Tsunami Hazard Map of Everett, Washington—Model Results

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WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES OPEN FILE REPORT 2014-03 NOAA Center for Tsunami Research Pacific Marine Environmental Laboratory Tsunami Hazard Map of Everett, Washington Tsunami Hazard Map of Everett, Washington: December 2014 Model Results for Magnitude 7.3 and 6.7 Seattle Fault Earthquakes

by Timothy J. Walsh1, Diego Arcas2, Vasily V. Titov2, and Chris C. Chamberlin2 1Washington Division of Geology and Earth Resources, MS 47007, Olympia, WA 98504-7007; [email protected] 2NOAA Center for Tsunami Research, NOAA/PMEL-UW/JISAO, 7600 Sand Point Way NE, Seattle, WA 98115

Mw 7.3 Mw 6.7 Modeled Inundation Maximum Current Modeled Inundation Maximum Current 48° 02′ 57.80″ N 48° 03′ 03.35″ N 48° 02′ 57.80″ N 48° 03′ 03.35″ N 48° 02′ 57.80″ N 48° 03′ 03.35″ N 48° 02′ 57.80″ N 48° 03′ 03.35″ N 122° 14′ 37.15″ W S 122° 07′ 51.55″ W 122° 14′ 37.15″ W S 122° 07′ 51.55″ W 122° 14′ 37.15″ W S 122° 07′ 51.55″ W NE 122° 14′ 37.15″ W S 122° 07′ 51.55″ W NE NE u NE u u 529 MARYSVILLE n MARYSVILLE u 529 MARYSVILLE n 529 MARYSVILLE n n 529 n n n y n y y s y s s i s i i gh d id gh d gh d u e ugh ou e ou e o 14 Ave 14 Ave 14 14 Ave l o e l l S 14 Ave Sl S S B B B B y l y y l y l e v e lv e v e v b d d b d b d C b C C r E E C r E r E o r o o o D l D l D l u D l u u u m m m e m e e n e e n e n e i b v NE n e i b v NE i b v NE i b N r A r v E r A r A a i A a i a i a 52nd Ave NE a i a 52nd Ave NE a 52nd Ave NE M a 52nd Ave NE M M d M d d d n n n

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12th St NE 12th St NE 12th St NE 12th St NE N Broadway N Broadway N Broadway N Broadway

10th St 10th St 10th St 10th St Ferry Ferry Ferry Ferry Baker Baker Baker St Baker St St 12th Is. 12th St Is. 12th Is. 12th Is.

15th St Spencer 15th St Spencer 15th St Spencer 15th St Spencer

Island Island Sound Possesion Island

Possesion Sound Possesion Island Sound Possesion Possesion Sound Possesion

Colby Ave Colby Ave Colby Ave

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19th St 4th St SE 19th St 4th St SE 19th St 4th St SE 19th St 4th St SE

Broadway Broadway Broadway

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22nd St 22nd St 22nd St 22nd St EVERETT EVERETT EVERETT Naval EVERETT Naval Naval 12th St SE 12th St 12th St SE 12th St SE 25th St SE 25th St 25th St Station 204 25th St 204 Station 204 Station 204 Naval Everett Everett Everett

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Cherry 2 29th St SE 2 29th St SE 2 29th St SE 2 29th St SE Pacific Ave Pacific Ave Pacific Ave Pacific Ave SE SE SE 51st Ave Inundation Depth (feet) 51st Ave SE 51st Ave 51st Ave Maximum Current (knots) 34th St 0–2 34th St 34th St 34th St 0–3 Inundation Depth (feet)

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r k Inferred AD 900 to 930 r 0–3 u u 9–10 u u 47° 57′ 32.05″ N M M 47° 57′ 32.05″ N M 47° 57′ 32.05″ N M 47° 57′ 32.05″ N 122° 14′ 25.70″ W W tsunami deposit 122° 14′ 25.70″ W W Station Everett) 122° 14′ 25.70″ W W tsunami deposit 122° 14′ 25.70″ W W SCALE 1:32,000 Figure 1 Figure 2 1 0.5 0 1 mile Figure 3 Figure 4

