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It is a qualitative scale that ranges from IXI (1-11) and measures the amount of damage caused by an event. Snohomish, King and Island counties would be expected to see the. Coupeville, WA 98239, Main Line: This is a hypothetical scenario created by Mark Murphy of the Snohomish County Department of Emergency Management. The evidence shows each lake rests on different free-floating jigsaw pieces of planetary crust, separated by the southern Whidbey Island fault. They didnt grow up here, they havent heard this story. This means that a large area feels the shaking, but the intensity is less than a similar shallow earthquake. The southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. Mudslides. Even when the location of a fault is known, there is much additional work to determine how hazardous it may be. One model suggests it extends to about 30 miles east of Yakima. Within minutes, he spotted something groundbreaking. The map is from a 2007 report (click here to download) on seismic design categories in Washington. There are also tsunami evacuation signs on the highways. These cookies will be stored in your browser only with your consent. Finding and learning about faults requires many different aspects of geology and geophysics. By sampling sediment from the marsh to the beach berm, Sherrod and his research partner, Harvey Kelsey, developed a timeline of the oceans climb. In effect, the wave energy is trapped by the edges of the body of water. The seismic mapping had cost millions of dollars far beyond what most geologists on a government budget could scrape together. Photo from https://buildingfailures.files.wordpress.com/2014/02/tiltedbuilding.jpg. (360) 678-5111 This map is from a 2007 report on the seismic design categories in Washington. Videos: Strong M6.0 earthquake rattles Mindanao in the Philippines, Dramatic earthquake increase in Hawaii! Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. Each of these aftershocks would be a significant earthquake if it happened on its own. 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). 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. Do not exit a building during the shaking. 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. District Court: (800) 946-9765, South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario. Unlike The Big One, scientists who have studied the southern Whidbey fault have far less understanding of when the next sudden shift might hit. The 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. Part 2 will be full Martial Law and mandatory vaccines? The Geologic Information Portal has a Natural Hazards theme that shows active faults and earthquakes. Seattle Fault and Whidbey Faults HAZARD MAPS As part of the Hazard Mitigation Planning process, mapping of the hazards that have the potential to affect the jurisdiction is performed using geographic information systems (GIS) software. Johnsons curiosity changed the course of his career. The combination of all of these effects is what makes earthquakes such a powerful geologic hazard. 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. Oblique convergence and clockwise rotation along the continental margin are the inferred driving forces for ongoing deformation. 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). A reverse fault occurs when two blocks are pushed together and one moves up and over the other. The 2011 Tohoku earthquake in Japan occurred on this type of fault and released enough energy to slightly change the Earths axis of rotation. Most are too small to be felt or cause damage. Washington State Earthquake Hazard Map. The Cascadia subduction zone last ruptured over 300 years ago on January 26, 1700. But Forson says you also need to know what to do when the shaking happens. Photo from, Liquefaction can be a big problem. Even when an earthquake happens on a fault that doesnt reach the surface, the ground can still show signs of cracking. After large earthquakes there are usually many aftershock earthquakes. Scientists are not sure how far east it goes. The southern Whidbey Island fault divides the two. When this happens, even a very small slope can cause the ground to slide. The last large earthquake on the Cascadia subduction zone was in 1700. Until much more recently, no one really understood what it could do to a region of over 4 million people. Since the last ice age, the southern Whidbey Island fault zone has probably spawned several highly destructive shallow earthquakes. Johnson and others (1996 #4751) described multiple sub-parallel strands and referred to the overall structure as the "southern Whidbey Island fault zone," and this name is also used herein for this zone of faults that crosses the southern part of Whidbey Island. Notice the Seattle Fault Zone bounding the Seattle Basin to the south. Its certainly not to scare you. Other types of seismic energy (S waves) also travel through the earth, but they move with a side-to-side (shearing) motion. Know what to expect. It devastated the coast of the Pacific Northwest and sent an orphan tsunami to Japan. Finding faults and knowing how often they rupture is one of the most important tasks to keep society safe from these hazards. 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?? 