannot be directly measured without subsurface exposures. Natural and artificial exposures of the 1872 COMPONENT OF DIP SLIP Owens Valley fault zone in the Lone Pine area show that most fault planes dip steeply (70° to 90°) and trend approximately parallel to the scarp of For the 1872 earthquake, we estimate the dip-slip component from the Lone Pine fault. Erosional retreat of 1 m or more is common for the fan morphology, detailed profiles and weathering features along the scarp, youngest fault scarps. and scarp-derived sediments exposed in a backhoe trench across the fault. Figure 4 shows profiles of the present ground surface at eight sites, prepared by the method of Wallace (1977). From these profiles, we recon- Profiles and Weathering Features of the Fault Scarp structed 1872 post-earthquake surface profiles from features of the present fault scarp that record, or are remnants of, the 1872 pre-earthquake scarp. The Lone Pine fault scarp has an upper convex portion, a steep These features include the upper convex slope, the wash-controlled slope, mid-slope, and a lower concave portion (Fig. 3). The scarp is compound, exposed desert varnish rings, caliche coatings on clasts, and weathering of the result of more than one slip event. The steep mid-slope is the erosion- cobbles and boulders. The varnish rings on boulders exposed in the scarp ally modified scarp of the most recent slip event, whereas the upper convex show the actual position of an earlier ground surface (Smith, 1979),

PROFILE 11

boulder 1, figure 5- desert varnish ring-

boulder 2, figure 5 -

TRENCH

Lone Pine Fault

PROFILE 14

PROFILE 12 desert varnish ring

PROFILE 13

PROFILE 15 desert varnish ring

patchy caliche coating

meters

reconstructed 1872 present surface estimated 1907 post-earthquake profile surface profile surface profile

Figure 4. Present and reconstructed 1872 post-earthquake and 1907 profiles across Lone Pine fault scarp. Locations of profiles shown on Figure 6. 758 LUBETKIN AND CLARK

Figure 5. Lone Pine scarp in 1907 (left) and 1978 (right), showing changes in free face and debris and wash slopes during 71 yr. Little or no change has occurred on the upper convex slope (above A-A'). Individual cobbles and boulders (numbered) are recognizable in both photographs, although camera positions were not identical. View west at profile 11, 35 m north of LPC 3 (Figs. 4, 6). Rod is 4 m long. 1907 photograph is by W. D. Johnson, no. 685; USGS Library, Denver. whereas caliche coatings and disintegrated clasts, which develop near but varnish on boulders coincides with the portion of the scarp that has been below the surface (Birkeland, 1974), commonly indicate only a lower limit nearly stable during the past 80 yr. This stability strongly suggests that the for the position of the earlier surface. The reconstructed 1872 profiles upper convex slope and its down-dip projection through the surface repre- closely approximate the scarp just after the earthquake, before erosional or sented by the varnish rings represents the actual ground-surface profile depositional modification. before and immediately after the most recent faulting in 1872. Detailed comparisons between 19071 and 1978 photographs at var- The lower portion of each reconstructed profile includes the lower ious places along the fault scarp show that the upper convex slope and the original fan surface, the wash slope, and a projection of the wash slope into wash slope have experienced little degradation or aggradation during this the fault. Several 1907 photographs show only a small debris slope and an period, except for incision of the upper convex slope by some narrow rills. apparently older wash slope (for example, Fig. 5, left). A larger debris In contrast, material eroded from the mid-slope buries the lower portion of slope now covers part of the older wash slope. Eventually a new the scarp (Fig. 5). Both these photographs and more recent field compari- wash slope will result from reworking of material from the scarp and sons show no more than a few centimetres of change in the upper convex new debris slope. We project the older wash slope to our estimated slope and little change in the wash slope, surfaces that have been essen- position of the fault plane to help reconstruct the post-1872 earthquake tially stable for nearly 80 yr. profiles of Figure 4. Desert-varnish rings on boulders provide evidence that the former We estimate a dip-slip component of 1 to 2 m along this fault in 1872 ground surface around the boulders must have been stable for a period of (Fig. 6), by measuring slip on these reconstructed 1872 post-earthquake time at least as great as that required for development of such coatings profiles. We assumed fault dips of both 70° and 90° in order to bracket the above the surface, probably on the order of hundreds of years (Dorn and most likely value of dip slip. We also estimated 1872 dip slip at five other others, 1986,1987). Projections of the planes of exposed rings toward the sites with very small debris slopes (63 and 70 to 73, Fig. 6) by projecting, fault scarp are coplanar with the lower part of the upper convex slope (Fig. in the field, the upper convex slope to the fault plane. We approximate the 4). That is, the former ground surface recorded by the rings of desert position of the 1872 fault plane from the position of exposed boulders in the mid-slope of the scarp, together with observed fault-plane dips and our estimate that post-1872 scarp retreat throughout the study area varies •Photographs taken by Willard D. Johnson during a study of the effects of the 1872 earthquake. The photos are in the Denver library of the U.S. Geological from 0 to 2 m. Survey. Johnson's work was reported by Hobbs (1910). The presence of a horizontal component of offset introduces a small LATE QUATERNARY ACTIVITY, LONE PINE FAULT, CALIFORNIA 759

i» a. a. i a J o \ » ii I ii

1 -I 1 1 1 1 r i 1 r 500 1000 1500 HORIZONTAL DISTANCE ALONG FAULT TRACE ( METERS )

