Photo from, Liquefaction can be a big problem. Once a fault is located, it is important to know if it is active. 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 Seattle fault is a good example of a fault that is mostly reverse. Secure .gov websites use HTTPS Stay inside until the shaking stops and it is safe to go outside. 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." An earthquake can be a scary event. Consider subscribing to our blog, Washington State Geology News, to receive notifications when new information is published. Hey Biden! Theres approximately a 14% chance of another approximately M9 earthquake occurring in the next 50 years. Visit our School Seismic Safety page for more information. The most important thing you can do before the next earthquake is to prepare. Most faults are considered active if they have evidence for movement (this includes earthquakes) within the past 12,000 years (the Holocene time period). You can look at different geological hazard mapson the website of the Department of Natural Resources. from Whidbey Island to Vancouver Island (Figure 1). A low-angle fault, which is not conclusively earthquake related, separates a diamicton from the overlying recessional outwash deposit. The 1964 M9.2 Alaska earthquake created a large tsunami from the fault rupture, and many smaller tsunamis from on-land and underwater landslides. At a downtown coffee shop, the mugs begin to chatter. This fault will have an earthquake in the future, but we cannot predict exactly when. Avoid stopping near or under buildings, trees, overpasses, or utility wires. Story telling is an important part of the Native tradition and is how their history is passed down to the next generation. The map also shows potentially active faults from a separate 2014 report (click here to download). Electricity, water, natural gas, and phones may not work. In Washington, the risk from earthquake-induced landslides is large. This earthquake is along the southern Whidbey Island fault, a less-known, less-studied subterranean boundary. 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. This fault zone was originally named the Devils This map of gravity residuals measured over the puget lowland reveals a pattern of deep, fault bounded basins (cool colors) and uplifts (warm colors). Often this cracking happens because a soft part of the ground liquefies during the shaking. The experts say few are ready. . 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. In this sense, the shaking of the ground is the sound of rocks breaking and moving deep within the Earth. Sensitive seismographs located throughout the state, and all over the world, measure this seismic energy. After large earthquakes there are usually many aftershock earthquakes. 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. It might as well have been sitting in a drawer, Johnson said. A pair of scientists with the U.S. Geological Survey first theorized that a fissure between two major blocks of the earths crust might run through this slice of Puget Sound. 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. The largest active fault that will affect Washington (and the whole Pacific Northwest) is the Cascadia subduction zone. A few miles southeast across the white-capped waves of Admiralty Bay, Lake Hancock rises and falls with the tides. The best thing you can do is to become prepared. Johnson and others (1996 #4751) described the structure and stratigraphy of the southern Whidbey Island fault zone. This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. PI22343). The buildings sank when ground shaking weakened the underlying sediments. All faults, regardless of size, can be dangerous if they rupture. The affiliate sales will help us to continue the hard work we are putting in this website. 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. Because they can travel great distances, tsunamis generated from earthquakes across the ocean can still cause damage. Share sensitive information only on official, secure websites. Photo from Pacific Northwest Seismic Network Seismo Blog. These types of faults are common, but usually small. Expect and help to extinguish fires. Hold on to any sturdy shelter until the shaking stops. Throughout the world shallow earthquakes generally refer to earthquakes that are less than ~45 miles deep. The western half of Washington state is considered earthquake country, with the potential for very large quakes. In Washington, we do not have tsunami walls. A 2014 map shows what we know about the age of faults in Washington. And being ready means being able to support yourself, your loved ones, your neighborhood for 2 weeks. 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. Once we got it, we were sort of shocked to see these big faults in the Puget lowlands, he said. Then consider that the Seattle Fault is a complex of faults with various branches that run at or just below the surface. <>/XObject<>/ExtGState<>/Pattern<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Also, very large earthquakes were difficult to measure accurately. 4 0 obj The buildings sank when ground shaking weakened the underlying sediments. (360) 678-5111 They didnt recognize the significance of what they found. This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. This might include flammable appliances like a water heater, tall items like book cases, or heavy pictures. In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. When the landslide hit the water it may have created a tsunami. % South Whidbey Island Fault Zone. A half dozen people reaching for the last can of soup, someone could lose their life over that. The fault zone, known to geologists as SWIF, cuts through Puget Sound in a diagonal line roughly from Port Townsend to the southern tip of Whidbey Island, then to Mukilteo, Bothell, North Bend and possibly farther east below the Cascades. The medic said colleagues were becoming sick and emotionally overwhelmed These fault strands follow the valley edges and control the location of the Snoqualmie River along some portions of the valley. Source: United States Geological Survey. Small talk stops. