Secure .gov websites use HTTPS 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 There are also tsunami evacuation signs on the highways. The map also shows potentially active faults from a separate 2014 report (click here to download). Large earthquakes are likely to happen in Washington during your lifetime. On a brilliant November day, Sherrod took in the panorama from the parks bluff. These faults and earthquakes usually occur at great depth (tens to hundreds of miles). Expect aftershocks. The last large earthquake on the Cascadia subduction zone was in 1700. Notable earthquakes in bold happened in Washington. Snohomish, King and Island counties would be expected to see the. Fir trees near the failure are tilted and indicate rotation into the lake (to the left of the photo). The Mercalli Intensity scale is another historical way to measure the intensity of an earthquake. Southeast Extension of the Southern Whidbey Island Fault By Human Capital March 19, 2019. sw_whidbeyfault_rev122706.pdf (28.68 KB) After the shaking stopped the sand regained its strength. 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). The study of seismic waves is called seismology and has allowed scientists to learn much about the internal structure of the Earth. Coupeville, WA 98239, Camano Office It will happen; we dont know when.. Learn about at-risk areas and become prepared. This fault zone was originally named the Devils Sherrod shrugged his shoulders. It is capable of generating severe earthquakes that would impact the entire west coast. Most are too small to be felt or cause damage. The map is from a, This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. 572 Last Review Date: 2016-11-29 Even places that are far from active faults are still at risk during a large Cascadia subduction zone earthquake. These and other problems led to the search for a scale that was based on the physical processes that happen during an earthquake. The threat to Puget Sound from a quake along the Cascadia Subduction Zone, off the coast of Washington, Oregon and California, is well documented. Superior Court:(800) 254-2755 Before modern record keeping, Native Americans lived in the Pacific Northwest for thousands of years. 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). A half dozen people reaching for the last can of soup, someone could lose their life over that. Hey Biden! Some of these faults are in remote areas. The evidence shows each lake rests on different free-floating jigsaw pieces of planetary crust, separated by the southern Whidbey Island fault. Coupeville, WA 98239, Main Line: Earthquakes can trigger landslides and tsunamis which can happen after the main event. A magnitude 7.4 along the southern Whidbey fault would rattle 18 counties in Washington, according to a federal projection . You also have the option to opt-out of these cookies. The fault's length depends on whom you ask, Sherrod said. 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. This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. If a large earthquake happens, be prepared for many more earthquakes. You will not be able to google what to do in an earthquake when it is happening. When an earthquake happens there will not be time to google what you are supposed to do. 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. Why is Strange Sounds focusing so much on disaster preps? These faults and earthquakes occur in oceanic crust as it is subducted beneath the continent. Most damage and loss of life in earthquakes is a result of ground shaking. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. In general, larger faults make larger earthquakes. In the month after the main earthquake there were about 60 M7 and M6 earthquakes. Moving inland, the Seattle Fault is capable of a magnitude 7. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). 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. A special type of shallow fault, called a subduction zone or megathrust, occurs where an oceanic plate moves beneath a continental plate. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. 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. The Westport area is now the first in North America to have acommunity vertical evacuation structure, a building strong enough to resist earthquake and tsunami wave forces and give people a platform above the expected wave heights. We do know that it is active and will likely produce a large M67.5 earthquake when it next ruptures. 4 0 obj These quakes are capable of magnitudes from 7 to over 9. Drop, Cover, and Hold On whenever you feel shaking. HomePrograms and ServicesGeologyGeologic Hazards. Share sensitive information only on official, secure websites. " A lot of people are transplants, " Forson said. Avoid stopping near or under buildings, trees, overpasses, or utility wires. A normal fault occurs when two blocks are pulled away from each other. Charles Richter and Beno Gutenberg discovered that for every magnitude of earthquake, there are about ten times more earthquakes of the next lower magnitude. Floods. By sampling sediment from the marsh to the beach berm, Sherrod and his research partner, Harvey Kelsey, developed a timeline of the oceans climb. 