Figure 6. Variation of 1872 and total dip slip along Lone Pine fault. A. Plan view of Lone Pine fault showing locations of numbered profiles (P; Fig. 4), displacement measurement sites (numerals; Table 1), trench (T; Fig. 7), and offset debris flow (D; Fig. 11), on the abandoned fan of Lone Pine Creek. LPC 2 and LPC 3 are abandoned channels of Lone Pine Creek. See Figure 2 for location of fault. B. Estimated dip slip in 1872 (heavy lines) and cumulative dip slip since abandonment of fan (light lines) at locations shown in A, for assumed fault dips of 70° (open circles) and 90° (solid circles). Length of lines approximates uncertainty in measurements.

error into our analysis of each profile. This error depends mainly on local Subsurface Exposure surface slope parallel to the scarp. Because this slope is small at all of our profiles, the resulting error is generally less than that from the measure- A backhoe trench excavated across the Lone Pine fault scarp during ments and assumptions used in reconstructing the dip-slip component at this study (T, Fig. 6) exposed the eroded and buried portion of the fault each profile. scarp and a small filled-in graben at the base of the scarp (Fig. 7). The We conclude that the most recent slip event recognizable in the trench exposure shows that the dip-slip component along this trace in 1872 reconstructed profiles is that associated with the 1872 earthquake, not an was about 1.5 m, and the scarp has retreated about 0.8 m since then. The older or younger one. We base our conclusion on the reports of extensive post-fan deposits east of the main trace record a series of earthquakes, ground rupturing, with creation of scarps, along faults of the Owens Valley explained below and in Figure 7. fault zone in 1872, the lack of any reported post-1872 faulting, and on the extensive steep mid-slope preserved along the scarp. In the brief pre-1872 EARTHQUAKES RECORDED BY THE historic record, the only earthquake that might have been large enough to DIP-SLIP COMPONENT produce surface rupture was a "similar earthquake" "about 80 years before the shocks of 1872" described by Paiute Indians (Townley and Allen, Consideration of total scarp height, dip slip in 1872, and coatings on 1939, p. 21). Neither surface displacement nor any other effects have been boulders exposed in the scarp across the Lone Pine fan suggests that slip reported for this earlier earthquake. Its existence is doubtful (Martel, during three earthquakes created the scarp. In Figure 6, we show the 1984). scarp's total dip-slip component for assumed fault dips of 70° and 90°. 760 LUBETKIN AND CLARK

RECONSTRUCTED 1872 POST-EARTHQUAKE PROFILE METERS Figure 7. Subsurface exposure of Lone Pine fault (location 8 6 4 at T, Fig. 6). A. Interpretive log of backhoe trench. Derived from descriptive log in Lubetkin (1980); modified by subsequent anal- yses of photographs of the trench wall. An aggradational wedge of debris eroded from fault scarps (units A, B, C, and D) overlies original outwash fan deposit (unit F). Unit A is gravelly silt; unit B, sandy silt to pebbly sandy silt; unit C, gravelly silty sand; unit D, gravelly sand to gravelly silty sand; unit F, gravelly silty sand. Unit D, a debris deposit, contains greater fraction of 50-mm and BOTTOM OF TRENCH larger clasts than units B and C to the east and may actually consist of two gravelly sand lenses that could not be discrimi- nated. Principal trace of Lone Pine fault is westernmost fault. This fault juxtaposes unit F to the west against unit D to the east. Above unit D, this fault contact changes to an erosional contact between units F and A and is the eroded and buried 1872 fault scarp. Unit A postdates 1872 faulting and is the debris deposit produced by continuing scarp erosion and retreat. Units B and C are wash deposits that developed from erosion of scarps of two pre-1872 earthquakes. B. Postulated development of the Lone Pine fault scarp at the backhoe trench. (1) First earthquake creates a 1.8- to 2.3-m- high east-facing scarp and a graben in unit F. Existence of fault at 2.9 on horizontal scale is not certain; block west of it may have fallen from main scarp. (2) Subsequent erosion of east-facing scarp creates lens of coarse debris (unit D) at base of scarp and wash deposit (unit C) to the east, filling in graben. (3) Second earthquake creates 1.5- to 2.2-m-high scarp at base of older, eroded scarp. Additionally, the graben east of the scarp has deep- ened, offsetting unit C. (4) Subsequent erosion and retreat of this most recent portion of the scarp adds debris to unit D at the base of the scarp. Erosion has reduced the low west-facing scarp shown in drawing 3 and redeposited the material to the west, still shown as unit C for simplicity. A second wash deposit (unit B) fills the graben. 1978 profile, shown in Figure 7A, includes 1.5 m of offset from 1872. Unit A is debris that has accumulated from erosion and spalling of the 1872 fault scarp and has subsequently buried the scarp. The faults in the graben did not move in 1872, FIGURE 7 EXPLANATION as unit B is not offset. Only a small wash deposit has developed from the 1872 earthquake. This evolutionary drawing does not CORRELATION OF UNITS include any variations caused by horizontal slip.

1 Holocene This total slip component was either measured from the profiles of Figure 4 or calculated from other field measurements (Fig. 8; Table 1). Maximum dip-slip components of 5 to 6.5 m occur along the southern part of the scarp. Dip slip diminishes northward, particularly beyond the Los Angeles J Pleistocene Aqueduct. Parts of the scarp between profile 14 and Los Angeles Aque- duct (Fig. 6) do not show total dip slip because of significant deposition of

Original Fan Deposit Debris Deposit Wash Deposit sediment from LPC 2 (Fig. 2) along the base of the scarp in this area. The 1872 component of dip slip has not been significantly obscured along this segment, however. ^^^ Granitic clast > 100 mm across. If the 1872 earthquake is a characteristic event (as defined by

Contact, dashed where location uncertain. Schwartz and Coppersmith, 1984) for this fault during late Quaternary time, the comparison of total dip slip to 1872 dip slip indicates that a total — ~ Fault. of three 1872-type slip events have produced the present fault scarp. This LATE QUATERNARY ACTIVITY, LONE PINE FAULT, CALIFORNIA 761

Figure 8. Method used to estimate Q; faian susurfacr e dip slip component of Lone Pine scarp at measurement sites shown in Figure 6. Scarp height, Y, and width, X, were measured graphically from scarp profiles or with plane table and alidade (Table 1). Yj, dip slip for assumed ver- projected fault planes tical fault; Y2, dip slip for fault with assumed 70° dip. For all estimates of dip slip, we assumed a = /? = 4°.

