The faults length depends on whom you ask, Sherrod said. 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. This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. Excavations across several LiDAR scarps show evidence for multiple post-glacial folding and faulting event on faults with reverse oblique sense of slip. endobj Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. The trench did expose faults, but it was not possible to conclusively demonstrate offset of Holocene units. Liquefaction has caused significant damage during earthquakes in Washington. The fault's length depends on whom you ask, Sherrod said. Scientists are not sure how far east it goes. Southeast Extension of the Southern Whidbey Island Fault Although both seiches and tsunamis can be large and destructive, they are created differently. Photo by Steve Palmer. Most are too small to be felt or cause damage. The average time between large earthquakes is about 535 years, but has been as little as 200 years, and more than 1,000 years. A lock () or https:// means youve safely connected to the .gov website. These quakes are capable of magnitudes from 7 to over 9. 2 0 obj One or possibly two of the unconformities are interpreted as event horizons. Large and damaging earthquakes are inevitable in Washington, but no one knows exactly when they will happen. It could also create dangerous currents and hazards to the north including Everett. The Safe America Foundation suggests texting as a way of communication. This map of gravity residuals measured over the puget lowland reveals a pattern of deep, fault bounded basins (cool colors) and uplifts (warm colors). This kind of landslide is called an earthquake-triggered landslides. One of these cracks appeared along the pathway around Green Lake. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. endobj Earthquakes, tornadoes, hurricanes, pandemics, too many people think it cant happen to them and they still think that they can still make a quick run to Walmart to pick up enough to last for 2-3 days and then the govt. A seiche is a large standing wave caused by the resonance of a particular period of wave energy. If you are already planning your Christmas gifts, please buy with us on Amazon. Hold on to any sturdy shelter until the shaking stops. The Cascadia subduction zone last ruptured over 300 years ago on January 26, 1700. DO NOT get in a doorway. In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. 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. Using the stratigraphic column from the Freeport quadrangle map, confirm that you can recognize . Throughout the world shallow earthquakes generally refer to earthquakes that are less than ~45 miles deep. 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. Image from the Pacific Geoscience Center of the Natural Resources of Canada. Geologists do not yet know how often earthquakes happen on this fault. Tsunamis and seiches can also be triggered by large slides, both on land and underwater. 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. The tsunami becomes taller as the ocean becomes shallow. A national credit rating service has improved its opinion of WhidbeyHealths financial future. The boundary between the two plates covers a large area and can lock together. A magnitude 7.4 along the southern Whidbey fault would rattle 18 counties in Washington, according to a federal projection . Small normal faults are found along the top of folds in eastern Washington in the Saddle Mountain graben. Scientists are not sure how far east it goes. If everyone tries to use their cell phones, it can overload the system. Sherrod says practically every place they. 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. , * NOTE: Hazard maps for each jurisdiction will only be included if that jurisdiction is at risk to that hazard., Copyright Island County. The southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. HOLOCENE FAULT SCARPS AND SHALLOW MAGNETIC ANOMALIES ALONG THE SOUTHERN WHIDBEY ISLAND FAULT ZONE NEAR WOODINVILLE, WASHINGTON By Brian L. Sherrod1, Richard J. Blakely2, Craig Weaver1, Harvey Kelsey3, Elizabeth Barnett1, and Ray Wells4 1 U.S. Geological Survey, Dept. The South Whidbey Island Fault is also dangerous. Plate Tectonics | Pacific Northwest Seismic Network HomePrograms and ServicesGeologyGeologic Hazards. 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. Tap/click on "gear icon" for options and settings. It usually also means that there are earthquakes (even small ones) on the fault. 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. Along the coast residents may have between 20 and 30 minutes to get to higher ground. He combed through state and federal data to understand the risks, and to help train first responders. Watch the video below to learn how you can be ready for the next earthquake. 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. @\;L;=}%FC*l $@ 4x: 888O~xrsxx'/*rGRF\gI%~x(G-^-hjjq kx/V ou0hyegy0;ei`Tx&ilZ )TmZ$vb,`bQm|DR5x/ Tsunamis and seiches are destructive waves which can be triggered by certain types of large earthquakes. Once in the open, Drop, Cover, and Hold On. A strike-slip fault occurs when two blocks move past each other. Once we got it, we were sort of shocked to see these big faults in the Puget lowlands, he said. On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. The marshy deposits are about a meter higher at Lake Hancock. You saw its potential in the 9.1 magnitude Tohuku earthquake and tsunami that hit northeastern Japan in March 2011. Though it was not directly related to Johnsons work, he asked a friend working for Mobil Oil to pass along the information. 