[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. Seattle Earthquakes, Types of Quakes & Fault Lines - TripSavvy Subsidence dated to between AD 1445 and 1655 has been reported in Mud Bay (just west of Olympia). Puget Sound quake likely in Seattle Fault zone, geologists say - Phys.org 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. [106] There is an intriguing view from Stanley, Villaseor & Benz (1999) (see Fig. King County Emergency Management. ), Aeromagnetic mapping in 1999 showed a very prominent anomaly[172] (such as typically indicates a contrast of rock type); that, along with paleoseismological evidence of a major Holocene earthquake, has led to a suggestion that this structure "may be associated with faulting". [198], Does the SHZ extend north? [52], Subsequent mapping shows the SWIF wrapping around the eastern end of the Seattle Basin to merge with the Rattlesnake Mountain Fault Zone (RMFZ); the RMFZ, despite the approximately 15 bend and different context, is now believed to be the southern extension of the SWIF. 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. 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. Today's Earthquakes in Olympic Peninsula, Washington (A tsunami generated by a quake on the offshore Cascadia Subduction Zone would be . 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? In the wedge model of Pratt et al. This may explain why the Seattle and Tacoma faults seem to have ruptured at nearly the same time.[127]. [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. Western Washington lies over the Cascadia subduction zone, where the Juan de Fuca Plate is subducting towards the east (see diagram, right). Tacoma's Gain is Seattle's Pain. It is coincident with, and possibly a result of uplift on, the Rattlesnake Mountain Fault Zone (RMFZ), a band of at least eleven faults that show both dip-slip (vertical) and right-lateral strike-slip motion. [113], Determination of the western terminus of the Seattle Fault has been problematic, and has implications for the entire west side of the Puget Lowland. William Pietsch - Distribution Grid Managment Analyst - Puget Sound At the edge of this older rock is the Rogers Belt, a geologically interesting zone running from the area of Sultan (due east of Everett) to Mount Vernon (just north of the bend in the Devils Mountain Fault). Rainier, along the DDMFZ, and under Puget Sound between Olympia and approximately the Southern Whidbey Island Fault. [58], Paleoseismological studies of the SWIF are scant. This fault produced a large earthquake that left a geologic record of surface offsets about 1100 years ago. 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. [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). Despite not having active plate tectonics, the eastern United States still experiences earthquakes. [185] The prospect of a major earthquake on the Doty Fault poses a serious hazard to the entire Puget Sound region as it threatens vital economic lifelines: At Chehalis there is but a single freeway (Interstate 5) and a single rail line connecting the Puget Sound region with the rest of the west coast; the only alternate routes are very lengthy.[186]. Ongoing mapping is revealing more faults. The San Juan Island and Leach River faults crossing the southern end of Vancouver Island are significant and undoubtedly connected with the DarringtonDevils Mountain and Southern Whidbey Island faults, and certainly of particular interest to the residents of Victoria, B.C. Study of surface deformation suggests possible unmapped faults near Federal Way, running between Sumner and Steilacoom, and south of Renton.[223]. normal. [140] Recent geophysical modeling suggests that the Dewatto lineament is the expression of a blind (concealed), low-angle, east-dipping thrust fault, named the Dewatto fault. The Puget Sound faults under the highly populated Seattle and Puget Sound region of Washington state form a regional network of interrelated seismologic geologic faults. These faults are not quite aligned with the Olympia structure, striking N75W (285) rather than N45W (315). [9] Not until 1992 was the first of the lowland faults, the Seattle Fault, confirmed to be an actual fault with Holocene activity, and the barest minimum of its history established.[10]. 