southern whidbey island fault map

Videos: Strong M6.0 earthquake rattles Mindanao in the Philippines, Dramatic earthquake increase in Hawaii! Since their initial discovery, research has shown that the actual number of earthquakes is somewhere between 5 and 10 for each change in magnitude. We do know that it is active and will likely produce a large M67.5 earthquake when it next ruptures. Finding faults and knowing how often they rupture is one of the most important tasks to keep society safe from these hazards. The faults length depends on whom you ask, Sherrod said. Both of these things can cause equal or greater damage than the actual earthquake. Areas like these are also susceptible to liquefaction. And being ready means being able to support yourself, your loved ones, your neighborhood for 2 weeks. Volcanic eruptions. Customers lift their eyes from phone screens. The San Andreas fault in California is a good example of a very active strike-slip fault. In places where there is little vegetation, different rock types and faults can be found with relative ease. The medic said colleagues were becoming sick and emotionally overwhelmed When this happens, even a very small slope can cause the ground to slide. Southeast Extension of the Southern Whidbey Island Fault, Washington: Implications for Earthquake Hazards, 12201 Sunrise Valley Drive Reston, VA 20192, Region 2: South Atlantic-Gulf (Includes Puerto Rico and the U.S. Virgin Islands), Region 12: Pacific Islands (American Samoa, Hawaii, Guam, Commonwealth of the Northern Mariana Islands). Coupeville, WA 98239, Main Line: A reverse fault occurs when two blocks are pushed together and one moves up and over the other. An increase of 2 means that ~1,000 times more energy is released. The Geologic Information Portal has a Natural Hazards theme that shows active faults and earthquakes. Photo by G.K. Gilbert, from the Steinbrugge Collection of the UC Berkeley Earthquake Engineering Research Center. Each year we map additional areas and learn more about existing faults and (or) discover new ones. We work closely with the Washington Emergency Management Division, the Washington Seismic Safety Committee, and the Federal Emergency Management Agency to ensure that the best-available science is used in the development of hazard mitigation plans. Both types of faults can cause ground shaking during an earthquake and may cause permanent deformation of the ground. After the earthquake, many things you count on may not be available. Both studies suggested that the SWIF These faults and earthquakes occur in oceanic crust as it is subducted beneath the continent. Whats up with the 50 US nuclear bombs stored at the Incirlik Air Base in Turkey, right on the same fault line California hasnt seen a catastrophic earthquake recently. Standing becomes almost impossible as the jolts turn to rolling waves. Avoid stopping near or under buildings, trees, overpasses, or utility wires. Scientists have used the stories from tribes along the entire Pacific Northwest coast to learn that the last large earthquake on the Cascadia subduction zone was about AD 1700. The 1949 earthquake near Tacoma triggered a landslide near the Tacoma Narrows that caused a local tsunami. The largest active fault that will affect Washington (and the whole Pacific Northwest) is the Cascadia subduction zone. This means that when the Seattle fault ruptures the south side of the fault moves up relative to the north side. 4 0 obj The material becomes so weak that it behaves more like a liquid than a solid. Geologic maps of 7.5-minute topographic quadrangles covering parts of the Seattle fault and southern Whidbey Island fault zone are available on the DNR website as: Sign-up for DNR enewsletters. For the most up-to-date information, please refer to the interactive fault map. Photo courtesy of National Center for Tsunami Research, NOAA. Deformed recessional outwash deposits and Holocene deposits were exposed; three unconformities separated the units. 3 0 obj For example, a M7 earthquake releases 32 times more energy than a M6 earthquake, and 1,000 times more than a M5 earthquake. It is not yet possible to predict when a fault will have an earthquake. The Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. California Geological Survey. The southern Whidbey Island fault zone (SWIF) is a mostly concealed, northwest-trending structure extending across southern Whidbey Island toward Vancouver Island (Figures 1 and 2). Excavations across several LiDAR scarps show evidence for multiple post-glacial folding and faulting event on faults with reverse oblique sense of slip. These older faults do not have any evidence for recent activity, but the Earth is always changing. The Survey works to increase public and scientific understanding of fault and earthquake hazards in our state. Tsunami waves can travel over 500 miles per hour in the open ocean. The spectacular falls flow over the remains of a newly discovered 20-million-year-old volcano, apparently formed atop the main part of the fault zone as magma rose upward along weak fault planes. Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. The 1964 M9.2 Alaska earthquake created a large tsunami from the fault rupture, and many smaller tsunamis from on-land and underwater landslides. It devastated the coast of the Pacific Northwest and sent an orphan tsunami to Japan. Kelsey and others (2004 #7651) compared sea-level histories at two salt marshes that straddle a northeast strand of the southern Whidbey Island fault zone: Crockett Marsh (site 572-1) located north of the northeastern fault strand is 8 km north of Hancock Marsh (site 572-2), south of the fault strand. Information from seismic-reflection profiles, outcrops, boreholes, and potential field surveys is used to interpret the structure and history of the southern Whidbey Island fault in the Puget Lowland of western Washington. Most are too small to be felt or cause damage. Some faults reach the surface and can be found by geologists. The Cascadia subduction zone last ruptured over 300 years ago on January 26, 1700. Its significantly larger than the Seattle Fault, and South Whidbey could hand us a magnitude 7.5 earthquake. Most are too small to be felt or cause damage. A community meeting about a shelter at the Harbor Inn may have yielded more questions than answers. Stay away from glass, windows, outside doors and walls, and anything that could fall down. A drill rig left of the blockade is collecting data about the failure. The map is from a 2007 report (click here to download) on seismic design categories in Washington. Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. Map Releases; Topographic (Topo) Maps; Volcanic Maps; All Maps; Multimedia Gallery. 1 School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada 2 Department of Earth and Environment, Boston University, Boston, Massachusetts 02215, USA The moment magnitude scale replaced the Richter scale in the late 1970s. Sheriff:(360) 679-7310, Juror Recordings Learn about at-risk areas and become prepared. The Seattle Fault is also likely to create a tsunami that would inundate Harbor Island and much of SODO, Interbay, and the waterfront. The Mercalli Intensity scale is another historical way to measure the intensity of an earthquake. Clicking on the map will download the publication. However, we can learn which faults are active and which are inactive. This scenario was modeled on the part of the SWIF from Woodinville to just west of Whidbey Island. So the fault remained mostly a mystery until the 1990s. Across the northern portion of Bainbridge Island, light radar or lidar images taken from airplanes clearly show the Seattle Fault running right on the surface. In this sense, the shaking of the ground is the sound of rocks breaking and moving deep within the Earth. Small fires are the most common hazard after an earthquake. It will happen; we dont know when.. . The more you know what to expect, the better prepared you will be to help yourself, your family, and others around you. Knowing how often large earthquakes have happened in the past helps us to know how often they might occur in the future. He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. Years ago, Howard Gower and James Yount came to the Puget lowlands to study earthquake risks and stumbled on what appeared to be a fault in Island and Snohomish counties. The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. There must be tsunami deposits of the same age along much of the Oregon and Washington coast in order to qualify as an earthquake. The southern Whidbey Island fault (SWIF) stretches from the vicinity of Victoria, B.C., across Puget Sound as far as the Cascade Range. Strait of Juan de Fuca Fault Map 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. Finding and mapping these faults is an important mission of the Washington Geological Survey. Story telling is an important part of the Native tradition and is how their history is passed down to the next generation. What scientists dont know is its timing interval. After the shaking stopped the sand regained its strength. They knew something was there, said Sam Johnson, a retired USGS geologist who would follow up on their work. Moving inland, the Seattle Fault is capable of a magnitude 7. This means that a tsunami made by an earthquake on the Cascadia subduction zone will start to impact the Washington coast in less than 15 minutes. Scientists have also dated large underwater landslides and turbidites that travel from the continental edge far out into the ocean basin. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. The boundary between the two plates covers a large area and can lock together. Superior Court:(800) 254-2755 Ready to retrofit? For example, the Cascadia subduction zone has had between 15 to 19 earthquakes over the past 10,000 years. The Darrington-Devils Mountain fault zone is located in southern Skagit County and northern Snohomish County. Expect aftershocks. The map is from a 2007 report (click here to download) on seismic design categories in Washington. A magnitude 7.4 along the southern Whidbey fault would rattle 18 counties in Washington, according to a federal projection . Were working on pedestrian evacuation maps that show the best routes for pedestrians to take to evacuate, said Forson. This can cause landslides to occur where they wouldnt normally happen. Oil companies descended in search of riches. People stagger into the streets