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. For the most up-to-date information, please refer to the interactive fault map. This means that when the Seattle fault ruptures the south side of the fault moves up relative to the north side. Moving inland, the Seattle Fault is capable of a magnitude 7. The fault's length depends on whom you ask, Sherrod said. In general, larger faults make larger earthquakes. But they didnt document it hardly at all.. The crustal faults the Seattle Fault, the South Whidbey Island Fault, the Tacoma Fault those are less well known, said Forson. The map also shows potentially active faults from a separate 2014 report (click here to download). On an inactive fault, the sea would have risen at the same rate at both locations. Stop as quickly as safety permits and stay in the vehicle. Dishes jitter off tables, shattering on the floor. A drill rig left of the blockade is collecting data about the failure. The process of breaking and moving rock releases a large amount of energy that travels through the Earth as seismic waves. 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. The South Whidbey Island Fault and Darrington Devil's Mountain Fault bound the Everett Basin. Expect aftershocks. These and other problems led to the search for a scale that was based on the physical processes that happen during an earthquake. He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. Kristin D. Morell 1 *, Christine Regalla 2, Lucinda J. Leonard 3, Colin Amos 4, Vic Levson 5. After the earthquake, many things you count on may not be available. 572 Last Review Date: 2016-11-29 1 NE 7th Street Sherrod says practically every place they. This website uses cookies to improve your experience while you navigate through the website. Faults often occur at and near the boundary of large tectonic plates because the plates are moving in different directions. In effect, the wave energy is trapped by the edges of the body of water. A special type of shallow fault, called a subduction zone or megathrust, occurs where an oceanic plate moves beneath a continental plate. The last major earthquake was over 300 years ago. Everything points to one thing, Sherrod said, waving his hand across the inland sea. This date was confirmed by records in Japan of an orphan tsunami and by many lines of geologic evidence. Over time, fault movement has created some interesting geologic features. 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. Sherrod and others, 2008 #7652) report results from four trenches located near Crystal Lake: Flying Squirrel trench (572-5), Mountain Beaver trench (572-6), Beef Barley trench (572-7), and French Onion trench (572-8). The next earthquake is inevitable, but the variability makes it difficult to know exactly when. It usually also means that there are earthquakes (even small ones) on the fault. Although we cannot predict exactly when the next earthquake will happen, we can predict the general distribution of earthquake sizes. The faults length depends on whom you ask, Sherrod said. East of Puget Sound, the SWIF makes landfall between the cities of Seattle and Everett but is concealed . Seconds later, its as if Whidbey Island is trapped in a cocktail shaker, lurching back and forth. This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. Brick chimneys cascade off rooftops. The southern Whidbey Island fault divides the two. If everyone tries to use their cell phones, it can overload the system. In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. Until much more recently, no one really understood what it could do to a region of over 4 million people. Each type has different kinds of earthquakes. 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). A lock () or https:// means youve safely connected to the .gov website. The trenches exposed glacial deposits disrupted by faults and liquefaction features. 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. This kind of grouping gives us information about how common earthquakes might be and how large an area may be affected. The threat to Puget Sound from a quake along the Cascadia Subduction Zone, off the coast of Washington, Oregon and California, is well documented. 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). Because they rupture at such great depth, their seismic energy is distributed over a large area. Sherrod shrugged his shoulders. Liquefaction has caused significant damage during earthquakes in Washington. Learning earthquake faults around where we live is a first good way to prepare the next devastating earthquake. But it didnt. The southern Whidbey Island fault: An active structure in the Puget Lowland Washington, Geological Society of America Bulletin 1996;108;334-354. Most damage and loss of life in earthquakes is a result of ground shaking. Part 2 will be full Martial Law and mandatory vaccines? While the intensity of this seismic event has now decreased, a big earthquake is overdue in the region. Do you know what to do if there is an earthquake? The trench did expose faults, but it was not possible to conclusively demonstrate offset of Holocene units. These large underwater slides only occur during very large earthquakes and are one way to learn about earthquakes that happened thousands of years ago. In Seattle, the quake damaged buildings, weakened bridges, started fires and opened cracks in the earth. Discover in this article the most dangerous earthquake zones for Seattle and its area: The Cascadia Subduction Zone, the Seattle Fault and the South Whidbey Island Fault. Earthquakes occur nearly every day in Washington. Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. View of the Sunset Lake liquefaction failure about three weeks after the earthquake. Unlike sound, ground shaking can be amplified or attenuated (made less) depending on the type of material at the Earths surface. Scientists have been trying to understand how often earthquakes happen for over 100 years. These faults and earthquakes usually occur at great depth (tens to hundreds of miles). Fir trees near the failure are tilted and indicate rotation into the lake (to the left of the photo). x\[s8~OU)! They didnt grow up here, they havent heard this story. Faults can also be grouped based on what part of the crust they occur in. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). 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. Each year we map additional areas and learn more about existing faults and (or) discover new ones. This part of the Japanese coast had not seen this type of seismic rupture in some 800 years, and what failed was that walls built to keep tsunami waves were not high enough. 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 . Tsunamis and seiches can also be triggered by large slides, both on land and underwater. The southern Whidbey Island fault should be considered capable of generating large earthquakes (Ms ?? Stratigraphy and diatom assemblages of the marsh cores suggest Crockett Marsh underwent a 12 m of abrupt uplift relative to sea level at a time that relative sea level remained the same at Hancock Marsh. Seismologists estimate that such quakes and tsunami waves occur roughly every 500 years on average on the Cascadia Subduction Zone. The map is from a 2007 report (click here to download) on seismic design categories in Washington. An increase of 2 means that ~1,000 times more energy is released. 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. The buildings in this photo were built on soft materials that liquefied during the 1964 Niigata earthquake in Japan. Shallow faults produce earthquakes in the upper 18 miles (30 kilometers) of the Earths crust. Strabge sounds very good report thanks a lot. . Evacuate to higher ground if you are near a large body of water. The term active can have different meanings. In places where there is little vegetation, different rock types and faults can be found with relative ease. Once the shaking has stopped, exit the building if it is safe to do so. This is a very good example of a strike-slip fault. The shaking usually lasts less than a minute and doesnt generally cause a tsunami or have many aftershocks. USA Earthquake Hazard Map. 121 N East Camano Dr Move away from buildings, streetlights, and utility wires if you can. This means that the internet, your cell phone, grocery stores, and gas stations may also not work. Many faults have not been studied enough to know if they are active. Tap/click on "gear icon" for options and settings. The San Andreas fault in California is a good example of a very active strike-slip fault. That could spell trouble not only for its namesake island but for south and north King County and further west. This averages to ~660 to 525 years between events, but there is a lot of variation. , * NOTE: Hazard maps for each jurisdiction will only be included if that jurisdiction is at risk to that hazard., Copyright Island County. An official website of the United States government. The shaking can damage or destroy buildings and other infrastructure. One model suggests it extends to about 30 miles east of Yakima. Fault Activity Map of California. Image from the, Aquatic Lands Habitat Restoration Program, South Lake Washington Restoration Project, Scientific and Technical Support to Aquatic Programs, Washington Geologic Survey Publications Catalog, Washington Geologic Survey Photograph Collection, Wetlands of High Conservation Value Map Viewer, Timber Sale Remaining Volume by Purchaser Reports, Spanish - Brocha, Salal y Otros Productos Forestales, Complete: Baker to Bellingham Non-Motorized Recreation Plan, Community Wildfire Resilience and Preparedness, Utility Wildland Fire Prevention Advisory Committee, Blanchard, Reiter, Walker Valley and Nearby Islands, Teanaway Community Forest Advisory Committee, Teanaway Community Forest Advisory Committee Past Meetings, Faults and Earthquakes in Washington State, Pacific Northwest Seismic Network Seismo Blog, https://buildingfailures.files.wordpress.com/2014/02/tiltedbuilding.jpg, Pacific Geoscience Center of the Natural Resources of Canada. Higher risk areas are in orange and lower risk areas are in green. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. 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. On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. HomePrograms and ServicesGeologyGeologic Hazards. 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. Charles Richter and Beno Gutenberg discovered that for every magnitude of earthquake, there are about ten times more earthquakes of the next lower magnitude. This uplift creates a very broad wave called a tsunami. Johnson et al. Audio; Before and After Images; Images; Slideshows; Stereograms; Videos; Webcams; . Small fires are the most common hazard after an earthquake. /L\Axc4Q/w4Ks^#, sRITgZf>,e}iI5,F_ADGc?f e@L. South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario Fire (Vegetation Condition Class) . Each of the earthquakes listed on the bottom of the screen is capable of significant damage. Some of these faults are in remote areas. The Seattle Fault is also likely to create a tsunami that would inundate Harbor Island and much of SODO, Interbay, and the waterfront. 