While the great subduction events release much energy (around magnitude 9), that energy is spread over a large area, and largely centered near the coast. Sail Date: October 2022 . These include (from north to south, see map) the: Devils Mountain Fault Strawberry Point and Utsalady Point faults Southern Whidbey Island Fault (SWIF) Tobin says offshore faults tend to cause bigger earthquakes and are a larger tsunami risk. ecc.kc@kingcounty.gov. They estimate the fault is within a few miles of the surface and was active as recently as 1,000 to 1,100 years ago. Ancient quake and tsunami in Puget Sound shake researchers [60] Such seismic hazards were a major issue in the siting of the plant, as it is tucked between two active strands, and the influent and effluent pipelines cross multiple zones of disturbed ground. (1997), while observing the "remarkable straight boundaries that we interpret as evidence of structural control",[171] refrained from calling this structure a fault. Subsidence dated to between AD 1445 and 1655 has been reported in Mud Bay (just west of Olympia). The answer is still unresolved. This bend has distorted the subducting slab into an arch that has lifted the Olympic Mountains and prevented them from subducting. South of Monroe the folds of the Rogers Belt are obscured by subsequent volcanic formations, but other faults parallel to the RMFZ (e.g., the Snoqualmie Valley and Johnson's Swamp fault zones) extend the general trend of NNW faulting as far as Monroe. A Cascadia event could cause dangerous currents in Puget Sound, reaching speeds up to 9 knots in the Agate Passage north of Bainbridge Island and 6 knots off of Discovery Park in Seattle. OLYMPIA, Wash. - A 9. Saint Helens and Mt. Combined with continued aggressive electric conservation efforts, Energize . Seismic waves transmit the energy Puget Sound faults - Wikipedia Olympic Peninsula, Washington has had: (M1.5 or greater) 0 earthquakes in the past 24 hours. The history and capabilities of the Frigid Creek Fault are not known. Publication Year: 2010: Title: A magnitude 7.1 earthquake in the Tacoma Fault Zone A plausible scenario for the southern Puget Sound region, Washington: DOI: 10.3133/fs20103023: Authors: Deep quakes are the most common large earthquakes that occur in the Puget Sound region. The Devils Mountain Fault (DMF) runs about 125km (75 miles) from the town of Darrington in the Cascade foothills due west to the northern tip of Whidbey Island, and on towards Victoria, British Columbia, where the DMF is believed to join the Leech River fault system at the southern end of Vancouver Island. There is no firm evidence that this has occurred in the Seattle fault zone near Puget Sound, although a low terrace of 1 m or less formed during a moderate earthquake would be difficult to. [42] Marine seismic reflection surveys show it striking northwest across the eastern end of the Strait of Juan de Fuca. slope, need not be high. While these models vary in some details, both indicate that the Seattle Fault itself is capable of a magnitude 7.5 earthquake. [181] What is unknown is whether this was due to a great subduction earthquake, to the noted earthquake on the Seattle Fault about that time, or to an earthquake on a local fault (e.g., the Olympia structure); there is some evidence that there were two earthquakes over a short time period. This is only one of a series of active large crustal faults in the Puget Lowland. Railroad Development in the Seattle/Puget Sound Region, 1872-1906 In the map above these are represented by the pair of dotted lines at the lower right. Turkey's fault line is similar to faults under Puget Sound [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. [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. Puget Sound and San Juan islands. The principal effects of this complex interplay of forces on the near-surface crust underlying the Puget Lowland are: Further complicating this is a feature of unknown structure and origin, the OlympicWallowa Lineament (OWL). 