southern whidbey island fault map

of Earth and Space Sciences, Box 351310, Univ. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. The shaking can also cause landslides, surface ruptures, ground cracks, liquefaction, tsunamis, and seiches (standing waves). When earthquakes occur on faults that reach the Earths surface, the ground may rupture. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. 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. A community meeting about a shelter at the Harbor Inn may have yielded more questions than answers. In much of Washington, dense vegetation covers the land and makes finding faults very difficult. 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. 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. Share sensitive information only on official, secure websites. In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. <> But they didnt document it hardly at all.. Many faults have not been studied enough to know if they are active. Landslides can be caused by strong ground shaking during an earthquake. Then the world rattles up and down. We do not encourage people to evacuate in vehicles. These include (from north to south, see map) the: Devils Mountain Fault Strawberry Point and Utsalady Point faults Southern Whidbey Island Fault (SWIF) Rogers Belt (Mount Vernon Fault/Granite Falls Fault Zone) Cherry Creek Fault Zone Rattlesnake Mountain Fault Zone Seattle Fault Tacoma Fault Saddle Mountain Faults Its significantly larger than the Seattle Fault, and South Whidbey could hand us a magnitude 7.5 earthquake. 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 The buildings sank when ground shaking weakened the underlying sediments. However, we can learn which faults are active and which are inactive. Image from the Pacific Geoscience Center of the Natural Resources of Canada. During site visits in 2005, Sherrods team found evidence of four SWIF earthquakes in the past 30,000 years. One of the most important new technologies for finding faults (and landslides too) is called lidar. Johnson et al. 552 - Hood Canal fault zone (Class B) 570 - Seattle fault zone 572 - Southern Whidbey Island fault zone 575 - Saddle Mountain faults 581 - Tacoma fault zone. This new method allows geologists to see through trees and vegetation to find new faults. Because they rupture at such great depth, their seismic energy is distributed over a large area. Save my name, email, and website in this browser for the next time I comment. View of the Sunset Lake liquefaction failure about three weeks after the earthquake. Sensitive seismographs located throughout the state, and all over the world, measure this seismic energy. The most important thing you can do before the next earthquake is to prepare. These faults and earthquakes occur in oceanic crust as it is subducted beneath the continent. Snohomish, King and Island counties would be expected to see the. Watch the video below to learn how you can be ready for the next earthquake. Depending on the type of fault, the ground can move laterally, vertically, or a combination of both. Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. Liquefaction is when wet soil or sediment loses strength because it is being shaken during an earthquake. 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. The map is from a 2007 report (click here to download) on seismic design categories in Washington. Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. The marshy deposits are about a meter higher at Lake Hancock. This averages to ~660 to 525 years between events, but there is a lot of variation. The publication Faults and Earthquakes in Washington State is a state-wide compilation of active faults and folds. Know what other hazards you might face. The experts say few are ready. Large earthquakes are likely to happen in Washington during your lifetime. The friend obliged. The ground shaking from these earthquakes can last for several minutes. Large earthquakes are less common but can cause significant damage to the things we count on in everyday life, such as buildings, roads, bridges, dams, and utilities. 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. Earthquakes can trigger landslides and tsunamis which can happen after the main event. The process of breaking and moving rock releases a large amount of energy that travels through the Earth as seismic waves. A lock () or https:// means youve safely connected to the .gov website. Do you live or work near an area that could have liquefaction? After the earthquake, many things you count on may not be available. <>/XObject<>/ExtGState<>/Pattern<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 612 792] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Others, like the Seattle fault and southern Whidbey Island fault zone, cross under major cities and pose a significant hazard. 