Ready to retrofit? For example, it is unlikely that you will be able to use electricity, cell phones, or the internet. There are many other active faults in Washington and any of these could produce a large earthquake in the future. These aftershocks can last for hours to weeks or months. Evacuate to higher ground if you are near a large body of water. Floods. Since about 1870 there have been about 15 large earthquakes (greater than M5) in the state. Each of these aftershocks would be a significant earthquake if it happened on its own. Most damage and loss of life in earthquakes is a result of ground shaking. endobj Even if the earthquake is too small to be felt by people, seismographs can detect it. #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. 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). stream The Straight Creek fault in the Cascade Range is an example of this kind of fault and has ~5060 miles of movement across it. Its certainly not to scare you. 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. Much of the land along the southwestern part of the lake cracked and subsided. 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. Geologists do not yet know how often earthquakes happen on this fault. A community meeting about a shelter at the Harbor Inn may have yielded more questions than answers. Doctor reveals the horrors Italian medics are facing in overwhelmed hospitals where dying patients are being left untreated as experts warn UK and US are just two weeks behind Italy and the public are not SCARED enough, An intensive care doctor in northern Italy has described the scale of the crisis Brick chimneys cascade off rooftops. Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. The average time between large earthquakes is about 535 years, but has been as little as 200 years, and more than 1,000 years. Clicking on the map will download the publication. Hover over a cluster of earthquakes to learn about the different types in the Pacific Northwest. This map is from a 2007 report on the seismic design categories in Washington. 121 N East Camano Dr Avoid stopping near or under buildings, trees, overpasses, or utility wires. 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. During site visits in 2005, Sherrods team found evidence of four SWIF earthquakes in the past 30,000 years. 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. With Medical Martial Law imposed in Washington state. A seiche is a large standing wave caused by the resonance of a particular period of wave energy. Earthquakes on shallow faults typically last 20 to 60 seconds and the shaking is localized to the general area of the fault. A lot of people are transplants, Forson said. 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. The age of the earthquake is learned by dating the organic material in these tsunami deposits. Mudslides. Source: United States Geological Survey. Areas like these are also susceptible to liquefaction. Tsunami waves can travel over 500 miles per hour in the open ocean. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. The bluff, where the cabins now sit, could have jutted up in the most recent Whidbey fault quake, Sherrod said. Drop, Cover, and Hold On whenever you feel shaking. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Some residents may lose housing temporarily or permanently. 1 0 obj 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). Learn about at-risk areas and become prepared. 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 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. A drill rig left of the blockade is collecting data about the failure. This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. 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. Both studies suggested that the SWIF Over time, fault movement has created some interesting geologic features. You saw its potential in the 9.1 magnitude Tohuku earthquake and tsunami that hit northeastern Japan in March 2011. Large and damaging earthquakes are inevitable in Washington, but no one knows exactly when they will happen. 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. A low-angle fault, which is not conclusively earthquake related, separates a diamicton from the overlying recessional outwash deposit. Most are too small to be felt or cause damage. The fault zone is up to 57 km, correlates with gravity and magnetic anomalies (Finn and others, 1991 #4753; Blakely and others, 1999 #4747), and has been interpreted as a complex zone of transpressional deformation (Johnson and others, 1996 #4751). Washington has the second highest risk in the U.S. of these large and damaging earthquakes because of its geologic setting. North Anatolian Fault is currently locked, accumulating stresses which could be suddenly released anytime now like the Hayward Fault in California, Videos: New destructive M7.5 earthquake hits Turkey a few hours after largest quake in 100 years kills 1300. Disoriented drivers wonder whats wrong with their cars, then realize something much bigger is amiss. Check out the liquefaction susceptibility and NEHRP site class maps on the Geologic Hazard Maps page. Photo from, Liquefaction can be a big problem. People stagger into the streets to avoid an avalanche of debris. An abrupt rise or decline in sea level would reveal if the fault had triggered a quake before. Faults can also be grouped based on what part of the crust they occur in. Most faults in Washington are a mix of a strike-slip fault and a thrust or reverse fault. Photo courtesy of National Center for Tsunami Research, NOAA. After large earthquakes there are usually many aftershock earthquakes. In some areas getting up a hill to higher ground will be difficult. What about the localized tsunami risk? 