They knew something was there, said Sam Johnson, a retired USGS geologist who would follow up on their work. You will not be able to google what to do in an earthquake when it is happening. Coupeville, WA 98239, Main Line: Experts believe a magnitude 9.0 could happen there anytime in the next 200 years or so. Source: United States Geological Survey. The Safe America Foundation suggests texting as a way of communication. Some faults reach the surface and can be found by geologists. Johnson, on a whim, acquired the data that would prove its existence beyond a doubt. This video from the 2011 Tohoku subduction zone earthquake shows the earthquakes before, during, and after the main M8.7 event on March 11 (at 1:50 in the video). Tap/click on "gear icon" for options and settings. These older faults do not have any evidence for recent activity, but the Earth is always changing. This movement created a tsunami in Puget Sound and triggered a large landslide into Lake Washington. Sometimes there may be a layer of volcanic ash or charcoal that has been deformed by the fault. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. 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 However, we can learn which faults are active and which are inactive. This is a hypothetical scenario created by Mark Murphy of the Snohomish County Department of Emergency Management. They didnt grow up here, they havent heard this story. This category only includes cookies that ensures basic functionalities and security features of the website. STAY THERE until the shaking stops. In places where there is little vegetation, different rock types and faults can be found with relative ease. If you are in bed: STAY there and COVER your head and neck with a pillow. These cookies will be stored in your browser only with your consent. Black squares are urban sewer outfalls, which don't match the bubble plumes' locations. 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 Seattle fault last ruptured about 1,100 years ago in AD 900950. Additional fault studies by state and federal geologists in the next few years will help determine the frequency and severity of earthquakes along these fault zones. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. 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. Geologists do not yet know how often earthquakes happen on this fault. The 1964 M9.2 Alaska earthquake created a large tsunami from the fault rupture, and many smaller tsunamis from on-land and underwater landslides. By clicking Accept, you consent to the use of ALL the cookies. 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 You saw its potential in the 9.1 magnitude Tohuku earthquake and tsunami that hit northeastern Japan in March 2011. Hundreds could die, with thousands more injured. Know what other hazards you might face. Photo from Pacific Northwest Seismic Network Seismo Blog. The process of breaking and moving rock releases a large amount of energy that travels through the Earth as seismic waves. For the most up-to-date information, please refer to the interactive fault map. You have entered an incorrect email address! It is a qualitative scale that ranges from IXI (1-11) and measures the amount of damage caused by an event. 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." Swarm of hundreds of small earthquakes rattle Vancouver Island. Photo from, This image shows the how the 1700 AD tsunami from the Pacific Northwest crossed the Pacific Ocean. A strike-slip fault occurs when two blocks move past each other. Washington State Earthquake Hazard Map. Like other faults, when enough stress builds up, the megathrust will rupture. This fault will have an earthquake in the future, but we cannot predict exactly when. Washington has dozens of active faults and fault zones. Its a natural curiosity.. The southern Whidbey Island fault (SWIF) stretches from the vicinity of Victoria, B.C., across Puget Sound as far as the Cascade Range. This website uses cookies to improve your experience while you navigate through the website. Scientists are not sure how far east it goes. California Geological Survey. It could also create dangerous currents and hazards to the north including Everett. Even when the location of a fault is known, there is much additional work to determine how hazardous it may be. Many faults have not been studied enough to know if they are active. from Whidbey Island to Vancouver Island (Figure 1). Avoid stopping near or under buildings, trees, overpasses, or utility wires. Sometimes Geologists can use the offset land surface to understand how much the fault moved during the earthquake. 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. This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. Armentrout, J. J. Miller, C. Finn, C. S. Weaver. Close to shore, this same wave could reach heights of 30100 feet or more. 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. Southeast Extension of the Southern Whidbey Island Fault By Human Capital March 19, 2019. sw_whidbeyfault_rev122706.pdf (28.68 KB) The height difference likely was caused by a 7.5 magnitude earthquake on the fault about 2,700 years ago, Sherrod said. This can cause landslides to occur where they wouldnt normally happen. Once we got it, we were sort of shocked to see these big faults in the Puget lowlands, he said. Facades crumble off buildings along Oak Harbors Pioneer Way, and some of the oldest structures in Langley and Coupeville collapse in a roaring cloud of dust. A small quake was registered in the Coupeville area just this summer. This uplift creates a very broad wave called a tsunami. 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. Consider subscribing to our blog, Washington State Geology News, to receive notifications when new information is published. Nearly all earthquakes occur on faults, features in the Earth where rocks move past each other. 