southern whidbey island fault map southern whidbey island fault map

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. Photo from, This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. Despite its location well offshore, a Cascadia quake would likely kill at least 10,000 and injure more than 30,000 in Washington, Murphy found. Large earthquakes are less common but can cause significant damage to the things we count on in everyday life, such as buildings, roads, bridges, dams, and utilities. This was a problem because no two locations would agree on the size of the same earthquake. 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. It is capable of generating severe earthquakes that would impact the entire west coast. 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. stream Higher risk areas are in orange and lower risk areas are in green. Earthquakes cause damage by moving and shaking the ground, sometimes for several minutes. And experts fear it could be even worse than The Big One.. So the fault remained mostly a mystery until the 1990s. You have entered an incorrect email address! A half dozen people reaching for the last can of soup, someone could lose their life over that. Do you live or work near an area that could have liquefaction? Learning earthquake faults around where we live is a first good way to prepare the next devastating earthquake. A community meeting about a shelter at the Harbor Inn may have yielded more questions than answers. Also check out Ear to the Ground, published by the Department of Natural Resources. The shaking can damage or destroy buildings and other infrastructure. We use the term deep to talk about faults and earthquakes deeper than about 18 miles. Notable earthquakes in bold happened in Washington. Scientists have been trying to understand how often earthquakes happen for over 100 years. Tohoku killed nearly 16,000 people; most died as a result of drowning or being crushed in the tsunami. The Seattle fault last ruptured about 1,100 years ago in AD 900950. Before modern record keeping, Native Americans lived in the Pacific Northwest for thousands of years. After the shaking stopped the sand regained its strength. Hold on to any sturdy shelter until the shaking stops. Brick chimneys cascade off rooftops. Each peak of the Olympics stuck out with picturesque clarity in the distance. Trenches by Sherrod and others, 2008 #7652) are less than 1 km south of KP1 and KP2 and Sherrod and others (2008 #7652) conclude that deformation in the area is due to surface-rupturing earthquakes. Washington has the second highest risk in the U.S. of these large and damaging earthquakes because of its geologic setting. Seattle Fault Lines. 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. The below map shows that Seattle and its surroundings is constantly being rattled by small earthquakes and tremors. Save my name, email, and website in this browser for the next time I comment. Necessary cookies are absolutely essential for the website to function properly. These aftershocks can last for hours to weeks or months. The study of seismic waves is called seismology and has allowed scientists to learn much about the internal structure of the Earth. 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. They didnt grow up here, they havent heard this story. This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. Photo from https://buildingfailures.files.wordpress.com/2014/02/tiltedbuilding.jpg. Photo by G.K. Gilbert, from the Steinbrugge Collection of the UC Berkeley Earthquake Engineering Research Center. Move away from buildings, streetlights, and utility wires if you can. A thrust fault is a special kind of reverse fault that has a shallow dip. In addition, the Survey performs seismic safety evaluations of schools. 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. That could spell trouble not only for its namesake island but for south and north King County and further west. The 2011 Tohoku earthquake in Japan occurred on this type of fault and released enough energy to slightly change the Earths axis of rotation. In this photo, visitors to Green Lake Park near Seattle, Washington, have parked their bicycles as they look at the cracks made by the April 1949 earthquake. Stop as quickly as safety permits and stay in the vehicle. Armentrout, J. J. Miller, C. Finn, C. S. Weaver. On an inactive fault, the sea would have risen at the same rate at both locations. 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. If a large earthquake happens, be prepared for many more earthquakes. Lidar maps show the Earths surface without vegetation. Doorways do not provide protection from falling or flying objects and you may not be able to remain standing. Power could be out for days. Sometimes Geologists can use the offset land surface to understand how much the fault moved during the earthquake. of Earth and Space Sciences, Box 351310, Univ. Most of the populated areas of the state have a 4080% chance of having an earthquake in the next 50 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. Large earthquakes are likely to happen in Washington during your lifetime. Secure .gov websites use HTTPS When an earthquake happens there will not be time to google what you are supposed to do. Tap/click on "gear icon" for options and settings. We do know that it is active and will likely produce a large M67.5 earthquake when it next ruptures. 