southern whidbey island fault map

Superior Court:(800) 254-2755 Tsunamis are a common result of large earthquakes in Washington. HAZARD MAPS As part of the Hazard Mitigation Planning process, mapping of the hazards that have the potential to affect the jurisdiction is performed using geographic information systems (GIS) software. We use the term deep to talk about faults and earthquakes deeper than about 18 miles. The shaking usually lasts less than a minute and doesnt generally cause a tsunami or have many aftershocks. Deformed recessional outwash deposits and Holocene deposits were exposed; three unconformities separated the units. Secure .gov websites use HTTPS In the 1990s, scientists producedan animationthat shows inundation, and people wont have much time to run to higher ground. People stagger into the streets to avoid an avalanche of debris. Using the stratigraphic column from the Freeport quadrangle map, confirm that you can recognize . ; (5) large-scale liquefaction features in upper Quaternary sediments within the fault zone; and (6) minor historical seismicity. 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). When the ground shakes during an earthquake, it moves up and down, acting like additional gravity. During site visits in 2005, Sherrods team found evidence of four SWIF earthquakes in the past 30,000 years. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. Its significantly larger than the Seattle Fault, and South Whidbey could hand us a magnitude 7.5 earthquake. Its just the way scientists work, he said. The moment magnitude scale is a type of logarithmic scale, where each increase of 1 means ~32 times more energy is released. Proceed cautiously once the earthquake has stopped. The tsunami becomes taller as the ocean becomes shallow. If folding on the Little Bear Creek lineament resulted in one or two of unconformities, the poorly constrained timing of the earthquakes is younger than 12,000 yr BP and older than about 2,850 cal yr BP. Also check out Ear to the Ground, published by the Department of Natural Resources. Finding and learning about faults requires many different aspects of geology and geophysics. STAY THERE until the shaking stops. The Safe America Foundation suggests texting as a way of communication. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. It might as well have been sitting in a drawer, Johnson said. Image from the Pacific Geoscience Center of the Natural Resources of Canada. The Survey conducts and publishes geologic mapping to identify and characterize faults throughout the state. Scientists are not sure how far east it goes. In addition, the Survey performs seismic safety evaluations of schools. Under a scenario played out in a 2019 U.S. Department of Homeland Security study, state-maintained bridges would be severely damaged, leaving them unusable for months or years. 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. Earthquakes on shallow faults typically last 20 to 60 seconds and the shaking is localized to the general area of the fault. Contact Us, Whidbey Office This movement created a tsunami in Puget Sound and triggered a large landslide into Lake Washington. These quakes are capable of magnitudes from 7 to over 9. Its certainly not to scare you. 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. Know what to expect. Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. Photo by Steve Palmer. Seattle Fault and Whidbey Faults HAZARD MAPS As part of the Hazard Mitigation Planning process, mapping of the hazards that have the potential to affect the jurisdiction is performed using geographic information systems (GIS) software. Evacuate to higher ground if you are near a large body of water. Radiocarbon ages of macrofossils constrain uplift timing to 2.83.2 ka. But opting out of some of these cookies may affect your browsing experience. This map is from a 2007 report on the seismic design categories in Washington. In the Puget Sound region, it takes a trained eye to recognize rocky outcrops and subtly raised ground as evidence of a fault. Close to shore, this same wave could reach heights of 30100 feet or more. EVERETT The South Whidbey Island Fault is connected to a system of powerful earthquake fault lines stretching from Victoria, B.C., to Yakima that is capable of unleashing a devastating. The Seattle fault last ruptured about 1,100 years ago in AD 900950. The video is also available in Spanish and there is a fun activity/coloring book that can be found here. Washington has the second highest risk in the U.S. of these large and damaging earthquakes because of its geologic setting. Kelsey and others (2004 #7651) suggest that the earthquake resulted in 2.5 m uplift of the salt marsh on the north side of the fault strand relative to the marsh on the south side; no fault scarp has been identified between the marshes. This is called liquefaction and is discussed in the next section. This movement happens because stress builds up as tectonic plates