southern whidbey island fault map

Faults can also occur within a tectonic plate when the plate itself is deforming. Within this rich oral history there are many references to events like earthquakes and tsunamis. 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 The moment magnitude scale replaced the Richter scale in the late 1970s. Notice the Seattle Fault Zone bounding the Seattle Basin to the south. southern Whidbey Island fault zone (Class A) No. However, we can learn which faults are active and which are inactive. The southern Whidbey Island fault divides the two. Learn about at-risk areas and become prepared. Cover your head and neck with your arms to protect against falling debris. Bookcases and china cabinets topple, trapping people beneath. Do not exit a building during the shaking. But scientists theorize that the area has suffered only four . Most damage and loss of life in earthquakes is a result of ground shaking. The years have gone by. Seattle Fault Lines. This fault will have an earthquake in the future, but we cannot predict exactly when. Official websites use .gov . So I think it is worth your time to learn more about the biggest seismic riskss and major fault lines criss-crossing this part of the Pacific Northwest, namely: Now lets visit the 3 most dangerous earthquake faults for Seattle one by one: The Cascadia Subduction Zone is a giant fault running from Cape Mendocino, Calif. past Oregon and Washington and doesnt end until its north of Vancouver Island in Canada. Proceed cautiously once the earthquake has stopped. The fault's length depends on whom you ask, Sherrod said. The threat to Puget Sound from a quake along the Cascadia Subduction Zone, off the coast of Washington, Oregon and California, is well documented. Sensitive seismographs located throughout the state, and all over the world, measure this seismic energy. Paleoseismologists have found places that record many of these tsunami deposits. Photo from, Liquefaction can be a big problem. Scientists have also dated large underwater landslides and turbidites that travel from the continental edge far out into the ocean basin. 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. One model suggests it extends to about 30 miles east of Yakima. Stratigraphy in the Flying Squirrel trench showed gentle warping of late glacial and post-glacial sediments; no faults were exposed. Around Puget Sound, it seems everyone knows about The Big One, the potential magnitude 9.0 Cascadia Subduction Zone megaquake some scientists say is due any day. 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. In the late 1960s, speculators considered the Puget Sound region a frontier for petroleum exploration. When a fault with vertical movement ruptures the ocean floor, it lifts up part of the ocean. Experts have warned that UK outbreak may be around two weeks behind Italys. Roads, bridges, or ramps may have been damaged by the earthquake. In 2017, he began studying the possible aftermath of a major SWIF quake. They havent dug up enough history to estimate. The ground shaking from these earthquakes can last for several minutes. Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Visit our School Seismic Safety page for more information. Each peak of the Olympics stuck out with picturesque clarity in the distance. Photo from https://buildingfailures.files.wordpress.com/2014/02/tiltedbuilding.jpg. Stories from tribes near Seattle have also helped us to learn that the last earthquake on the Seattle fault was about AD 900950. USA Earthquake Hazard Map. Like a sonogram, the seismic surveys allowed Johnson to see outlines of massive fissures in the earths crust. Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. The publication Faults and Earthquakes in Washington State is a state-wide compilation of active faults and folds. Do you know what to do if there is an earthquake? Were working on pedestrian evacuation maps that show the best routes for pedestrians to take to evacuate, said Forson. That place is the Ocosta School. The boundary between the two plates covers a large area and can lock together. Learning earthquake faults around where we live is a first good way to prepare the next devastating earthquake. A normal fault occurs when two blocks are pulled away from each other. (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. The tsunami becomes taller as the ocean becomes shallow. The Geologic Information Portal has a Natural Hazards theme that shows active faults and earthquakes. Oil companies descended in search of riches. 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. Deformed recessional outwash deposits and Holocene deposits were exposed; three unconformities separated the units. They didnt recognize the significance of what they found. 