southern whidbey island fault map southern whidbey island fault map

Know what to expect. In fact, until the 1980s, no one knew SWIF existed. The SWIF has been assessed by the USGS as capable of generating the largest crustal earthquake in Puget Sound. The Cascadia subduction zone last ruptured over 300 years ago on January 26, 1700. Large earthquakes, like those from the Cascadia subduction zone on January 26, 1700, often create tsunamis. The last major earthquake was over 300 years ago. In 2017, he began studying the possible aftermath of a major SWIF quake. In addition, the Survey performs seismic safety evaluations of schools. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. 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. Even if the earthquake is too small to be felt by people, seismographs can detect it. There are also many faults that have not been studied enough to know if they are active. Others, like the Seattle fault and southern Whidbey Island fault zone, cross under major cities and pose a significant hazard. Washington has the second highest risk in the U.S. of these large and damaging earthquakes because of its geologic setting. Within minutes, he spotted something groundbreaking. The best thing you can do is to become prepared. Electricity, water, natural gas, and phones may not work. Much of the Southern Whidbey Island fault zone (SWIF), which runs in a north-westward direction from Woodinville to near Port Townsend, Washington, remains mostly . These sediments were laid down 20,000 to 60,000 years ago, before the last ice age. Most faults in Washington are a mix of a strike-slip fault and a thrust or reverse fault. The Survey conducts and publishes geologic mapping to identify and characterize faults throughout the state. endobj The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. The southern Whidbey Island fault (SWIF) stretches from the vicinity of Victoria, B.C., across Puget Sound as far as the Cascade Range. Unlike The Big One, scientists who have studied the southern Whidbey fault have far less understanding of when the next sudden shift might hit. %PDF-1.5 Stratigraphy in the Flying Squirrel trench showed gentle warping of late glacial and post-glacial sediments; no faults were exposed. This is a very good example of a strike-slip fault. Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. The years have gone by. In Washington, we do not have tsunami walls. 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. One model suggests it extends to about 30 miles east of Yakima. Watch the video below to learn how you can be ready for the next earthquake. During site visits in 2005, Sherrods team found evidence of four SWIF earthquakes in the past 30,000 years. With Medical Martial Law imposed in Washington state. 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. This means that the internet, your cell phone, grocery stores, and gas stations may also not work. By sampling sediment from the marsh to the beach berm, Sherrod and his research partner, Harvey Kelsey, developed a timeline of the oceans climb. Some types of seismic energy (P waves) are similar to sound energy that is released if you break a twig or slide a chair across the floor. Other types of seismic energy (S waves) also travel through the earth, but they move with a side-to-side (shearing) motion. This uplift creates a very broad wave called a tsunami. Photo courtesy of National Center for Tsunami Research, NOAA. 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. This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. A national credit rating service has improved its opinion of WhidbeyHealths financial future. Sherrods son has since completed graduate school in applied geosciences. Fir trees near the failure are tilted and indicate rotation into the lake (to the left of the photo). The shaking can damage or destroy buildings and other infrastructure. After the shaking stopped the sand regained its strength. 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 biggest one is called the South Whidbey Island fault, and it's thought to run from Victoria, B.C., through Woodinville and possibly beyond. You can look at different geological hazard mapson the website of the Department of Natural Resources. and the Red Cross will be there to care for them. Southeast Extension of the Southern Whidbey Island Fault By Human Capital March 19, 2019. sw_whidbeyfault_rev122706.pdf (28.68 KB) Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. Much of the land along the southwestern part of the lake cracked and subsided. However, seismic tomography studies (Brocher and others, 2001 #4718) reveal that only the northwestern end of the fault zone in the southeastern Strait of Juan de Fuca is associated with a strong velocity contrast. Official websites use .gov So they dont necessarily know the threats they face.. Avoid stopping near or under buildings, trees, overpasses, or utility wires. But the mapping offered geological clues that the newly found fault was indeed capable of future quakes. #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. 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. In Seattle, the quake damaged buildings, weakened bridges, started fires and opened cracks in the earth. You also have the option to opt-out of these cookies. Make an emergency response plan for you and your family. Throughout the world shallow earthquakes generally refer to earthquakes that are less than ~45 miles deep. These faults and earthquakes occur in oceanic crust as it is subducted beneath the continent. 