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. Theres approximately a 14% chance of another approximately M9 earthquake occurring in the next 50 years. Southern Whidbey Island Fault Zone Mapped through Snoqualmie Valley 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). This movement created a tsunami in Puget Sound and triggered a large landslide into Lake Washington. Share sensitive information only on official, secure websites. 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. Source: United States Geological Survey. Finding and learning about faults requires many different aspects of geology and geophysics. The Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. But they didnt document it hardly at all.. Armentrout, J. J. Miller, C. Finn, C. S. Weaver. 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. This scenario was modeled on the part of the SWIF from Woodinville to just west of Whidbey Island. from Whidbey Island to Vancouver Island (Figure 1). 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. Ready to retrofit? Learn how your comment data is processed. Johnson et al. This is a hypothetical scenario created by Mark Murphy of the Snohomish County Department of Emergency Management. At a downtown coffee shop, the mugs begin to chatter. /L\Axc4Q/w4Ks^#, sRITgZf>,e}iI5,F_ADGc?f e@L. Strait of Juan de Fuca Fault Map The Puget Sound faults under the highly populated Seattle and Puget Sound region of Washington state form a regional network of interrelated seismologic geologic faults. Washington, Seattle, WA 98195 2 U.S. Geological Survey, 345 Middlefield Road, M/S . The material becomes so weak that it behaves more like a liquid than a solid. As an example, parts of Seattle and certain areas of downtown Olympia are built on softer ground that will amplify ground shaking during an earthquake. Faults often occur at and near the boundary of large tectonic plates because the plates are moving in different directions. Although we know much about active faults and earthquakes, there is much more to learn. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. Sometimes Geologists can use the offset land surface to understand how much the fault moved during the earthquake. Photo courtesy of National Center for Tsunami Research, NOAA. Because they can travel great distances, tsunamis generated from earthquakes across the ocean can still cause damage. 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. 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. Please visit our Geologic Information Portal and Geologic Hazard Maps page for the most up-to-date listing of all of our hazard maps. %PDF-1.5 Every year Western. This uplift creates a very broad wave called a tsunami. stream Theres an uneasy hush. (360) 678-5111 It devastated the coast of the Pacific Northwest and sent an orphan tsunami to Japan. Some people in places like SODO and Harbor Island may have to flee to higher floors in a building. 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. Unlike The Big One, scientists who have studied the southern Whidbey fault have far less understanding of when the next sudden shift might hit. The last time was 1,000 years ago between 900 and 903 A.D., said Forson. Official websites use .gov The southern Whidbey Island fault, and several others, were exposed for the first time from a camouflage of forest, ocean and glacial sediment. 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). The San Andreas in California, for example, left gaping scars in the Earths crust, at the surface. But it didnt. Additionally, because the continent moves up and over the ocean plate, large amounts of sea water are displaced and cause damaging tsunamis. 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. Most faults are considered active if they have evidence for movement (this includes earthquakes) within the past 12,000 years (the Holocene time period). Some of these faults are in remote areas. Why is Strange Sounds focusing so much on disaster preps? This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. A small quake was registered in the Coupeville area just this summer. Until much more recently, no one really understood what it could do to a region of over 4 million people. As of January 12, 2017, the USGS maintains a limited number of metadata fields that characterize the Quaternary faults and folds of the United States. Stay away from glass, windows, outside doors and walls, and anything that could fall down. The Eastern Sierra fault along the east side of the Sierra Nevada mountains in California is a good example of an active normal fault. In some areas getting up a hill to higher ground will be difficult. 