Oblique convergence and clockwise rotation along the continental margin are the inferred driving forces for ongoing deformation. The southern Whidbey Island fault zone (SWIF), as previously mapped using borehole data, potential field anomalies, and marine seismic reflection surveys, consists of three subparallel, northwest trending strands extending ~100 km from near Vancouver Island to the northern Puget Lowland. In general, larger faults make larger earthquakes. It devastated the coast of the Pacific Northwest and sent an orphan tsunami to Japan. A community meeting about a shelter at the Harbor Inn may have yielded more questions than answers. Prepare to be on your own for at least three days. 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. Mudslides. The fault, not so much. Jump from 60 to 600 per week in just 5 years in Pahala, Is the Cascadia Subduction Zone about to blow? This fault produces some of the largest and most damaging earthquakes in the world (M9). 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. This scenario was modeled on the part of the SWIF from Woodinville to just west of Whidbey Island. The South Whidbey Island Fault and Darrington Devil's Mountain Fault bound the Everett Basin. These faults and earthquakes occur in the continental crust of North America. The tsunamis can travel far inland and deposit layers of sand and organic material. All Rights Reserved 2021, Site Disclaimer Snohomish, King and Island counties would be expected to see the. If everyone tries to use their cell phones, it can overload the system. If a large earthquake happens, be prepared for many more earthquakes. Maps. The Mercalli Intensity scale is another historical way to measure the intensity of an earthquake. Expect aftershocks. Seismologists estimate that such quakes and tsunami waves occur roughly every 500 years on average on the Cascadia Subduction Zone. Roads, bridges, or ramps may have been damaged by the earthquake. Johnson et al. Know what other hazards you might face. 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. The San Andreas in California, for example, left gaping scars in the Earths crust, at the surface. A major southern Whidbey quake, on the other hand, could kill and injure many more, according to Murphy. Faults often occur at and near the boundary of large tectonic plates because the plates are moving in different directions. But quiet period wont last, Strongest earthquake in 40 years rattle residents of Buffalo, NY, Is Istanbul next? In the area of North Bend, the fault zone is 4 miles wide and consists of a series of parallel faults. If you are already planning your Christmas gifts, please buy with us on Amazon. 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. The moment magnitude scale replaced the Richter scale in the late 1970s. The western half of Washington state is considered earthquake country, with the potential for very large quakes. 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. The largest active fault that will affect Washington (and the whole Pacific Northwest) is the Cascadia subduction zone. The publication Faults and Earthquakes in Washington State is a state-wide compilation of active faults and folds. The San Andreas fault in California is a good example of a very active strike-slip fault. Theyre FREE CLICK HERE to subscribe, EAR TO THE GROUND WITH DNR & COMMISSIONER FRANZ, Tree Link helps you answer questions about urbantrees. These faults and earthquakes occur in oceanic crust as it is subducted beneath the continent. 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. Do you live or work near an area that could have liquefaction? Other faults are inactive and are left over from much older periods of deformation. An official website of the United States government. Scientists dont know. But they didnt document it hardly at all.. In Washington, the risk from earthquake-induced landslides is large. The next earthquake is inevitable, but the variability makes it difficult to know exactly when. For example, in the open ocean a tsunami may be less than a few feet tall. 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. View Earthquake Map Faults Interactive fault map and comprehensive geologically based information on known or suspected active faults and folds in the United States. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. Faults are features in the Earths crust where rock periodically breaks and moves, releasing seismic energy and creating 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. You just need one person to crash or a power line to fall over the road, and the roads are unusable.. A magnitude 7.4 along the southern Whidbey fault would rattle 18 counties in Washington, according to a federal projection . Landslide at Salmon Beach was triggered by the 1949 Tacoma earthquake and caused a tsunami. The Moment Magnitude Scale (M) measures the total amount of seismic energy (known as moment to engineers and seismologists) released by an earthquake. 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). Even places that are far from active faults are still at risk during a large Cascadia subduction zone earthquake. The Port of Coupeville will apply for a grant to fund two electric vehicle charging stations. A .gov website belongs to an official government organization in the United States. They conclude the observed features have a glaciotectonic origin and are not seimotectonic. The threat to Puget Sound from a quake along the Cascadia Subduction Zone, off the coast of Washington, Oregon and California, is well documented. 