to avoid an avalanche of debris. At the Brightwater treatment plant in Woodinville and at Crystal Lake in Maltby, the government researchers found telltale slopes of offset ground, known as scarps, indicative of a long-ago quake. The map also shows potentially active faults from a separate 2014 report (click here to download). In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. We do not encourage people to evacuate in vehicles. Even places that are far from active faults are still at risk during a large Cascadia subduction zone earthquake. Recent geologic mapping by Washington State Department of Natural Resources (DNR) geologists reveals that this major fault zone extends through the Snoqualmie River valley in the vicinity of Carnation, Fall City, and North Bend. Keaton and Perry (2006 #7653) excavated two trenches on the south end of the Brightwater treatment plant (KP1 site 572-3, and KP2 site 572-4). The average time between large earthquakes is about 535 years, but has been as little as 200 years, and more than 1,000 years. The French Onion trench exposed glaciolacustrine claystones, till, colluvial deposits, and Holocene soils. Other faults may lie entirely underground, or could be covered by vegetation and (or) sediment. The years have gone by. Experts have warned that UK outbreak may be around two weeks behind Italys. The shaking usually lasts less than a minute and doesnt generally cause a tsunami or have many aftershocks. Coupeville, WA 98239, Camano Office In fact, until the 1980s, no one knew SWIF existed. Hover over a cluster of earthquakes to learn about the different types in the Pacific Northwest. ; (5) large-scale liquefaction features in upper Quaternary sediments within the fault zone; and (6) minor historical seismicity. These differences are related to the overall pattern of stress in the crust, what types of rocks the crust is made from, and how many faults there are. Some residents may lose housing temporarily or permanently. Even when an earthquake happens on a fault that doesnt reach the surface, the ground can still show signs of cracking. In the late 1960s, speculators considered the Puget Sound region a frontier for petroleum exploration. . DO NOT get in a doorway. These quakes are capable of magnitudes from 7 to over 9. Swarm of hundreds of small earthquakes rattle Vancouver Island. Fir trees near the failure are tilted and indicate rotation into the lake (to the left of the photo). The publication Faults and Earthquakes in Washington State is a state-wide compilation of active faults and folds. If a large earthquake happens, be prepared for many more earthquakes. East of Puget Sound, the SWIF makes landfall between the cities of Seattle and Everett but is concealed . The biggest one is called the South Whidbey Island fault, and it's thought to run from Victoria, B.C., through Woodinville and possibly beyond. Make an emergency response plan for you and your family. Image from the, Aquatic Lands Habitat Restoration Program, South Lake Washington Restoration Project, Scientific and Technical Support to Aquatic Programs, Washington Geologic Survey Publications Catalog, Washington Geologic Survey Photograph Collection, Wetlands of High Conservation Value Map Viewer, Timber Sale Remaining Volume by Purchaser Reports, Spanish - Brocha, Salal y Otros Productos Forestales, Complete: Baker to Bellingham Non-Motorized Recreation Plan, Community Wildfire Resilience and Preparedness, Utility Wildland Fire Prevention Advisory Committee, Blanchard, Reiter, Walker Valley and Nearby Islands, Teanaway Community Forest Advisory Committee, Teanaway Community Forest Advisory Committee Past Meetings, Faults and Earthquakes in Washington State, Pacific Northwest Seismic Network Seismo Blog, https://buildingfailures.files.wordpress.com/2014/02/tiltedbuilding.jpg, Pacific Geoscience Center of the Natural Resources of Canada. The key, Sherrods group would discover, was buried on Whidbey Island under layers of mud, peat moss and decaying marsh grass in the murky tidal waters at Crockett Lake, alongside the Coupeville ferry dock. There are many other active faults in Washington and any of these could produce a large earthquake in the future. This is an active fault.. Theres a must-see documentary film called Cascadia The Big One that exposes whats currently going on in this region of the Cascade volcanoes and the Pacific NorthWest. HomePrograms and ServicesGeologyGeologic Hazards. A normal fault occurs when two blocks are pulled away from each other. The fault's length depends on whom you ask, Sherrod said. This might include flammable appliances like a water heater, tall items like book cases, or heavy pictures. He combed through state and federal data to understand the risks, and to help train first responders. Earthquakes occur nearly every day in Washington. The Flying Squirrel and Mountain Beaver trenches cross the Cottage Lake lineament. Power could be out for days. The Richter scale was developed in southern California in 1935 and was based on the local ground motion. What we know about this fault is that its ruptured may times in the pastit will happen again. The buildings sank when ground shaking weakened the underlying sediments. This was a problem because no two locations would agree on the size of the same earthquake. The southern Whidbey Island fault should be considered capable of generating large earthquakes (Ms ?? Thats why were pushing for a lot of vertical evacuation structures to be built hotels or schools, because its not an easy problem to solve, he said. All faults, regardless of size, can be dangerous if they rupture. One or possibly two of the unconformities are interpreted as event horizons. Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. These types of faults are common, but usually small. 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. 1 0 obj Additional fault studies by state and federal geologists in the next few years will help determine the frequency and severity of earthquakes along these fault zones. The shaking can also cause landslides, surface ruptures, ground cracks, liquefaction, tsunamis, and seiches (standing waves). (1996) used seismic-reflection profiles in Puget Sound near Whidbey Island, sea-cliff exposures on Whidbey Island, and sparse borehole data to map and interpret the SWIF as a broad fault zone (6 to 11 km wide) dipping steeply to the northeast. <> These include (from north to south, see map) the: Devils Mountain Fault Strawberry Point and Utsalady Point faults Southern Whidbey Island Fault (SWIF) Rogers Belt (Mount Vernon Fault/Granite Falls Fault Zone) Cherry Creek Fault Zone Rattlesnake Mountain Fault Zone Seattle Fault Tacoma Fault Saddle Mountain Faults Roads, bridges, or ramps may have been damaged by the earthquake. The continued movement along faults over millions of years can build mountains, tear a continent apart, and move tectonic plates thousands of miles. Audio; Before and After Images; Images; Slideshows; Stereograms; Videos; Webcams; . <>/XObject<>/ExtGState<>/Pattern<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Brick chimneys cascade off rooftops. Bookcases and china cabinets topple, trapping people beneath. District Court: (800) 946-9765, South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario. Photo by Steve Palmer. Washington has the second highest risk in the U.S. of these large and damaging earthquakes because of its geologic setting. The threat to Puget Sound from a quake along the Cascadia Subduction Zone, off the coast of Washington, Oregon and California, is well documented. Many universities and other organizations (such as Cascadia Region Earthquake Working Group and the Pacific Northwest Seismic Network) also work to understand active faults in Washington. The northwest-trending southern Whidbey Island fault zone occurs along a significant terrane boundary between basement blocks underlain by Eocene marine basalts of the Coast Range province to the southwest and pre-Tertiary metamorphic rocks of the Cascades province to the northeast. They conclude the observed features have a glaciotectonic origin and are not seimotectonic. Then consider that the Seattle Fault is a complex of faults with various branches that run at or just below the surface. Once we got it, we were sort of shocked to see these big faults in the Puget lowlands, he said. Scientists have been trying to understand how often earthquakes happen for over 100 years. A major southern Whidbey quake, on the other hand, could kill and injure many more, according to Murphy. Tap/click on "gear icon" for options and settings. The team also found that accumulated movement on the fault has uplifted old Snoqualmie River sediments to their current position on ridges, in some places several hundreds of feet above the modern Snoqualmie valley floor. @\;L;=}%FC*l $@ 4x: 888O~xrsxx'/*rGRF\gI%~x(G-^-hjjq kx/V ou0hyegy0;ei`Tx&ilZ )TmZ$vb,`bQm|DR5x/ Large earthquakes are likely to happen in Washington during your lifetime. #4747 Blakely, R.J., Wells, R.E., and Weaver, C.S., 1999, Puget Sound aeromagnetic maps and data: U.S. Geological Survey Open-File Report 99-514. This map is from a 2007 report on the seismic design categories in Washington. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. This map of gravity residuals measured over the puget lowland reveals a pattern of deep, fault bounded basins (cool colors) and uplifts (warm colors). Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. Necessary cookies are absolutely essential for the website to function properly. southern Whidbey Island fault zone (Class A) No. This website uses cookies to improve your experience while you navigate through the website. For example, a building on soft soil will experience more shaking than the same building on bedrock. Photo from, This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. Shallow faults produce earthquakes in the upper 18 miles (30 kilometers) of the Earths crust. Earthquakes on shallow faults typically last 20 to 60 seconds and the shaking is localized to the general area of the fault. South Whidbey Island Fault Earthquake Scenario: 7.4 Magnitude Buildings Damaged: 320,776 Fatalities: 90 - 432 Injuries: 2,920 - 7,361 Economic Loss: $15,590,000,000 SeaTac Fault Earthquake Scenario: 7.2 Magnitude Buildings Damaged: 375,954 Fatalities: 16 - 123 Injuries: 1,394 - 3,404 Economic Loss: $13,400,000,000 Tacoma Fault

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