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. The Mercalli Intensity scale is another historical way to measure the intensity of an earthquake. A community meeting about a shelter at the Harbor Inn may have yielded more questions than answers. Southeast Extension of the Southern Whidbey Island Fault By Human Capital March 19, 2019. sw_whidbeyfault_rev122706.pdf (28.68 KB) After the earthquake, many things you count on may not be available. Devastating wind storms. Geologists have used the location of these shallow, intermediate, and deep earthquakes to learn about subduction zones throughout the world. The largest active fault that will affect Washington (and the whole Pacific Northwest) is the Cascadia subduction zone. 1 NE 7th Street Unlike sound, ground shaking can be amplified or attenuated (made less) depending on the type of material at the Earths surface. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. 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 Secure .gov websites use HTTPS The Cascadia subduction zone along the Washington and Oregon coast is one of the biggest hazards to our state and is a good examples of this kind of fault. This means that the internet, your cell phone, grocery stores, and gas stations may also not work. Its significantly larger than the Seattle Fault, and South Whidbey could hand us a magnitude 7.5 earthquake. If you are in bed: STAY there and COVER your head and neck with a pillow. 3. Aftermath: Infrastructure won't fare well in a big quake Map Releases; Topographic (Topo) Maps; Volcanic Maps; All Maps; Multimedia Gallery. It is a qualitative scale that ranges from IXI (1-11) and measures the amount of damage caused by an event. View Earthquake Map Faults Interactive fault map and comprehensive geologically based information on known or suspected active faults and folds in the United States. Knowing how often large earthquakes have happened in the past helps us to know how often they might occur in the future. The medic said colleagues were becoming sick and emotionally overwhelmed 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. You can look at different geological hazard mapson the website of the Department of Natural Resources. Even when an earthquake happens on a fault that doesnt reach the surface, the ground can still show signs of cracking. southern Whidbey Island fault zone (Class A) No. Scientists are not sure how far east it goes. The study of seismic waves is called seismology and has allowed scientists to learn much about the internal structure of the Earth. Restoring tap water to some homes could take over a year. These sediments were laid down 20,000 to 60,000 years ago, before the last ice age. Some residents may lose housing temporarily or permanently. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. These faults and earthquakes usually occur at great depth (tens to hundreds of miles). The shaking can damage or destroy buildings and other infrastructure. These cookies do not store any personal information. Official websites use .gov The process of breaking and moving rock releases a large amount of energy that travels through the Earth as seismic waves. Even when the location of a fault is known, there is much additional work to determine how hazardous it may be. Tsunamis are a common result of large earthquakes in Washington. Puget Sound faults - Wikipedia The shaking usually lasts less than a minute and doesnt generally cause a tsunami or have many aftershocks. The risk is complicated, but there are millions of people who live in the Seattle area, said Forson. Seattle Fault Lines. 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. All Rights Reserved 2021, Site Disclaimer Earthquakes can be measured in many ways, but the most accepted method is called moment magnitude. (1999 . This earthquake is along the southern Whidbey Island fault, a less-known, less-studied subterranean boundary. Bubbles of methane rising from seafloor in Puget Sound This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. Evidence for Quaternary movement on the southern Whidbey Island fault includes (1) offset and disrupted upper Quaternary strata imaged on seismic-reflection profiles; (2) borehole data that suggests as much as 420 m of structural relief on the Tertiary-Quaternary boundary in the fault zone; (3) several meters of displacement along exposed faults in upper Quaternary sediments; (4) late Quaternary folds with limb dips of as much as ???9?? 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. Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. 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. The southern Whidbey Island fault (SWIF) stretches from the vicinity of Victoria, B.C., across Puget Sound as far as the Cascade Range. Ground shaking is a hazard near the epicenter of an earthquake and also in areas far from the earthquake where amplification occurs. 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 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. 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. Close to shore, this same wave could reach heights of 30100 feet or more. <> In Washington, the risk from earthquake-induced landslides is large. Were working on pedestrian evacuation maps that show the best routes for pedestrians to take to evacuate, said Forson. Cover your head and neck with your arms to protect against falling debris. 