^fan surface

conclusion is supported by the position of coatings on a 3 x 5 m boulder TABLE 1. DIMENSIONS AND CUMULATIVE DIP SLIP OF LONE PINE SCARP exposed in the scarp between profiles 12 and 13 (Fig. 6). This boulder Location* Scarpî Scarpt Cumulative dip slip§ records at least three slip events (Fig. 9). height (Y) width (X) 90° 70° Interpretation of the sedimentary record exposed in the backhoe 1 6.2 17 5.0 5.5 2 16.8 4.1 4.5 trench also is consistent with three slip events (Fig. 7). East of the main 3 10.8 3.2 3.5 4 + 5 17.6 3.9 4.3 fault and scarp exposed in the trench wall, there is a 6.5-m-wide graben 6 13.9 5.0 5.5 that has been filled by debris shed primarily from the west. The stratig- 7 13.2 4.4 4.8 8 15.2 4.4 4.8 raphy exposed in the trench wall suggests that this graben formed during 9 18.4 5.0 5.5 10 13.6 4.8 5.2 two pre-1872 slip events but did not deepen in 1872. The oldest slip event 11 13.6 2.8 3.1 is recorded by the step-like offsets of the surface of the original outwash fan 12 12.0 3.2 3.5 13 15.8 3.6 3.9 deposit (unit F) and the increased thickness of the part of the subsequent 14 8.8 2.2 2.4 15 9.0 2.1 2.3 wash deposit (unit C) that occupies the graben relative to the thickness of 16 8.8 0.5 0.5 unit C east of the graben. A second earthquake with associated deepening 17 18.0 0.6 0.7 18 14,2 0.6 0.7 of the graben is recorded by the similar increased thickness of the next 19 7.0 0.2 0.2 younger wash deposit (unit B) within the graben and by the east-side-up *At measurement sites of Figure 6. step in the contact between units B and C. This east-side-up step was tin metres; see Figure 8. produced by slip along the fault shown at horizontal station 6.2 in Figure -In metres; calculated as shown in Figure 8 for assumed fault dips of 90° and 70°. 7A. The low scarp that developed in unit C along this fault (3, Fig. 7B) was eroded, and the material was redeposited immediately to the west (4, Fig. 7B); hence this fault does not project vertically through unit C. The faults at the east end of the graben apparently did not rupture in 1872, because unit B, which predates the 1872 earthquake, is not offset. We could not find a contact within the older debris deposit (unit D) to evince its formation from two earthquakes. We found little evidence for soil development in unit D or any of the units exposed by the trench, including the relatively stable parts of unit F, which have been exposed longest to soil-forming processes. Finding such a contact in colluvial debris, without soil formation, might expectably be difficult. The large boulder shown in profile 11 (Fig. 4) suggests that the latest large event before 1872 produced about as much vertical offset as did the 1872 event. The desert-varnish coating on this boulder above the ring is

Figure 9. Boulder in scarp of Lone Pine fault that apparently records three slip events. Line A separates areas of different weathering and coincides with the projection of the original upper-fan surface. The part of this boulder above line A apparently lay above the ground surface before scarp development. Two rings of desert varnish, B and C, may record later stable positions of the ground surface, each fol- lowing prehistoric faulting. Rod is 1.5 m long. View north between profiles 12 and 13 (Fig. 6). 762 LUBETKIN AND CLARK fairly uniform, suggesting that the boulder was completely buried before channel and an offset debris flow (LPC 3 and D, Fig. 6). The channel the latest pre-1872 event. If the upper scarp surface does approach some apparently predates the scarp and has thus been offset by three events. The stable form as seen in the historic record, then that surface must have been debris flow is younger and has been offset by only two events. This above the boulder before the earlier event. Otherwise, a darker zone of interpretation of the relict channel and offset debris flow differs from that varnish would likely be present over that part of the boulder exposed for a in earlier reports (Lubetkin, 1980; Lubetkin and Clark, 1985) and is the longer time. Reconstruction of profile 11 suggests a minimum value for result of additional field study. vertical offset accompanying a pre-1872 event of about 1 m (Fig. 4). Our estimate of the number of earthquakes recorded in the scarp Offset Relict Channel assumes that all surface displacement results from sudden coseismic slip with possibly some afterslip, rather than long-term creep. We also assume The oldest large channel developed in the fan, LPC 3 (Figs. 2, 6) is that this fault experiences recurrent great earthquakes, rather than many partly buried in the graben east of the scarp, but it has been cut to similar small to moderate earthquakes accompanied by small surface slip. depth in both the upthrown block west of the scarp and in the rest of the We have not been able to document modern creep on either the Lone abandoned fan east of the graben. Incision in the upthrown block in Pine fault or the Owens Valley fault, although Bonilla (1968) inferred the response to faulting is minor near the scarp. The channel does not show a possibility of post-1872 creep on both. Repeated surveys show no dis- major erosional response to faulting because it was probably abandoned placement of the aqueduct at the Lone Pine fault (Fig. 2), in spite of local before creation of the scarp. Although we could not readily identify the cracks in the canal liner (R. G. Wilson, Los Angeles Department of Water center of the channel in the graben, we estimate 12 to 18 m of right-lateral and Power (LADWP), 1986, personal commun.). Surveyed lines span- offset of the top of the north margin of the channel at the scarp (Fig. 10). ning the Lone Pine fault and associated faults east of it show no fault creep The north channel wall west of the scarp, on the relatively upthrown from 1968 to 1986 (H. Mayeda and R. McGhie, LADWP, 1987, personal block, is well defined; however, in the graben this wall is less distinct and commun.). Photographic evidence and field observations also indicate a has a larger uncertainty in its projection to the fault (Fig. 10). We assume lack of creep along this fault during the past 70 to 80 yr. In addition, we that this channel shows cumulative horizontal offset from the three earth- could find no reports of creep offset of streets, utilities, or houses along the quakes identified from analysis of the dip-slip component. If three events main Owens Valley fault trace. created the horizontal offset of this channel, the average horizontal component for each would be 4 to 6 m (Table 2). COMPONENT OF HORIZONTAL SLIP The arcuate, subparallel normal faults at the eastern side of the graben offset this channel vertically, but not horizontally along strike. The Although the scarp across the abandoned fan is testimony to a large channel curves to the left downstream in the graben, lending a false ap- vertical component of slip, the horizontal component at this scarp is much pearance of left-lateral offset at its eastern margin (Fig. 2). larger. We measured this horizontal component of slip from an offset relict LPC 3 is the channel shown in Plate XXb of Hobbs (1910), described