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. Its a natural curiosity.. USA Earthquake Hazard Map. 121 N East Camano Dr Doorways do not provide protection from falling or flying objects and you may not be able to remain standing. View Earthquake Map Faults Interactive fault map and comprehensive geologically based information on known or suspected active faults and folds in the United States. In much of Washington, dense vegetation covers the land and makes finding faults very difficult. Large earthquakes, like those from the Cascadia subduction zone on January 26, 1700, often create tsunamis. Armentrout, J. J. Miller, C. Finn, C. S. Weaver. The average time between large earthquakes is about 535 years, but has been as little as 200 years, and more than 1,000 years. Volcanic eruptions. A small quake was registered in the Coupeville area just this summer. . 1 0 obj This is sometimes called "The Big One" by news media. Camano Island, WA 98282, Mailing Address He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. Mudslides. Although we know much about active faults and earthquakes, there is much more to learn. In the area of North Bend, the fault zone is 4 miles wide and consists of a series of parallel faults. Washington State Earthquake Hazard Map. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. The Moment Magnitude Scale (M) measures the total amount of seismic energy (known as moment to engineers and seismologists) released by an earthquake. 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. 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. Dishes jitter off tables, shattering on the floor. Kelsey and others (2004 #7651) compared sea-level histories at two salt marshes that straddle a northeast strand of the southern Whidbey Island fault zone: Crockett Marsh (site 572-1) located north of the northeastern fault strand is 8 km north of Hancock Marsh (site 572-2), south of the fault strand. Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. Stay away from glass, windows, outside doors and walls, and anything that could fall down. 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 . They didnt grow up here, they havent heard this story. The risk is complicated, but there are millions of people who live in the Seattle area, said Forson. In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. @\;L;=}%FC*l $@ 4x: 888O~xrsxx'/*rGRF\gI%~x(G-^-hjjq kx/V ou0hyegy0;ei`Tx&ilZ )TmZ$vb,`bQm|DR5x/ The southern Whidbey Island fault should be considered capable of generating large earthquakes (Ms ?? 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. However, we can learn which faults are active and which are inactive. This scenario was modeled on the part of the SWIF from Woodinville to just west of Whidbey Island. For example, in the open ocean a tsunami may be less than a few feet tall. Faults are features in the Earths crust where rock periodically breaks and moves, releasing seismic energy and creating an earthquake. Geologists have used the location of these shallow, intermediate, and deep earthquakes to learn about subduction zones throughout the world. Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. For example, a building on soft soil will experience more shaking than the same building on bedrock. The shaking can damage or destroy buildings and other infrastructure. PI22343). SWIF ranges from 12 miles underground at its deepest to right at sea level in a few scattered spots, like Cama Beach, Holmes Harbor and Woodinville, according to Sherrods research. Do not exit a building during the shaking. 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). Gower (1980 #6229) showed and named the "southern Whidbey Island fault," and Gower and others (1985 #4725) showed this fault on their seismotectonic map of the Puget Sound region and briefly outlined its geologic relationships. Third, the South Whidbey Island Fault running from northwest to southeast of the southern tip of the island. The map is from a 2007 report (click here to download) on seismic design categories in Washington. Make an emergency response plan for you and your family. The next earthquake is inevitable, but the variability makes it difficult to know exactly when. The Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. Oil companies descended in search of riches. Photo from, This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. Identify and secure items in your home or work that could cause damage. Within minutes, he spotted something groundbreaking. The San Andreas fault in California is a good example of a very active strike-slip fault. A thrust fault is a special kind of reverse fault that has a shallow dip. Brick chimneys cascade off rooftops. 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. This movement created a tsunami in Puget Sound and triggered a large landslide into Lake Washington. Knowing how often large earthquakes have happened in the past helps us to know how often they might occur in the future. 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??
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