1 - 10 of 77 American Spirit Cruise Reviews. [69] The principal zone of faulting extends from the Woods Creek Fault to the Granite Falls Fault Zone (GFFZ), slightly offset from the WCF and running under the town of Granite Falls. Despite not having active plate tectonics, the eastern United States still experiences earthquakes. [180], That Olympia and the south Sound are at risk of major earthquakes is shown by evidence of subsidence at several locations in southern Puget Sound some 1100 years ago. A Massive Earthquake Is Coming to CascadiaAnd It Can't Be Stopped [39] On the basis of marine seismic reflection surveying in the Strait of Juan de Fuca it has been suggested that the DMF, SPF, and UPF are structurally connected (at least in the segment crossing Whidbey Island). Get directions. The Bellingham BayChaplain fault zone was first mapped by Cheney in 1976 as running from near Chaplain Lake (north of Sultan) NNW past Bellingham Bay. [67] However, subsequent mapping shows that the Woods Creek Fault (WCF), a four-mile wide strip of oblique-slip and strike-slip faults just to the west and passing directly under Sultan, appears to be the more significant fault, and better aligned with Mount Vernon. But it does not appear that there have been studies of the deeper structure of these faults, or whether there has been any recent activity. Gonzalez: That Seattle Fault tsunami has been modeled by others. Puget Sound Energy. Geologic Hazard Maps | WA - DNR [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]. A principal finding is that "[c]rustal seismicity in the southern Puget Sound region appears to be controlled by a key block of Crescent Formation occurring just south of the Seattle fault. This fault produced a large earthquake that left a geologic record of surface offsets about 1100 years ago. [219] Various other faults in the North Cascades are older (being offset by the Straight Creek Fault) and are unrelated to the faults in Puget Sound. Also, the sedimentary Chuckanut Formation (part of the NWCS, green) north of the DMF correlates to the Suak and Roslyn Formations just north of Manastash Ridge. However, the Hood Canal fault has been "largely inferred"[147] due to a paucity of evidence, including lack of definite scarps and any other signs of active seismicity. These are usually fairly short, and not believed to be significantly seismogenic. Cheney also mapped the Lake Chaplain Fault, parallel and just east of the MVF, from Lake Chaplain to Granite Falls. This pocket is catching a stream of terranes (crustal blocks about 20 to 30km thick[18]) which the Pacific plate is pushing up the western edge of North America, and in the process imparting a bit of clockwise rotation to southwestern Washington and most of Oregon; the result has been characterized as a train wreck. [76], The Cherry Creek fault zone (CCFZ) was discovered in 2010 while mapping the area at the north end of the Rattlesnake Mountain fault zone (RMFZ). This formation, up to 15km thick, is largely buried (from one to ten kilometers deep), and known mainly by magnetotellurics and other geophysical methods. Recent EQ List Observing these topographical features, some parallel gravity gradients, and a "very active zone of minor seismicity", William Rogers inferred in 1970 a "fault or other major structural feature".[64]. Piecing together the puzzle of the Seattle Fault Zone The Pacific Northwest Seismic Network (PNSN) reported at least three earthquakes within the past few days. Movement on the southern segment of the DDMFZ that converges with the SCF the Darrington Fault was, as on the SCF itself, right-lateral. [109] It extends as far east as (and probably terminates at) the Rattlesnake Mountain Fault Zone (RMFZ; the southern extension of the SWIF) near Fall City. Puget Sound Energy transmission line project Energize Eastside. Five Puget Sound cities likely to feel strong shaking in a megaquake ISNS 2359 Earthquakes and Volcanoes Chapter 5 Questions - Quizlet PNSN Recent Events | Pacific Northwest Seismic Network Black lines show the South Whidbey Island Fault Zone, the Seattle Fault Zone and the Tacoma Fault Zone. A marine seismic reflection study[177] found evidence of faulting at the mouth of Budd Inlet, just north of the Olympia structure, and aligning with faint lineaments seen in the lidar imagery. [129] The western part is an active eastwest striking north dipping reverse fault that separates the Seattle Uplift and the Tacoma Basin, with approximately 30 miles (50km) of identified surface rupture. Rainier is offset because the faults are deep and the conduits do not rise quite vertically.) About 1,100 years ago, a major earthquake rocked Puget Sound, suddenly shooting what is now Restoration Point on Bainbridge Island up about 23 feet while Seattle 's West Point sunk more than. [132], Scarps associated with Holocene uplift of the Tacoma fault have been traced westward to Prickett Lake (southwest of Belfair, see map). Review for American Constellation to U.S.A. chatuga. Energize Eastside project is building a new substation and upgrading approximately 16 miles of existing transmission lines from Redmond to Renton. One problem with this is that the parts of the SWIF east of Puget Sound do not show the velocity contrasts that would indicate contrasting rock types. What makes the DotySalzer Fault (and the short Chehalis Fault striking due east from Chehalis) stand out from the many