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. An official website of the United States government. The map also shows potentially active faults from a separate 2014 report (click here to download). What are the most dangerous fault lines for Seattle? We also use third-party cookies that help us analyze and understand how you use this website. The risk is complicated, but there are millions of people who live in the Seattle area, said Forson. 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. But it didnt. 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 after a region-wide event, it could take that long for help to come from the rest of the country and world. Most of the populated areas of the state have a 4080% chance of having an earthquake in the next 50 years. Even when the location of a fault is known, there is much additional work to determine how hazardous it may be. Finding nothing of serious monetary value, the companies abandoned reams of information they had gathered through seismic surveys. 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. Evacuate to higher ground if you are near a large body of water. If the epicenter is Everett, the SWIF could cause. Faults can also occur within a tectonic plate when the plate itself is deforming. Some faults reach the surface and can be found by geologists. One model suggests it extends to about 30 miles east of Yakima. Depending on the type of fault, the ground can move laterally, vertically, or a combination of both. Small fires are the most common hazard after an earthquake. 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. California Department of Conservation. His team wanted to find the rate of sea level rise along the shore. These fault strands follow the valley edges and control the location of the Snoqualmie River along some portions of the valley. These sediments were laid down 20,000 to 60,000 years ago, before the last ice age. 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. If they know theres data available that could help them in any way, they want to get it. The ground shaking from these earthquakes can last for several minutes. Get On The List To Receive Your Daily Dose Of Weird News And Amazing Phenomena. The southern Whidbey Island fault divides the two. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. And experts fear it could be even worse than The Big One.. Another big one is expected, and it could be devastating. x\[s8~OU)! 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). In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. Earthquakes occur nearly every day in Washington. endobj A national credit rating service has improved its opinion of WhidbeyHealths financial future. 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. <> What we know about this fault is that its ruptured may times in the pastit will happen again. Cover your head and neck with your arms to protect against falling debris. Since the last ice age, the southern Whidbey Island fault zone has probably spawned several highly destructive shallow earthquakes. This means that a tsunami made by an earthquake on the Cascadia subduction zone will start to impact the Washington coast in less than 15 minutes. Were working on pedestrian evacuation maps that show the best routes for pedestrians to take to evacuate, said Forson. Its certainly not to scare you. The Survey conducts and publishes geologic mapping to identify and characterize faults throughout the state. A special type of shallow fault, called a subduction zone or megathrust, occurs where an oceanic plate moves beneath a continental plate. 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." The last major earthquake was over 300 years ago. 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). Deep faults can occur where two tectonic plates collide and one of the plates is forced beneath the other. Contact Us, Whidbey Office One of these cracks appeared along the pathway around Green Lake. Until much more recently, no one really understood what it could do to a region of over 4 million people. Camano Island, WA 98282, Mailing Address Its significantly larger than the Seattle Fault, and South Whidbey could hand us a magnitude 7.5 earthquake. and the Red Cross will be there to care for them. He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. Floods. Electricity, water, natural gas, and phones may not work. Notable earthquakes in bold happened in Washington. In the month after the main earthquake there were about 60 M7 and M6 earthquakes. Earthquakes occur nearly every day in Washington. #4747 Blakely, R.J., Wells, R.E., and Weaver, C.S., 1999, Puget Sound aeromagnetic maps and data: U.S. Geological Survey Open-File Report 99-514. The friend obliged. Other types of seismic energy (S waves) also travel through the earth, but they move with a side-to-side (shearing) motion. These large underwater slides only occur during very large earthquakes and are one way to learn about earthquakes that happened thousands of years ago. 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 The Darrington-Devils Mountain fault zone is located in southern Skagit County and northern Snohomish County. The material becomes so weak that it behaves more like a liquid than a solid. The shaking can also cause landslides, surface ruptures, ground cracks, liquefaction, tsunamis, and seiches (standing waves). What makes these faults mega is that the amount of energy released is hundreds to thousands of times more than almost any other type of fault. 