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. And what were looking at is water.. Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. 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. Like a sonogram, the seismic surveys allowed Johnson to see outlines of massive fissures in the earths crust. You will not be able to google what to do in an earthquake when it is happening. Someone screams. Photo courtesy of MOHAI (neg. 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. These quakes are capable of magnitudes from 7 to over 9. Stratigraphy in the Flying Squirrel trench showed gentle warping of late glacial and post-glacial sediments; no faults were exposed. A strike-slip fault occurs when two blocks move past each other. 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. Sherrod remembers his son, age 5 at the time, playing with toy trucks on the mossy banks of the marsh while the scientists worked. These faults and earthquakes occur in oceanic crust as it is subducted beneath the continent. Its a natural curiosity.. 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. Knowing how often large earthquakes have happened in the past helps us to know how often they might occur in the future. You just need one person to crash or a power line to fall over the road, and the roads are unusable.. In the late 1960s, speculators considered the Puget Sound region a frontier for petroleum exploration. endobj Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. A thrust fault is a special kind of reverse fault that has a shallow dip. The SWIF was first recognized and mapped at a regional scale by Gower and others (1985) on the basis of gravity and aeromagnetic anomaly maps. This was a problem because no two locations would agree on the size of the same earthquake. " A lot of people are transplants, " Forson said. Jump from 60 to 600 per week in just 5 years in Pahala, Is the Cascadia Subduction Zone about to blow? The Survey has developed several types of hazard maps for different types of earthquake- and fault-related hazards: The maps are used by state and local governments to develop and update hazard-mitigation and response plans, and to mark geologically hazardous areas. 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. Oil companies descended in search of riches. Scientists dont know. The friend obliged. The fault, not so much. But quiet period wont last, Strongest earthquake in 40 years rattle residents of Buffalo, NY, Is Istanbul next? The seismic mapping had cost millions of dollars far beyond what most geologists on a government budget could scrape together. Armentrout, J. J. Miller, C. Finn, C. S. Weaver. 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. Earthquakes occur nearly every day in Washington. The southern Whidbey fault is unlike more visible faults on the West Coast. Geologists do not yet know how often earthquakes happen on this fault. They conclude the observed features have a glaciotectonic origin and are not seimotectonic. Tohoku killed nearly 16,000 people; most died as a result of drowning or being crushed in the tsunami. Theres an uneasy hush. The Flying Squirrel and Mountain Beaver trenches cross the Cottage Lake lineament. Recent geologic mapping by Washington State Department of Natural Resources (DNR) geologists reveals that this major fault zone extends through the Snoqualmie River valley in the vicinity of Carnation, Fall City, and North Bend. Though it was not directly related to Johnsons work, he asked a friend working for Mobil Oil to pass along the information. 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). Geologists are constantly trying to better understand the faults in our state. 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 These aftershocks can last for hours to weeks or months. Scientists are not sure how far east it goes. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. Never use a lighter or match near damaged areas. Tsunami waves can travel over 500 miles per hour in the open ocean. 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. 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. The Survey conducts and publishes geologic mapping to identify and characterize faults throughout the state. Notable earthquakes in bold happened in Washington. 1 0 obj The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. Other faults are inactive and are left over from much older periods of deformation. Ready to retrofit? Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. Stay away from glass, windows, outside doors and walls, and anything that could fall down. 2 0 obj Sometimes Geologists can use the offset land surface to understand how much the fault moved during the earthquake. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. An official website of the United States government. and the Red Cross will be there to care for them. Still think well avoid Gods wrath, its not going to happen regardless of what the multi millionaire TV preachers tell you. The fault's length depends on whom you ask, Sherrod said. The video is also available in Spanish and there is a fun activity/coloring book that can be found here. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. <> These cookies do not store any personal information. Coupeville, WA 98239, Camano Office Scientists are not sure how far east it goes. A national credit rating service has improved its opinion of WhidbeyHealths financial future. Each of these aftershocks would be a significant earthquake if it happened on its own. 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.