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. And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. Electricity, water, natural gas, and phones may not work. That could spell trouble not only for its namesake island but for south and north King County and further west. In this sense, the shaking of the ground is the sound of rocks breaking and moving deep within the Earth. Faults can also be grouped based on what part of the crust they occur in. The Mercalli Intensity scale is another historical way to measure the intensity of an earthquake. Learn about at-risk areas and become prepared. In 2017, he began studying the possible aftermath of a major SWIF quake. Each of the earthquakes listed on the bottom of the screen is capable of significant damage. The 1949 earthquake near Tacoma triggered a landslide near the Tacoma Narrows that caused a local tsunami. A team headed by Joe Dragovich of DNRs Division of Geology and Earth Resources,assisted by geologists from King County, Pacific Northwest Seismic Network, Colorado College, and Washington State University, has been mapping in this area for the past three years. This movement happens because stress builds up as tectonic plates move. Walsh said that Whidbey Island through the years has been subjected to a number of small quakes, roughly 2 or 3 on the Richter scale. 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. 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. 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. Hover over a cluster of earthquakes to learn about the different types in the Pacific Northwest. 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. But the mapping offered geological clues that the newly found fault was indeed capable of future quakes. . This might include flammable appliances like a water heater, tall items like book cases, or heavy pictures. The moment magnitude scale replaced the Richter scale in the late 1970s. Earthquakes between 45 and 185 miles deep are called intermediate, and earthquakes over 185 miles deep are called deep. On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. This earthquake caused parts of Restoration Point near on Bainbridge Island to be lifted 35 feet straight up. Subtle scarps and topographic lineaments on Pleistocene surfaces are visible on high-resolution LiDAR topography at a number of locations (Sherrod and others, 2008 #7652); the northeast-side-up scarps exhibit 15 m of vertical relief, late glacial and post-glacial sediments (Sherrod and others, 2008 #7652). The Cascadia Subduction Zone (also known as the CSZ) is a 700-mile long fault zone located off the western coastline of British Columbia, Washington, Oregon and northern California. After the shaking stopped the sand regained its strength. The shaking can also cause landslides, surface ruptures, ground cracks, liquefaction, tsunamis, and seiches (standing waves). Maps. But Forson says you also need to know what to do when the shaking happens. The Cascadia subduction zone along the Washington and Oregon coast is one of the biggest hazards to our state and is a good examples of this kind of fault. 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. What about the localized tsunami risk? A lock () or https:// means youve safely connected to the .gov website. This is similar to how sound is quieter when you move away from a speaker. Photo courtesy of National Center for Tsunami Research, NOAA. Make an emergency response plan for you and your family. Faults are features in the Earths crust where rock periodically breaks and moves, releasing seismic energy and creating an earthquake. Large and damaging earthquakes are inevitable in Washington, but no one knows exactly when they will happen. Videos: Strong M6.0 earthquake rattles Mindanao in the Philippines, Dramatic earthquake increase in Hawaii! Expect and help to extinguish fires. In effect, the wave energy is trapped by the edges of the body of water. Learn how your comment data is processed. There are also tsunami evacuation signs on the highways. Fir trees near the failure are tilted and indicate rotation into the lake (to the left of the photo). For example, a building on soft soil will experience more shaking than the same building on bedrock. Do you know what to do if there is an earthquake? stream A reverse fault occurs when two blocks are pushed together and one moves up and over the other. The Straight Creek fault in the Cascade Range is an example of this kind of fault and has ~5060 miles of movement across it. Latest earthquakes map and list (past 24 hours, M2.5+) from the ANSS (Advanced National Seismic System). Johnson et al. 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. This map of gravity residuals measured over the puget lowland reveals a pattern of deep, fault bounded basins (cool colors) and uplifts (warm colors). 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. They havent dug up enough history to estimate. Most faults in Washington are a mix of a strike-slip fault and a thrust or reverse fault. If folding on the Little Bear Creek lineament resulted in one or two of unconformities, the poorly constrained timing of the earthquakes is younger than 12,000 yr BP and older than about 2,850 cal yr BP. 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). These quakes are capable of magnitudes from 7 to over 9. Moving inland, the Seattle Fault is capable of a magnitude 7. Small fires are the most common hazard after an earthquake. 