other faults south of Tacoma is its eastwest strike; the significance of this is not known. A new view is developing that the regional tectonic boundary is not under Hood Canal, but just to the west, involving the Saddle Mountain fault zone (discussed below) and associated faults. After all, Olympia, which is the closest of the cities to the megathrust fault, is estimated to experience the least severe shaking; at the same time, many cities on the east side of the Puget Sound further away from the fault experience much stronger shaking. Cluster of earthquakes in Puget Sound considered 'normal', earthquake researchers say. The geology also suggests that the DMF is moving obliquely up a ramp that rises to the east,[35] possibly an ancient coastal shore. [123] Other studies have faults extending NW or WNW from the SF towards Dabob Bay;[124] these are now recognized as part of the Dabob Bay fault zone. KUOW Public Radio on Twitter: "A UW researcher says the fault line that [38] These earthquakes probably caused tsunamis, and several nearby locations have evidence of tsunamis not correlated with other known quakes. 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. 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. Study: Tsunami from Cascadia mega-quake would submerge Puget Sound 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). 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. If, as this model suggests, the various faults are interconnected within the thrust sheet, there is a possibility that one earthquake could trigger others. In the wedge model of Pratt et al. [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. 206-296-3830. Not until 2001 was it identified as a fault zone,[12] and only in 2004 did trenching reveal Holocene activity. [5] The southern limit nearly matches the southern limit of the glaciation; possibly the seismicity reflects rebound of the upper crust after being stressed by the weight of the glacial ice. [191] How they might be connected is unknown. https://en.wikipedia.org/w/index.php?title=Puget_Sound_faults&oldid=1132982136, Creative Commons Attribution-ShareAlike License 3.0, A great subduction earthquake, such as the. For the following reviews the primary source of information is the U.S. Geological Survey's Quaternary fault and fold database (QFFDB), which includes details of discovery, a technical description, and bibliography for each fault; a specific link is provided (where available) at the end of each section. [62] These ridges (part of a broader regional pattern that reflects the roots of the former Calkins Range[63]) are formed of sediments that collected in the Everett basin during the Eocene, and were subsequently folded by northeast-directed compression against the older Cretaceous and Jurassic rock to the east that bound the Puget Lowland. 10+ Cruises Age 2020s. Energy builds up as elastic strain in rocks. The Puget Sound Region is crisscrossed by fault lines and zones and also located close to the Cascadia Subduction Zone, where the Juan de Fuca and North American tectonic plates meet. It aligns with the West Coast fault and Queen Charlotte Fault system of strike-slip fault zones (similar to the San Andreas Fault in California) on the west side of Vancouver Island, but does not itself show any significant or through-going strike-slip movement. Puget Sound Lidar Consortium Finding faults scarp(n). [6] The first definite indications of most of these faults came from gravitational mapping in 1965,[7] and their likely existence noted on mapping in 1980 and 1985. The Seattle fault isn't a single strand, but a zone of subterranean fractures that extends across Puget Sound, passing under Seattle and reaching as far east as Issaquah. Though the Olympia Structure (a suspected fault) runs towards the SHZ, and delineates the northern edge of an exposed section of the Crescent Formation, it appears to be an upper crustal fold, part of a pattern of folding that extends southeast to cross the Columbia River near The Dalles, and unrelated to the mid and lower crustal SHZ. WASHINGTON: Methane Bubbles Up From Seafloor Near Seattle Scientists look for answers in methane bubbles rising from bottom of [155] North of the Seattle Fault accommodation of regional movement may be along the northwest-striking Dabob Bay Fault Zone. On this Wikipedia the language links are at the top of the page across from the article title. Though these faults have been traced for only a little ways, the southeast striking anticlines they are associated with continue as far as Riffe Lake, near Mossyrock. Bubbles of methane rising from seafloor in Puget Sound Geologic map of southwestern Washington (GM-34). Washington's fault lines tend to sweep east-west. 14 earthquakes in the past 30 days. But the western segment the Devils Mountain Fault has left-lateral movement. 