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. Videos: Strong M6.0 earthquake rattles Mindanao in the Philippines, Dramatic earthquake increase in Hawaii! California Geological Survey. The shaking can damage or destroy buildings and other infrastructure. A magnitude 7.4 along the southern Whidbey fault would rattle 18 counties in Washington, according to a federal projection . The southern Whidbey Island fault divides the two. The years have gone by. This is similar to how sound is quieter when you move away from a speaker. Within minutes, he spotted something groundbreaking. 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. Official websites use .gov They knew something was there, said Sam Johnson, a retired USGS geologist who would follow up on their work. At the time, Johnson worked in southwest Washington, searching for natural gas and oil deposits. The trenches exposed glacial deposits disrupted by faults and liquefaction features. The last large earthquake on the Cascadia subduction zone was in 1700. Oblique convergence and clockwise rotation along the continental margin are the inferred driving forces for ongoing deformation. In fact, new faults are found every year during our geologic mapping efforts. We use the term deep to talk about faults and earthquakes deeper than about 18 miles. This earthquake caused parts of Restoration Point near on Bainbridge Island to be lifted 35 feet straight up. District Court: (800) 946-9765, South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario. He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. SWIF ranges from 12 miles underground at its deepest to right at sea level in a few scattered spots, like Cama Beach, Holmes Harbor and Woodinville, according to Sherrods research. 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. These include the: Southern Whidbey Island Fault (SWIF) Seattle Fault Devils Mountain Fault Strawberry Point fault Utsalady Point fault 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. The affiliate sales will help us to continue the hard work we are putting in this website. Washington, Seattle, WA 98195 2 U.S. Geological Survey, 345 Middlefield Road, M/S . Resources on tsunami danger and preparedness in Westport, Grays Harbor County, Long Beach Peninsula, and Coastal evacuation maps. 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). Seattle Fault Lines. 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. Every year Western. 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. 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. Secure .gov websites use HTTPS Tsunamis and seiches are destructive waves which can be triggered by certain types of large earthquakes. southern Whidbey Island fault zone (Class A) No. In effect, the wave energy is trapped by the edges of the body of water. 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. Theyre FREE CLICK HERE to subscribe, EAR TO THE GROUND WITH DNR & COMMISSIONER FRANZ, Tree Link helps you answer questions about urbantrees. This fault produces some of the largest and most damaging earthquakes in the world (M9). 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 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. Here, were looking at one of the bigger faults in the region, he said. Although both seiches and tsunamis can be large and destructive, they are created differently. People are already fighting over toilet paper, just imagine what will it be like when they go shopping for food and the shelves are almost empty. Bending of the fault and transpressional deformation began during the late middle Eocene and continues to the present. For the most up-to-date information, please refer to the interactive fault map. California Department of Conservation. The Survey works to increase public and scientific understanding of fault and earthquake hazards in our state. Share sensitive information only on official, secure websites. We pray for people of WA and our all north Americans as well. Additionally, because the continent moves up and over the ocean plate, large amounts of sea water are displaced and cause damaging tsunamis. Make an emergency response plan for you and your family. The publication Faults and Earthquakes in Washington State is a state-wide compilation of active faults and folds. 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. A thrust fault is a special kind of reverse fault that has a shallow dip. 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. Identify and secure items in your home or work that could cause damage. Johnson et al. 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. This scenario was modeled on the part of the SWIF from Woodinville to just west of Whidbey Island. It devastated the coast of the Pacific Northwest and sent an orphan tsunami to Japan. The western half of Washington state is considered earthquake country, with the potential for very large quakes. A damaging earthquake is inevitable on this fault, but we do not know exactly when it will happen. 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 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. The experts say few are ready. A lock () or https:// means youve safely connected to the .gov website. A .gov website belongs to an official government organization in the United States. The Seattle fault is a good example of a fault that is mostly reverse. 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. (360) 678-5111 Latest earthquakes map and list (past 24 hours, M2.5+) from the ANSS (Advanced National Seismic System). Hold on to any sturdy shelter until the shaking stops. Tsunamis triggered by earthquakes usually require at least a M7 event. Sherrods son has since completed graduate school in applied geosciences. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. A baristas hand hovers over the bean grinder. . Then consider that the Seattle Fault is a complex of faults with various branches that run at or just below the surface. It might as well have been sitting in a drawer, Johnson said. Buildings could sustain extensive damage. Westport currently is the only location with a vertical evacuation structure designed for a tsunami. On a brilliant November day, Sherrod took in the panorama from the parks bluff. Tsunamis and seiches can also be triggered by large slides, both on land and underwater. Devastating wind storms. Excavations across several LiDAR scarps show evidence for multiple post-glacial folding and faulting event on faults with reverse oblique sense of slip. These cookies do not store any personal information. For example, the DNR team found evidence that the rocks creating Snoqualmie Falls are much younger than previously thought. Johnson and others (1996 #4751) described multiple sub-parallel strands and referred to the overall structure as the "southern Whidbey Island fault zone," and this name is also used herein for this zone of faults that crosses the southern part of Whidbey Island. But scientists theorize that the area has suffered only four . However, we can learn which faults are active and which are inactive. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. We just dont know when.. PI22343). It may not be possible to find water, fuel, or food until services are restored days or even weeks after the event. The video is also available in Spanish and there is a fun activity/coloring book that can be found here. If you are in bed: STAY there and COVER your head and neck with a pillow. This averages to ~660 to 525 years between events, but there is a lot of variation. This means that a large area feels the shaking, but the intensity is less than a similar shallow earthquake. The last time was 1,000 years ago between 900 and 903 A.D., said Forson. Customers lift their eyes from phone screens. 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. One model suggests it extends to about 30 miles east of Yakima. Reverse faults are usually steep and occur in regions of compression. Photo courtesy of MOHAI (neg. Since their initial discovery, research has shown that the actual number of earthquakes is somewhere between 5 and 10 for each change in magnitude. The Mercalli Intensity scale is another historical way to measure the intensity of an earthquake. In the month after the main earthquake there were about 60 M7 and M6 earthquakes. Geologic maps show the types and ages of rocks and younger deposits that are found at or near the Earth's surface. And what were looking at is water.. Notable earthquakes in bold happened in Washington. The fault probably originated during the early Eocene as a dextral strike-slip fault along the eastern side of a continental-margin rift. Read more below to learn about how and where earthquakes occur, what to do before, during, and after an earthquake, and what scientists are doing to learn more about them. Then the world rattles up and down. Secure .gov websites use HTTPS For example, a M7 earthquake releases 32 times more energy than a M6 earthquake, and 1,000 times more than a M5 earthquake. 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. Other faults are inactive and are left over from much older periods of deformation. Notice the Seattle Fault Zone bounding the Seattle Basin to the south. Large earthquakes, like those from the Cascadia subduction zone on January 26, 1700, often create tsunamis. Learning earthquake faults around where we live is a first good way to prepare the next devastating earthquake. 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. Finding and mapping these faults is an important mission of the Washington Geological Survey. Before modern record keeping, Native Americans lived in the Pacific Northwest for thousands of years. One of the best views of SWIF should be from Grand Avenue Park in Everett. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. 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. After the earthquake, many things you count on may not be available. The below map shows that Seattle and its surroundings is constantly being rattled by small earthquakes and tremors. 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. Bookcases and china cabinets topple, trapping people beneath. The faults length depends on whom you ask, Sherrod said. <> Along the coast residents may have between 20 and 30 minutes to get to higher ground. endobj The Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. Theres an uneasy hush. There must be tsunami deposits of the same age along much of the Oregon and Washington coast in order to qualify as an earthquake. Camano Island, WA 98282, Mailing Address Also check out Ear to the Ground, published by the Department of Natural Resources. These combination faults are called oblique faults and include the Seattle fault, southern Whidbey Island fault zone, and DarringtonDevils Mountain fault zone. 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 moment magnitude scale replaced the Richter scale in the late 1970s. The combination of all of these effects is what makes earthquakes such a powerful geologic hazard. Washington has dozens of active faults and fault zones. Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. Know what other hazards you might face. Faults can be grouped based on their relative movement into three types. One of the most important new technologies for finding faults (and landslides too) is called lidar. 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. In this sense, the shaking of the ground is the sound of rocks breaking and moving deep within the Earth. A normal fault occurs when two blocks are pulled away from each other. A paleoseismologist will look for surface ruptures along faults and may use carbon-14 dating to learn when the rupture happened. In Washington, we do not have tsunami walls. Maps. In Washington, the risk from earthquake-induced landslides is large. Its significantly larger than the Seattle Fault, and South Whidbey could hand us a magnitude 7.5 earthquake. Move away from buildings, streetlights, and utility wires if you can. Someone screams. 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.

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