100.5 1 kilometer

Snohomish delta distributaries—Ebey Slough, Steamboat Slough, Union Slough, Table 1. Scenario A seismic fault parameters for a Seattle fault MW 7.3 earthquake, after others, 2002)—indicates that there were at least two earthquakes in the 1500 years Gower, H. D., 1978, Tectonic map of the Puget Sound region, Washington, showing locations of Walsh, T. J.; Caruthers, C. G.; Heinitz, A. C.; Myers, E. P., III; Baptista, A. M.; Erdakos, G. B.; INTRODUCTION Marysville DISCUSSION and the Snohomish River—was probably also deposited by the tsunami from the Titov and others (2003). Strike is measured from north and dip direction is 90ºperpendicular before the AD 900 to 930 event. These earthquakes, however, did not uplift faults, principal folds, and large-scale Quaternary deformation: U.S. Geological Survey Kamphaus, R. A., 2000, Tsunami hazard map of the southern Washington coast—Modeled clockwise from the strike azimuth. In 1995, Congress directed the National Oceanic and Atmospheric Administration AD 900 to 930 earthquake (Bourgeois and Johnson, 2001). The locations of these to the strike azimuth. One investigation has identified paleotsunami deposits in the Everett area. prominent wavecut platforms similar to the one made by the AD 900 to 930 event, Open-File Report 78-426, 22 p., 1 plate, scale 1:250,000. tsunami inundation from a Cascadia subduction zone earthquake: Washington Division of Geology and Earth Resources Geologic Map GM-49, 1 sheet, scale 1:100,000, with 12 p. text. (NOAA) to develop a plan to protect the West Coast from locally generated deposits are shown in Figures 1 and 3. Fault segment Width (km) Length (km) Strike (deg) Dip (deg) Slip (m) Bourgeois and Johnson (2001) identified numerous locations along sloughs of the which suggests that not all earthquakes along the Seattle fault have the same Jacoby, G. C.; Williams, P. L.; Buckley, B. M., 1992, Tree ring correlation between prehistoric landslides and abrupt tectonic events in Seattle, Washington: Science, v. 258, no. 5088, [http://www.dnr.wa.gov/publications/ ger_gm49_tsunami_hazard_southern_coast.zip] tsunamis. A panel of representatives from NOAA, the Federal Emergency A1 35.0 15.2 87.9 60.0 1.0 Snohomish River delta that showed evidence of abrupt subsidence and an Snohomish amount of vertical or horizontal displacement. Kelsey and others (2008) suggested p. 1621-1623. Walsh, T. J.; Myers, E. P., III; Baptista, A. M., 2002a, Tsunami inundation map of the Port Management Agency, the U.S. Geological Survey (USGS), and the five Pacific River delta A2 35.0 6.3 86.6 60.0 1.0 apparently continuous sheet of sand that overlies a soil dated to about AD that at least some of the previous earthquakes may have been produced by Gedney (Hat) MODELING Johnson, S. Y.; Dadisman, S. V.; Childs, J. R.; Stanley, W. D., 1999, Active tectonics of the Seattle Angeles, Washington area: Washington Division of Geology and Earth Resources Open File coast states wrote the plan and submitted it to Congress, which created the Island nd A3 35.0 8.9 96.0 60.0 12.0 800–980 (Figs. 1 and 3), a range that completely contains the inferred age of the Report 2002-1, 1 sheet, scale 1:24,000. [http://www.dnr.wa.gov/publications/ger_ofr2002-1_ u The model of Titov and Synolakis (1998), also known as the Method of Splitting bedding-plane slip on a fault-bend fold and were not located on the main Seattle fault and central Puget Sound, Washington—Implications for earthquake hazards: Geological National Tsunami Hazard Mitigation Program (NTHMP) in October 1996. The o A4 35.0 3.2 128.8 60.0 11.0 last Seattle fault earthquake (AD 900 to 930). These workers also found evidence tsunami_hazard_portangeles.pdf] S 5 fault at all. Another significant limitation is that the resolution of the modeling is Society of America Bulletin, v. 111, no. 7, p. 1042-1053, 1 plate. NTHMP is a program designed to reduce the impact of tsunamis through warning Tsunami (MOST) model (Titov and González, 1997), was used by NCTR A5 35.0 11.5 99.3 60.0 4.0 for an older tsunami deposit (not shown on the figures) whose age is not well no greater nor more accurate than the bathymetric and topographic data Kelsey, H. M.; Sherrod, B. L.; Nelson, A. R.; Brocher, T. M., 2008, Earthquakes generated from Walsh, T. J.; Myers, E. P., III; Baptista, A. M., 2002b, Tsunami inundation map of the Port n modelers. It uses a grid of topographic and bathymetric elevations and calculates a A6 35.0 14.9 81.0 60.0 1.0 guidance, hazard assessment, and mitigation. A key component of the hazard io constrained. The tsunami model for Scenario A correlates well with all of the AD used—data cells are locally up to 50 m on a side. bedding plane-parallel reverse faults above an active wedge thrust, Seattle fault zone: Townsend, Washington area: Washington Division of Geology and Earth Resources Open ss wave elevation and depth-averaged velocity at each grid point at specified time assessment for tsunamis is delineation of areas subject to tsunami inundation. e 900 to 930 tsunami deposit locations—the upstream extent of the model is Geological Society of America Bulletin, v. 120, no. 11-12, p. 1581-1597. File Report 2002-2, 1 sheet, scale 1:24,000. [http://www.dnr.wa.gov/publications/ s Everett The models do not include the influences of changes in tides and are s 4 intervals to simulate the generation, propagation, and inundation of tsunamis. Scenario B. Seattle Fault Mw 6.7 Event ger_ofr2002-2_tsunami_hazard_porttownsend.pdf] These maps are produced using computer models of earthquake-generated o approximately coincident with the most upstream tsunami deposits. However, referenced to mean high water. The tide stage and tidal currents can amplify or Kimball, J. P., 1897, Physiographic geology of the Puget Sound basin (in 2 parts): American P 3 Walsh, T. J.; Myers, E. P., III; Baptista, A. M., 2003a, Tsunami inundation map of the Neah Bay, tsunamis from nearby seismic sources. The modeling for this map was performed 5 In this MOST model study, two deformation models for the Seattle fault were This scenario along the Seattle fault is a modified version of the earthquake because the sloughs are now protected by levees, the tsunami modeled here will Geologist, v. 19, no. 4, p. 225-237 (part 1); v. 19, no. 5, p. 304-322 (part 2). Everett reduce the impact of a tsunami on a specific community. At the Everett tide gage, Washington, area: Washington Division of Geology and Earth Resources Open File Report by the NOAA Center for Tsunami Research (NCTR) at NOAA’s Pacific Marine used: Scenario A simulates the AD 900 to 930 event as a credible worst-case scenario used by the Earthquake Engineering Research Institute (EERI) and behave differently from the AD 900 to 930 event even if the model perfectly Lander, J. F.; Lockridge, P. A.; Kozuch, M. J., 1993, Tsunamis affecting the west coast of the 2 tide gauge the diurnal range (the difference in height between mean higher high water and 2003-2, 1 sheet, scale 1:24,000. [http://www.dnr.wa.gov/publications/ger_ofr2003-2_tsunami_ 2 scenario of magnitude Mw 7.3. Scenario B simulates a less severe, but more likely WAEMD for recent seismic hazard assessment studies (Stewart, 2005). This United States, 1806-1992: U.S. National Geophysical Data Center Key to Geophysical Environmental Laboratory (PMEL) in Seattle and the results are shown in Figures matched the dynamics of that earthquake. mean lower low water) is about 11 ft (3.4 m) (accessed on August 8, 2014, at hazard_neahbay.pdf] Mw 6.7 event. Details of the Seattle fault scenarios are given in Titov and others scenario represents a less severe, but more likely event than Scenario A. A Seattle Records Documentation 29, 243 p. 1 through 4. Other potential tsunami sources for this area are not well enough understood http://www.tidesandcurrents.noaa.gov). This means that, while the modeling can