Figure 10. View west along LPC 3 (Fig. 2) toward scarp of Lone Pine fault, showing 12 to 18 m of right-lateral offset of top of north wall of channel. Dashed lines in foreground show our estimate of the extreme range in likely position of top of pre-offset channel wall in the graben east of fault, projected westward to scarp. Dashed line down face of scarp is eastward projection to the base of scarp from top of channel wall that lies west of the fault; tics near base of scarp show ±1 m, our estimate of uncertainty in this projected position. Estimated offset assumes uniform and equal post-offset erosion of channel walls and continuation of pre-offset channel walls straight to the fault trace, as in our projections. W. D. Johnson photo 690, USGS Library, Denver; nearly identical to W. D. Johnson photo 686, which appears in Hobbs (1910) as Plate XXb. LATE QUATERNARY ACTIVITY, LONE PINE FAULT, CALIFORNIA 763

TABLE 2. MEASURED AND CALCULATED SLIP AT LPC 3 AND DEBRIS FLOW, LONE PINE SCARP

Horizontal Dip Total Average/Event^ component* component* slipt _ Horizontal Dip Total component component slip

LPC3§

Crest of lateral 10.3 11.2 2.2 2.4 10.5 11.5 5.2 5.6 1.1 1.2 5.3 5.8 deposit Debris flow ** Medial channel 10.5 12 1.7 1.9 10.5 >12 5.3 6 5.3 >6

Note: data in metres. •Measured. •¡Calculated. SThrce events. Horizontal component measured at north wall of channel (Fig. 10); dip component taken from profile 11 (Fig. 6). **Two events. Horizontal component measured for two possible fault positions, at the base of, and at the top of, scarp; dip component measured for two possible fault dips, 70° and 90°. Dip component of medial channel not used for total slip (see text). there as showing 20 ft (~6 m) of right offset. Bateman (1961) challenged young, ephemeral part of the channel. A 20-ft (~6 m) horizontal offset is this interpretation because he could see neither field evidence for this offset within our 3-event average horizontal offset of 4 to 6 m at LPC 3. nor find reference to it in W. D. Johnson's unpublished notes in U.S. Geological Survey (USGS) archives. Indeed Bateman (1961) quoted Offset Debris Flow Johnson's unpublished statement that this scarp showed no evidence for horizontal offset. We have obtained further information from Johnson's A debris flow complex that fills much of the northern relict channel letters to Hobbs, however. These letters form the basis for much of Hobbs' of the fan (LPC 2, Fig. 2) has also been offset by the Lone Pine fault. This paper (Hobbs, 1910, p. 354) and are in the University of Michigan Li- complex consists of many individual tongue-like masses of metamorphic brary. In his letter to Hobbs of May 29,1907, Johnson recorded "sugges- debris derived from the Alabama Hills. These debris flows invaded the tions of lateral movement..." of this channel of "... about 20 feet." This abandoned channel of LPC 2 and followed it to the scarp. One of the most part of Johnson's letter clearly is the basis for the caption of Hobbs' Plate recent debris flows has been offset right laterally 10.3 to 12 m and verti- XXb. Johnson's later statement in USGS archives is apparently wrong; it cally 2.2 to 2.4 m, east side down (younger debris flow, Fig. 11) where it contradicts his own field observations and ours. Offset of the eroded crosses the Lone Pine fault. Net oblique offset of this debris flow is 10.5 to channel margins is subtle but distinct on aerial photos and discernible in >12 m (Table 2). the field. An intriguing possibility is that Johnson saw a 20-ft offset of a The common debris-flow components, such as coarse-grained lateral

0 L meters Contour Interval 1 m Arbitrary Datum Figure 11. Geologic map of offset debris flow along Lone Pine fault. Lo- cation shown on Figure 6.

