A UW researcher says the fault line that caused earthquake that shook southern Turkey near the Turkish-Syrian border this week and killed more than 7,000 people is similar to the faults under Puget Sound. Yet the SHZ and WRZ may be integral to the regional geology of Puget Sound, possibly revealing some deep and significant facets, and may also present significant seismic hazard. One animation shows the expected path of a Puget Sound tsunami generated by a quake on the Seattle Fault. This is supported by geologically recent scarps and other signs of active faulting on the Saddle Mountain faults, and also discovery of a geophysical lineament running through Pleasant Harbor (south of Brinnon) that appears to truncate strands of the Seattle Fault. Another model (of Stanley, Villaseor & Benz 1999, USGS Open-File Report 990311) not so much in competition with the first as complementing it used seismic and other data to create a 3-D tectonic model of the whole crust; this was then analyzed using finite element methods to determine regional geodynamic characteristics. Its capable magnitude is a megathrust quake exceeding 9.0. That wave is quite severe, quite high. There's a one-in-10 chance that the next . [8] As of 1985 only the Saddle Mountain Faults had been shown to have Holocene activity (since the last ice age, about 12,000 years ago). (E.g., the Olympia Fault is aligned with and appears to be the northernmost member of a set of faults between Olympia and Chehalis that may extend to the Columbia River, and there has been a suggestion that the Tacoma Fault may connect with the White RiverNaches River fault on the east side of the Cascades.[24]). Page 2 of 4 / 2012-2013 Type of Earthquake Most earthquake hazards result from ground shaking caused by seismic waves that radiate out from a fault when it ruptures. [203] This line is the southernmost of a band of NE trending faults and topographical lineaments that extend from the Oregon coast into the North Cascades. A magnitude 7.1 earthquake in the Tacoma Fault Zone A plausible scenario for the southern Puget Sound region, Washington May 18, 2010 Citation Information. The Seattle Fault, a zone of east-west thrust faults under the Puget Sound and Seattle, last ruptured in a magnitude-7.0 to -7.5 earthquake about 1,100 years ago. Kinematic analysis suggests that if shortening (compression) in the Puget Lowland is directed to the northeast (i.e., parallel to Hood Canal and the Saddle Mountain deformation zone) and thus oblique to the Dewatto lineament, it should be subject to both strike-slip and dip-slip forces, implying a fault. These bends are located where they intercept a "subtle geological structure"[202] of "possible fundamental importance",[203] a NNE striking zone (line "A" on the map) of various faults (including the Tokul Creek Fault NNE of Snoqualmie) and early-Miocene (about 24 Ma) volcanic vents and intrusive bodies (plutons and batholiths) extending from Portland to Glacier Peak;[204] it also marks the change in regional fault orientation noted above. Analyze Instructions: Close. [46] Seismic tomography studies show that this portion of the SWIF marks a strong contrast of seismic velocities, such as is expected of Crescent Formation basalts in contact with the metamorphic basement rocks of the Cascades geologic province to the east. An earthquake occurs along a south-moving fault. The Doty fault particularly seems to have gained prominence with geologists since it was associated with an aeromagnetic anomaly,[184] and a report in 2000 credited it capable of a magnitude 6.7 to 7.2 earthquake. Cluster of earthquakes in Puget Sound considered 'normal', earthquake researchers say. A Seattle Fault quake could be as large as M7.5,160 but less than M7.0 is more probable. [118], Studies of the Seattle Fault west of Bremerton have revealed a complexity of geological structure and faulting. (See, There is a preliminary report of aeromagnetic and gravity mapping placing the eastern edge of the Siletz terrane under Lake Washington. And the magnitude used to generate that wave is only about 7.5, as opposed to a magnitude-9 earthquake off the coast. The Devils Mountain Fault separates two similar but distinctive ensembles of Mesozoic (pre-Tertiary, before the dinosaurs died) or older rock. It therefore seems reasonable that the rest of the SWIF (and its apparent extension, the RMFZ) follows the Coast RangeCascade contact, and (these faults being active) constitutes the CRBF. [102] Or the Crescent margin may simply (and quietly) just run south-southeast under Seattle to the WRZ. [61], North of Everett is an area of parallel ridges and stream drainages oriented approximately NW-SE, evident even on non-geological