move. Washington has few large normal faults because it is mostly in a region of compression. Seattle Fault Lines. By Julia-Grace Sanders The Everett Herald May 14, 2021 2:40 pm, Luella Meaux: November 21, 1929 January 21, 2023, Claudia Anderson: October 1, 1939 January 31, 2023, Chieko Yamane Miller: July 26, 1936 February 16, 2023, Guarding the flock: Chicken farms rely on specialized dogs, Flying colors: Irish artist finds success on Whidbey. By finding the age of the deformed layer, a paleoseismologist can determine the minimum age of the fault. The Pacific Tsunami Warning Center is located in Hawaii and is responsible for issuing alerts to all the countries that border the Pacific Ocean. Walsh said that Whidbey Island through the years has been subjected to a number of small quakes, roughly 2 or 3 on the Richter scale. <>>> 1 0 obj Sometimes there may be a layer of volcanic ash or charcoal that has been deformed by the fault. After the earthquake, many things you count on may not be available. This means that when the Seattle fault ruptures the south side of the fault moves up relative to the north side. Check out the liquefaction susceptibility and NEHRP site class maps on the Geologic Hazard Maps page. A national credit rating service has improved its opinion of WhidbeyHealths financial future. By sampling sediment from the marsh to the beach berm, Sherrod and his research partner, Harvey Kelsey, developed a timeline of the oceans climb. An increase of 2 means that ~1,000 times more energy is released. Geologists at the Survey spend time mapping the geology of the state, looking for faults, folds, landslides, and different rock types. 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. The April 1949 Tacoma earthquake measured 7.1 on the Richter Scale and caused damage from southern Oregon to British Columbia. Once the shaking has stopped, exit the building if it is safe to do so. Faults can be grouped based on their relative movement into three types. Each of the earthquakes listed on the bottom of the screen is capable of significant damage. It is not yet possible to predict when a fault will have an earthquake. Higher risk areas are in orange and lower risk areas are in green. Some parts of major cities (including Seattle, Tacoma, and Olympia) have been built on land that was reclaimed from soft and wet tidal ocean areas. 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), The southern Whidbey Island fault: An active structure in the Puget Lowland, Washington, S. Y. Johnson, C. J. Potter, J.M. The Cascadia Subduction Zone (also known as the CSZ) is a 700-mile long fault zone located off the western coastline of British Columbia, Washington, Oregon and northern California. He said scientists have known about the southern Whidbey fault for decades. ?7) and represents a potential seismic hazard to residents of the Puget Lowland. There are many other active faults in Washington and any of these could produce a large earthquake in the future. The threat to Puget Sound from a quake along the Cascadia Subduction Zone, off the coast of Washington, Oregon and California, is well documented. If the epicenter is Everett, the SWIF could cause. The Port of Coupeville will apply for a grant to fund two electric vehicle charging stations. Like a sonogram, the seismic surveys allowed Johnson to see outlines of massive fissures in the earths crust. The buildings sank when ground shaking weakened the underlying sediments. Maps. On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. Tsunamis and seiches can also be triggered by large slides, both on land and underwater. A special type of shallow fault, called a subduction zone or megathrust, occurs where an oceanic plate moves beneath a continental plate. Johnson, on a whim, acquired the data that would prove its existence beyond a doubt. An official website of the United States government. Most faults are considered active if they have evidence for movement (this includes earthquakes) within the past 12,000 years (the Holocene time period). This kind of landslide is called an earthquake-triggered landslides. Floods. The southern Whidbey Island fault (SWIF) stretches from the vicinity of Victoria, B.C., across Puget Sound as far as the Cascade Range. Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. 