southern whidbey island fault map

The 1964 M9.2 Alaska earthquake created a large tsunami from the fault rupture, and many smaller tsunamis from on-land and underwater landslides. Share sensitive information only on official, secure websites. Some events appear to be only 200 years apart, and others are more than 1,000. 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. 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. The last earthquake on the Seattle fault (about AD 950) triggered a landslide and seiche in Lake 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). Seismic waves travel at hundreds to thousands of miles per hour and quickly reach the surface where they are felt or measured. Scientists are not sure how far east it goes. Johnson, on a whim, acquired the data that would prove its existence beyond a doubt. Disoriented drivers wonder whats wrong with their cars, then realize something much bigger is amiss. In the month after the main earthquake there were about 60 M7 and M6 earthquakes. Drop, Cover, and Hold On whenever you feel shaking. 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. It usually also means that there are earthquakes (even small ones) on the fault. In Washington, the risk from earthquake-induced landslides is large. By sampling sediment from the marsh to the beach berm, Sherrod and his research partner, Harvey Kelsey, developed a timeline of the oceans climb. 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). 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." California Geological Survey. For example, a M7 earthquake releases 32 times more energy than a M6 earthquake, and 1,000 times more than a M5 earthquake. This kind of landslide is called an earthquake-triggered landslides. Sometimes Geologists can use the offset land surface to understand how much the fault moved during the earthquake. These types of faults are common, but usually small. However, we can learn which faults are active and which are inactive. Sherrod says practically every place they. This northwest-trending fault comprises a broad (as wide as 6-11 km), steep, northeast-dipping zone that includes several splays with inferred strike-slip, reverse, and thrust displacement. Kristin D. Morell 1 *, Christine Regalla 2, Lucinda J. Leonard 3, Colin Amos 4, Vic Levson 5. Photo from, This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. Oil companies descended in search of riches. The shaking can damage or destroy buildings and other infrastructure. Official websites use .gov One of the most important new technologies for finding faults (and landslides too) is called lidar. For several years, scientists pondered where this important regional fault zone continues southwestward from its mapped location in the Everett area. Later movement on this long-term active fault zone cut the volcano. If the epicenter is Everett, the SWIF could cause. That could spell trouble not only for its namesake island but for south and north King County and further west. It could also create dangerous currents and hazards to the north including Everett. A lock () or https:// means youve safely connected to the .gov website. The 2011 Tohoku earthquake in Japan occurred on this type of fault and released enough energy to slightly change the Earths axis of rotation. <>/XObject<>/ExtGState<>/Pattern<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Faults can be grouped based on their relative movement into three types. View of the Sunset Lake liquefaction failure about three weeks after the earthquake. 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. 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. endobj This website uses cookies to improve your experience while you navigate through the website. Avoid stopping near or under buildings, trees, overpasses, or utility wires. 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 . The southern Whidbey fault is shallow, running right under Snohomish County as opposed to many miles off shore like the Cascadia fault. View Earthquake Map Faults Interactive fault map and comprehensive geologically based information on known or suspected active faults and folds in the United States. Washington has the second highest risk in the U.S. of these large and damaging earthquakes because of its geologic setting. A special type of shallow fault, called a subduction zone or megathrust, occurs where an oceanic plate moves beneath a continental plate. You also have the option to opt-out of these cookies. He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. 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. A strike-slip fault occurs when two blocks move past each other. An official website of the United States government. The average time between large earthquakes is about 535 years, but has been as little as 200 years, and more than 1,000 years. The western half of Washington state is considered earthquake country, with the potential for very large quakes. The Safe America Foundation suggests texting as a way of communication. After the shaking stopped the sand regained its strength. On a brilliant November day, Sherrod took in the panorama from the parks bluff. Seismologists estimate that such quakes and tsunami waves occur roughly every 500 years on average on the Cascadia Subduction Zone. California Department of Conservation. USA Earthquake Hazard Map. East of Puget Sound, the SWIF makes landfall between the cities of Seattle and Everett but is concealed . Stay away from glass, windows, outside doors and walls, and anything that could fall down. 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. Map Releases; Topographic (Topo) Maps; Volcanic Maps; All Maps; Multimedia Gallery. Floods. Also issued a warning for the UK that the Italian chaos could come to Britain The more you know what to expect, the better prepared you will be to help yourself, your family, and others around you. Faults can also be grouped based on what part of the crust they occur in. This kind of grouping gives us information about how common earthquakes might be and how large an area may be affected. 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. Seattle Fault Lines. The trench did expose faults, but it was not possible to conclusively demonstrate offset of Holocene units. The continued movement along faults over millions of years can build mountains, tear a continent apart, and move tectonic plates thousands of miles. Sometimes there may be a layer of volcanic ash or charcoal that has been deformed by the fault. Why is Strange Sounds focusing so much on disaster preps? Part 2 will be full Martial Law and mandatory vaccines? So they dont necessarily know the threats they face.. This map shows areas of seismic risk from high (red) to low (grayish-green). But quiet period wont last, Strongest earthquake in 40 years rattle residents of Buffalo, NY, Is Istanbul next? Mudslides. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. Both types of faults can cause ground shaking during an earthquake and may cause permanent deformation of the ground. Hold on to any sturdy shelter until the shaking stops. Consider a magnitude 7.4 quake with Whidbey Island at or near the epicenter. . The tsunamis can travel far inland and deposit layers of sand and organic material. For example, if there is one M7 earthquakes in an area every 1,000 years, then there will be about 10 M6 earthquakes, 100 M5 earthquakes, and 1,000 M4 earthquakes during the same 1,000 years. 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. These large underwater slides only occur during very large earthquakes and are one way to learn about earthquakes that happened thousands of years ago. But scientists theorize that the area has suffered only four . The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. 121 N East Camano Dr Reverse faults are usually steep and occur in regions of compression. Get On The List To Receive Your Daily Dose Of Weird News And Amazing Phenomena. A thrust fault is a special kind of reverse fault that has a shallow dip. In general, larger faults make larger earthquakes. The San Andreas fault in California is a good example of a very active strike-slip fault. Liquefaction is when wet soil or sediment loses strength because it is being shaken during an earthquake. 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. The bluff, where the cabins now sit, could have jutted up in the most recent Whidbey fault quake, Sherrod said. The southern Whidbey Island fault divides the two. Both studies suggested that the SWIF An abrupt rise or decline in sea level would reveal if the fault had triggered a quake before. The evidence shows each lake rests on different free-floating jigsaw pieces of planetary crust, separated by the southern Whidbey Island fault. 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. /L\Axc4Q/w4Ks^#, sRITgZf>,e}iI5,F_ADGc?f e@L. These older faults do not have any evidence for recent activity, but the Earth is always changing. Ground shaking is a hazard near the epicenter of an earthquake and also in areas far from the earthquake where amplification occurs. Resources on tsunami danger and preparedness in Westport, Grays Harbor County, Long Beach Peninsula, and Coastal evacuation maps. Many faults have not been studied enough to know if they are active. Earthquakes occur nearly every day in Washington. It will happen; we dont know when.. Because they rupture at such great depth, their seismic energy is distributed over a large area. 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. 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). They havent dug up enough history to estimate. Devastating wind storms. Stratigraphy in the Flying Squirrel trench showed gentle warping of late glacial and post-glacial sediments; no faults were exposed. Southeast Extension of the Southern Whidbey Island Fault By Human Capital March 19, 2019. sw_whidbeyfault_rev122706.pdf (28.68 KB) After large earthquakes there are usually many aftershock earthquakes. The term active can have different meanings. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. You will not be able to google what to do in an earthquake when it is happening. These faults and earthquakes occur in the continental crust of North America. If a large earthquake happens, be prepared for many more earthquakes. 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. Most injuries occur when people inside change rooms or try to leave the building. A normal fault occurs when two blocks are pulled away from each other. Small fires are the most common hazard after an earthquake. Throughout the world shallow earthquakes generally refer to earthquakes that are less than ~45 miles deep. Using the stratigraphic column from the Freeport quadrangle map, confirm that you can recognize . Earthquakes between 45 and 185 miles deep are called intermediate, and earthquakes over 185 miles deep are called deep. Know what other hazards you might face. HomePrograms and ServicesGeologyGeologic Hazards. When this happens, even a very small slope can cause the ground to slide. Someone screams. Doorways do not provide protection from falling or flying objects and you may not be able to remain standing. Across the northern portion of Bainbridge Island, light radar or lidar images taken from airplanes clearly show the Seattle Fault running right on the surface. One of the best views of SWIF should be from Grand Avenue Park in Everett. Photo from https://buildingfailures.files.wordpress.com/2014/02/tiltedbuilding.jpg. Contact Us, Whidbey Office Its just the way scientists work, he said. The Pacific Tsunami Warning Center is located in Hawaii and is responsible for issuing alerts to all the countries that border the Pacific Ocean. 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. Earthquakes can trigger landslides and tsunamis which can happen after the main event. When an earthquake happens there will not be time to google what you are supposed to do. One of these cracks appeared along the pathway around Green Lake. (1999 . Faults can also occur within a tectonic plate when the plate itself is deforming. 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. 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. Fir trees near the failure are tilted and indicate rotation into the lake (to the left of the photo). The 1949 earthquake near Tacoma triggered a landslide near the Tacoma Narrows that caused a local tsunami. Photo from Pacific Northwest Seismic Network Seismo Blog. And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. A lock () or https:// means youve safely connected to the .gov website. The most recent hit roughly 2,700 years ago. A community meeting about a shelter at the Harbor Inn may have yielded more questions than answers. After a large earthquake it is common to have other large earthquakes for hours, days, and even weeks. Within this rich oral history there are many references to events like earthquakes and tsunamis. Like other faults, when enough stress builds up, the megathrust will rupture. Washington has dozens of active faults and fault zones. STAY THERE until the shaking stops. Since the last ice age, the southern Whidbey Island fault zone has probably spawned several highly destructive shallow earthquakes. When the ground shakes during an earthquake, it moves up and down, acting like additional gravity. Stop as quickly as safety permits and stay in the vehicle. And what were looking at is water.. Johnson et al. Photo by G.K. Gilbert, from the Steinbrugge Collection of the UC Berkeley Earthquake Engineering Research Center. (1996) used seismic-reflection profiles in Puget Sound near Whidbey Island, sea-cliff exposures on Whidbey Island, and sparse borehole data to map and interpret the SWIF as a broad fault zone (6 to 11 km wide) dipping steeply to the northeast. 