Walsh, T. J.; Myers, E. P., III; Baptista, A. M., 2003b, Tsunami inundation map of the Quileute, 01 2 mi Lynett, P. J.; Borrero, Jose; Son, Sangyoung; Wilson, Rick; K. Miller, Kevin, 2014, Assessment of This map is part of a series of tsunami inundation maps produced by the area of Figures 1–4 (2003) and Walsh and others (2003c). The fault parameters (Tables 1 and 2) were fault earthquake Mw 6.5 or greater is forecast to have a 5 percent chance of to be included in this assessment. The southern Whidbey Island fault zone crosses Washington, area: Washington Division of Geology and Earth Resources Open File Report be a useful tool to guide evacuation planning, it is not of sufficient resolution to be the tsunami-induced current hazard, Geophysical Research Letters, v. 41, n. 6, p. 2048–2055. Washington Division of Geology and Earth Resources (WADGER), in derived in a workshop convened by Walsh and attended by T. M. Brocher, T. L. occurrence over a 50-year period (Stewart, 2005). Puget Sound a short distance south of Everett (Dragovich and others, 2002) but is 2003-1, 1 sheet, scale 1:24,000. [http://www.dnr.wa.gov/publications/ger_ofr2003-1_tsunami_ useful for land-use planning. doi:10.1002/2013GL058680. cooperation with the Washington Emergency Management Division (WAEMD), Pratt, B. L. Sherrod, and C. S. Weaver, all from the USGS, and Diego Arcas, F. I. The scenario earthquake used in the EERI studies used a 24-km-long fault not understood well enough to build a credible seismic scenario model. Tsunamis hazard_quileute.pdf] Nelson, A. R.; Johnson, S. Y.; Wells, R. E.; Pezzopane, S. K.; Kelsey, H. M.; Sherrod, B. L.; González, H. O. Mofjeld, V. V. Titov, and A. J. Venturato, all from NOAA. The centered beneath the cities of Seattle and Bellevue; this resulted in little vertical Walsh, T. J.; Titov, V. V.; Venturato, A. J.; Mofjeld, H. O.; González, F. I., 2003c, Tsunami hazard as a contribution to the NTHMP. Completed maps are the southern Washington can also be caused by landslides, both subaqueous and subaerial. Historic Bradley, L.-A.; Koehler, R. D., III; Bucknam, R. C.; Haugerud, R. A.; Laprade, W. T., 2002, Port ACKNOWLEDGMENTS map of the Elliott Bay area, Seattle, Washington—Modeled tsunami inundation from a coast (Walsh and others, 2000), Port Angeles (Walsh and others, 2002a), Port seismic parameters from this workshop were simplified from the rupture models deformation under the water of Puget Sound and minimized the effect of a landslide-induced tsunamis occurred multiple times in Lake Roosevelt, the Field and laboratory data from an earthquake history study of the Toe Jam Hill fault, Townsend Seattle fault earthquake: Washington Division of Geology and Earth Resources Open File Townsend (Walsh and others, 2002b), Neah Bay (Walsh and others, 2003a), discussed above but are broadly in agreement. Time-amplitude histories for potential tsunami. For the present study, the scenario was modified by shifting the impoundment behind Grand Coulee Dam (Lander and others, 1993), in the This project was supported by NTHMP in cooperation with WAEMD. Bainbridge Island, Washington: U.S. Geological Survey Open-File Report 02-60, 1 v., 2 5 Report 2003-14, 1 sheet, scale 1:50,000. [http://www.dnr.wa.gov/publications/ger_ofr2003-14_ scenario tsunamis were generated for five simulated tide gauges and are shown on event westward along the Seattle fault such that the fault begins at the western end Information about NTHMP is available at http://nthmp.tsunami.gov/. During the plates. [http://pubs.usgs.gov/of/2002/ofr-02-0060/] Quileute area (Walsh and others, 2003b), Seattle (Walsh and others, 2003c), s Tacoma tidal flats in 1894 (Kimball, 1897), the Tacoma Narrows in 1949 tsunami_hazard_elliottbay.pdf] ou Figures 5 and 6. of the original EERI fault and continues west under the central Puget Sound for 24 study, NCTR maintained close communication with WAEMD and WADGER Pratt, T. L.; Johnson, S. Y.; Potter, C. J.; Stephenson, W. J.; Finn, C. A., 