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. Relatively shallow crustal earthquakes, generally less than 25km (16 miles) deep, caused by stresses and faulting in the near-surface crustal structures. These include the: Southern Whidbey Island Fault (SWIF) Seattle Fault Devils Mountain Fault Strawberry Point fault Utsalady Point fault Calawah fault Barnes Creek The Seattle fault zone is where the forward edge of the slab, coming to the top of the ramp, breaks and slips into the Seattle Basin. News Media at VA Puget Sound health care, 206-764-2435, 206-764-2317. [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. [115] This seems reasonable enough, as Hood Canal is a prominent physiographic boundary between the Olympic Mountains and Puget Lowlands, and believed to be the location of a major fault. Even before Washington became a state in 1889, Puget Sound beaches had been exploited as log dumps, farmed for shellfish, occupied as homesites and enjoyed for recreation. But today, after 131 years of statehood, residents of this region still don't know if they have a legal right to walk across a privately . However, most seismic activity is not associated with any known fault. The Canyon River Fault is believed to have caused a similar-sized earthquake less than 2,000 years ago;[167] this is a particular hazard to the Wynoochee Dam (to the west). Olympic Peninsula, Washington has had: (M1.5 or greater) 0 earthquakes in the past 24 hours. 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. The Doty Fault appears to terminate against, or possibly merge with, the Salzer Creek Fault at Chehalis; the Salzer Creek Fault is traced another seven miles east of Chehalis. They run . 48), along the edge of a formation known as the Southern Washington Cascades Conductor. The Devils Mountain Fault is seismically active, and there is evidence of Holocene offsets. In some places, such as along the South Fork of the Stillaguamish River between Arlington and Granite Falls, there are also contrasting geological contacts. Puget Sound Energy Maps and Records Non-Disclosure Agreement: (NDA ONLY) ko ru zh es vi hi: PSE Map Request Form and Non-Disclosure Agreement: 07/29/2022: Puget Sound Lidar Consortium Finding faults scarp(n). 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. [158] Vertical movement on these faults has created prominent scarps that have dammed Price Lake and (just north of Saddle Mountain) Lilliwaup Swamp. 1 - 10 of 83 American Seattle Cruise Reviews. Document name Date Description Additional versions; 2809: 4/1/2021: . Geologic Map. . On the other hand, the contrasting character of the east-striking and southeast-striking segments is unsettling, and the change of direction somewhat difficult to reconcile with the observed fault traces. Most of these "faults" are actually zones of complex faulting at the boundaries between sedimentary basins (synclines, "") and crustal uplifts (anticlines, ""). Washington's faults: Where the Earth moves the Seattle area 112 earthquakes in the past 365 days. Puget Sound and San Juan islands. One study of seismic vulnerability of bridges in the Seattle Tacoma area[4] estimated that an M 7 earthquake on the Seattle or Tacoma faults would cause nearly as much damage as a M 9 subduction earthquake. [75], The strongly expressed topographical lineaments at the north end of the Rogers Belt pose a perplexing problem, as they show no definite offset where they are bisected by the left-lateral oblique-slip Devils Mountain Fault. "[50], The contrast of seismic velocities seen to the northwest is lacking in this section, suggesting that it is not the Coast RangeCascade contact. [142]) This reflects westward thrusting of the Seattle Uplift into the Dewatto basin, a northwestern extension of the Tacoma basin. [174] Although no surface traces of faulting have been found in either the Holocene glacial sediments or the basalts of the Black Hills,[175] on the basis of well-drilling logs a fault has been mapped striking southeast from Offut Lake (just west of Rainier); it appears to be in line with the easternmost fault mapped in the CentraliaChehalis area.[176]. In 1870, as construction of the Northern Pacific began, Seattle numbered fewer than 1,200 souls. The true length of the UPF is likely twice as long, as it forms the southern margin of an aeromagnetic high that extends another 25km to the southeast. The Seattle Fault was first recognized as a significant seismic hazard in 1992, when a set of reports showed that about 1,100 years ago it was the scene of a major earthquake of about magnitude 7 - an event that entered Native American oral legend. [56] But detailed mapping just past the intersection shows only a complex and confused pattern of faulting, with no indication that there is, or is not, through-going faulting. Does the public have a right to walk across a - Puget Sound Institute These faults are: the Kopiah Fault (note the curious curve), Newaukum Fault, Coal Creek Fault, and three other unnamed faults. [91] The relationship between these two fault zones is not entirely clear. KUOW - Turkey's fault line is similar to faults under Puget Sound The WRZ and SHZ are associated with the southern Washington Cascades conductor (SWCC), a formation of enhanced electrical conductivity[194] lying roughly between Riffe Lake and Mounts St. Helens, Adams, and Rainier, with a lobe extending north (outlined in yellow, right). "Most often, when we think of tsunamis, we think of our outer coast and communities along the Pacific Ocean. ISNS 2359 Earthquakes and Volcanoes Chapter 5 Questions - Quizlet 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). Aeromagnetic anomaly maps (USGS OFR 99-514). Read More. As all of these are thrust and reverse faults, they probably result from northeast directed regional compression. Arcos' work suggests. Prior to 2000, prominent aeromagnetic anomalies strongly suggested that the fault zone continued southeast, perhaps as far as the town of Duvall, but this was uncertain as the SWIF is largely concealed, and the faint surface traces generally obliterated by urban development. Display Faults. These lineaments have been associated with possible zones of faulting in the crust and subducting plate.