572 Last Review Date: 2016-11-29 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 team determined that the Rattlesnake Mountain fault zone, originally mapped by DNR geologist Tim Walsh in the 1980s, is likely the southern continuation of the southern Whidbey Island fault, extending this fault zone from the Strait of Juan de Fuca to Rattlesnake Mountain near North Bend. , * NOTE: Hazard maps for each jurisdiction will only be included if that jurisdiction is at risk to that hazard., Copyright Island County. The buildings in this photo were built on soft materials that liquefied during the 1964 Niigata earthquake in Japan. Earthquakes on shallow faults typically last 20 to 60 seconds and the shaking is localized to the general area of the fault. %PDF-1.5 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). Others, like the Seattle fault and southern Whidbey Island fault zone, cross under major cities and pose a significant hazard. Mapping along the Snoqualmie River valley also helped answer the important question of where the Seattle fault lies east of its last mapped position near Issaquah. Tohoku killed nearly 16,000 people; most died as a result of drowning or being crushed in the tsunami. Stay inside until the shaking stops and it is safe to go outside. The trenches exposed glacial deposits disrupted by faults and liquefaction features. Check out the liquefaction susceptibility and NEHRP site class maps on the Geologic Hazard Maps page. 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. The SWIF has been assessed by the USGS as capable of generating the largest crustal earthquake in Puget Sound. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. The shaking usually lasts less than a minute and doesnt generally cause a tsunami or have many aftershocks. This is similar to how sound is quieter when you move away from a speaker. The Survey works to increase public and scientific understanding of fault and earthquake hazards in our state. Then the world rattles up and down. Audio; Before and After Images; Images; Slideshows; Stereograms; Videos; Webcams; . By finding the age of the deformed layer, a paleoseismologist can determine the minimum age of the fault. Maps. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Additionally, because the continent moves up and over the ocean plate, large amounts of sea water are displaced and cause damaging tsunamis. And what were looking at is water.. The Cascadia subduction zone just off the Washington coast is this kind of fault and is one of the largest geologic hazards to our state. Why is Strange Sounds focusing so much on disaster preps? (1999 . This video from the 2011 Tohoku subduction zone earthquake shows the earthquakes before, during, and after the main M8.7 event on March 11 (at 1:50 in the video). Because they can travel great distances, tsunamis generated from earthquakes across the ocean can still cause damage. On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. Johnson and others (1996) have described the southern Whidbey Island fault ( figure 1) as a broad (6 - 11 km) transpressional zone comprising three main splays, within which the local late Quaternary uplift rate is at least 0.6 mm/yr. The DNR team found that the Seattle fault is intercepted by the southern Whidbey Island fault zone in the vicinity of Fall City. These cookies do not store any personal information. An official website of the United States government. The map also shows potentially active faults from a separate 2014 report (click here to download). Part 2 will be full Martial Law and mandatory vaccines? Sherrod remembers his son, age 5 at the time, playing with toy trucks on the mossy banks of the marsh while the scientists worked. It is capable of generating severe earthquakes that would impact the entire west coast. But it didnt. In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. Washington has few large normal faults because it is mostly in a region of compression. Coupeville, WA 98239, Camano Office Black lines are trace projections of the South Whidbey Island Fault, Seattle Fault Zone, and Tacoma Fault Zone faults and the N-S Hood Canal and Puget Sound faults of S. Y. Johnson et al. People stagger into the streets to avoid an avalanche of debris. Another piece can be seen under the elevated lanes of northbound Interstate 5 in South Seattle not far from the Rainier brewery. For some active faults, such as the Seattle fault or Cascadia subduction zone, we can also learn how often large earthquakes have happened in the past. The Flying Squirrel and Mountain Beaver trenches cross the Cottage Lake lineament. Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. That could spell trouble not only for its namesake island but for south and north King County and further west. The Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. All faults, regardless of size, can be dangerous if they rupture. On a brilliant November day, Sherrod took in the panorama from the parks bluff. Much of the Southern Whidbey Island fault zone (SWIF), which runs in a north-westward direction from Woodinville to near Port Townsend, Washington, remains mostly . In fact, new faults are found every year during our geologic mapping efforts. It can also make landslides that are much bigger than expected. The Survey is working with the Office of the Superintendent of Public Instruction (OSPI) and Reid Middleton, an engineering firm, to perform seismic safety assessments of 220 school buildings across the state. This fault zone was