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. The implications of this are not only "the possibility of a moderate to large crustal earthquake along the SHZ", but that the tectonics under Puget Sound are more complicated than yet understood, and may involve differences in the regional stress patterns not reflected in current earthquake hazard assessments. . In some places, such as along the South Fork of the Stillaguamish River between Arlington and Granite Falls, there are also contrasting geological contacts. Locations of some previously mapped faults have been adjusted on the latest map. 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. Pratt et al. That wave is quite severe, quite high. [126], An emerging view is that the Dewatto fault marks the western edge of the relatively rigid Seattle Uplift (see map). The SE striking Scammon Creek Fault seems to be terminated by the Salzer Creek Fault (the exact relationship is not clear), with the latter continuing east for another seven miles. [98] This turns and runs just south of Victoria, nearly in-line with the SWIF. Puget Sound Tsunami Simulation - National Oceanic and Atmospheric Western Washington lies over the Cascadia subduction zone, where the Juan de Fuca Plate is subducting towards the east (see diagram, right). And in between these two the Strawberry Point Fault (SPF) skirts the south side of Ault Field, splits into various strands that bracket Strawberry Point, and then disappear (possibly ending) under the delta of the Skagit River. However, the SWCC is relatively shallow (no more than 15 km deep), and likely is draped over pre-Tertiary bedrock. [29] This prospect is especially intriguing as a possible explanation of a cluster of seismic events around 1100 years ago.[30]. This is because the Olympic terrane is moving (relative to North America) northeast; its continued clockwise rotation is akin to a giant wheel rolling up the western side of the North Cascade crystalline core. Other faults to the south and southeast the Frigid Creek Fault and (to the west) Canyon River Fault suggest an extended zone of faulting at least 45km long. Does the public have a right to walk across a - Puget Sound Institute [183] While the towns of Centralia and Chehalis in rural Lewis County may seem distant (about 25 miles) from Puget Sound, this is still part of the Puget Lowland, and these faults, the local geology, and the underlying tectonic basement seem to be connected with that immediately adjacent to Puget Sound. [Paper No. Whether the faulting continues eastward is not yet determined. [116] Subsequent authors were confident enough to trace the fault west of Bremerton to just north of Green Mountain (the northwestern corner of the Blue Hills uplift see "E" on the map a topographically prominent exposure of uplifted basalt) and just short of Hood Canal;[117] but reluctant to map the fault further west as the distinctive aeromagnetic lineament used to locate the Seattle Fault dies out just west of Bremerton. 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. E.g., mapping along the Rattlesnake Mountain Fault Zone has revealed a complex network of active or potentially active faults across (and likely beyond) the lower Snoqualmie Valley, including the Cherry Creek Fault Zone, scene of the 1996 M 5.3 Duvall earthquake. [68] Both of these faults (and some others) appear to terminate against the left-lateral Sultan River Fault at the western margin of the NNE-striking Cherry Creek Fault Zone (CCFZ; see next section). It has been speculated that the OS might connect with the seismically active Saint Helens Zone (discussed below), which would imply that the OS is both locked and being stressed, raising the possibility of a major earthquake. Earthquake - King County The energy of the somewhat smaller Benioff earthquakes is likewise diluted over a relatively large area. The fault type is subducting. One of these faults, the Sequim Fault Zone (striking east from the town of Sequim), crosses Discovery Bay (and various possible extensions of the Hood Canal Fault) and bounds the Port Ludlow Uplift ("uplift of unknown origin" on the map); it appears to extend to the Southern Whidbey Island Fault. Active faults and earthquakes in Washington state Seismic Scenario Catalog NEHRP site class and liquefaction susceptibility Seismic design categories Hazardous Minerals Lahar Hazards Landslides and landforms Inactive and abandoned mines Contact Us Susan Schnur Editor-in-Chief 360-701-6122 DNR is led by Commissioner of Public Lands Hilary Franz

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