of Earth and Space Sciences, Box 351310, Univ. Proceed cautiously once the earthquake has stopped. This is an active fault.. Reverse faults are usually steep and occur in regions of compression. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. Power could be out for days. Each peak of the Olympics stuck out with picturesque clarity in the distance. After the shaking stopped the sand regained its strength. Deformed recessional outwash deposits and Holocene deposits were exposed; three unconformities separated the units. Disoriented drivers wonder whats wrong with their cars, then realize something much bigger is amiss. This is a very good example of a strike-slip fault. The Eastern Sierra fault along the east side of the Sierra Nevada mountains in California is a good example of an active normal fault. PDF Cretaceous-Jurassic accreted terrains - University of Washington A 2014 map shows what we know about the age of faults in Washington. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. endobj The fault's length depends on whom you ask, Sherrod said. This movement created a tsunami in Puget Sound and triggered a large landslide into Lake Washington. Southern Whidbey Island Fault Zone Mapped through Snoqualmie Valley An official website of the United States government. Photo from, Liquefaction can be a big problem. And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. The southern Whidbey Island fault: An active structure in the Puget Lowland Washington, Geological Society of America Bulletin 1996;108;334-354. After large earthquakes there are usually many aftershock earthquakes. Even when an earthquake happens on a fault that doesnt reach the surface, the ground can still show signs of cracking. The evidence shows each lake rests on different free-floating jigsaw pieces of planetary crust, separated by the southern Whidbey Island fault. Know what other hazards you might face. These faults and earthquakes occur in oceanic crust as it is subducted beneath the continent. Most of the populated areas of the state have a 4080% chance of having an earthquake in the next 50 years. southern Whidbey Island fault zone (Class A) No. Consider whether earthquake insurance is right for you. Finding and learning about faults requires many different aspects of geology and geophysics. Photo from Pacific Northwest Seismic Network Seismo Blog. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Seattle's Faults: Maps That Highlight Our Shaky Ground For earthquakes that occurred before seismographs were invented, the Mercalli Intensity scale was used to make maps of damage and determine the size and location of an earthquake. The map is from a 2007 report (click here to download) on seismic design categories in Washington. Volcanic eruptions. This kind of grouping gives us information about how common earthquakes might be and how large an area may be affected. Source: United States Geological Survey. That place is the Ocosta School. % Below you will find links to view and download hazard maps created for each jurisdiction included in the current mitigation planning process. <> If a large earthquake happens, be prepared for many more earthquakes. Additionally, because the continent moves up and over the ocean plate, large amounts of sea water are displaced and cause damaging tsunamis. What are the most dangerous fault lines for Seattle? In the Puget Sound region, it takes a trained eye to recognize rocky outcrops and subtly raised ground as evidence of a fault. On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. 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 The tsunamis can travel far inland and deposit layers of sand and organic material. Some faults reach the surface and can be found by geologists. During site visits in 2005, Sherrods team found evidence of four SWIF earthquakes in the past 30,000 years. Tsunamis and seiches are destructive waves which can be triggered by certain types of large earthquakes. Large earthquakes are likely to happen in Washington during your lifetime. Do you know what to do if there is an earthquake? Earthquakes cause damage by moving and shaking the ground, sometimes for several minutes. Depending on the type of fault, the ground can move laterally, vertically, or a combination of both. The map also shows potentially active faults from a separate 2014 report (click here to download). Snohomish, King and Island counties would be expected to see the. 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. Scientists are not sure how far east it goes. An earthquake can be a scary event. The average time between large earthquakes is about 535 years, but has been as little as 200 years, and more than 1,000 years. In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. The 1949 earthquake near Tacoma triggered a landslide near the Tacoma Narrows that caused a local tsunami. The Survey conducts and publishes geologic mapping to identify and characterize faults throughout the state. Emergency Management Hazard Maps - Island County, Washington Save my name, email, and website in this browser for the next time I comment. It startled Johnson that such massive faults had gone undetected for so long. Another piece can be seen under the elevated lanes of northbound Interstate 5 in South Seattle not far from the Rainier brewery. And when are documentary film called Cascadia The Big One, Dangerous Inland Earthquake Destroys Homes and Schools near Jakarta, Indonesia, Terrifying video shows olive grove turned into a Gigantic Canyon after Turkeys earthquake split land in huge rifts. This is sometimes called "The Big One" by news media. The process of breaking and moving rock releases a large amount of energy that travels through the Earth as seismic waves. Small fires are the most common hazard after an earthquake. 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. 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. These cookies do not store any personal information. 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. This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. Other faults are inactive and are left over from much older periods of deformation. Lidar maps show the Earths surface without vegetation. America is going to pay for sitting back doing nothing while almost 70 million babies were slaughtered and their body parts sold to the highest bidder for the last 43 years. @\;L;=}%FC*l $@ 4x: 888O~xrsxx'/*rGRF\gI%~x(G-^-hjjq kx/V ou0hyegy0;ei`Tx&ilZ )TmZ$vb,`bQm|DR5x/ South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario Fire (Vegetation Condition Class) . For example, the Cascadia subduction zone has had between 15 to 19 earthquakes over the past 10,000 years. 