1997, Seismic reflection Bellingham (Walsh and others, 2004), Anacortes–Whidbey Island (Walsh and th (González, 2003), and in the lower Columbia River in 1965 (Aberdeen Daily Walsh, T. J.; Titov, V. V.; Venturato, A. J.; Mofjeld, H. O.; González, F. I., 2004, Tsunami hazard e images beneath Puget Sound, western Washington State—The Puget Lowland thrust sheet others, 2005), and Tacoma (Walsh and others, 2009). rn Whidbey Island km (Fig. 5). This scenario uses a simplified fault model with a constant depth and World, February 1, 1965). Shipman (2001) reported a landslide-induced tsunami and, upon completion of the study, a suite of model-derived mapping products map of the Bellingham area, Washington—Modeled tsunami inundation from a Cascadia W Everett Scenario A. Seattle Fault M 7.3 Event hypothesis: Journal of Geophysical Research, v. 102, no. B12, p. 27,469-27,489. h w dip angle and uniform 2.8 m vertical uplift derived by scaling down Scenario A to were delivered to both agencies in the form of electronic files and, where subduction zone earthquake: Washington Division of Geology and Earth Resources Open File id generated from Camano Island that inundated a Native American village on P b Rogers, W. P., 1970, A geological and geophysical study of the central Puget Sound lowland: u e This scenario is identical to the Seattle fault scenario defined by Titov and others account for the overall smaller magnitude (Table 2). appropriate, hard copy representations. Reviews by Stephen Slaughter Report 2004-15, 1 sheet, scale 1:50,000. [http://www.dnr.wa.gov/publications/ger_ofr2004-15_ 101 ge y Gedney (Hat) Island, probably early in the 19th century, as reconstructed from PALEOSEISMOLOGY OF THE I University of Washington Doctor of Philosophy thesis, 123 p., 9 plates. tsunami_hazard_bellingham.pdf] t s (2003) and was also previously used for modeling inundation in Tacoma (WADGER) and John Schelling (WAEMD) were helpful. la Native American oral history. Figure 7 shows the presumed landslide scar and the n Sherrod, B. L.; Bucknam, R. C.; Leopold, E. B., 2000, Holocene relative sea level changes along Walsh, T. J.; Titov, V. V.; Venturato, A. J.; Mofjeld, H. O.; González, F. I., 2005, Tsunami hazard S d (Venturato and others, 2007). This scenario was designed to be a maximum Table 2. Scenario B seismic fault parameters for a Seattle fault MW 6.7 earthquake, SEATTLE FAULT clearly vulnerable Gedney Island immediately to the south. While landslide the Seattle fault at Restoration Point, Washington: Quaternary Research, v. 54, no. 3, o fa modified from the scenario earthquake used by EERI (Stewart, 2005). Strike is measured map of the Anacortes–Whidbey Island area, Washington—Modeled tsunami inundation from u u n l 2 credible event and uses the vertical deformation constraints from the AD 900 to sources clearly present at least a localized tsunami threat, modeling those REFERENCES p. 384-393. Geographic features now known to be associated with the Seattle fault have been d t from north and dip direction is 90ºperpendicular clockwise fromto the the strike strike azimuth. azimuth. a Cascadia subduction zone earthquake: Washington Division of Geology and Earth zo n 930 earthquake along the Seattle fault (Bucknam and others, 1992). It is described tsunamis is beyond the scope of this effort. Shipman, Hugh, 2001, The fall of Camano Head—A Snohomish account of a large landslide and Resources Open File Report 2005-1, 1 sheet, scale 1:62,500. [http://www.dnr.wa.gov/ noted for many years. In his journal entry for May 29, 1792, Vancouver (1798) e Fault segment Width (km) Length (km) Strike (deg) Dip (deg) Slip (m) Atwater, B. F., 1999, Radiocarbon dating of a Seattle earthquake to A.D. 900–930 [abstract]: noted that the fault-uplifted and wavecut bedrock platform at Restoration Point on by six fault segments of varying length and strike, with slip ranging from 1 to 12 Seismological