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. Later movement on this long-term active fault zone cut the volcano. Tsunamis and seiches can also be triggered by large slides, both on land and underwater. These cookies do not store any personal information. In the 1990s, scientists producedan animationthat shows inundation, and people wont have much time to run to higher ground. The Survey works to increase public and scientific understanding of fault and earthquake hazards in our state. South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario Fire (Vegetation Condition Class) . The below map shows that Seattle and its surroundings is constantly being rattled by small earthquakes and tremors. A lot of people are transplants, Forson said. 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. In this sense, the shaking of the ground is the sound of rocks breaking and moving deep within the Earth. Image from the Pacific Geoscience Center of the Natural Resources of Canada. The risk is complicated, but there are millions of people who live in the Seattle area, said Forson. The Seattle Fault is also likely to create a tsunami that would inundate Harbor Island and much of SODO, Interbay, and the waterfront. Liquefaction can be a big problem. Ready to retrofit? The map also shows potentially active faults from a separate 2014 report (click here to download). The last earthquake on the Seattle fault (about AD 950) triggered a landslide and seiche in Lake Washington. 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. Doorways do not provide protection from falling or flying objects and you may not be able to remain standing. 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. Source: United States Geological Survey. The most recent hit roughly 2,700 years ago. Every year Western. 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). The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Once a fault is located, it is important to know if it is active. The Moment Magnitude Scale (M) measures the total amount of seismic energy (known as moment to engineers and seismologists) released by an earthquake. Theres a must-see documentary film called Cascadia The Big One that exposes whats currently going on in this region of the Cascade volcanoes and the Pacific NorthWest. One or possibly two of the unconformities are interpreted as event horizons. For each increase in earthquake magnitude, there are about 10 times fewer earthquakes. x\[s8~OU)! Theyre FREE CLICK HERE to subscribe, EAR TO THE GROUND WITH DNR & COMMISSIONER FRANZ, Tree Link helps you answer questions about urbantrees. This fault zone was originally named the Devils The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. The Survey is working with the Office of the Superintendent of Public Instruction (OSPI) and Reid Middleton, an engineering firm, to perform seismic safety assessments of 220 school buildings across the state. Landslides can be caused by strong ground shaking during an earthquake. A community meeting about a shelter at the Harbor Inn may have yielded more questions than answers. 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. During site visits in 2005, Sherrods team found evidence of four SWIF earthquakes in the past 30,000 years. Other faults are inactive and are left over from much older periods of deformation. Seismologists estimate that such quakes and tsunami waves occur roughly every 500 years on average on the Cascadia Subduction Zone. These large underwater slides only occur during very large earthquakes and are one way to learn about earthquakes that happened thousands of years ago. The video is also available in Spanish and there is a fun activity/coloring book that can be found here. /L\Axc4Q/w4Ks^#, sRITgZf>,e}iI5,F_ADGc?f e@L. Earthquakes on faults like these may cause tsunamis in the Puget Sound region. If the epicenter is Everett, the SWIF could cause. This is a very good example of a strike-slip fault. His team wanted to find the rate of sea level rise along the shore. 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. He said scientists have known about the southern Whidbey fault for decades. Camano Island, WA 98282, Mailing Address (Andy Bronson / The Herald). @\;L;=}%FC*l $@ 4x: 888O~xrsxx'/*rGRF\gI%~x(G-^-hjjq kx/V ou0hyegy0;ei`Tx&ilZ )TmZ$vb,`bQm|DR5x/ It is not yet possible to predict when a fault will have an earthquake. endobj The Darrington-Devils Mountain fault zone is located in southern Skagit County and northern Snohomish County. 