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. Official websites use .gov Sherrod says practically every place they. The Geologic Information Portal has a Natural Hazards theme that shows active faults and earthquakes. When an earthquake happens there will not be time to google what you are supposed to do. Small normal faults are found along the top of folds in eastern Washington in the Saddle Mountain graben. Early mapping of the three subparallel, northwest trending strands of the southern Whidbey Island fault zone was constrained by borehole data, potential field anomalies, marine seismic reflection surveys. Bending of the fault and transpressional deformation began during the late middle Eocene and continues to the present. That place is the Ocosta School. DO NOT get in a doorway. Facades crumble off buildings along Oak Harbors Pioneer Way, and some of the oldest structures in Langley and Coupeville collapse in a roaring cloud of dust. The shaking can damage or destroy buildings and other infrastructure. Theyre FREE CLICK HERE to subscribe, EAR TO THE GROUND WITH DNR & COMMISSIONER FRANZ, Tree Link helps you answer questions about urbantrees. A .gov website belongs to an official government organization in the United States. Earthquakes can be measured in many ways, but the most accepted method is called moment magnitude. and the Red Cross will be there to care for them. The below map shows that Seattle and its surroundings is constantly being rattled by small earthquakes and tremors. endobj California Department of Conservation. Brick chimneys cascade off rooftops. Johnsons curiosity changed the course of his career. These aftershocks can last for hours to weeks or months. Visit our School Seismic Safety page for more information. You can look at different geological hazard mapson the website of the Department of Natural Resources. Do you live or work near an area that could have liquefaction? Roads, bridges, or ramps may have been damaged by the earthquake. A lot of people are transplants, Forson said. Before modern record keeping, Native Americans lived in the Pacific Northwest for thousands of years. By clicking Accept, you consent to the use of ALL the cookies. While the intensity of this seismic event has now decreased, a big earthquake is overdue in the region. Some of these faults are in remote areas. 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. In 1985, with little concrete evidence of its existence, the pair included the possible fault on a geologic map published by the USGS. In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. Liquefaction can be a big problem. Although we know much about active faults and earthquakes, there is much more to learn. Because they rupture at such great depth, their seismic energy is distributed over a large area. Official websites use .gov Most are too small to be felt or cause damage. The southern Whidbey Island fault divides the two. Why is Strange Sounds focusing so much on disaster preps? PO Box 5000 572 Last Review Date: 2016-11-29 Along the coast residents may have between 20 and 30 minutes to get to higher ground. Sherrods son has since completed graduate school in applied geosciences. Another piece can be seen under the elevated lanes of northbound Interstate 5 in South Seattle not far from the Rainier brewery. Scientists have also dated large underwater landslides and turbidites that travel from the continental edge far out into the ocean basin. The evidence shows each lake rests on different free-floating jigsaw pieces of planetary crust, separated by the southern Whidbey Island fault. Knowing how often large earthquakes have happened in the past helps us to know how often they might occur in the future. But Forson says you also need to know what to do when the shaking happens. This uplift creates a very broad wave called a tsunami. Then the world rattles up and down. The South Whidbey Island Fault and Darrington Devil's Mountain Fault bound the Everett Basin. The Cascade block to the northeast is floored by diverse assemblages of pre-Tertiary rocks; the Coast Range block to the southwest is floored by lower Eocene marine basaltic rocks of the Crescent Formation. 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. 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. Still think well avoid Gods wrath, its not going to happen regardless of what the multi millionaire TV preachers tell you. What makes these faults mega is that the amount of energy released is hundreds to thousands of times more than almost any other type of fault. The seismic mapping had cost millions of dollars far beyond what most geologists on a government budget could scrape together. 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. Stop as quickly as safety permits and stay in the vehicle. In Washington, we do not have tsunami walls. This date was confirmed by records in Japan of an orphan tsunami and by many lines of geologic evidence. When a fault with vertical movement ruptures the ocean floor, it lifts up part of the ocean. In some areas getting up a hill to higher ground will be difficult. Resources on tsunami danger and preparedness in Westport, Grays Harbor County, Long Beach Peninsula, and Coastal evacuation maps. An abrupt rise or decline in sea level would reveal if the fault had triggered a quake before. District Court: (800) 946-9765, South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario. Even when an earthquake happens on a fault that doesnt reach the surface, the ground can still show signs of cracking. These include the: Southern Whidbey Island Fault (SWIF) Seattle Fault Devils Mountain Fault Strawberry Point fault Utsalady Point fault Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. The mission of the Washington Geological Survey is to collect, develop, use, distribute, and preserve geologic information to promote the safety, health, and welfare of the citizens, protect the environment, and support the economy of Washington. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. A major southern Whidbey quake, on the other hand, could kill and injure many more, according to Murphy. endobj Please visit our Geologic Information Portal and Geologic Hazard Maps page for the most up-to-date listing of all of our hazard maps. It will happen; we dont know when.. After a large earthquake it is common to have other large earthquakes for hours, days, and even weeks. Below you will find links to view and download hazard maps created for each jurisdiction included in the current mitigation planning process. Finding nothing of serious monetary value, the companies abandoned reams of information they had gathered through seismic surveys. All faults, regardless of size, can be dangerous if they rupture. Large earthquakes, like those from the Cascadia subduction zone on January 26, 1700, often create tsunamis. This fault zone was originally named the Devils Faulting produced warping at the site of greater than 2 m. Radiocarbon ages provide a maximum age for the folding event of 12,09011,670 cal yr BP. One of the best views of SWIF should be from Grand Avenue Park in Everett. Johnson and others . Learn how your comment data is processed. Washington, Seattle, WA 98195 2 U.S. Geological Survey, 345 Middlefield Road, M/S . He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. The best thing you can do is to become prepared. Geologists have used the location of these shallow, intermediate, and deep earthquakes to learn about subduction zones throughout the world. 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. Like other faults, when enough stress builds up, the megathrust will rupture. Fault Activity Map of California. Consider subscribing to our blog, Washington State Geology News, to receive notifications when new information is published. <>/XObject<>/ExtGState<>/Pattern<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> The northwestern part of the fault zone forms the northeastern limit of the Port Townsend basin (Brocher and others, 2001 #4718). At the Washington Geological Survey, active means that a fault has evidence for movement within the Holocene time period (since about 12,000 years ago). Small fires are the most common hazard after an earthquake. Washington State Earthquake Hazard Map. The Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. Earthquakes can trigger landslides and tsunamis which can happen after the main event. 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. southern Whidbey Island fault zone (Class A) No. Over time, fault movement has created some interesting geologic features. 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. Earthquakes occur nearly every day in Washington. Scientists are not sure how far east it goes. One or possibly two of the unconformities are interpreted as event horizons. For earthquakes that occurred before seismographs were invented, the Mercalli Intensity scale was used to make maps of damage and determine the size and location of an earthquake. Strabge sounds very good report thanks a lot. On an inactive fault, the sea would have risen at the same rate at both locations. Landslides can be caused by strong ground shaking during an earthquake. The bluff, where the cabins now sit, could have jutted up in the most recent Whidbey fault quake, Sherrod said. We do not encourage people to evacuate in vehicles. Experts have warned that UK outbreak may be around two weeks behind Italys. Every year Western. Once we got it, we were sort of shocked to see these big faults in the Puget lowlands, he said. The southern Whidbey fault is unlike more visible faults on the West Coast. For example, in the open ocean a tsunami may be less than a few feet tall. Here, were looking at one of the bigger faults in the region, he said. This new method allows geologists to see through trees and vegetation to find new faults. Everything points to one thing, Sherrod said, waving his hand across the inland sea. Disoriented drivers wonder whats wrong with their cars, then realize something much bigger is amiss. View Earthquake Map Faults Interactive fault map and comprehensive geologically based information on known or suspected active faults and folds in the United States. Photo from, Liquefaction can be a big problem. The more you know what to expect, the better prepared you will be to help yourself, your family, and others around you. This fundamental tool for earth scientists, maps show map units, faults and folds, cross sections, and other regional or local features, depending on map scale. Unlike sound, ground shaking can be amplified or attenuated (made