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. The moment magnitude scale is a type of logarithmic scale, where each increase of 1 means ~32 times more energy is released. The years have gone by. Hold on to any sturdy shelter until the shaking stops. Many universities and other organizations (such as Cascadia Region Earthquake Working Group and the Pacific Northwest Seismic Network) also work to understand active faults in Washington. Johnsons curiosity changed the course of his career. One model suggests it extends to about 30 miles east of Yakima. We pray for people of WA and our all north Americans as well. They knew something was there, said Sam Johnson, a retired USGS geologist who would follow up on their work. Learn about at-risk areas and become prepared. After the shaking stopped the sand regained its strength. On a brilliant November day, Sherrod took in the panorama from the parks bluff. Consider subscribing to our blog, Washington State Geology News, to receive notifications when new information is published. Learn how your comment data is processed. The southern Whidbey fault is unlike more visible faults on the West Coast. 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. Tsunami waves can travel over 500 miles per hour in the open ocean. Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. 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. Finding faults and knowing how often they rupture is one of the most important tasks to keep society safe from these hazards. A half dozen people reaching for the last can of soup, someone could lose their life over that. The buildings in this photo were built on soft materials that liquefied during the 1964 Niigata earthquake in Japan. The 2011 Tohoku earthquake in Japan occurred on this type of fault and released enough energy to slightly change the Earths axis of rotation. 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. A reverse fault occurs when two blocks are pushed together and one moves up and over the other. Tap/click on "gear icon" for options and settings. 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 average time between large earthquakes is about 535 years, but has been as little as 200 years, and more than 1,000 years. Standing becomes almost impossible as the jolts turn to rolling waves. The map also shows potentially active faults from a separate 2014 report (click here to download). The South Whidbey Island Fault is also dangerous. A lock () or https:// means youve safely connected to the .gov website. The map is from a 2007 report (click here to download) on seismic design categories in Washington. 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. 3 0 obj Everything points to one thing, Sherrod said, waving his hand across the inland sea. Brick chimneys cascade off rooftops. Radiocarbon dating and other paleoseismic methods have also confirmed this date. Geologists are constantly trying to better understand the faults in our state. 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). 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. Still think well avoid Gods wrath, its not going to happen regardless of what the multi millionaire TV preachers tell you. Scientists have also dated large underwater landslides and turbidites that travel from the continental edge far out into the ocean basin. ?7) and represents a potential seismic hazard to residents of the Puget Lowland. Although we cannot predict exactly when the next earthquake will happen, we can predict the general distribution of earthquake sizes. Here, were looking at one of the bigger faults in the region, he said. After large earthquakes there are usually many aftershock earthquakes. Oil companies descended in search of riches. The buildings sank when ground shaking weakened the underlying sediments. Power could be out for days. Even when an earthquake happens on a fault that doesnt reach the surface, the ground can still show signs of cracking. 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. A damaging earthquake is inevitable on this fault, but we do not know exactly when it will happen. Earthquakes on shallow faults typically last 20 to 60 seconds and the shaking is localized to the general area of the fault. Most injuries occur when people inside change rooms or try to leave the building. Areas like these are also susceptible to liquefaction. Large earthquakes are less common but can cause significant damage to the things we count on in everyday life, such as buildings, roads, bridges, dams, and utilities. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. It is not yet possible to predict when a fault will have an earthquake. District Court: (800) 946-9765, South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario. We just dont know when.. After the shaking stopped the sand regained its strength. Radiocarbon ages of macrofossils constrain uplift timing to 2.83.2 ka. Sometimes there may be a layer of volcanic ash or charcoal that has been deformed by the fault. Ready to retrofit? Because they can travel great distances, tsunamis generated from earthquakes across the ocean can still cause damage. Others, like the Seattle fault and southern Whidbey Island fault zone, cross under major cities and pose a significant hazard. A baristas hand hovers over the bean grinder. 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. The southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. This uplift creates a very broad wave called a tsunami. Johnson, on a whim, acquired the data that would prove its existence beyond a doubt. 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. The trench did expose faults, but it was not possible to conclusively demonstrate offset of Holocene units. In this photo, visitors to Green Lake Park near Seattle, Washington, have parked their bicycles as they look at the cracks made by the April 1949 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.