maps. Some upper-crustal formations (such as the Western and Eastern Melange Belts, see, There is a general north or northeast directed compression within the Lowland causing folds, which eventually break to become, This page was last edited on 11 January 2023, at 17:28. Here, the Cherry Creek and Tokul Creek faults zones on the east side of the RMFZ are conjugate to the SWIF on the west side. [95], (Rattlesnake Mountain Fault Zone not included in QFFDB. In the map above these are represented by the pair of dotted lines at the lower right. Glacially deposited and shaped fill covers most of the lower elevations of Puget Sound. Base map is hillshaded DEM derived from LiDAR data (pixel size 1.8 m) from Puget Sound LiDAR Consortium; illumination from azimuth 05, at 5 above the horizon; datum is NAD83, UTM zone 10N. Strands of the east-striking Devils Mountain Fault cross the northern tip of Whidbey Island at Dugualla Bay and north side of Ault Field (Whidbey Island Naval Air Station). 206-296-3830. Tacoma, WA. The structure of the Seattle Fault zone still have great uncertainty and there exist a number of interpretations. The ultimate driver of the stresses that cause earthquakes are the motions of the tectonic plates: material from the Earth's mantle rises at spreading centers, and moves out as plates of oceanic crust which eventually are subducted under the more buoyant plates of continental crust. The alternative, that younger faulting in the Rogers Belt has offset the DMF Cheney argued that the MVF had offset the DMF 47km. Movement on the southern segment of the DDMFZ that converges with the SCF the Darrington Fault was, as on the SCF itself, right-lateral. These lineaments have been associated with possible zones of faulting in the crust and subducting plate.[212]. A Puget Sound Fault running down the center of Puget Sound (and Vashon Island) was once proposed,[220] but seems to have not been accepted by the geological community. Just past them is the parallel Olympia Structure, which as a geophysical lineament has been traced to a point due east of Chehalis;[189] these would seem to be related somehow, but the nature of that relationship is not yet known. It does bound the north side of the Chehalis basin, but the south boundary of the Black Hills Uplift is more properly the southeast striking Scammon Creek Fault that converges with the DotySalzer Creek Fault just north of Chehalis. [134] Most authors align it with the strong gravitational anomaly (which typically reflects where faulting has juxtaposed rock of different density) and topographical lineament down Commencement Bay. This is a seemingly accidental alignment of topographic features that runs roughly east-southeast from the north side of the Olympic Peninsula to the Wallowa Mountains in northeastern Oregon. This is the Dewatto lineament, believed to result from an east-dipping low-angle thrust fault where the western flank of the Seattle Uplift has been pushed into the northwestern corner of the Tacoma Basin. This map is useful in showing the location and approximate length of faults but does not provide the impact an earthquake from a fault could have on the area surrounding. It's the other counties in the Puget . A single earthquake in Seattle could cause a catastrophic situation for the northwest corner of the state, a new report from Washington's Department of Natural Resources found. [210] The zone between these two lines, reflecting changes in regional structure, seismicity, fault orientation, and possibly the underlying lithospheric structure, appears to be a major structural boundary in the Puget Lowland. The energy of the somewhat smaller Benioff earthquakes is likewise diluted over a relatively large area. [213] Seismicity sometimes occurs in zones, such as has been observed under Mercer Island, or from downtown Seattle towards Kirkland[214] but whether particular zones reflect undiscovered faults, or might be the source of damaging earthquakes, is generally unknown. It is not known to be seismic indeed, there is very little seismicity south of the Tacoma Basin as far as Chehalis[169] and not even conclusively established to be a fault. [49] Yet it is also notable that "most seismicity in the northern Puget Sound occurs along and southwest of the southern Whidbey Island fault at typical depths of 1527 km within the lower part of the Crescent Formation. Review for American Spirit to U.S.A. Gilliancruise. The Woods Lake Fault, running past Lake Chaplain, corresponds closest to the mapped position of the southern end of Cheney's Mount Vernon Fault. This boundary would be the contact where northward movement of the basement rock of the Puget Lowland against the Olympic