Research Letters, v. 70, no. 2, p. 232. tsunami in Possession Sound during the early 1800s: TsuInfo Alert, v. 3, no. 6, p. 13-14. publications/ger_ofr2005-1_tsunami_hazard_anacortes_whidbey.pdf] B1 35.0 6.3 86.6 45.0 2.8 Limitations of the Maps Bainbridge Island “did not possess that beautiful variety of landscape, being an m (Table 1). Atwater, B. F.; Moore, A. L., 1992, A tsunami about 1000 years ago in Puget Sound, Washington: [http://www.dnr.wa.gov/Publications/ger_tsuinfo_2001_v3_no6.pdf] B2 35.0 8.9 96.0 45.0 2.8 almost impenetrable wilderness of lofty trees” that characterized the rest of his 1 The largest source of uncertainty in these model results is the input earthquake Science, v. 258, no. 5088, p. 1614-1617. Stewart, Mark, editor, 2005, Scenario for a magnitude 6.7 earthquake on the Seattle Fault: Scenario A (M 7.3) Scenario B (M 6.7) B3 35.0 3.2 128.8 45.0 2.8 Earthquake Engineering Research Institute and Washington Military Department Emergency explorations in Puget Sound. Kimball (1897) also noted the uplifted wavecut w w event because the nature of the tsunami depends on the initial deformation. The Blakely, R. J.; Wells, R. E.; Weaver, C. S., 1999, Puget Sound aeromagnetic maps and data: U.S. 2 1. Central Puget Sound B4 35.0 5.8 99.3 45.0 2.8 Management Division, 162 p. platform at Restoration Point, measured its height, and identified the marine earthquake scenarios used in this modeling were selected to honor the Geological Survey Open-File Report 99-514, version 1.0. [http://geopubs.wr.usgs.gov/ open-file/of99-514/] ten Brink, U. S.; Molzer, P. C.; Fisher, M. A.; Blakely, R. J.; Bucknam, R. C.; Parsons, T. E.; fossils found there. He also described the Newcastle Hills, part of the hanging 1 paleoseismic constraints, but the next Seattle fault earthquake may be 405 Blakely, R. J.; Wells, R. E.; Weaver, C. S.; Johnson, S. Y., 2002, Location, structure, and Crosson, R. S.; Creager, K. C., 2002, Subsurface geometry and evolution of the Seattle fault 0 RESULTS substantially different from those that have been characterized. Sherrod and wall of the fault, as a ‘postglacial eruption’. Daneš and others (1965) interpreted seismicity of the Seattle fault zone, Washington—Evidence from aeromagnetic anomalies, zone and the Seattle basin, Washington: Seismological Society of America Bulletin, v. 92, no. 5, p. 1737-1753. the large gravity and magnetic anomalies through central Puget Sound, and an −1 Maximum inundation depth and current velocity are model outputs and are others (2000) show that a prior uplift event at Restoration Point (predating the AD geologic mapping, and seismic-reflection data: Geological Society of America Bulletin, al Bainbridge an West on associated abrupt change in sedimentary section thickness, as an active fault with C Island t displayed on Figures 1 through 4. The depth intervals chosen for Figure 1 (0–2 ft, 900 to 930 event) was smaller. Paleoseismic trenching of structures subsidiary to v. 114, no. 2, p. 169-177. ten Brink, U. S.; Song, Jianli; Bucknam, R. C., 2006, Rupture models for the A.D. 900–930 Point Seattle g 2 2. Possession Sound d n oo Seattle fault earthquake from uplifted shorelines: Geology, v. 34, no. 7, p. 585-588. about 11 km of displacement. Rogers (1970) collected additional gravity and H mode hi 2–6 ft, and 6–8 ft) broadly represent hazard to people—inundation up to an the Seattle fault—thought to be coseismic with the main fault trace (Nelson and Bourgeois, Joanne; Johnson, S. Y., 2001, Geologic evidence of earthquakes at the Snohomish led Sea s ttle a 1 A1 A2 fau Bellevue delta, Washington, in the past 1200 yr: Geological Society of America Bulletin, v. 113, no. 4, Titov, V. V.; González, F. I., 1997, Implementation and testing of the Method of Splitting Tsunami magnetic data across the structure and named it the Seattle–Bremerton fault. A3 lt W adult’s knees, from the knees to the head, and over the head. The modeling for