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. 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. Experts have warned that UK outbreak may be around two weeks behind Italys. 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. All faults, regardless of size, can be dangerous if they rupture. Scientists are not sure how far east it goes. These maps are created by small planes that use a specific type of laser to measure the elevation of the ground. Some of these faults are in remote areas. The trenches exposed glacial deposits disrupted by faults and liquefaction features. This movement happens because stress builds up as tectonic plates move. 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. His team wanted to find the rate of sea level rise along the shore. This means that when the Seattle fault ruptures the south side of the fault moves up relative to the north side. Snohomish, King and Island counties would be expected to see the. On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. At a downtown coffee shop, the mugs begin to chatter. In the month after the main earthquake there were about 60 M7 and M6 earthquakes. Sensitive seismographs located throughout the state, and all over the world, measure this seismic energy. <> The DNR team found that the Seattle fault is intercepted by the southern Whidbey Island fault zone in the vicinity of Fall City. This map shows areas of seismic risk from high (red) to low (grayish-green). High-resolution LiDAR topographic maps have since revealed several potential faults scarps, and subsequent studies provide more detailed information about the fault zone's past. What are the most dangerous fault lines for Seattle? 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. 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. The spectacular falls flow over the remains of a newly discovered 20-million-year-old volcano, apparently formed atop the main part of the fault zone as magma rose upward along weak fault planes. (1999 . 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. Necessary cookies are absolutely essential for the website to function properly. America is going to pay for sitting back doing nothing while almost 70 million babies were slaughtered and their body parts sold to the highest bidder for the last 43 years. The combination of all of these effects is what makes earthquakes such a powerful geologic hazard. When this happens, even a very small slope can cause the ground to slide. They conclude the observed features have a glaciotectonic origin and are not seimotectonic. Brick chimneys cascade off rooftops. When an earthquake happens there will not be time to google what you are supposed to do. 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). This was a problem because no two locations would agree on the size of the same earthquake. Even places that are far from active faults are still at risk during a large Cascadia subduction zone earthquake. 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. When a fault with vertical movement ruptures the ocean floor, it lifts up part of the ocean. 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. This is an active fault.. Once we got it, we were sort of shocked to see these big faults in the Puget lowlands, he said. 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. The term active can have different meanings. 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. Higher risk areas are in orange and lower risk areas are in green. Unlike sound, ground shaking can be amplified or attenuated (made less) depending on the type of material at the Earths surface. Over time, fault movement has created some interesting geologic features. Earthquakes between 45 and 185 miles deep are called intermediate, and earthquakes over 185 miles deep are called deep. We also use third-party cookies that help us analyze and understand how you use this website. Large earthquakes are likely to happen in Washington during your lifetime. Earthquakes can trigger landslides and tsunamis which can happen after the main event. The last time was 1,000 years ago between 900 and 903 A.D., said Forson. The map also shows potentially active faults from a separate 2014 report (click here to download). Seismic waves travel at hundreds to thousands of miles per hour and quickly reach the surface where they are felt or measured. Still think well avoid Gods wrath, its not going to happen regardless of what the multi millionaire TV preachers tell you. The southern Whidbey Island fault: An active structure in the Puget Lowland Washington, Geological Society of America Bulletin 1996;108;334-354. Until much more recently, no one really understood what it could do to a region of over 4 million people. The shaking usually lasts less than a minute and doesnt generally cause a tsunami or have many aftershocks. Bending of the fault and transpressional deformation began during the late middle Eocene and continues to the present. In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. Latest earthquakes map and list (past 24 hours, M2.5+) from the ANSS (Advanced National Seismic System). Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. The Geologic Information Portal has a Natural Hazards theme that shows active faults and earthquakes. Do not exit a building during the shaking. Seattle Fault Lines. In places where there is little vegetation, different rock types and faults can be found with relative ease. We just dont know when.. But they didnt document it hardly at all.. Were working on pedestrian evacuation maps that show the best routes for pedestrians to take to evacuate, said Forson. Proceed cautiously once the earthquake has stopped. 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. It may not be possible to find water, fuel, or food until services are restored days or even weeks after the event. Seconds later, its as if Whidbey Island is trapped in a cocktail shaker, lurching back and forth. We use the term deep to talk about faults and earthquakes deeper than about 18 miles. Even when an earthquake happens on a fault that doesnt reach the surface, the ground can still show signs of cracking. Before modern record keeping, Native Americans lived in the Pacific Northwest for thousands of years. Most are too small to be felt or cause damage. Emergency planners all had a simple message: Its not IF a disaster will happen, its WHEN. Learn about at-risk areas and become prepared. 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. Videos: Strong M6.0 earthquake rattles Mindanao in the Philippines, Dramatic earthquake increase in Hawaii! 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. Geologists have used the location of these shallow, intermediate, and deep earthquakes to learn about subduction zones throughout the world. 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. Click the "Seismogenic Features" button in the Map Contents window to display faults and earthquakes. This map is from a 2007 report on the seismic design categories in Washington. Dishes jitter off tables, shattering on the floor. Oil companies descended in search of riches. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. Hundreds could die, with thousands more injured. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. Photo from Pacific Northwest Seismic Network Seismo Blog. Geologists are constantly trying to better understand the faults in our state. Within this rich oral history there are many references to events like earthquakes and tsunamis. The age of the earthquake is learned by dating the organic material in these tsunami deposits. 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). Scientists dont know. Liquefaction has caused significant damage during earthquakes in Washington. Geologic maps show the types and ages of rocks and younger deposits that are found at or near the Earth's surface. The most recent hit roughly 2,700 years ago. Visit our School Seismic Safety page for more information. Identify and secure items in your home or work that could cause damage. A lock () or https:// means youve safely connected to the .gov website. 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. Earthquakes on faults like these may cause tsunamis in the Puget Sound region. Image from the Pacific Geoscience Center of the Natural Resources of Canada. Prepare to be on your own for at least three days. Finding nothing of serious monetary value, the companies abandoned reams of information they had gathered through seismic surveys. 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. Evacuate to higher ground if you are near a large body of water. Sherrod remembers his son, age 5 at the time, playing with toy trucks on the mossy banks of the marsh while the scientists worked. A drill rig left of the blockade is collecting data about the failure. Since about 1870 there have been about 15 large earthquakes (greater than M5) in the state. Nearly all earthquakes occur on faults, features in the Earth where rocks move past each other. Then consider that the Seattle Fault is a complex of faults with various branches that run at or just below the surface. 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. Moving inland, the Seattle Fault is capable of a magnitude 7. Know what other hazards you might face. ?7) and represents a potential seismic hazard to residents of the Puget Lowland. Secure .gov websites use HTTPS Most are too small to be felt or cause damage. Oblique convergence and clockwise rotation along the continental margin are the inferred driving forces for ongoing deformation. 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 fault, not so much. endobj 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. The San Andreas in California, for example, left gaping scars in the Earths crust, at the surface. 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. Here, were looking at one of the bigger faults in the region, he said. The Eastern Sierra fault along the east side of the Sierra Nevada mountains in California is a good example of an active normal fault. This map shows different seismic design categories that correlate with amount of seismic risk. The more you know what to expect, the better prepared you will be to help yourself, your family, and others around you. Roads, bridges, or ramps may have been damaged by the earthquake. Finding and mapping these faults is an important mission of the Washington Geological Survey. Earthquakes on shallow faults typically last 20 to 60 seconds and the shaking is localized to the general area of the fault. 