Peninsula is accommodated; it would be expected to be a significant seismological zone. Marine seismic reflection surveys on either side of Whidbey Island extend the known length of these faults to at least 26 and 28km (about 15 miles). Both the SPF and UPF are said to be oblique-slip transpressional; that is, the faults show both horizontal and vertical slip as the crustal blocks are pressed together. (2001),[111] relying on seismic tomography data from the "Seismic Hazards Investigation in Puget Sound" (SHIPS) experiment, retains the thrusting slab and master ramp concepts, but interprets the Tacoma fault as a reverse fault (or back thrust) that dips north towards the south dipping Seattle fault (see diagram); as a result the Seattle Uplift is being popped up like a horst. Doubts on the connectivity of these faults led to abandonment of this name in 1986[65] when Cheney mapped the Mount Vernon fault (MVF) from near Sultan northwest past Lummi Island (west side of Bellingham Bay, visible at the top of the map), crossing the Devils Mountain Fault (DMF, part of the DarringtonDevils Mountain Fault Zone) near Mount Vernon. It appears that the Seattle Uplift is acting as a rigid block, with the Tacoma, Dewatto, and Seattle faults being the southern, western, and northern faces. [83], The CCFZ appears to be related to the parallel Tokul Creek fault zone to the south; both appear to be conjugate faults[84] to the northwest-trending SWIF. Job Description. News Media at VA Puget Sound health care, 206-764-2435, 206-764-2317. [Paper No. The first item on your list though is the fault of builders and nobody else. [53] Reckoned between Victoria and approximately Fall City the length of the SWIF is around 150km (90 miles). 1958 and Geologic Map GM-34 for details.). [215] There is a general pattern where most of these faults partition a series of basins and uplifts, each about 20km wide. Rainier, along the DDMFZ, and under Puget Sound between Olympia and approximately the Southern Whidbey Island Fault. Washington State Earthquake Hazard Map Seattle Fault Lines 552 - Hood Canal fault zone (Class B) 570 - Seattle fault zone 572 - Southern Whidbey Island fault zone 575 - Saddle Mountain faults 581 - Tacoma fault zone USA Earthquake Hazard Map Source: United States Geological Survey Ready to retrofit? Please follow the steps below: . See. [130] This is likely not coincidental, as it appears that the Tacoma and Seattle faults converge at depth (see diagram above) in a way that northsouth compression tends to force the Seattle Uplift up, resulting in dip-slip movement on both fault zones. [32] And it is suggested that the Great Seattle Quake of approximately 1,100 years ago, and other coseismic events in southern Puget Sound around that time, were a single event that affected this entire block, with a magnitude of around 8, possibly triggered by an earthquake deeper in the crust.[33]. New gravity data provide information [abstract]", "Fault locking, block rotation and crustal deformation in the Pacific Northwest", "The Everett fault: a newly discovered late Quaternary fault in north-central Puget Sound, Washington [abstract]", "Late Holocene earthquakes on the Toe Jam Hill fault, Seattle fault zone, Bainbridge Island, Washington", "Field and laboratory data from an earthquake history study of scarps in the hanging wall of the Tacoma fault, Mason and Pierce Counties, Washington", "Three-dimensional velocity structure of Siletzia and other accreted terranes in the Cascadia forearc of Washington", "Geologic map of the Skokomish Valley and Union 7.5-minute quadrangles, Mason County, Washington", "Supplement to Geologic Maps of the Lilliwaup, Skokomish Valley, and Union 7.5-minute Quadrangles, Mason County, Washington Geologic Setting and Development Around the Great Bend of Hood Canal", "Geologic map of the Hoodsport 7.5-minute quadrangle, Mason County, Washington", "Geologic map of the Brinnon 7.5-minute quadrangle, Jefferson and Kitsap Counties, Washington", "Geologic map of the Seabeck and Poulsbo 7.5-minute quadrangles, Kitsap and Jefferson Counties, Washington", "Evidence for earthquake-induced subsidence ~1100 yr ago in coastal marshes of southern Puget Sound, Washington", 10.1130/0016-7606(2001)113<1299:EFEISA>2.0.CO;2, "Holocene fault scarps and shallow magnetic anomalies along the Southern Whidbey Island Fault Zone near Woodinville, Washington", "Finding concealed active faults: Extending the southern Whidbey Island fault across the Puget Lowland, Washington", "Holocene fault scarps near Tacoma, Washington, USA", "The Catfish Lake Scarp, Allyn, Washington: Preliminary Field Data and Implications for Earthquake Hazards posed by the Tacoma Fault", "Seismic