EXPLANATION

Alluvium (Holocene)

Debris derived from scarp (Holocene)

Younger debris flow (Holocene) / contact , dashed where approximately / located

Medial channel deposits Older debris flow (Holocene) top of fault scarp , A hachures point downslope Alluvial fan (Pleistocene!) — Composed [ | Lateral deposits large granitic boulder primarily of glacial outwash 764 LUBETKIN AND CLARK deposits and fine-grained medial channel deposits (Johnson, 1965; Jahns, phology indicate a latest Pleistocene age for the surface of the abandoned 1949), are obvious and have sharp boundaries. The outer flank of the Lone Pine fan. In addition, these criteria for relative dating demonstrate lateral deposit is not as steep as on most fresh debris flows of similar that the abandoned fan surface is younger than the surface of the alluvial coarseness. The scarcity of matrix at the surface suggests some deflation of fans west of the Alabama Hills, which we consider to be 150 to 50 ka. the lateral deposits. Boulders larger than 0.5 m exposed on the surface of the abandoned The narrow graben at the base of the east-facing fault scarp conceals fan show ~5 to 30 mm of weathering relief (Fig. 12). This relief is the immediate continuation of the lateral deposit and the medial channel, expressed by protruding mafic inclusions and dikes, large feldspar pheno- so that the offsets cannot be precisely measured. We projected the trends of crysts, and by a slight bell-like configuration at the base of boulders (indi- the crest of the lateral deposit and the medial channel across the graben cating greater weathering and erosion above ground). Boulders of similar from the downthrown block to estimate their offsets, however. granitic lithology located on the surface of fans west of the Alabama Hills We measured both the horizontal and dip-slip components of fault show greater weathering relief of 30 to 150 mm (Fig. 12) and a more offset of this youngest debris flow along the crest of the southern lateral exaggerated bell shape. In contrast, those on the Holocene Lone Pine fan, deposit and alongthe medial channel. We did not use the dip-slip compo- east of the Alabama Hills and south of the abandoned fan, show less than 5 nent of offset of the medial channel because of possible post-offset erosion mm of weathering relief; inclusions and dikes commonly are flush with the and deposition of its relatively fine material, and we did not use offset of surrounding boulder surfaces. the southern margin of the lateral deposit because of possible postdeposi- Granular disintegration of buried granitic boulders also indicates that tional alteration. the alluvial fans west of Alabama Hills are older than the abandoned fan of The dip-slip component of offset of the debris flow indicates that it Lone Pine Creek. The fans west of Alabama Hills have a greater percen- has been offset by two events. Although we cannot deduce 1872 dip slip tage of disintegrated or partially disintegrated granitic clasts, a relationship from the scarp profile at the debris flow, 1872 dip slip at flanking locations used to separate glacial deposits of different ages (Birman, 1964; Burke and (P 15 and 71, Fig. 6) is 0.8 to 1.6 m, about half of the dip slip of the crest Birkeland, 1979). From 5% to 50% of the subsurface granitic clasts at six of the south lateral deposit of the debris flow, 2.2 to 2.4 m. This relation- locations in the fan deposits west of the Alabama Hills are at least slightly ship of dip slip indicates that two events have offset the debris flow. disintegrated, whereas fewer than 5% of the subsurface granitic clasts of the Horizontal offset of the debris flow, 10.3 to 12 m, also suggests two events. abandoned fan in soil pits are slightly disintegrated. Average horizontal slip for two events would be 5.2 to 6 m, which is The degree of weathering of the fans west of the Alabama Hills within the range of average horizontal slip of 4 to 6 m for three events at suggests that they are contemporary with moraines of the Tahoe glaciation the offset channel (LPC 3) 200 m to the south (Table 2). (ca. 150 to 50 ka; Burke and Birkeland, 1979; Dorn and others, 1987) of the eastern Sierra Nevada. This agrees with the conclusions of Knopf AGE OF THE ABANDONED FAN SURFACE (1918) and Richardson (1975). The criteria of relative age are internally consistent and indicate that the abandoned Lone Pine fan is distinctly Shorelines of Pleistocene Lake Owens are older than the abandoned younger than the fans west of the Alabama Hills. outwash fan. Gravelly beach deposits with some tufa coatings and low We consider the abandoned Lone Pine fan to be contemporary with wave-cut cliffs of this lake are preserved along short reaches of the eastern the younger (Tioga) glaciation, which ended about 10 ka (Adam, 1967; flank of the Alabama Hills at a maximum elevation of 1,144 m. These Mezger and Burbank, 1986). Weathering on this fan is similar to that on shoreline features record a temporary highstand of Lake Owens. The old deposits of the Tioga glaciation along the eastern slope of the Sierra shoreline does not cut the surface of the abandoned fan, nor does geomor- Nevada. The modern channel of Lone Pine Creek has incised nearly 20 m phic or sedimentary evidence indicate that the fan was built into a lake at into the head of the abandoned fan and about 10 m into the upstream this high-water stand. The abandoned fan surface therefore postdates the terraces. This major incision suggests that Lone Pine Creek had the dis- highstand of the lake. charge and competence of glacial or final glacial conditions at the time of Lithoid tufa from the beach gravels yields a 14C age of 21,000 ± 130 abandonment. Yet the relatively small size of the modern fan of Lone Pine yr (USGS 609, Fig. 1). We took this sample from near the stratigraphic Creek precludes a large content of primary outwash. These observations top of the shoreline deposit. It gives an approximate age for the highstand indicate that abandonment was near the end of the Tioga glaciation. of the lake and a maximum age for the fan surface. Because large amounts of outwash would have been produced up to the 14C dates from tufa can be in error because of contamination by later end of the Tioga glaciation, we consider that most of the fan surface is atmospheric carbon or the presence of older carbon in the lake water. The relatively young, probably closer to 10 ka than to 21 ka. date, however, is consistent with the record from downstream Lake Searles Although the youngest channel on the fan, LPC 2, continued to be and from Pleistocene lakes of the Great Basin. The continuous highstands active after the first faulting event, LPC 2 is a late feature of the fan. Its of Lake Searles from -24 to 17 ka required overflow from Lake Owens channel and associated deposits cover less than about 5% of the fan surface (Smith, 1976,1983; Smith and Street-Perrott, 1983), although the record west of the scarp. Hence most of the fan surface was constructed before from Searles Lake indicates Lake Owens also overflowed from 12 to 10 ka LPC 2 came into relatively brief use before abandonment. (Smith and Street-Perrott, 1983). In addition, Lakes Lahontan and Bonne- Thus the tufa-dated shoreline, the regional record of Pleistocene ville, in the Great Basin, had highstands 16.5 and 13.5 to 12.5 ka, respec- lakes, and relative weathering strongly indicate that the faulted surface of tively (Scott and others, 1983; Thompson and others, 1986; Benson and the abandoned fan of Lone Pine Creek is between 10 and 21 ka, probably Thompson, 1987), and Lake Russell (Pleistocene Mono Lake) had its last closer to 10 ka. highstand 14 to 12 ka (Lajoie and Robinson, 1982). If younger carbon has contaminated the tufa, the shoreline could possibly represent an older, LATE QUATERNARY RECURRENCE INTERVALS early Wisconsin lake, but in the absence of additional information, we AND SLIP RATES provisionally accept 21 ka as the maximum age of the surface of the abandoned Lone Pine fan. The fault offset and postulated earthquake history recorded by the Techniques that determine relative age provide a minimum age for scarp permit us to calculate average late Quaternary recurrence intervals the surface of the Lone Pine fan. The amount of sculpting and degree of and slip rates, although we have not dated individual events. Three slip weathering of granitic boulders, soil-oxidation color, and fan surface mor- events since 10 to 21 ka give minimum and maximum average recurrence LATE QUATERNARY ACTIVITY, LONE PINE FAULT, CALIFORNIA 765