less) depending on the type of material at the Earths surface. Stay away from glass, windows, outside doors and walls, and anything that could fall down. And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. The southeastern and central parts of the southern Whidbey Island fault zone form the southwest margin of the Everett basin and northeast boundary of the Seattle basin. In the late 1960s, speculators considered the Puget Sound region a frontier for petroleum exploration. % The marshy deposits are about a meter higher at Lake Hancock. The years have gone by. The map is from a 2007 report (click here to download) on seismic design categories in Washington. The southern Whidbey fault is shallow, running right under Snohomish County as opposed to many miles off shore like the Cascadia fault. Ground shaking is a hazard near the epicenter of an earthquake and also in areas far from the earthquake where amplification occurs. With Medical Martial Law imposed in Washington state. " A lot of people are transplants, " Forson said. 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. These maps are created by small planes that use a specific type of laser to measure the elevation of the ground. This northwest-trending fault comprises a broad (as wide as 6-11 km), steep, northeast-dipping zone that includes several splays with inferred strike-slip, reverse, and thrust displacement. Volcanic eruptions. Photo from https://buildingfailures.files.wordpress.com/2014/02/tiltedbuilding.jpg. Theres an uneasy hush. Often this cracking happens because a soft part of the ground liquefies during the shaking. Both of these things can cause equal or greater damage than the actual earthquake. The material becomes so weak that it behaves more like a liquid than a solid. It is mandatory to procure user consent prior to running these cookies on your website. For example, a M7 earthquake releases 32 times more energy than a M6 earthquake, and 1,000 times more than a M5 earthquake. Unlike The Big One, scientists who have studied the southern Whidbey fault have far less understanding of when the next sudden shift might hit. 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. USA Earthquake Hazard Map. A seiche is a large standing wave caused by the resonance of a particular period of wave energy. In general, larger faults make larger earthquakes. . Someone screams. Wagner and Wiley (1983 #6230) and Wagner and Tomson (1987 #6249) mapped and briefly discussed offshore parts of this fault zone and also used the name "southern Whidbey Island fault." 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 Geologists are constantly trying to better understand the faults in our state. People who look for evidence of past movement on faults are usually called paleoseismologists (from paleo-ancient and seismologist-one who studies earthquakes). The buildings in this photo were built on soft materials that liquefied during the 1964 Niigata earthquake in Japan. Most are too small to be felt or cause damage. The publication Faults and Earthquakes in Washington State is a state-wide compilation of active faults and folds. The DNR team found that the Seattle fault is intercepted by the southern Whidbey Island fault zone in the vicinity of Fall City. Once in the open, Drop, Cover, and Hold On. Standing becomes almost impossible as the jolts turn to rolling waves. This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. The southern Whidbey Island fault, and several others, were exposed for the first time from a camouflage of forest, ocean and glacial sediment. If everyone tries to use their cell phones, it can overload the system. Emergency planners all had a simple message: Its not IF a disaster will happen, its WHEN. A strike-slip fault occurs when two blocks move past each other. Also issued a warning for the UK that the Italian chaos could come to Britain An earthquake can be a scary event. 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). (Andy Bronson / The Herald). The age of the earthquake is learned by dating the organic material in these tsunami deposits. Paleoseismologists have found places that record many of these tsunami deposits. Hover over a cluster of earthquakes to learn about the different types in the Pacific Northwest. Not all faults are active. This map shows different seismic design categories that correlate with amount of seismic risk. 3 0 obj Make an emergency response plan for you and your family. Drop, Cover, and Hold On whenever you feel shaking. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario Fire (Vegetation Condition Class) . Depending on the type of fault, the ground can move laterally, vertically, or a combination of both. These fault strands follow the valley edges and control the location of the Snoqualmie River along some portions of the valley. Sheriff:(360) 679-7310, Juror Recordings Story telling is an important part of the Native tradition and is how their history is passed down to the next generation.