Amplification within the Seattle Basin, Washington State: Insights from SHIPS Seismic Tomography Experiments", "Tectonics and Conductivity Structures in the Southern Washington Cascades", "Analysis of Deep Seismic Reflection and Other Data From the Southern Washington Cascades", "Tectonics and Seismicity of the Southern Washington Cascade Range", "Subduction zone and crustal dynamics of western Washington: A tectonic model for earthquake hazards evaluation", 10.1130/0016-7606(1994)106<0217:lmapet>2.3.co;2, "Geologic map of the Snoqualmie Pass 60 minute by 30 minute quadrangle, Washington", "Subsurface Geometry and Evolution of the Seattle Fault Zone and the Seattle Basin, Washington", "Rupture models for the A.D. 900930 Seattle fault earthquake from uplifted shorelines", "Stratigraphy of Eocene rocks in a part of King County, Washington", "Geologic map of Washington Southwest Quadrant", "Geologic Map of the East Olympia 7.5-minute Quadrangle, Thurston County, Washington", "Field data for a trench on the Canyon River fault, southeast Olympic Mountains, Washington", "Crustal Extension at Mount St. Helens, Washington", "Final Technical Report: Two Post-Glavial Earthquakes on the Saddle Mountain West Fault, southeastern Olympic Peninsula, Washington", "Earthquake scenario and probabilistic ground shaking maps for the Portland, Oregon, metropolitan area", "Bedrock Geologic Map of the Seattle 30' by 60' Quadrangle, Washington", Preliminary Atlas of Active Shallow Tectonic Deformation in the Puget Lowland, Washington (USGS Open-File Report 2010-1149). They run . normal. 09 Feb 2023 03:01:00 external structure, lines, and riggings; stand deck watches, such as helmsman and lookout underway; stand pier sentry, fire security, anchor, and . In 1870, as construction of the Northern Pacific began, Seattle numbered fewer than 1,200 souls. Sail Date: October 2022 . These faults are: the Kopiah Fault (note the curious curve), Newaukum Fault, Coal Creek Fault, and three other unnamed faults. Geologic map of northwestern Washington (GM-50). Puget Sound, Washington has had: (M1.5 or greater) 0 earthquakes in the past 24 hours. One study compared the relative elevation of two marshes on opposite sides of Whidbey Island, and determined that approximately 3,000 years ago an earthquake of M 6.57.0 caused 1 to 2 meters of uplift. Conjugate faults are secondary faults that branch off from opposite sides of a strike-slip fault at approximately the same angle. Since 2000 studies of LIDAR and high-resolution aeromagnetic data have identified scarps near Woodinville which trenching has confirmed to be tectonically derived and geologically recent. North Olympic Peninsula VA Clinic at VA Puget Sound health care, 360-565-7420. Also intersecting at Mount St. Helens is a NE (045) trending line (red) of Pleistocene (about 4 Ma) plug domes and a topographic lineament (followed in part by Highway 12). Puget Sound Energy. [44] Another problem with the SWIF/RMFZ as CRBF is that a large westward step is required to connect from the RMFZ to the Saint Helens Zone (SHZ; see map), whereas the RMFZ turns easterly to align with the OWL. 182-3]", "Western limits of the Seattle fault zone and its interaction with the Olympic Peninsula, Washington", "Seismic reflection imaging across the eastern portions of the Tacoma fault zone", "The western extension of the Seattle fault: new insights from seismic reflection data", "Seismic Characterization of the Seattle and Southern Whidbey Island Fault Zones in the Snoqualmie River Valley, Washington", "Fault number 552, Hood Canal fault zone", "Radiocarbon Ages of Probable Coseismic Features from the Olympic Peninsula and Lake Sammamish, Washington", "Geologic map of the Summit Lake 7.5-minute quadrangle, Thurston and Mason Counties, Washington", "The Olympia structure; ramp or discontinuity? In some places, such as along the South Fork of the Stillaguamish River between Arlington and Granite Falls, there are also contrasting geological contacts. Read More. And though the faults in this area are not notably seismogenic, the southeast striking faults seem to be en echelon with the Olympia structure (fault? [72] The WMB is an assemblage of Late Jurassic and Cretaceous rock (some of it as much as 166 million years old) collected in the accretionary wedge (or prism) of a subduction zone. [155] North of the Seattle Fault accommodation of regional movement may be along the northwest-striking Dabob Bay Fault Zone. These include (from north to south, see map) the: The Puget Sound region (Puget Lowland[1]) of western Washington contains the bulk of the population and economic assets of the state, and carries seven percent of the international trade of the United States.