southern whidbey island fault map

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. Small normal faults are found along the top of folds in eastern Washington in the Saddle Mountain graben. Some events appear to be only 200 years apart, and others are more than 1,000. 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 . A baristas hand hovers over the bean grinder. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. It could also create dangerous currents and hazards to the north including Everett. Earthquakes cause damage by moving and shaking the ground, sometimes for several minutes. Black lines show the South Whidbey Island Fault Zone, the Seattle Fault Zone and the Tacoma Fault Zone. Sometimes there may be a layer of volcanic ash or charcoal that has been deformed by the fault. Volcanic eruptions. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. The last large earthquake on the Cascadia subduction zone was in 1700. Resources on tsunami danger and preparedness in Westport, Grays Harbor County, Long Beach Peninsula, and Coastal evacuation maps. Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. What about the localized tsunami risk? You will not be able to google what to do in an earthquake when it is happening. /L\Axc4Q/w4Ks^#, sRITgZf>,e}iI5,F_ADGc?f e@L. stream The southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. Its significantly larger than the Seattle Fault, and South Whidbey could hand us a magnitude 7.5 earthquake. East of Puget Sound, the SWIF makes landfall between the cities of Seattle and Everett but is concealed . Information from seismic-reflection profiles, outcrops, boreholes, and potential field surveys is used to interpret the structure and history of the southern Whidbey Island fault in the Puget Lowland of western Washington. Jump from 60 to 600 per week in just 5 years in Pahala, Is the Cascadia Subduction Zone about to blow? Paleoseismologists have found places that record many of these tsunami deposits. The buildings sank when ground shaking weakened the underlying sediments. 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. Everything points to one thing, Sherrod said, waving his hand across the inland sea. This is sometimes called "The Big One" by news media. These and other problems led to the search for a scale that was based on the physical processes that happen during an earthquake. The map is from a, This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. Since about 1870 there have been about 15 large earthquakes (greater than M5) in the state. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. Although we know much about active faults and earthquakes, there is much more to learn. For each increase in earthquake magnitude, there are about 10 times fewer earthquakes. This means that a large area feels the shaking, but the intensity is less than a similar shallow earthquake. You can look at different geological hazard mapson the website of the Department of Natural Resources. Doorways do not provide protection from falling or flying objects and you may not be able to remain standing. <> Beef Barley and French Onion trenches cross the Little Bear Creek lineament. This date was confirmed by records in Japan of an orphan tsunami and by many lines of geologic evidence. %PDF-1.5 Unlike sound, ground shaking can be amplified or attenuated (made less) depending on the type of material at the Earths surface. This kind of grouping gives us information about how common earthquakes might be and how large an area may be affected. We use the term deep to talk about faults and earthquakes deeper than about 18 miles. Areas like these are also susceptible to liquefaction. District Court: (800) 946-9765, South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario. However, we can learn which faults are active and which are inactive. 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. Armentrout, J. J. Miller, C. Finn, C. S. Weaver. Prepare to be on your own for at least three days. The Straight Creek fault in the Cascade Range is an example of this kind of fault and has ~5060 miles of movement across it. A lock () or https:// means youve safely connected to the .gov website. A 2014 map shows what we know about the age of faults in Washington. The San Andreas fault in California is a good example of a very active strike-slip fault. Notice the Seattle Fault Zone bounding the Seattle Basin to the south. The key, Sherrods group would discover, was buried on Whidbey Island under layers of mud, peat moss and decaying marsh grass in the murky tidal waters at Crockett Lake, alongside the Coupeville ferry dock. Each of these aftershocks would be a significant earthquake if it happened on its own. HomePrograms and ServicesGeologyGeologic Hazards. People who look for evidence of past movement on faults are usually called paleoseismologists (from paleo-ancient and seismologist-one who studies earthquakes). STAY THERE until the shaking stops. The age of the earthquake is learned by dating the organic material in these tsunami deposits. Stories from tribes near Seattle have also helped us to learn that the last earthquake on the Seattle fault was about AD 900950. A national credit rating service has improved its opinion of WhidbeyHealths financial future. The Cascadia subduction zone last ruptured over 300 years ago on January 26, 1700. It might as well have been sitting in a drawer, Johnson said. At the time, Johnson worked in southwest Washington, searching for natural gas and oil deposits. Know what other hazards you might face. Over time, fault movement has created some interesting geologic features. If a large earthquake happens, be prepared for many more earthquakes. Scientists are not sure how far east it goes. 