A ABANDONED FAN SURFACE WEST FAN SURFACE WEST LONE PINE FAN OF ALABAMA HILLS - OF ALABAMA HILLS - SURFACE SUBDUED MORPHOLOGY DISTINCT MORPHOLOGY <> cc 100-, LU 1 50- co en 0 < 100i 50'

0 100 DC z 50- (n cc 0 LU 100 30 60 90 120 150 180 -aj 3 o 50 CD 0 Figure 12. Maximum weathering 100- relief of granitic boulders on fan sur- Z faces near Lone Pine. A. Graphs UJ 50- O IT =1 presenting the measurements of maxi- 0 30 60 90 mum weathering relief on at least 50 MAXIMUM WEATHERING RELIEF IN MILLIMETERS granitic boulders at each test site (1 to 10). Weathering relief measurements are grouped into 30-mm increments. B. Locations (1 to 10) of boulder- B weathering test sites. See Figure 1 for explanation of symbols.

intervals along the Lone Pine fault of 5,000 and 10,500 yr. The 5,000-yr earthquake, on the basis of differences in maximum slope angles and interval assumes that most of the fan surface was deposited about 10 to 15 evidence of low erosion rates on gentler slopes. The actual erosion rate, ka, and the first earthquake happened shortly before abandonment at 10 and its variations with time and slope, are unknown; hence this time ka. The next pre-1872 event then occurred about 5 ka. The 10,500-yr interval cannot be directly measured. interval assumes that most of the fan was deposited about 21 ka, just We combine the range of recurrence interval with the range of aver- before the first earthquake. The next pre-1872 event then occurred about age total slip/event2 from Table 2, 4.3 to 6.3 m, to estimate the range of 10.5 ka, just after abandonment. We favor the shorter recurrence interval. slip rates allowed by our data (Clark and others, 1984). The extremes of Scarp morphology suggests that the calculated recurrence intervals are reasonable. The maximum slope for the youngest pre-1872 scarp 2 Although we use the full dip-slip component to estimate the number of events ranges from 30° to 38° and is distinctly less than the maximum slope angle and recurrence, the slip-rate calculation should use a smaller dip-slip component, for the 1872 portion of the scarp (-70° to 90°). The time required to because our measurements are from one side of a shallow graben (Fig. 2). Net dip slip across this graben is possibly as little as one-half of the dip slip reported here for modify the scarp formed in the last pre-1872 rupture event to its 1872 its west side. Because the horizontal component dominates net slip, however, and in shape is the true interval between those two events. The interval between view of the large uncertainties in our age estimates, the effects of this uncertainty in those slip events appears to be much longer than the 115 yr since the 1872 graben depth on slip rate are not significant. 766 LUBETKIN AND CLARK

these ranges yield slip rates between 0.4 and 1.3 mm/yr. Because we think extensively with Sarah Beanland of New Zealand Geological Survey about the fan surface is probably closer to the minimum rather than the maxi- her work in Owens Valley. We have benefited from discussions with P. C. mum age, we favor the larger values in this range. Bateman, M. G. Bonilla, A. R. Gillespie, R. H. Jahns, K. R. Lajoie, D. P. Schwartz, G. I. Smith, and R. E. Wallace; and reviews by M. G. Bonilla, RELATIONSHIP OF THE LONE PINE FAULT S. J. Martel, K. E. Sieh, and R. J. Weldon. TO THE OWENS VALLEY FAULT ZONE