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. However, we can learn which faults are active and which are inactive. <>/XObject<>/ExtGState<>/Pattern<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. What about the localized tsunami risk? Washington has few large normal faults because it is mostly in a region of compression. Fault Activity Map of California. This category only includes cookies that ensures basic functionalities and security features of the website. Photo by G.K. Gilbert, from the Steinbrugge Collection of the UC Berkeley Earthquake Engineering Research Center. Geologists at the Survey spend time mapping the geology of the state, looking for faults, folds, landslides, and different rock types. In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. Avoid stopping near or under buildings, trees, overpasses, or utility wires. When the ground shakes during an earthquake, it moves up and down, acting like additional gravity. Coupeville, WA 98239, Main Line: A drill rig left of the blockade is collecting data about the failure. Within this rich oral history there are many references to events like earthquakes and tsunamis. For example, it is unlikely that you will be able to use electricity, cell phones, or the internet. The term active can have different meanings. Because they rupture at such great depth, their seismic energy is distributed over a large area. #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. California Department of Conservation. Most are too small to be felt or cause damage. Make an emergency response plan for you and your family. People who look for evidence of past movement on faults are usually called paleoseismologists (from paleo-ancient and seismologist-one who studies earthquakes). Deformed recessional outwash deposits and Holocene deposits were exposed; three unconformities separated the units. Scientists at the Washington Geological Survey, the U.S. Geological Survey, universities, and many private geologic consulting firms work diligently to understand how often earthquakes happen on various faults throughout Washington. Stop as quickly as safety permits and stay in the vehicle. Buildings could sustain extensive damage. Expect aftershocks. Radiocarbon dating and other paleoseismic methods have also confirmed this date. 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 northwestern part of the fault zone forms the northeastern limit of the Port Townsend basin (Brocher and others, 2001 #4718). But the mapping offered geological clues that the newly found fault was indeed capable of future quakes. 121 N East Camano Dr 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." Earthquakes on faults like these may cause tsunamis in the Puget Sound region. M 7.4 Scenario Earthquake - Southern Whidbey Island fault-southern Overview Interactive Map Regional Information Impact ShakeMap Technical Origin Download Event KML Earthquakes Hazards Data & Products Learn Monitoring Research M 7.4 Scenario Earthquake - Southern Whidbey Island fault-southern 2017-05-12 20:14:09 (UTC) 48.036N 122.452W 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. These faults and earthquakes occur in the continental crust of North America. Moving inland, the Seattle Fault is capable of a magnitude 7. This date was confirmed by records in Japan of an orphan tsunami and by many lines of geologic evidence. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). He said scientists have known about the southern Whidbey fault for decades. 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. This means that a large area feels the shaking, but the intensity is less than a similar shallow earthquake. Later movement on this long-term active fault zone cut the volcano. One of the best views of SWIF should be from Grand Avenue Park in Everett. A paleoseismologist will look for surface ruptures along faults and may use carbon-14 dating to learn when the rupture happened. and the Red Cross will be there to care for them. The Geologic Information Portal has a Natural Hazards theme that shows active faults and earthquakes. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. At the Brightwater treatment plant in Woodinville and at Crystal Lake in Maltby, the government researchers found telltale slopes of offset ground, known as scarps, indicative of a long-ago quake. When the landslide hit the water it may have created a tsunami. 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. His team wanted to find the rate of sea level rise along the shore. Earthquakes occur nearly every day in Washington. Subtle scarps and topographic lineaments on Pleistocene surfaces are visible on high-resolution LiDAR topography at a number of locations (Sherrod and others, 2008 #7652); the northeast-side-up scarps exhibit 15 m of vertical relief, late glacial and post-glacial sediments (Sherrod and others, 2008 #7652). 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. Its certainly not to scare you. Devils Mountain Fault -- Online Professional Paper - USGS Videos: Strong M6.0 earthquake rattles Mindanao in the Philippines, Dramatic earthquake increase in Hawaii! The Seattle fault is a good example of a fault that is mostly reverse. For each increase in earthquake magnitude, there are about 10 times fewer earthquakes. Since the last ice age, the southern Whidbey Island fault zone has probably spawned several highly destructive shallow earthquakes. Earthquakes can trigger landslides and tsunamis which can happen after the main event. We do not encourage people to evacuate in vehicles. Washington has the second highest risk in the U.S. of these large and damaging earthquakes because of its geologic setting. Other faults are inactive and are left over from much older periods of deformation.