[212]. $30-$33/hr Electrician Job at University of Puget Sound [191] How they might be connected is unknown. And the magnitude used to generate that wave is only about 7.5, as opposed to a magnitude-9 earthquake off the coast. Let's make your home safer There's a one-in-10 chance that the next . (See, There is a preliminary report of aeromagnetic and gravity mapping placing the eastern edge of the Siletz terrane under Lake Washington. Tobin says offshore faults tend to cause bigger earthquakes and are a larger tsunami risk. [132], Scarps associated with Holocene uplift of the Tacoma fault have been traced westward to Prickett Lake (southwest of Belfair, see map). Somewhere between Puget Sound and Cascades foothills these two geological provinces come into contact. North Olympic Peninsula VA Clinic at VA Puget Sound health care, 360-565-7420. (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. to the north, past Lummi Island is contrary to the prevailing consensus that the DMF is not offset. The Pacific Northwest Seismic Network (PNSN) reported at least three earthquakes within the past few days. While there is a bit of uplifted pre-Tertiary rock between the SPF and UPF, this does not truly fit the uplift and basin pattern described above because of the small scale (2km wide rather than around 20), and because the uplift here is entirely like a wedge being popped out between two nearly vertical faults, rather than being forced over a ramp such as is involved with the Seattle and Tacoma faults. [195] The southwestern boundary of the SWCC, where it is believed to be in near vertical contact with the Eocene basalts of the Crescent Formation, forms a good part of the 90km (56 mile) long SHZ. This map of Puget Sound shows the location of the methane plumes (yellow and white circles) detected along the ship's path (purple). Geologic Hazard Maps | WA - DNR Extensive research has since shown the Seattle Fault to be part of a regional system of faults . The energy of the somewhat smaller Benioff earthquakes is likewise diluted over a relatively large area. 3511 NE Second St. Renton, WA 98056. A similar line aligns with the termination of the WRZ, SHZ, and Gales Creek Fault Zone (northwest of Portland), with faulting along the upper Nehalem River on the Oregon coast,[211] and a topographical contrast at the coast (between Neahkahnie Mountain and the lower Nehalem River valley) distinct enough to be seen on the seismicity map above (due west of Portland). [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. 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 The structure of the Seattle Fault zone still have great uncertainty and there exist a number of interpretations. $30 to $33 Hourly. It is believed that all of these faults, folds, basins, and uplifts are related. Nor does this uplift delineate any significant basin between it and the Devils Mountain Fault. [122] This trend extends further north where the Pleasant Harbor lineament appears to terminate other westward extensions of the SFZ. 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. [170] Gower, Yount & Crosson (1985), labelling it "structure L", mapped it from Shelton (near the Olympic foothills) southeast to Olympia (pretty nearly right under the state Legislature), directly under the town of Rainier, to a point due east of the Doty Fault, and apparently marking the northeastern limit of a band of southeast striking faults in the Centralia-Chehalis area. [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. [90], The RMFZ continues NNW past Fall City and Carnation, where strands of the RMFZ have been mapped making a gentle turn of 15 to 20 west to meet the Southern Whidbey Island Fault zone (SWIF, discussed above); the RMFZ is therefore considered to be an extension of the SWIF. Saint Helens and Mt. Clearance, service lines and meter locations. [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. Over 7,000 people are dead after a magnitude 7.8 earthquake shook southern Turkey, near the Turkish-Syrian border. "Puget Sound and related inland marine waters, including all salt waters of the state of Washington inside the international boundary line between Washington and British Columbia, and lying east of the junction of the Pacific Ocean and the Strait of Juan de Fuca, and the rivers and streams draining to Puget Sound as mapped by water resource .