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. 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. The Seattle Fault is also likely to create a tsunami that would inundate Harbor Island and much of SODO, Interbay, and the waterfront. Scientists have been trying to understand how often earthquakes happen for over 100 years. This averages to ~660 to 525 years between events, but there is a lot of variation. 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. It is not yet possible to predict when a fault will have an earthquake. For example, a M7 earthquake releases 32 times more energy than a M6 earthquake, and 1,000 times more than a M5 earthquake. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. Once in the open, Drop, Cover, and Hold On. Please visit our Geologic Information Portal and Geologic Hazard Maps page for the most up-to-date listing of all of our hazard maps. 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 The fault probably originated during the early Eocene as a dextral strike-slip fault along the eastern side of a continental-margin rift. They didnt grow up here, they havent heard this story. Share sensitive information only on official, secure websites. Transpressional deformation along the southern Whidbey Island fault is indicated by alongstrike variations in structural style and geometry, positive flower structure, local unconformities, out-of-plane displacements, and juxtaposition of correlative sedimentary units with different histories. In addition, the Survey performs seismic safety evaluations of schools. These cookies will be stored in your browser only with your consent. The affiliate sales will help us to continue the hard work we are putting in this website. Swarm of hundreds of small earthquakes rattle Vancouver Island. PI22343). Learn how your comment data is processed. endobj Earthquakes occur nearly every day in Washington. Because Japan was so well prepared, mostretrofitted buildingsoutside of the tsunami zone survived. 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. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. . Westport currently is the only location with a vertical evacuation structure designed for a tsunami. In fact, new faults are found every year during our geologic mapping efforts. Over time, fault movement has created some interesting geologic features. The seismic mapping had cost millions of dollars far beyond what most geologists on a government budget could scrape together. The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. Since their initial discovery, research has shown that the actual number of earthquakes is somewhere between 5 and 10 for each change in magnitude. Superior Court:(800) 254-2755 You just need one person to crash or a power line to fall over the road, and the roads are unusable.. Even if the earthquake is too small to be felt by people, seismographs can detect it. The Mercalli Intensity scale is another historical way to measure the intensity of an earthquake. The South Whidbey Island Fault and Darrington Devil's Mountain Fault bound the Everett Basin. Other types of seismic energy (S waves) also travel through the earth, but they move with a side-to-side (shearing) motion. The SWIF was first recognized and mapped at a regional scale by Gower and others (1985) on the basis of gravity and aeromagnetic anomaly maps. Sensitive seismographs located throughout the state, and all over the world, measure this seismic energy. PDF Holocene Fault Scarps and Shallow Magnetic Anomalies Along the Southern Each type has different kinds of earthquakes. A half dozen people reaching for the last can of soup, someone could lose their life over that. 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 . These maps are created by small planes that use a specific type of laser to measure the elevation of the ground. The friend obliged. Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. Until much more recently, no one really understood what it could do to a region of over 4 million people. Many landslide-prone areas of Washington are also located near active faults. 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. Also issued a warning for the UK that the Italian chaos could come to Britain East of Puget Sound, the SWIF makes landfall between the cities of Seattle and Everett but is concealed . Quake fault under Whidbey linked to potential mainland dangers Expect aftershocks. Photo courtesy of National Center for Tsunami Research, NOAA. Theres approximately a 14% chance of another approximately M9 earthquake occurring in the next 50 years. The Straight Creek fault in the Cascade Range is an example of this kind of fault and has ~5060 miles of movement across it. This map is from a 2007 report on the seismic design categories in Washington. Geologic maps show the types and ages of rocks and younger deposits that are found at or near the Earth's surface. Johnsons curiosity changed the course of his career. Move away from buildings, streetlights, and utility wires if you can. Unlike sound, ground shaking can be amplified or attenuated (made less) depending on the type of material at the Earths surface. 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." 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 southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. This fault will have an earthquake in the future, but we cannot predict exactly when. Earthquakes between 45 and 185 miles deep are called intermediate, and earthquakes over 185 miles deep are called deep. 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. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. Watch the video below to learn how you can be ready for the next earthquake. Never use a lighter or match near damaged areas. Floods. A reverse fault occurs when two blocks are pushed together and one moves up and over the other. Stories from tribes near Seattle have also helped us to learn that the last earthquake on the Seattle fault was about AD 900950. Finding Concealed Active Faults: Extending the Southern Whidbey Island Coupeville, WA 98239, Main Line: Trenches by Sherrod and others, 2008 #7652) are less than 1 km south of KP1 and KP2 and Sherrod and others (2008 #7652) conclude that deformation in the area is due to surface-rupturing earthquakes. Oblique convergence and clockwise rotation along the continental margin are the inferred driving forces for ongoing deformation. One of the most important new technologies for finding faults (and landslides too) is called lidar. At a downtown coffee shop, the mugs begin to chatter. If you are already planning your Christmas gifts, please buy with us on Amazon. 1 0 obj Liquefaction has caused significant damage during earthquakes in Washington. Moving inland, the Seattle Fault is capable of a magnitude 7. x\[s8~OU)! 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. Also, very large earthquakes were difficult to measure accurately. Earthquakes on shallow faults typically last 20 to 60 seconds and the shaking is localized to the general area of the fault. Plate Tectonics | Pacific Northwest Seismic Network Then the world rattles up and down. Excavations across several LiDAR scarps show evidence for multiple post-glacial folding and faulting event on faults with reverse oblique sense of slip. The Southern Whidbay Island Fault represents another major earthquake threat for Seattle and its residents. Seismologists estimate that such quakes and tsunami waves occur roughly every 500 years on average on the Cascadia Subduction Zone. Washington, Seattle, WA 98195 2 U.S. Geological Survey, 345 Middlefield Road, M/S . And what were looking at is water.. For the most up-to-date information, please refer to the interactive fault map. Story telling is an important part of the Native tradition and is how their history is passed down to the next generation. An earthquake occurs when rock inside the Earth moves or breaks. Necessary cookies are absolutely essential for the website to function properly. Know what to expect. Most of the populated areas of the state have a 4080% chance of having an earthquake in the next 50 years. Emergency planners all had a simple message: Its not IF a disaster will happen, its WHEN. Finding and mapping these faults is an important mission of the Washington Geological Survey. Most faults are considered active if they have evidence for movement (this includes earthquakes) within the past 12,000 years (the Holocene time period). 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. But scientists theorize that the area has suffered only four . The next earthquake is inevitable, but the variability makes it difficult to know exactly when. The Port of Coupeville will apply for a grant to fund two electric vehicle charging stations. Ready to retrofit? Visit our School Seismic Safety page for more information. 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. View of the Sunset Lake liquefaction failure about three weeks after the earthquake. A lot of people are transplants, Forson said. On a frigid, blustery day in December 2018, Sherrod revisited the site where he conducted much of his field work. A strike-slip fault occurs when two blocks move past each other. It is mandatory to procure user consent prior to running these cookies on your website. Shallow faults produce earthquakes in the upper 18 miles (30 kilometers) of the Earths crust. This earthquake is along the southern Whidbey Island fault, a less-known, less-studied subterranean boundary. Large earthquakes, like those from the Cascadia subduction zone on January 26, 1700, often create tsunamis. 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? After the earthquake, many things you count on may not be available. Radiocarbon dating and other paleoseismic methods have also confirmed this date. Theyre FREE CLICK HERE to subscribe, EAR TO THE GROUND WITH DNR & COMMISSIONER FRANZ, Tree Link helps you answer questions about urbantrees. A major southern Whidbey quake, on the other hand, could kill and injure many more, according to Murphy. The faults length depends on whom you ask, Sherrod said. Earthquakes can trigger landslides and tsunamis which can happen after the main event. Ground shaking is a hazard near the epicenter of an earthquake and also in areas far from the earthquake where amplification occurs. A magnitude 7.4 along the southern Whidbey fault would rattle 18 counties in Washington, according to a federal projection . These quakes are capable of magnitudes from 7 to over 9. Fault Activity Map of California With Medical Martial Law imposed in Washington state. Some events appear to be only 200 years apart, and others are more than 1,000. Hold on to any sturdy shelter until the shaking stops. This can cause landslides to occur where they wouldnt normally happen. Some people in places like SODO and Harbor Island may have to flee to higher floors in a building. California Department of Conservation. 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. Audio; Before and After Images; Images; Slideshows; Stereograms; Videos; Webcams; . The publication Faults and Earthquakes in Washington State is a state-wide compilation of active faults and folds. The Pacific Tsunami Warning Center is located in Hawaii and is responsible for issuing alerts to all the countries that border the Pacific Ocean. Map of Puget Sound and Hood Canal in north-central - ResearchGate Faults are features in the Earths crust where rock periodically breaks and moves, releasing seismic energy and creating an earthquake. Within minutes, he spotted something groundbreaking. In effect, the wave energy is trapped by the edges of the body of water. For example, in the open ocean a tsunami may be less than a few feet tall. 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. Both types of faults can cause ground shaking during an earthquake and may cause permanent deformation of the ground. Deep faults can occur where two tectonic plates collide and one of the plates is forced beneath the other. 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). We also use third-party cookies that help us analyze and understand how you use this website. His team wanted to find the rate of sea level rise along the shore. Surface Geology | WA - DNR On a brilliant November day, Sherrod took in the panorama from the parks bluff.
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