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 The southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. Charles Richter and Beno Gutenberg discovered that for every magnitude of earthquake, there are about ten times more earthquakes of the next lower magnitude. Sherrods son has since completed graduate school in applied geosciences. Because they can travel great distances, tsunamis generated from earthquakes across the ocean can still cause damage. A normal fault occurs when two blocks are pulled away from each other. Another big one is expected, and it could be devastating. The map also shows potentially active faults from a separate 2014 report (click here to download). Secure .gov websites use HTTPS In the Puget Sound region, it takes a trained eye to recognize rocky outcrops and subtly raised ground as evidence of a fault. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Much of the land along the southwestern part of the lake cracked and subsided. A major southern Whidbey quake, on the other hand, could kill and injure many more, according to Murphy. An earthquake can be a scary event. 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. Most injuries occur when people inside change rooms or try to leave the building. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. An official website of the United States government. 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. The moment magnitude scale is a type of logarithmic scale, where each increase of 1 means ~32 times more energy is released. These cookies do not store any personal information. The affiliate sales will help us to continue the hard work we are putting in this website. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. The largest active fault that will affect Washington (and the whole Pacific Northwest) is the Cascadia subduction zone. The next earthquake is inevitable, but the variability makes it difficult to know exactly when. The Flying Squirrel and Mountain Beaver trenches cross the Cottage Lake lineament. Third, the South Whidbey Island Fault running from northwest to southeast of the southern tip of the island. A reverse fault occurs when two blocks are pushed together and one moves up and over the other. These sediments were laid down 20,000 to 60,000 years ago, before the last ice age. The southern Whidbey fault is shallow, running right under Snohomish County as opposed to many miles off shore like the Cascadia fault. This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. During site visits in 2005, Sherrods team found evidence of four SWIF earthquakes in the past 30,000 years. The southern Whidbey Island fault, and several others, were exposed for the first time from a camouflage of forest, ocean and glacial sediment. 4 0 obj Photo by Steve Palmer. Earthquakes occur nearly every day in Washington. Stay away from glass, windows, outside doors and walls, and anything that could fall down. Share sensitive information only on official, secure websites. Washington, Seattle, WA 98195 2 U.S. Geological Survey, 345 Middlefield Road, M/S . But quiet period wont last, Strongest earthquake in 40 years rattle residents of Buffalo, NY, Is Istanbul next? Earthquakes on faults like these may cause tsunamis in the Puget Sound region. Seconds later, its as if Whidbey Island is trapped in a cocktail shaker, lurching back and forth. Photo from Pacific Northwest Seismic Network Seismo Blog. For example, the Cascadia subduction zone has had between 15 to 19 earthquakes over the past 10,000 years. The best thing you can do is to become prepared. Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. The seismic mapping had cost millions of dollars far beyond what most geologists on a government budget could scrape together. Finding and mapping these faults is an important mission of the Washington Geological Survey. You saw its potential in the 9.1 magnitude Tohuku earthquake and tsunami that hit northeastern Japan in March 2011. A low-angle fault, which is not conclusively earthquake related, separates a diamicton from the overlying recessional outwash deposit. The fault probably originated during the early Eocene as a dextral strike-slip fault along the eastern side of a continental-margin rift. Johnson, on a whim, acquired the data that would prove its existence beyond a doubt. These maps are created by small planes that use a specific type of laser to measure the elevation of the ground. Get On The List To Receive Your Daily Dose Of Weird News And Amazing Phenomena. Small normal faults are found along the top of folds in eastern Washington in the Saddle Mountain graben. Snohomish, King and Island counties would be expected to see the. 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 Safe America Foundation suggests texting as a way of communication. Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. from Whidbey Island to Vancouver Island (Figure 1). Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. 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. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. southern Whidbey Island fault zone (Class A) No. The tsunamis can travel far inland and deposit layers of sand and organic material. Since about 1870 there have been about 15 large earthquakes (greater than M5) in the state. These faults and earthquakes occur in the continental crust of North America. The last time was 1,000 years ago between 900 and 903 A.D., said Forson. Once a fault is located, it is important to know if it is active. He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. Liquefaction is when wet soil or sediment loses strength because it is being shaken during an earthquake. In this sense, the shaking of the ground is the sound of rocks breaking and moving deep within the Earth. The buildings in this photo were built on soft materials that liquefied during the 1964 Niigata earthquake in Japan. The Eastern Sierra fault along the east side of the Sierra Nevada mountains in California is a good example of an active normal fault. If you are already planning your Christmas gifts, please buy with us on Amazon. Earthquakes on shallow faults typically last 20 to 60 seconds and the shaking is localized to the general area of the fault. <> On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. Camano Island, WA 98282, Mailing Address Do not exit a building during the shaking. But they didnt document it hardly at all.. It startled Johnson that such massive faults had gone undetected for so long. 