originally named the Devils Each of the earthquakes listed on the bottom of the screen is capable of significant damage. When this happens, even a very small slope can cause the ground to slide. endobj America is going to be punished just like the rest of the world. South Whidbey Island Fault Zone. The faults length depends on whom you ask, Sherrod said. In much of Washington, dense vegetation covers the land and makes finding faults very difficult. " A lot of people are transplants, " Forson said. Some types of seismic energy (P waves) are similar to sound energy that is released if you break a twig or slide a chair across the floor. A lock () or https:// means youve safely connected to the .gov website. The 1964 M9.2 Alaska earthquake created a large tsunami from the fault rupture, and many smaller tsunamis from on-land and underwater landslides. #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 northwest-trending fault zone extends more than 65 km across Possession Sound, southern Whidbey Island, Admiralty Inlet into the eastern Strait of Juan de Fuca. Know what to expect. An earthquake occurs when rock inside the Earth moves or breaks. Transpressional deformation along the southern Whidbey Island fault is indicated by alongstrike variations in structural style and geometry, positive flower structure, local unconformities, out-of-plane displacements, and juxtaposition of correlative sedimentary units with different histories. After large earthquakes there are usually many aftershock earthquakes. The age of the earthquake is learned by dating the organic material in these tsunami deposits. The San Andreas in California, for example, left gaping scars in the Earths crust, at the surface. An earthquake along the southern Whidbey Island fault reshaped the land some 2,700 years ago. Along the coast residents may have between 20 and 30 minutes to get to higher ground. One of the most important new technologies for finding faults (and landslides too) is called lidar. This uplift creates a very broad wave called a tsunami. What scientists dont know is its timing interval. In Washington, the risk from earthquake-induced landslides is large. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. California Department of Conservation. Disoriented drivers wonder whats wrong with their cars, then realize something much bigger is amiss. Earthquakes can trigger landslides and tsunamis which can happen after the main event. Finding nothing of serious monetary value, the companies abandoned reams of information they had gathered through seismic surveys. Tsunamis triggered by earthquakes usually require at least a M7 event. Even if the earthquake is too small to be felt by people, seismographs can detect it. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. The buildings sank when ground shaking weakened the underlying sediments. Since about 1870 there have been about 15 large earthquakes (greater than M5) in the state. Earthquakes occur nearly every day in Washington. The most recent hit roughly 2,700 years ago. Electricity, water, natural gas, and phones may not work. Floods. 1 NE 7th Street stream In places where there is little vegetation, different rock types and faults can be found with relative ease. Theres a reason the lands around the Pacific Ocean are called the Ring of Fire. The earthquakes, tsunamis, and the proximity of volcanos are all part of the same system. Map Releases; Topographic (Topo) Maps; Volcanic Maps; All Maps; Multimedia Gallery. 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. Oblique convergence and clockwise rotation along the continental margin are the inferred driving forces for ongoing deformation. For example, in the open ocean a tsunami may be less than a few feet tall. In addition, the Survey performs seismic safety evaluations of schools. A community meeting about a shelter at the Harbor Inn may have yielded more questions than answers. The Westport area is now the first in North America to have acommunity vertical evacuation structure, a building strong enough to resist earthquake and tsunami wave forces and give people a platform above the expected wave heights. <> This means that the internet, your cell phone, grocery stores, and gas stations may also not work. The medic said colleagues were becoming sick and emotionally overwhelmed Earthquakes between 45 and 185 miles deep are called intermediate, and earthquakes over 185 miles deep are called deep. Emergency planners all had a simple message: Its not IF a disaster will happen, its WHEN. Power could be out for days. A magnitude 7.4 along the southern Whidbey fault would rattle 18 counties in Washington, according to a federal projection . The Cascadia subduction zone along the Washington and Oregon coast is one of the biggest hazards to our state and is a good examples of this kind of fault. Faults often occur at and near the boundary of large tectonic plates because the plates are moving in different directions. Geologists at the Survey spend time mapping the geology of the state, looking for faults, folds, landslides, and different rock types.

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