A4 e Landslide on Camano Head (MOST) model: NOAA Technical Memorandum ERL PMEL-112, PB98-122773, 11 p. B1 B2 k 0 Scenario B yielded a maximum inundation depth of 3 ft. Note that tide flats are p. 482-494. Gower (1978) demonstrated that the uplift at Restoration Point was Holocene in B3 A5 La Titov, V. V.; González, F. I.; Mofjeld, H. O.; Venturato, A. J., 2003, NOAA TIME Seattle tsunami age and Bucknam and others (1992) showed that an earthquake produced 7 m of Bremerton A6 −1 shown in the aerial photo base maps—but are assumed to be underwater in the Camano Brocher, T. M.; Blakely, R. J.; Wells, R. E., 2004, Interpretation of the Seattle uplift, Washington, Restoration B4 Island as a passive-roof duplex: Seismological Society of America Bulletin, v. 94, no. 4, mapping project—Procedures, data sources, and products: NOAA Technical Memorandum uplift on the fault about 1000 years ago (Sherrod and others, 2000), probably Point 3. Port Gardner east waterway model—because the initial model conditions assume that the tide stage is at mean Mercer 90 2 p. 1379-1401. OAR PMEL-124, 21 p. between AD 900 and 930 (Atwater, 1999), and hereafter referred to as the AD 900 A1 Scenario A fault segments (Table 1) 5 Island high water. Current velocities are given in knots following Lynett and others’ Newcastle Hills 1 Brocher, T. M.; Parsons, T. E.; Blakely, R. J.; Christensen, N. I.; Fisher, M. A.; Wells, R. E.; Titov, V. V.; Synolakis, C. E., 1998, Numerical modeling of tidal wave run up: Journal of to 930 event. B1 Scenario B fault segments (Table 2) (2014, p. 2049–2050) proposed damage thresholds. They state: 1 SHIPS Working Group, 2001, Upper crustal structure in Puget Lowland, Waterway, Port, Coastal and Ocean Engineering, v. 124, n. 4, p. 157–171. Simulated tide gauge 0 In 1996, the first of a series of lidar (Light Detection and Ranging) surveys “although damage in harbors might vary based on the age and location of docks Washington—Results from the 1998 Seismic Hazards Investigations in Puget Sound: Journal Vancouver, George, 1798, repr. 1992, A voyage of discovery to the north Pacific Ocean, and −1 was flown over Bainbridge Island. This and subsequent lidar missions have 05 mi and boats, some generalities about the relationship between tsunami currents of Geophysical Research, v. 106, no. B7, p. 13,541-13,564. round the world; in which the coast of north-west American has been carefully examined and Suggested citation: Walsh, T. J.; Arcas, Diego; Titov, V. V.; enabled scientists to accurately locate expressions of the Seattle fault in a number 2 4. Snohomish channel entrance and damage can be determined....there is a noticeable threshold for damage Bucknam, R. C.; Hemphill-Haley, Eileen; Leopold, E. B., 1992, Abrupt uplift within the past accurately surveyed—Undertaken by His Majesty's command, principally with a view to Chamberlin, C. C., 2014, Tsunami hazard map of Everett, Figure 5. Location of study area, modeled segments of the Seattle fault, and simulated Wave amplitude (m) ascertain the existence of any navigable communication between the north Pacific and north Washington: model results for magnitude 7.3 and 6.7 Seattle of places and to site paleoseismic trenches across those faults in order to initiation at ~3 knots (1.5 m/s). When 3 knots is exceeded, the predicted Copyright © 1994–2014 Washington State Department of Ecology 1700 years at southern Puget Sound, Washington: Science, v. 258, no. 5088, p. 1611-1614. tide gauge stations used to model tsunami time-amplitude histories. 1 Atlantic Oceans; and performed in the years 1790, 1791, 1792, 1793, 1794, and 1795: G. G. and fault earthquake tsunamis: Washington Division of Geology determine fault age and potential recurrence intervals (Bucknam and others, 1999; damage state switches from no damage to minor to moderate damage. Thus, in Bucknam, R. C.; Sherrod, B. L.; Elfendahl, G. W., 1999, A fault scarp of probable Holocene age and Earth Resources Open File Report 2014-03, 1 sheet, J. Robinson [London], 3 v. 0 the simulated data, 3 knots represents the ﬁrst important current velocity in the Seattle fault zone, Bainbridge Island, Washington (abstract): Seismological Research scale 1:32,000. Nelson and others, 2002). At about the same time, the USGS began several Gedney (Hat) Island been trenched in central Puget Sound were generated by bedding-plane slip on −1 threshold. We then argue that the second threshold is at 6 knots (3 m/s), where Letters, v. 70, no. 2, p. 233. Venturato, A. J.; Arcas, Diego; Titov, V. V.; Mofjeld, H. O.; Chamberlin, C. C.; González, F. I., large-scale geophysical studies. An aeromagnetic study of the Puget Sound reverse faults—which can rupture independently of the master Seattle fault—and 2007, Tacoma, Washington, tsunami hazard mapping project— Modeling tsunami inundation Disclaimer: This product is provided ‘as is’ without warranty of any kind, either 5. Central Snohomish channel damage