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 Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. A paleoseismologist will look for surface ruptures along faults and may use carbon-14 dating to learn when the rupture happened. This fault produces some of the largest and most damaging earthquakes in the world (M9). Brick chimneys cascade off rooftops. Nearly all earthquakes occur on faults, features in the Earth where rocks move past each other. Ground shaking is a hazard near the epicenter of an earthquake and also in areas far from the earthquake where amplification occurs. Graphic from IRIS. There must be tsunami deposits of the same age along much of the Oregon and Washington coast in order to qualify as an earthquake. The more you know what to expect, the better prepared you will be to help yourself, your family, and others around you. This new method allows geologists to see through trees and vegetation to find new faults. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. The process of breaking and moving rock releases a large amount of energy that travels through the Earth as seismic waves. This photo shows a fence that was offset about 8.5 feet during the 1906 Great San Francisco Earthquake on the San Andreas fault. Learn about at-risk areas and become prepared. Washington State Earthquake Hazard Map. Other faults are inactive and are left over from much older periods of deformation. This scenario was modeled on the part of the SWIF from Woodinville to just west of Whidbey Island. Identify and secure items in your home or work that could cause damage. For example, a building on soft soil will experience more shaking than the same building on bedrock. Seattle Fault Lines. The fault, not so much. Geologists have used the location of these shallow, intermediate, and deep earthquakes to learn about subduction zones throughout the world. Like other faults, when enough stress builds up, the megathrust will rupture. This earthquake caused parts of Restoration Point near on Bainbridge Island to be lifted 35 feet straight up. We just dont know when.. Sherrod shrugged his shoulders. 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. Third, the South Whidbey Island Fault running from northwest to southeast of the southern tip of the island. This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. The April 1949 Tacoma earthquake measured 7.1 on the Richter Scale and caused damage from southern Oregon to British Columbia. The southern Whidbey Island fault divides the two. Along the coast residents may have between 20 and 30 minutes to get to higher ground. The last earthquake on the Seattle fault (about AD 950) triggered a landslide and seiche in Lake Washington. Radiocarbon ages of macrofossils constrain uplift timing to 2.83.2 ka. This diagram shows the many types of active faults and the general location of past earthquakes in Washington. Do you know what to do if there is an earthquake? During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. What scientists dont know is its timing interval. This is a hypothetical scenario created by Mark Murphy of the Snohomish County Department of Emergency Management. You saw its potential in the 9.1 magnitude Tohuku earthquake and tsunami that hit northeastern Japan in March 2011. The combination of all of these effects is what makes earthquakes such a powerful geologic hazard. Westport currently is the only location with a vertical evacuation structure designed for a tsunami. Sherrod remembers his son, age 5 at the time, playing with toy trucks on the mossy banks of the marsh while the scientists worked. 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. Theres approximately a 14% chance of another approximately M9 earthquake occurring in the next 50 years. It is capable of generating severe earthquakes that would impact the entire west coast. South Whidbey Island Fault Earthquake Scenario: 7.4 Magnitude Buildings Damaged: 320,776 Fatalities: 90 - 432 Injuries: 2,920 - 7,361 Economic Loss: $15,590,000,000 SeaTac Fault Earthquake Scenario: 7.2 Magnitude Buildings Damaged: 375,954 Fatalities: 16 - 123 Injuries: 1,394 - 3,404 Economic Loss: $13,400,000,000 Tacoma 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. You have entered an incorrect email address! It can also make landslides that are much bigger than expected. When the landslide hit the water it may have created a tsunami. The experts say few are ready. Contact Us, Whidbey Office In addition, the Survey performs seismic safety evaluations of schools. One of the most important new technologies for finding faults (and landslides too) is called lidar. Scientists dont know. Small fires are the most common hazard after an earthquake. Move away from buildings, streetlights, and utility wires if you can. An earthquake along the southern Whidbey Island fault reshaped the land some 2,700 years ago. 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. 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. But it didnt. southern Whidbey Island fault zone (Class A) No. Share sensitive information only on official, secure websites. endobj 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 ground shaking from these earthquakes can last for several minutes. This is a very good example of a strike-slip fault. For more information about earthquakes, faults, and emergency preparation, consider visiting the following sites: This map shows areas of seismic risk from high (red) to low (grayish-green). Part 2 will be full Martial Law and mandatory vaccines? % of Earth and Space Sciences, Box 351310, Univ. 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. Higher risk areas are in orange and lower risk areas are in green. 