121 N East Camano Dr You also have the option to opt-out of these cookies. You will not be able to google what to do in an earthquake when it is happening. Photo courtesy of MOHAI (neg. The continued movement along faults over millions of years can build mountains, tear a continent apart, and move tectonic plates thousands of miles. Additionally, because the continent moves up and over the ocean plate, large amounts of sea water are displaced and cause damaging tsunamis. These types of faults are common, but usually small. They didnt recognize the significance of what they found. Standing becomes almost impossible as the jolts turn to rolling waves. The plate that is forced down can have faults within it that still rupture and produce earthquakes. It may not be possible to find water, fuel, or food until services are restored days or even weeks after the event. Devastating wind storms. Using the stratigraphic column from the Freeport quadrangle map, confirm that you can recognize . Mapping along the Snoqualmie River valley also helped answer the important question of where the Seattle fault lies east of its last mapped position near Issaquah. Washington has the second highest risk in the U.S. of these large and damaging earthquakes because of its geologic setting. Expect aftershocks. After the shaking stopped the sand regained its strength. It usually also means that there are earthquakes (even small ones) on the fault. The more you know what to expect, the better prepared you will be to help yourself, your family, and others around you. An earthquake occurs when rock inside the Earth moves or breaks. Beef Barley and French Onion trenches cross the Little Bear Creek lineament. Tap/click on "gear icon" for options and settings. Third, the South Whidbey Island Fault running from northwest to southeast of the southern tip of the island. Watch the video below to learn how you can be ready for the next earthquake. The Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. Both studies suggested that the SWIF Each of the earthquakes listed on the bottom of the screen is capable of significant damage. This kind of landslide is called an earthquake-triggered landslides. You can look at different geological hazard mapson the website of the Department of Natural Resources. Finding and mapping these faults is an important mission of the Washington Geological Survey. 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. And what were looking at is water.. For example, the Cascadia subduction zone has had between 15 to 19 earthquakes over the past 10,000 years. Latest earthquakes map and list (past 24 hours, M2.5+) from the ANSS (Advanced National Seismic System). So they dont necessarily know the threats they face.. Throughout the world shallow earthquakes generally refer to earthquakes that are less than ~45 miles deep. At the time, Johnson worked in southwest Washington, searching for natural gas and oil deposits. Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. These aftershocks can last for hours to weeks or months. Most faults in Washington are a mix of a strike-slip fault and a thrust or reverse fault. A drill rig left of the blockade is collecting data about the failure. Brick chimneys cascade off rooftops. Another big one is expected, and it could be devastating. These faults and earthquakes occur in the continental crust of North America. % It will happen; we dont know when.. Each peak of the Olympics stuck out with picturesque clarity in the distance. These combination faults are called oblique faults and include the Seattle fault, southern Whidbey Island fault zone, and DarringtonDevils Mountain fault zone. Although we cannot predict exactly when the next earthquake will happen, we can predict the general distribution of earthquake sizes. Scientists dont know. Large earthquakes, like those from the Cascadia subduction zone on January 26, 1700, often create tsunamis. 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. The Seattle Fault is a zone of multiple shallow east-west thrust faults that cross the Puget Sound Lowland and through Seattle (in the U.S. state of Washington) in the vicinity of Interstate Highway 90.The Seattle Fault was first recognized as a significant seismic hazard in 1992, when a set of reports showed that about 1,100 years ago it was the scene of a major earthquake of about . Theres an uneasy hush. This earthquake caused parts of Restoration Point near on Bainbridge Island to be lifted 35 feet straight up. Hundreds could die, with thousands more injured. 4 0 obj Power could be out for days. The marshy deposits are about a meter higher at Lake Hancock. Then the world rattles up and down. Know what other hazards you might face. . This map of gravity residuals measured over the puget lowland reveals a pattern of deep, fault bounded basins (cool colors) and uplifts (warm colors). The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. Coupeville, WA 98239, Camano Office The buildings sank when ground shaking weakened the underlying sediments. The French Onion trench exposed glaciolacustrine claystones, till, colluvial deposits, and Holocene soils. Here, were looking at one of the bigger faults in the region, he said. The San Andreas in California, for example, left gaping scars in the Earths crust, at the surface. Although we know much about active faults and earthquakes, there is much more to learn. Also issued a warning for the UK that the Italian chaos could come to Britain An increase of 2 means that ~1,000 times more energy is released. This uplift creates a very broad wave called a tsunami. 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 Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. In Seattle, the quake damaged buildings, weakened bridges, started fires and opened cracks in the earth. Sometimes Geologists can use the offset land surface to understand how much the fault moved during the earthquake. PI22343). 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. South Whidbey Island Fault Zone. That could spell trouble not only for its namesake island but for south and north King County and further west. Restoring tap water to some homes could take over a year. Johnson et al. 