REFERENCES CITED

Because the Lone Pine fault is only one of several strands within the Adam, D. P., 1967, Late-Pleistocene and Recent palynology in the central Sierra Nevada, in Cushing, E. J., and Wright, Owens Valley fault zone, the late Quaternary average recurrence interval H. E., Jr., eds., Quaternary Paleoecology: INQUA Congress VII, Proceedings 7, Yale University Press, p. 275-301. Bateman, P. C., 1961, Willard D. Johnson and the strike-slip component of fault movement in the Owens Valley, for major earthquakes, the range of slip rates, and the nature of slip for the California earthquake of 1872: Seismological Society of America Bulletin, v. SI, p. 483-493. Beanland, Sarah, and Clark, M. M., 1987, The Owens Valley fault zone, eastern California, and surface rupture associated Lone Pine fault do not necessarily represent activity for the entire fault with the 1872 earthquake [abs.]: Seismological Society of America, Seismological Research Letters, v. 58, p. 32. zone. Information on relationships among the various faults in the zone, Benson, L. V., and Thompson, R. S., 1987, Lake-level variation in the Lahontan Basin for the past 50,000 years: Quaternary Research, v. 28, p. 69-85. and on changes in these relationships with time, are necessary for a com- Birkeland, P. W., 1974, Pedology, weathering and geomorphological research: New York, Oxford University Press, 285 p. Birman, J. H., 1964, Glacial geology across the crest of the Sierra Nevada, California: Geological Society of America plete analysis. The information we now have, however, allows us to make Special Paper 75,80 p. some preliminary estimates about behavior of the fault zone. Bonilla, M. G., 1968, Evidence for right-lateral movement on the Owens Valley, California, fault zone during the earthquake of 1872, and possible subsequent fault creep: Conference on Geological Problems of the San Andreas The Lone Pine fault shows a large vertical component of recent Fault System, Proceedings, Stanford University Publications in the Geological Sciences, v. 11, p. 4-5. Burke, R. M., and Birkeland, P. W., 1979, Réévaluation of multiparameter relative dating techniques and their application displacement in the region where the main Owens Valley trace does not. A to the glacial sequencealongtheeastern escarpment of the Sierra Nevada, California: Quaternary Research, v. 11, p. 21-51. prominent east-facing scarp marks the main Owens Valley trace from near Carver, G. A., Slemmons, D. B., and Glass, C. E., 1969, Surface faulting patterns in Owens Valley, California: Geological the north end of the adjacent Lone Pine fault to the north end of the Society of America Abstracts with Programs for 1969, v. 1, no. 3, p. 9-10. Clark, M. M„ Harms, K. K„ Lienkaemper, J. J„ Harwood, D. S„ Lajoie, K. R„ Matti, J. C, Perkins, J. A, Rymer, M. J., Alabama Hills (Fig. 1). The Lone Pine fault apparently accommodates Sarna-Wojcicki, A. M., Sharp, R. V., Sims, J. D., Tinsley, J. C., and Ziony, J. I., 1984, Preliminary slip-rate table and map of late-Quaternary faults of California: U.S. Geological Survey Open-File Report 84-106. local vertical displacement along the Owens Valley fault zone. This rela- Dora, R. I., Bamforth, T. A., Cahill, T. A., Dohrenwend, J. C, Turrin, B. D„ Donahue, D. J., Jull, A.J.T, Long, A., tionship does not necessarily indicate that the two faults rupture concur- Macko, M. E., Weil, E. B., Whitley, D. S., and Zabel, T. H., 1986, Cation-ratio and accelerator radiocarbon dating of rock varnish on Mojave artifacts and landforms: Science, v. 231, p. 830-833. rently, but that the vertical component of displacement has been Dom, R. I., Turrin, B. D., Jull, A.J.T., Linick, T. W., and Donahue, D. J., 1987, Radiocarbon and cation-ratio ages for rock varnish on Tioga and Tahoe moraina! boulders of Pine Creek, eastern Sierra Nevada, California, and their consistently distributed between them in late Quaternary time. paleoclimatic implications: Quaternary Research, v. 28, p. 38-49. Gilbert, G. K., 1884, A theory of the earthquakes of the Great Basin, with a practical application: American Journal of Science, 3rd series, v. 27, p. 49-53. TOTAL 1872 SLIP, HOLOCENE SLIP RATE, AND Hobbs, W. H., 1910, The earthquake of 1872 in the Owens Valley, California: Beitrage zur Geophysik, v. 10, p. 352-385. Jahns, R. H., 1949, Desert floods: Engineering and Science Monthly, v. 12, no. 8, p. 10-14. RECURRENCE FOR THE OWENS VALLEY FAULT ZONE Johnson, A. M., 1965, A model for debris flow [Ph.D. thesis]: University Park, Pennsylvania, The Pennsylvania State University, 248 p. Knopf, A., 1918, A geologic reconnaissance of the Inyo Range and the eastern slope of the southern Sierra Nevada, Adding the estimated 1872 horizontal component of slip along the California: U.S. Geological Survey Professional Paper 110,130 p. Lajoie, K. R., and Robinson, S. W., 1982, Late Quaternary glacio-lacustrine chronology, Mono Basin, Calif.: Geological Lone Pine fault, 4 to 6 m (Table 2), to the measured 1872 horizontal Society of America Abstracts with Programs, v. 4, p. 179. Lubetkin, L.K.C., 1980, Late Quaternary activity along the Lone Pine fault, Owens Valley fault zone, California [M.S. component of slip on the Owens Valley fault in Lone Pine of 2.7 to 4.9 m thesis]: Stanford, California, Stanford University, 85 p. (9 to 16 ft, Bateman, 1961; Hobbs, 1910) gives a maximum 1872 horizon- Lubetkin, L.K.C., and Clark, M. M., 1985, Late Quaternary activity along the Lone Pine fault, eastern California, in Stein, R. S., and