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 1949 earthquake near Tacoma triggered a landslide near the Tacoma Narrows that caused a local tsunami. Once the shaking has stopped, exit the building if it is safe to do so. Expect aftershocks. A seiche is a large standing wave caused by the resonance of a particular period of wave energy. Contact Us, Whidbey Office DO NOT get in a doorway. The affiliate sales will help us to continue the hard work we are putting in this website. These differences are related to the overall pattern of stress in the crust, what types of rocks the crust is made from, and how many faults there are. A half dozen people reaching for the last can of soup, someone could lose their life over that. The last earthquake on the Seattle fault (about AD 950) triggered a landslide and seiche in Lake Washington. For example, the DNR team found evidence that the rocks creating Snoqualmie Falls are much younger than previously thought. This was a problem because no two locations would agree on the size of the same earthquake. Volcanic eruptions. If you are in bed: STAY there and COVER your head and neck with a pillow. Most injuries occur when people inside change rooms or try to leave the building. After large earthquakes there are usually many aftershock earthquakes. These and other problems led to the search for a scale that was based on the physical processes that happen during an earthquake. In Washington, the risk from earthquake-induced landslides is large. Expect and help to extinguish fires. 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. Sometimes Geologists can use the offset land surface to understand how much the fault moved during the earthquake. Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. These maps are created by small planes that use a specific type of laser to measure the elevation of the ground. Sometimes there may be a layer of volcanic ash or charcoal that has been deformed by the fault. Its just the way scientists work, he said. @\;L;=}%FC*l $@ 4x: 888O~xrsxx'/*rGRF\gI%~x(G-^-hjjq kx/V ou0hyegy0;ei`Tx&ilZ )TmZ$vb,`bQm|DR5x/ Washington, Seattle, WA 98195 2 U.S. Geological Survey, 345 Middlefield Road, M/S . This map shows areas of seismic risk from high (red) to low (grayish-green). Photo courtesy of MOHAI (neg. Drop, Cover, and Hold On whenever you feel shaking. A baristas hand hovers over the bean grinder. Photo from Pacific Northwest Seismic Network Seismo Blog. A lock () or https:// means youve safely connected to the .gov website. Finding faults and knowing how often they rupture is one of the most important tasks to keep society safe from these hazards. On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. But Forson says you also need to know what to do when the shaking happens. After the shaking stopped the sand regained its strength. The shaking can damage or destroy buildings and other infrastructure. Some people in places like SODO and Harbor Island may have to flee to higher floors in a building. The Flying Squirrel and Mountain Beaver trenches cross the Cottage Lake lineament. 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. This map is from a 2007 report on the seismic design categories in Washington. The April 1949 Tacoma earthquake measured 7.1 on the Richter Scale and caused damage from southern Oregon to British Columbia. HomePrograms and ServicesGeologyGeologic Hazards. Beef Barley and French Onion trenches cross the Little Bear Creek lineament. Camano Island, WA 98282, Mailing Address 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. Much of the land along the southwestern part of the lake cracked and subsided. Roads, bridges, or ramps may have been damaged by the earthquake. The tsunami becomes taller as the ocean becomes shallow. These aftershocks can last for hours to weeks or months. Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. Hey Biden! These faults and earthquakes usually occur at great depth (tens to hundreds of miles). It may not be possible to find water, fuel, or food until services are restored days or even weeks after the event. Most faults in Washington are a mix of a strike-slip fault and a thrust or reverse fault. It forms the northern boundary of the Everett basin and lies along a series of high-amplitude aeromagnetic anomalies that extend from the Cascade Mountains to Vancouver Island, B.C. A reverse fault occurs when two blocks are pushed together and one moves up and over the other. Its certainly not to scare you. Experts have warned that UK outbreak may be around two weeks behind Italys. For example, the Cascadia subduction zone has had between 15 to 19 earthquakes over the past 10,000 years. The last time was 1,000 years ago between 900 and 903 A.D., said Forson. A few miles southeast across the white-capped waves of Admiralty Bay, Lake Hancock rises and falls with the tides. By sampling sediment from the marsh to the beach berm, Sherrod and his research partner, Harvey Kelsey, developed a timeline of the oceans climb. Strabge sounds very good report thanks a lot. Hover over a cluster of earthquakes to learn about the different types in the Pacific Northwest. 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. 