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. These quakes are capable of magnitudes from 7 to over 9. This is similar to how sound is quieter when you move away from a speaker. These sediments were laid down 20,000 to 60,000 years ago, before the last ice age. And experts fear it could be even worse than The Big One.. The mission of the Washington Geological Survey is to collect, develop, use, distribute, and preserve geologic information to promote the safety, health, and welfare of the citizens, protect the environment, and support the economy of Washington. After a large earthquake it is common to have other large earthquakes for hours, days, and even weeks. Higher risk areas are in orange and lower risk areas are in green. Electricity, water, natural gas, and phones may not work. The San Andreas fault in California is a good example of a very active strike-slip fault. The moment magnitude scale is a type of logarithmic scale, where each increase of 1 means ~32 times more energy is released. Consider subscribing to our blog, Washington State Geology News, to receive notifications when new information is published. Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. A normal fault occurs when two blocks are pulled away from each other. And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. Many landslide-prone areas of Washington are also located near active faults. The shaking can also cause landslides, surface ruptures, ground cracks, liquefaction, tsunamis, and seiches (standing waves). Finding nothing of serious monetary value, the companies abandoned reams of information they had gathered through seismic surveys. Small talk stops. Fir trees near the failure are tilted and indicate rotation into the lake (to the left of the photo). The trench did expose faults, but it was not possible to conclusively demonstrate offset of Holocene units. Please visit our Geologic Information Portal and Geologic Hazard Maps page for the most up-to-date listing of all of our hazard maps. A baristas hand hovers over the bean grinder. California Geological Survey. One of these cracks appeared along the pathway around Green Lake. These faults and earthquakes usually occur at great depth (tens to hundreds of miles). Sherrod shrugged his shoulders. 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. Reverse faults are usually steep and occur in regions of compression. They knew something was there, said Sam Johnson, a retired USGS geologist who would follow up on their work. One of the best views of SWIF should be from Grand Avenue Park in Everett. The 1949 earthquake near Tacoma triggered a landslide near the Tacoma Narrows that caused a local tsunami. Most of the populated areas of the state have a 4080% chance of having an earthquake in the next 50 years. 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. 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. For example, a M7 earthquake releases 32 times more energy than a M6 earthquake, and 1,000 times more than a M5 earthquake. 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. There are also many faults that have not been studied enough to know if they are active. One of the most important new technologies for finding faults (and landslides too) is called lidar. The map also shows potentially active faults from a separate 2014 report (click here to download). 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. It is mandatory to procure user consent prior to running these cookies on your website. Roads, bridges, or ramps may have been damaged by the earthquake. You just need one person to crash or a power line to fall over the road, and the roads are unusable.. A national credit rating service has improved its opinion of WhidbeyHealths financial future. 1 School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada 2 Department of Earth and Environment, Boston University, Boston, Massachusetts 02215, USA The material becomes so weak that it behaves more like a liquid than a solid. Sheriff:(360) 679-7310, Juror Recordings Washington has dozens of active faults and fault zones. Everything points to one thing, Sherrod said, waving his hand across the inland sea. Like other faults, when enough stress builds up, the megathrust will rupture. 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. Washington, Seattle, WA 98195 2 U.S. Geological Survey, 345 Middlefield Road, M/S . Were working on pedestrian evacuation maps that show the best routes for pedestrians to take to evacuate, said Forson. Drop to your hands and knees. endobj This is sometimes called "The Big One" by news media. In some areas getting up a hill to higher ground will be difficult. The southern Whidbey fault is unlike more visible faults on the West Coast. These fault strands follow the valley edges and control the location of the Snoqualmie River along some portions of the valley. Landslide at Salmon Beach was triggered by the 1949 Tacoma earthquake and caused a tsunami. Others, like the Seattle fault and southern Whidbey Island fault zone, cross under major cities and pose a significant hazard. Get On The List To Receive Your Daily Dose Of Weird News And Amazing Phenomena. and the Red Cross will be there to care for them.