Bucknam, R. C., eds., Proceedings of Workshop XXVIII on the Borah Peak, Idaho earthquake: U.S. tal-slip component approximately between 7 and 11 m for the Owens Geological Survey Open-File Report 85-290, p. 118-140. Martel, S. J., 1984, Late Quaternary activity on the Fish Springs fault, Owens Valley fault zone, California [M.S. thesis]: Valley fault zone at Lone Pine. Adding all or part of the dip-slip compo- Stanford, California, Stanford University. nent of 1872 on the Lone Pine fault (1 to 2 m) does not significantly Martel, S. J., Harrison, T. M., and Gillespie, A. R., 1987, Late Quaternary vertical displacement rate across the Fish Springs fault, Owens Valley, California: Quaternary Research, v. 27, p. 113-129. increase the total slip. This combined strike slip across the fault zone is Mezger, L., and Burbank, D., 1986, The glacial history of the Cottonwood Lakes area, southeastern Sierra Nevada: Geological Society of America Abstracts with Programs, v. 18, p. 157. large. It is comparable to the maximum strike slip of ~9.5 m reported for Oakeshott, G. B., Greensfelder, R. W„ and Kahle, J. E„ 1972, 1872-1972 ... one hundred years later: California the great Fort Tejon earthquake of 1857 on the San Andreas fault (Sieh, Geology, v. 25, p. 55-61. Richardson, L. K., 1975, Geology of the Alabama Hills, California [M.S. thesis]: Reno, Nevada, University of Nevada. 1978). Richter, C. F., 1958, Elementary seismology: San Francisco, W. H. Freeman, 768 p. Savage, J. C., and Lisowski, M., 1980, Deformation in Owens Valley, California: Seismological Society of America If we assume further that the Lone Pine fault characteristically rup- Bulletin, v. 70, no. 4, p. 1225-1232. tures at the same time as the Owens Valley fault, as it did in 1872, we can Savage, J. C., Church, J. P., and Prescott, W. H., 1975, Geodetic measurement of deformation in Owens Valley, California: Seismological Society of America Bulletin, v. 65, no. 4, p. 865-874. calculate a Holocene horizontal-slip rate for the Owens Valley fault zone at Schwartz, D. P., and Coppersmith, K. J., 1984, Fault behavior and characteristic earthquakes: Examples from the Wasatch and San Andreas fault: Journal of Geophysical Research, v. 89, p. 5681-5698. Lone Pine. Dividing the assumed characteristic total horizontal-slip com- Scott, W. E., McCoy, W. D., Schroba, R. R., and Rubin, M., 1983, Reinterpretation of exposed record of the last two ponent of 7 to 11 m at Lone Pine by the average recurrence interval for cycles of the Lahontan Basin, western United States: Quaternary Research, v. 20, p. 261-285. Sieh, Kerry, 1978, Slip along the San Andreas fault associated with the great 1857 earthquake: Seismological Society of such an earthquake, 5,000 to 10,500 yr, gives an average horizontal-slip America Bulletin, v. 68, no. 5, p. 1421-1448. Slemmons, D. B., and Cluff, L. S., 1968, Historic faulting in Owens Valley, California: Geological Society of America, rate of 0.7 to 2.2 mm/yr. This slip rate is near the average historic right- Special Paper 121, Abstracts for 1968, p. 559-560. lateral displacement rate of about 3 to 7 mm/yr measured geodetically by Smith, G. I., 1976, Paleoclimatic record in the upper Quaternary sediments of Searles Lake, California: Paleolimnology of Lake Biwa and the Japanese Pleistocene, v. 4, p. 577-603. Savage and others (1975) for 1928 to 1974 and by Savage and Lisowski 1983, Core KM-3, a surface-to-bedrock record of late Cenozoic sedimentation in Searles Valley, California: U.S. Geological Survey Professional Paper 1256,23 p. (1980) for 1974/1975 to 1979 between bench marks that span Owens Smith, G. I., and Street-Perrott, F. A., 1983, Pluvial lakes of the western United States, in Wright, H. E-, Jr., ed., Valley. This rate is also about the same as the maximum reported for Late-Quaternary environments of the United States: Minneapolis, University of Minnesota Press, v. 1, chap. 10, p. 190-212. normal faults of the Sierran range-front northwest of Owens Valley and is Smith, R.S.U., 1979, Holocene offset and seismicity along the Panamint Valley fault zone, western Basin and Range province, California: Tectonophysics, v. 52, p. 411-415. near the known maximum for any dextral strike-slip or normal fault of this Thompson, R. S., Benson, L., and Hattori, E. M., 1986, A revised chronology for the last Pleistocene lake cycle in the region (Clark and others, 1984). central Lahontan basin: Quaternary Research, v. 25, p. 1-9. Townley, S. D., and Allen, M. W., 1939, Descriptive catalogue of earthquakes of the Pacific Coast of the United States 1769-1928: Seismological Society of America Bulletin, v. 29, p. 1-297. Wallace, R. E., 1977, Profiles and ages of young fault scarps, north-central Nevada: Geological Society of America ACKNOWLEDGMENTS Bulletin, v. 88, p. 1267-1281. Whitney, J. D„ 1872, The Owens Valley earthquake: Overland Monthly, v. 9, p. 130-140,266-278. Zoback, M. L., and Beanland, Sarah, 1986, Stress and tectonism along the Walker Lane belt, western Great Basin [abs.]: This report is based on Lubetkin (1980) and Lubetkin and Clark EOS (American Geophysical Union Transactions), v. 67, p. 1225. (1985), with additional field investigations in 1985 and 1986, assisted by K. K. Harms and S. K. Pezzopane. Lubetkin's original field work was MANUSCRIPT RECEIVED BY THE SOCIETY NOVEMBER 12,1986 REVISED MANUSCRIPT RECEIVED SEPTEMBER 25,1987 funded in part by the Shell Fund of Stanford University. We conferred MANUSCRIPT ACCEPTED SEPTEMBER 29, 1987

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