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. This movement created a tsunami in Puget Sound and triggered a large landslide into Lake Washington. Westport currently is the only location with a vertical evacuation structure designed for a tsunami. The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. This means that a large area feels the shaking, but the intensity is less than a similar shallow earthquake. 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. Faults can also be grouped based on what part of the crust they occur in. In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. Superior Court:(800) 254-2755 Click the "Seismogenic Features" button in the Map Contents window to display faults and earthquakes. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. 1 NE 7th Street The map is from a, This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. Expect aftershocks. In fact, new faults are found every year during our geologic mapping efforts. And when are documentary film called Cascadia The Big One, Dangerous Inland Earthquake Destroys Homes and Schools near Jakarta, Indonesia, Terrifying video shows olive grove turned into a Gigantic Canyon after Turkeys earthquake split land in huge rifts. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. This is a hypothetical scenario created by Mark Murphy of the Snohomish County Department of Emergency Management. Identify and secure items in your home or work that could cause damage. Because Japan was so well prepared, mostretrofitted buildingsoutside of the tsunami zone survived. But the Cascadia Subduction Zone isnt just a fault; its an overlapping joint between tectonic plates, parts of the Earths crust that float on layers of molten rock. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). At the time, Johnson worked in southwest Washington, searching for natural gas and oil deposits. The buildings sank when ground shaking weakened the underlying sediments. Most damage and loss of life in earthquakes is a result of ground shaking. Each type has different kinds of earthquakes. Additionally, because the continent moves up and over the ocean plate, large amounts of sea water are displaced and cause damaging tsunamis. All Rights Reserved 2021, Site Disclaimer Geologists at the Survey spend time mapping the geology of the state, looking for faults, folds, landslides, and different rock types. 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. Landslide at Salmon Beach was triggered by the 1949 Tacoma earthquake and caused a tsunami. Coupeville, WA 98239, Main Line: By clicking Accept, you consent to the use of ALL the cookies. Drop to your hands and knees. The crustal faults the Seattle Fault, the South Whidbey Island Fault, the Tacoma Fault those are less well known, said Forson. A team headed by Joe Dragovich of DNRs Division of Geology and Earth Resources,assisted by geologists from King County, Pacific Northwest Seismic Network, Colorado College, and Washington State University, has been mapping in this area for the past three years. The fault's length depends on whom you ask, Sherrod said. After the shaking stopped the sand regained its strength. Nearly all earthquakes occur on faults, features in the Earth where rocks move past each other. Finding faults and knowing how often they rupture is one of the most important tasks to keep society safe from these hazards. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. In 1985, with little concrete evidence of its existence, the pair included the possible fault on a geologic map published by the USGS. The ground shaking from these earthquakes can last for several minutes. Most faults in Washington are a mix of a strike-slip fault and a thrust or reverse fault. In the month after the main earthquake there were about 60 M7 and M6 earthquakes. View Earthquake Map Faults Interactive fault map and comprehensive geologically based information on known or suspected active faults and folds in the United States. 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. A damaging earthquake is inevitable on this fault, but we do not know exactly when it will happen. In Seattle, the quake damaged buildings, weakened bridges, started fires and opened cracks in the earth. Knowing how often large earthquakes have happened in the past helps us to know how often they might occur in the future. Along the water at Cama Beach State Park, cabins on a bluff overlook Saratoga Passage, facing the general direction of Lake Hancock on Whidbey Island. Earthquakes can trigger landslides and tsunamis which can happen after the main event. Large earthquakes, like those from the Cascadia subduction zone on January 26, 1700, often create tsunamis. @\;L;=}%FC*l $@ 4x: 888O~xrsxx'/*rGRF\gI%~x(G-^-hjjq kx/V ou0hyegy0;ei`Tx&ilZ )TmZ$vb,`bQm|DR5x/ His team wanted to find the rate of sea level rise along the shore. Washington has few large normal faults because it is mostly in a region of compression. % 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. x\[s8~OU)! Mudslides. Map Releases; Topographic (Topo) Maps; Volcanic Maps; All Maps; Multimedia Gallery. The shaking can also cause landslides, surface ruptures, ground cracks, liquefaction, tsunamis, and seiches (standing waves). 