[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. Nurse Information Line at VA Puget Sound health care, 800-329-8387 x4. [58], Paleoseismological studies of the SWIF are scant. A 2001 study[148] using high-resolution seismic tomography questioned its existence. 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. 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. Turkey's fault line is similar to faults under Puget Sound Puget Sound quake likely in Seattle Fault zone, geologists say - Phys.org Initially it was not specified, and rather vaguely indicated to be west of Restoration Point (i.e., west of Puget Sound). Both of these are dip-slip (vertical) faults; the block between them has been popped up by compressive forces. [187] Such a length would be comparable to the length of the Seattle or Tacoma faults, and capable of an earthquake of M 6.7. [99] This last problem is partly solved because there is a locus of seismicity, and presumably faulting, extending from the northern end of the SHZ to the northern end of the Western Rainier Zone (see Fig. Scientists Search for New Faults in Puget Sound $30-$33/hr Electrician Job at University of Puget Sound 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. Washington's faults: Where the Earth moves the Seattle area Job Description. 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. Let's make your home safer Next to a 4-6 lines highways with 90db noise and cancerous pollution. (See, There is a preliminary report of aeromagnetic and gravity mapping placing the eastern edge of the Siletz terrane under Lake Washington. 112 earthquakes in the past 365 days. The Devils Mountain Fault separates two similar but distinctive ensembles of Mesozoic (pre-Tertiary, before the dinosaurs died) or older rock. These faults are: the Kopiah Fault (note the curious curve), Newaukum Fault, Coal Creek Fault, and three other unnamed faults. 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. KUOW Public Radio on Twitter: "A UW researcher says the fault line that It is uncertain how these faults relate to the structure, and whether they are deep-seated faults, or fractures due to bending of the shallow crust. [122] This trend extends further north where the Pleasant Harbor lineament appears to terminate other westward extensions of the SFZ. Some of these faults possibly developed in the Mesozoic, when these deposits were in the accretionary wedge;[72] the cross-cutting NE and NNE-striking faults that form the various basins resulted from a subsequent change to transtension. Ancient quake and tsunami in Puget Sound shake researchers 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). The Devils Mountain Fault is seismically active, and there is evidence of Holocene offsets. [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. [162] Trench studies indicate major earthquakes (in the range of M 6. to 7.8) on the Saddle Mountain faults [163] at nearly the same time (give or take a century) as the great quake on the Seattle Fault about 1100 years ago (900930 AD). 48), along the edge of a formation known as the Southern Washington Cascades Conductor. Geochemistry, Geophysics, Geosystems , 2021; 23 (1) DOI: 10.1029/2021GC010211 Cite This Page : Study: Tsunami from Cascadia mega-quake would submerge Puget Sound At the northern end the right-lateral McMurray Fault Zone (MFZ) straddles Lake McMurray, just south of the Devils Mountain Fault, and is suspected of being a major bounding fault. Does the public have a right to walk across a - Puget Sound Institute The Seattle Fault is the most studied of the regional faults, which has led to several models of its structure, which may also be relevant to other faults. Yet the former is only the first of at least six more parallel southeast striking faults, which do cross the Salzer Creek Fault. The EPZ is active, being the locale of the 1995 M 5 Point Robinson earthquake.[136]. 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. 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. Cheney also mapped the Lake Chaplain Fault, parallel and just east of the MVF, from Lake Chaplain to Granite Falls. They interpreted it as "simple folds in Eocene bedrock", though Sherrod (1998) saw sufficient similarity with the Seattle Fault to speculate that this is a thrust fault. [158] Vertical movement on these faults has created prominent scarps that have dammed Price Lake and (just north of Saddle Mountain) Lilliwaup Swamp. Combined with continued aggressive electric conservation efforts, Energize . Methane Plume Emissions Associated With Puget Sound Faults in the Cascadia Forearc CC BY 4.0 Authors: H. Paul Johnson University of Washington Seattle S. G. Merle National Oceanic and. 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. Tobin says offshore faults tend to cause bigger earthquakes and are a larger tsunami risk. Seattle Earthquakes, Types of Quakes & Fault Lines - TripSavvy New tsunami maps show how water could reach Seattle, Everett, Tacoma This fault produced a large earthquake that left a geologic record of surface offsets about 1100 years ago. Faults running on the Snohomish County-Skagit County line and between Port Townsend and Whidbey Island point toward Vancouver Island. The Seattle Fault is a zone of complex thrust and reverse faults between lines E and F on the map up to 7km wide and over 70km long that delineates the north edge of the Seattle Uplift. 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. But their significance to the Puget Sound area is unknown. 10+ Cruises Age 2020s. Five Puget Sound cities likely to feel strong shaking in a megaquake That wave is quite severe, quite high. [51] [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. Earthquakes and Faults | WA - DNR 09 Feb 2023 03:01:00 [Paper No. But the western segment the Devils Mountain Fault has left-lateral movement. ), The Coast Range Boundary Fault (CRBF) is hypothesized, expected on the basis of tectonic considerations, which may correlate in part with one or more currently known faults, or may involve as yet undiscovered faulting. Pratt et al. "[50], The contrast of seismic velocities seen to the northwest is lacking in this section, suggesting that it is not the Coast RangeCascade contact. E.g., HH mlange rock has been found in Manastash Ridge, 110km to the south (look for the small sliver of purple near the bottom of the diagram). This MSH-MR-GP lineament is believed to reflect a "long-lived deep-seated lithospheric flaw that has exerted major control on transfer of magma to the upper crust of southern Washington for approximately the last 25 [million years]";[203] it has been attributed to the geometry of the subducting Juan de Fuca plate.[205]. [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. [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. TTY Relay 711. 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. [216], An Everett Fault, running east-northeast along the bluffs between Mukilteo and Everett that is, east of the SWIF and at the southern edge of the Everett Basin has been claimed, but this does not appear to have been corroborated.[217]. [19] These terranes were covered by the basalts of the Crescent Formation (part of Siletzia). I've been in the business for 20 years and the way skilled labor has been treated up until very recently drove a ton of people away from the industry. The magnitude-4.0 earthquake that rattled people awake across the Puget Sound region last Wednesday probably struck on the western edge of the Seattle Fault, according to geologists. These faults also form the north and south boundaries of uplifted pre-Tertiary rock, suggesting that the faults come together at a lower level, much like one model of the Seattle and Tacoma faults, but at a smaller scale. Harold Tobin, . 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. Puget Sound Tsunami Simulation - National Oceanic and Atmospheric [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. Where it intersects the northwest-trending Johnsons Swamp fault zone, easternmost member of the RMFZ. 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. 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.