transitions from moderate to major. A third current speed threshold is Daneš, Z. F.; Bonno, M.; Brau, J. E.; Gilham, W. D.; Hoffman, T. F.; Johansen, D.; Jones, M. H.; (Blakely and others, 1999, 2002) enabled more accurate location of the fault along 2 from Tacoma and Seattle fault earthquakes: National Oceanic and Atmospheric expressed or implied, including, but not limited to, the implied warranties of they proposed that the Seattle fault zone is a wedge thrust, with the northern, less clear, but is logically around 9 knots (4.5 m/s).” Malfait, Bruce; Masten, J.; Teague, G. O., 1965, Geophysical investigation of the southern merchantability and fitness for a particular use. The Washington Department of Whidbey Administration, Pacific Marine Environmental Laboratory Technical Memorandum its entire length. Seismic studies, such as SHIPS (Seismic Hazards Investigations leading edge being a fault-bend wedge-thrust fold. 1 Puget Sound area, Washington: Journal of Geophysical Research, v. 70, no. 22, p. 5573-5580. Natural Resources and the authors of this product will not be liable to the user of These thresholds were developed almost entirely from observations in ports and Island OAR-PMEL-132, 23 p. this product for any activity involving the product with respect to the following: in Puget Sound; Brocher and others, 2001) and other geophysical studies in Puget There also is substantial evidence that earthquakes on the Seattle fault have 0 EVERETT Dragovich, J. D.; Logan, R. L.; Schasse, H. W.; Walsh, T. J.; Lingley, W. S., Jr.; Norman, D. K.; harbors and apply to newer harbor facilities. Older (40–50 year-old) or run-down Possession Sound Walsh, T. J.; Arcas, Diego; Venturato, A. J.; Titov, V. V.; Mofjeld, H. O.; Chamberlin, C. C.; (a) lost profits, lost savings, or any other consequential damages; (b) fitness of the Sound, have greatly increased the understanding of the fault at depth (Pratt and generated tsunamis. Atwater and Moore (1992) showed that tsunamis inundated −1 Gerstel, W. J.; Lapen, T. J.; Schuster, J. E.; Meyers, K. D., 2002, Geologic map of product for a particular purpose; or (c) use of the product or results obtained from facilities may have slightly lower thresholds (Rick Wilson, California Geological González, F. I., 2009, Tsunami hazard map of Tacoma, Washington—Model results for others, 1997; Johnson and others, 1999; ten Brink and others, 2002; Brocher and part of Whidbey Island and West Point about 1000 years ago (Figure 5). Jacoby 0 0.5 1 1.5 2 2.5 3 Washington—Northwest quadrant: Washington Division of Geology and Earth Resources use of the product. This product is considered to be exempt from the Geologist Survey, written commun., 2014). Figures 1–4 show depth of inundation and Geologic Map GM-50, 3 sheets, scale 1:250,000, with 72 p. text. [http://www.dnr.wa.gov/ Seattle fault and Tacoma fault earthquake tsunamis: Washington Division of Geology and Licensing Act [RCW 18.220.190 (4)] because it is geological research conducted others, 2004). Later, ten Brink and others (2006) evaluated existing fault models and others (1992) further showed that a tree in the tsunami deposit at West Point Time (hours since event) Earth Resources Open File Report 2009-9, 1 sheet, scale 1:24,000. [http://www.dnr.wa.gov/ by the State of Washington, Department of Natural Resources, Division of current velocity for the two scenarios. 012 miles Publications/ger_gm50_geol_map_nw_wa_250k.pdf] by using uplifted shorelines and concluded that the best-fitting model geometry is died the same season of the same year as a drowned forest carried into Lake Imagery from 2011 Washington State NAIP publications/ger_ofr2009-9_tsunami_hazard_tacoma.pdf] Geology and Earth Resources. Figure 6. Modeled tsunami amplitudes at the simulated tide gauges shown in Figure 5, González, F. I., compiler, 2003, Puget Sound tsunami sources—2002 workshop report: a south-dipping reverse fault with a shallow roof ramp consisting of at least two Figure 7. Historic landslide on Camano Head (inset, annotated) may have caused a Washington by a huge landslide from Mercer Island, strongly implicating the AD arranged by proximity to the Seattle fault. NOAA/Pacific Marine Environmental Laboratory Contribution No. 2526, 36 p. back thrusts. Kelsey and others (2008) suggested that some of the scarps that have 900 to 930 seismic event on the Seattle fault. A discontinuous sand layer along tsunami at nearby Gedney (Hat) Island and inundated a Native American village. Base map from 2011 Snohomish County NAIP color 3-foot-resolution aerial photos HARN State Plane coordinate system, Washington South FIPS 4602 North American Datum of 1983 Shaded relief generated from U.S. Geological Survery 10-meter digital elevation model Digital cartography by Anne C. Olson Editing and production by Alexander N. Steely and Jaretta M. Roloff http://www.dnr.wa.gov/geology/ © 2014 Washington Division of Geology and Earth Resources