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. The experts say few are ready. Consider a magnitude 7.4 quake with Whidbey Island at or near the epicenter. Audio; Before and After Images; Images; Slideshows; Stereograms; Videos; Webcams; . Check out the liquefaction susceptibility and NEHRP site class maps on the Geologic Hazard Maps page. Sherrods son has since completed graduate school in applied geosciences. Black lines show the South Whidbey Island Fault Zone, the Seattle Fault Zone and the Tacoma Fault Zone. In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. Tohoku killed nearly 16,000 people; most died as a result of drowning or being crushed in the tsunami. The Richter scale was developed in southern California in 1935 and was based on the local ground motion. The Flying Squirrel and Mountain Beaver trenches cross the Cottage Lake lineament. He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. Brick chimneys cascade off rooftops. The faults length depends on whom you ask, Sherrod said. Other faults may lie entirely underground, or could be covered by vegetation and (or) sediment. HomePrograms and ServicesGeologyGeologic Hazards. This map is from a 2007 report on the seismic design categories in Washington. Geoscientist Brian Sherrod stands near the submerged southern Whidbey Island fault line at the Brightwater Treatment Plant in Woodinville. 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. Finding and mapping these faults is an important mission of the Washington Geological Survey. In fact, new faults are found every year during our geologic mapping efforts. The age of the earthquake is learned by dating the organic material in these tsunami deposits. Some events appear to be only 200 years apart, and others are more than 1,000. These cookies do not store any personal information. An earthquake along the southern Whidbey Island fault reshaped the land some 2,700 years ago. 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 Disoriented drivers wonder whats wrong with their cars, then realize something much bigger is amiss. Other faults are inactive and are left over from much older periods of deformation. ; (5) large-scale liquefaction features in upper Quaternary sediments within the fault zone; and (6) minor historical seismicity. 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. It is mandatory to procure user consent prior to running these cookies on your website. The seismic mapping had cost millions of dollars far beyond what most geologists on a government budget could scrape together. 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. They conclude the observed features have a glaciotectonic origin and are not seimotectonic. Finding faults and knowing how often they rupture is one of the most important tasks to keep society safe from these hazards. In general, larger faults make larger earthquakes. The plate that is forced down can have faults within it that still rupture and produce earthquakes. The moment magnitude scale is a type of logarithmic scale, where each increase of 1 means ~32 times more energy is released. Every year Western. The southern Whidbey Island fault zone (SWIF) is a mostly concealed, northwest-trending structure extending across southern Whidbey Island toward Vancouver Island (Figures 1 and 2). Radiocarbon ages of macrofossils constrain uplift timing to 2.83.2 ka. Seattle Fault Lines. 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. People are already fighting over toilet paper, just imagine what will it be like when they go shopping for food and the shelves are almost empty. 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 fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. The map is from a 2007 report (click here to download) on seismic design categories in Washington. In addition, the Survey performs seismic safety evaluations of schools. Since the last ice age, the southern Whidbey Island fault zone has probably spawned several highly destructive shallow earthquakes. 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. Power could be out for days. Experts have warned that UK outbreak may be around two weeks behind Italys. Most are too small to be felt or cause damage. Mudslides. Both of these things can cause equal or greater damage than the actual earthquake. At the Brightwater treatment plant in Woodinville and at Crystal Lake in Maltby, the government researchers found telltale slopes of offset ground, known as scarps, indicative of a long-ago quake. Earthquakes cause damage by moving and shaking the ground, sometimes for several minutes. But they didnt document it hardly at all.. The western half of Washington state is considered earthquake country, with the potential for very large quakes. On a brilliant November day, Sherrod took in the panorama from the parks bluff. 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. 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. Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. A special type of shallow fault, called a subduction zone or megathrust, occurs where an oceanic plate moves beneath a continental plate. 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. % endobj One or possibly two of the unconformities are interpreted as event horizons. One model suggests it extends to about 30 miles east of Yakima. So the fault remained mostly a mystery until the 1990s. By finding the age of the deformed layer, a paleoseismologist can determine the minimum age of the fault. What scientists dont know is its timing interval. Sensitive seismographs located throughout the state, and all over the world, measure this seismic energy. A .gov website belongs to an official government organization in the United States. It may not be possible to find water, fuel, or food until services are restored days or even weeks after the event. 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. Another piece can be seen under the elevated lanes of northbound Interstate 5 in South Seattle not far from the Rainier brewery. Drop to your hands and knees. Customers lift their eyes from phone screens. Large earthquakes, like those from the Cascadia subduction zone on January 26, 1700, often create tsunamis. 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. Photo by Steve Palmer. Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. California Department of Conservation. If everyone tries to use their cell phones, it can overload the system. 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 . 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). These faults and earthquakes occur in oceanic crust as it is subducted beneath the continent. 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.