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. The southern Whidbey Island fault zone (SWIF), as previously mapped using borehole data, potential field anomalies, and marine seismic reflection surveys, consists of three subparallel, northwest trending strands extending ~100 km from near Vancouver Island to the northern Puget Lowland. An increase of 2 means that ~1,000 times more energy is released. Tsunami waves can travel over 500 miles per hour in the open ocean. endobj ?7) and represents a potential seismic hazard to residents of the Puget Lowland. STAY THERE until the shaking stops. This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. Liquefaction has caused significant damage during earthquakes in Washington. This is an active fault.. That may not sound like much more than the magnitude 6.8 quake of 2001 based on the numbers, but that the Nisqually quake occurred some 30 miles underground. The last large earthquake on the Cascadia subduction zone was in 1700. Learn about at-risk areas and become prepared. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Since their initial discovery, research has shown that the actual number of earthquakes is somewhere between 5 and 10 for each change in magnitude. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. When the landslide hit the water it may have created a tsunami. It devastated the coast of the Pacific Northwest and sent an orphan tsunami to Japan. You also have the option to opt-out of these cookies. The French Onion trench exposed glaciolacustrine claystones, till, colluvial deposits, and Holocene soils. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Washington has dozens of active faults and fault zones. This kind of landslide is called an earthquake-triggered landslides. Paleoseismologists have found places that record many of these tsunami deposits. America is going to be punished just like the rest of the world. In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Experts have warned that UK outbreak may be around two weeks behind Italys. These older faults do not have any evidence for recent activity, but the Earth is always changing. 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. Although we cannot predict exactly when the next earthquake will happen, we can predict the general distribution of earthquake sizes. Sherrod shrugged his shoulders. The continued movement along faults over millions of years can build mountains, tear a continent apart, and move tectonic plates thousands of miles. Earthquakes. After a large earthquake it is common to have other large earthquakes for hours, days, and even weeks. The trenches exposed glacial deposits disrupted by faults and liquefaction features. This website uses cookies to improve your experience while you navigate through the website. 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. The map also shows potentially active faults from a separate 2014 report (click here to download). 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. You just need one person to crash or a power line to fall over the road, and the roads are unusable.. A magnitude 7.4 along the southern Whidbey fault would rattle 18 counties in Washington, according to a federal projection . The 1949 earthquake near Tacoma triggered a landslide near the Tacoma Narrows that caused a local tsunami. That place is the Ocosta School. They havent dug up enough history to estimate. One of the best views of SWIF should be from Grand Avenue Park in Everett. Most are too small to be felt or cause damage. On a brilliant November day, Sherrod took in the panorama from the parks bluff. Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. Other faults may lie entirely underground, or could be covered by vegetation and (or) sediment. Evacuate to higher ground if you are near a large body of water. A lock () or https:// means youve safely connected to the .gov website. An earthquake occurs when rock inside the Earth moves or breaks. Johnson and others (1996 #4751) described the structure and stratigraphy of the southern Whidbey Island fault zone. In effect, the wave energy is trapped by the edges of the body of water. Liquefaction can be a big problem. 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). 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. 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. In the 1990s, scientists producedan animationthat shows inundation, and people wont have much time to run to higher ground. This fault zone was originally named the Devils 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). So they dont necessarily know the threats they face.. Tsunamis and seiches can also be triggered by large slides, both on land and underwater. Official websites use .gov The 1964 M9.2 Alaska earthquake created a large tsunami from the fault rupture, and many smaller tsunamis from on-land and underwater landslides. In the late 1960s, speculators considered the Puget Sound region a frontier for petroleum exploration. In 2017, he began studying the possible aftermath of a major SWIF quake. DO NOT get in a doorway. 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. There are also many faults that have not been studied enough to know if they are active. Most faults are considered active if they have evidence for movement (this includes earthquakes) within the past 12,000 years (the Holocene time period). For more information about earthquakes, faults, and emergency preparation, consider visiting the following sites: This map shows areas of seismic risk from high (red) to low (grayish-green).