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. This earthquake caused parts of Restoration Point near on Bainbridge Island to be lifted 35 feet straight up. When a fault with vertical movement ruptures the ocean floor, it lifts up part of the ocean. Armentrout, J. J. Miller, C. Finn, C. S. Weaver. Landslide at Salmon Beach was triggered by the 1949 Tacoma earthquake and caused a tsunami. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. Most of the populated areas of the state have a 4080% chance of having an earthquake in the next 50 years. 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. After a large earthquake it is common to have other large earthquakes for hours, days, and even weeks. The moment magnitude scale is a type of logarithmic scale, where each increase of 1 means ~32 times more energy is released. Once we got it, we were sort of shocked to see these big faults in the Puget lowlands, he said. There must be tsunami deposits of the same age along much of the Oregon and Washington coast in order to qualify as an earthquake. 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 Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. Graphic from IRIS. The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. 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. The most recent hit roughly 2,700 years ago. Third, the South Whidbey Island Fault running from northwest to southeast of the southern tip of the island. Brick chimneys cascade off rooftops. The buildings in this photo were built on soft materials that liquefied during the 1964 Niigata earthquake in Japan. 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. Also issued a warning for the UK that the Italian chaos could come to Britain Liquefaction can be a big problem. Earthquakes occur nearly every day in Washington. Each of these aftershocks would be a significant earthquake if it happened on its own. A paleoseismologist will look for surface ruptures along faults and may use carbon-14 dating to learn when the rupture happened. The team also found that accumulated movement on the fault has uplifted old Snoqualmie River sediments to their current position on ridges, in some places several hundreds of feet above the modern Snoqualmie valley floor. In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. 12201 Sunrise Valley Drive Reston, VA 20192, Region 2: South Atlantic-Gulf (Includes Puerto Rico and the U.S. Virgin Islands), Region 12: Pacific Islands (American Samoa, Hawaii, Guam, Commonwealth of the Northern Mariana Islands), The southern Whidbey Island fault: An active structure in the Puget Lowland, Washington, S. Y. Johnson, C. J. Potter, J.M. Areas like these are also susceptible to liquefaction. Deformed recessional outwash deposits and Holocene deposits were exposed; three unconformities separated the units. Hold on to any sturdy shelter until the shaking stops. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. . Official websites use .gov This means that when the Seattle fault ruptures the south side of the fault moves up relative to the north side. Stories from tribes near Seattle have also helped us to learn that the last earthquake on the Seattle fault was about AD 900950. Under a scenario played out in a 2019 U.S. Department of Homeland Security study, state-maintained bridges would be severely damaged, leaving them unusable for months or years. Some of these faults are in remote areas. endobj Photo from, This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. And being ready means being able to support yourself, your loved ones, your neighborhood for 2 weeks. At a downtown coffee shop, the mugs begin to chatter. The southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. Both of these things can cause equal or greater damage than the actual earthquake. Photo by G.K. Gilbert, from the Steinbrugge Collection of the UC Berkeley Earthquake Engineering Research Center. The combination of all of these effects is what makes earthquakes such a powerful geologic hazard. Deep faults can occur where two tectonic plates collide and one of the plates is forced beneath the other. With Medical Martial Law imposed in Washington state. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. There are also tsunami evacuation signs on the highways. 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 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. You also have the option to opt-out of these cookies. The DNR team found that the Seattle fault is intercepted by the southern Whidbey Island fault zone in the vicinity of Fall City. Were working on pedestrian evacuation maps that show the best routes for pedestrians to take to evacuate, said Forson. Many landslide-prone areas of Washington are also located near active faults. An increase of 2 means that ~1,000 times more energy is released. Superior Court:(800) 254-2755 On a frigid, blustery day in December 2018, Sherrod revisited the site where he conducted much of his field work. The Straight Creek fault in the Cascade Range is an example of this kind of fault and has ~5060 miles of movement across it. Bookcases and china cabinets topple, trapping people beneath. 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.