3 0 obj These fault strands follow the valley edges and control the location of the Snoqualmie River along some portions of the valley. He combed through state and federal data to understand the risks, and to help train first responders. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. 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). A lot of people are transplants, Forson said. Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. 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 western half of Washington state is considered earthquake country, with the potential for very large quakes. Consider a magnitude 7.4 quake with Whidbey Island at or near the epicenter. Both studies suggested that the SWIF The experts say few are ready. The Seattle fault last ruptured about 1,100 years ago in AD 900950. 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. 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. 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. Jump from 60 to 600 per week in just 5 years in Pahala, Is the Cascadia Subduction Zone about to blow? In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. Since the last ice age, the southern Whidbey Island fault zone has probably spawned several highly destructive shallow earthquakes. A thrust fault is a special kind of reverse fault that has a shallow dip. Some faults reach the surface and can be found by geologists. At the time, Johnson worked in southwest Washington, searching for natural gas and oil deposits. Excavations across several LiDAR scarps show evidence for multiple post-glacial folding and faulting event on faults with reverse oblique sense of slip. The medic said colleagues were becoming sick and emotionally overwhelmed After large earthquakes there are usually many aftershock earthquakes. Keaton and Perry (2006 #7653) excavated two trenches on the south end of the Brightwater treatment plant (KP1 site 572-3, and KP2 site 572-4). That place is the Ocosta School. Another piece can be seen under the elevated lanes of northbound Interstate 5 in South Seattle not far from the Rainier brewery. Once the shaking has stopped, exit the building if it is safe to do so. 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). Doorways do not provide protection from falling or flying objects and you may not be able to remain standing. A lock () or https:// means youve safely connected to the .gov website. This map of Puget Sound shows the location of the methane plumes (yellow and white circles) detected along the ship's path (purple). Most damage and loss of life in earthquakes is a result of ground shaking. These combination faults are called oblique faults and include the Seattle fault, southern Whidbey Island fault zone, and DarringtonDevils Mountain fault zone. The shaking can also cause landslides, surface ruptures, ground cracks, liquefaction, tsunamis, and seiches (standing waves). Get On The List To Receive Your Daily Dose Of Weird News And Amazing Phenomena. Its just the way scientists work, he said. Its significantly larger than the Seattle Fault, and South Whidbey could hand us a magnitude 7.5 earthquake. Because Japan was so well prepared, mostretrofitted buildingsoutside of the tsunami zone survived. 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). 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. In 1985, with little concrete evidence of its existence, the pair included the possible fault on a geologic map published by the USGS. You will not be able to google what to do in an earthquake when it is happening. A few miles southeast across the white-capped waves of Admiralty Bay, Lake Hancock rises and falls with the tides. Geologists at the Survey spend time mapping the geology of the state, looking for faults, folds, landslides, and different rock types. South Whidbey Island Fault Zone. We do know that it is active and will likely produce a large M67.5 earthquake when it next ruptures. 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. Some events appear to be only 200 years apart, and others are more than 1,000. Although both seiches and tsunamis can be large and destructive, they are created differently. Some people in places like SODO and Harbor Island may have to flee to higher floors in a building. Its certainly not to scare you. Small normal faults are found along the top of folds in eastern Washington in the Saddle Mountain graben. It is not yet possible to predict when a fault will have an earthquake. 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. What scientists dont know is its timing interval. The southern Whidbey Island fault should be considered capable of generating large earthquakes (Ms ?? On an inactive fault, the sea would have risen at the same rate at both locations. An earthquake occurs when rock inside the Earth moves or breaks. Most of the populated areas of the state have a 4080% chance of having an earthquake in the next 50 years. 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." 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. Everything points to one thing, Sherrod said, waving his hand across the inland sea. (Andy Bronson / The Herald). This kind of landslide is called an earthquake-triggered landslides. Consider whether earthquake insurance is right for you. You just need one person to crash or a power line to fall over the road, and the roads are unusable..