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. Disoriented drivers wonder whats wrong with their cars, then realize something much bigger is amiss. Because Japan was so well prepared, mostretrofitted buildingsoutside of the tsunami zone survived. They knew something was there, said Sam Johnson, a retired USGS geologist who would follow up on their work. In the 1990s, scientists producedan animationthat shows inundation, and people wont have much time to run to higher ground. On a brilliant November day, Sherrod took in the panorama from the parks bluff. The trenches exposed glacial deposits disrupted by faults and liquefaction features. 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. Earthquakes on shallow faults typically last 20 to 60 seconds and the shaking is localized to the general area of the fault. Strabge sounds very good report thanks a lot. America is going to be punished just like the rest of the world. A low-angle fault, which is not conclusively earthquake related, separates a diamicton from the overlying recessional outwash deposit. That could spell trouble not only for its namesake island but for south and north King County and further west. Do not exit a building during the shaking. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). After a large earthquake it is common to have other large earthquakes for hours, days, and even weeks. <>>> Swarm of hundreds of small earthquakes rattle Vancouver Island. from Whidbey Island to Vancouver Island (Figure 1). On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. It will happen; we dont know when.. 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 seismic mapping had cost millions of dollars far beyond what most geologists on a government budget could scrape together. One model suggests it extends to about 30 miles east of Yakima. Sometimes Geologists can use the offset land surface to understand how much the fault moved during the earthquake. Photo courtesy of MOHAI (neg. Many faults have not been studied enough to know if they are active. For example, in the open ocean a tsunami may be less than a few feet tall. 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 Seconds later, its as if Whidbey Island is trapped in a cocktail shaker, lurching back and forth. Someone screams. 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. Some people in places like SODO and Harbor Island may have to flee to higher floors in a building. And what were looking at is water.. Learning earthquake faults around where we live is a first good way to prepare the next devastating earthquake. Faults are features in the Earths crust where rock periodically breaks and moves, releasing seismic energy and creating an earthquake. An abrupt rise or decline in sea level would reveal if the fault had triggered a quake before. They didnt grow up here, they havent heard this story. But scientists theorize that the area has suffered only four . Even if the earthquake is too small to be felt by people, seismographs can detect it. The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. Faults can also be grouped based on what part of the crust they occur in. Once a fault is located, it is important to know if it is active. This can cause landslides to occur where they wouldnt normally happen. 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. In fact, until the 1980s, no one knew SWIF existed. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. 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. The map also shows potentially active faults from a separate 2014 report (click here to download). 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 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). By finding the age of the deformed layer, a paleoseismologist can determine the minimum age of the fault. What are the most dangerous fault lines for Seattle? Its a natural curiosity.. The San Andreas in California, for example, left gaping scars in the Earths crust, at the surface. After the shaking stopped the sand regained its strength. Within this rich oral history there are many references to events like earthquakes and tsunamis. The moment magnitude scale is a type of logarithmic scale, where each increase of 1 means ~32 times more energy is released. 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. These fault strands follow the valley edges and control the location of the Snoqualmie River along some portions of the valley. A strike-slip fault occurs when two blocks move past each other. If they know theres data available that could help them in any way, they want to get it. Restoring tap water to some homes could take over a year. A seiche is a large standing wave caused by the resonance of a particular period of wave energy. For example, the Cascadia subduction zone has had between 15 to 19 earthquakes over the past 10,000 years. 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. Tsunamis triggered by earthquakes usually require at least a M7 event. Here, were looking at one of the bigger faults in the region, he said. But quiet period wont last, Strongest earthquake in 40 years rattle residents of Buffalo, NY, Is Istanbul next? ?7) and represents a potential seismic hazard to residents of the Puget Lowland. Were working on pedestrian evacuation maps that show the best routes for pedestrians to take to evacuate, said Forson. 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. For example, it is unlikely that you will be able to use electricity, cell phones, or the internet. Consider subscribing to our blog, Washington State Geology News, to receive notifications when new information is published. Photo from https://buildingfailures.files.wordpress.com/2014/02/tiltedbuilding.jpg. 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. After large earthquakes there are usually many aftershock earthquakes. 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. Hover over a cluster of earthquakes to learn about the different types in the Pacific Northwest. Sheriff:(360) 679-7310, Juror Recordings 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.

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