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. Tsunamis triggered by earthquakes usually require at least a M7 event. Coupeville, WA 98239, Camano Office On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. Customers lift their eyes from phone screens. In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. Geologists and geophysicists at the Washington Geological Survey map out these areas of amplification to help reduce damage during an earthquake. Bending of the fault and transpressional deformation began during the late middle Eocene and continues to the present. Another big one is expected, and it could be devastating. Restoring tap water to some homes could take over a year. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). Landslides can be caused by strong ground shaking during an earthquake. Share sensitive information only on official, secure websites. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. Deformed recessional outwash deposits and Holocene deposits were exposed; three unconformities separated the units. In fact, until the 1980s, no one knew SWIF existed. In the late 1960s, speculators considered the Puget Sound region a frontier for petroleum exploration. The map is from a, This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. In this sense, the shaking of the ground is the sound of rocks breaking and moving deep within the Earth. The process of breaking and moving rock releases a large amount of energy that travels through the Earth as seismic waves. He said scientists have known about the southern Whidbey fault for decades. 1 NE 7th Street . In much of Washington, dense vegetation covers the land and makes finding faults very difficult. Other faults may lie entirely underground, or could be covered by vegetation and (or) sediment. Prepare to be on your own for at least three days. You have entered an incorrect email address! The largest active fault that will affect Washington (and the whole Pacific Northwest) is the Cascadia subduction zone. We also use third-party cookies that help us analyze and understand how you use this website. For example, the Cascadia subduction zone has had between 15 to 19 earthquakes over the past 10,000 years. Until much more recently, no one really understood what it could do to a region of over 4 million people. Once a fault is located, it is important to know if it is active. The shaking can also cause landslides, surface ruptures, ground cracks, liquefaction, tsunamis, and seiches (standing waves). 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. 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. Geologists are constantly trying to better understand the faults in our state. 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. Because they need large earthquakes that move the ocean floor, tsunamis are most commonly made by subduction zone faults like those found off the coasts of the Pacific Northwest, Japan, and Chile. 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. One model suggests it extends to about 30 miles east of Yakima. The southern Whidbey Island fault, and several others, were exposed for the first time from a camouflage of forest, ocean and glacial sediment. 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 A paleoseismologist will look for surface ruptures along faults and may use carbon-14 dating to learn when the rupture happened. 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. The study of seismic waves is called seismology and has allowed scientists to learn much about the internal structure of the Earth. The Eastern Sierra fault along the east side of the Sierra Nevada mountains in California is a good example of an active normal fault. endobj Third, the South Whidbey Island Fault running from northwest to southeast of the southern tip of the island. Do not exit a building during the shaking. There must be tsunami deposits of the same age along much of the Oregon and Washington coast in order to qualify as an earthquake. 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. Never use a lighter or match near damaged areas. Below you will find links to view and download hazard maps created for each jurisdiction included in the current mitigation planning process. With Medical Martial Law imposed in Washington state. Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. This fault zone was originally named the Devils Once the shaking has stopped, exit the building if it is safe to do so. A small quake was registered in the Coupeville area just this summer. 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). The below map shows that Seattle and its surroundings is constantly being rattled by small earthquakes and tremors. Photo from, Liquefaction can be a big problem. While the intensity of this seismic event has now decreased, a big earthquake is overdue in the region. Standing becomes almost impossible as the jolts turn to rolling waves. 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). By clicking Accept, you consent to the use of ALL the cookies. The age of the earthquake is learned by dating the organic material in these tsunami deposits. The publication Faults and Earthquakes in Washington State is a state-wide compilation of active faults and folds. When a fault with vertical movement ruptures the ocean floor, it lifts up part of the ocean. It is mandatory to procure user consent prior to running these cookies on your website. Some of these faults are in remote areas. 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. 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. Washington has few large normal faults because it is mostly in a region of compression. The next earthquake is inevitable, but the variability makes it difficult to know exactly when. Everything points to one thing, Sherrod said, waving his hand across the inland sea. Most faults in Washington are a mix of a strike-slip fault and a thrust or reverse fault.