southern whidbey island fault map

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. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). That place is the Ocosta School. 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. The SWIF has been assessed by the USGS as capable of generating the largest crustal earthquake in Puget Sound. Earthquakes can trigger landslides and tsunamis which can happen after the main event. The ground shaking from these earthquakes can last for several minutes. Black lines show the South Whidbey Island Fault Zone, the Seattle Fault Zone and the Tacoma Fault Zone. Aftershocks can be nearly as large as the main earthquake and can cause significant additional damage. View of the Sunset Lake liquefaction failure about three weeks after the earthquake. Sherrod says practically every place they. (360) 678-5111 document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. Under a scenario played out in a 2019 U.S. Department of Homeland Security study, state-maintained bridges would be severely damaged, leaving them unusable for months or years. 1 NE 7th Street Throughout the world shallow earthquakes generally refer to earthquakes that are less than ~45 miles deep. The fault probably originated during the early Eocene as a dextral strike-slip fault along the eastern side of a continental-margin rift. Here, were looking at one of the bigger faults in the region, he said. Later movement on this long-term active fault zone cut the volcano. In Washington, we do not have tsunami walls. This was a problem because no two locations would agree on the size of the same earthquake. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. Most of the populated areas of the state have a 4080% chance of having an earthquake in the next 50 years. The 2011 Tohoku earthquake in Japan occurred on this type of fault and released enough energy to slightly change the Earths axis of rotation. Restoring tap water to some homes could take over a year. We do not encourage people to evacuate in vehicles. This is a hypothetical scenario created by Mark Murphy of the Snohomish County Department of Emergency Management. Third, the South Whidbey Island Fault running from northwest to southeast of the southern tip of the island. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. Even places that are far from active faults are still at risk during a large Cascadia subduction zone earthquake. In the area of North Bend, the fault zone is 4 miles wide and consists of a series of parallel faults. 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. 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. Not all faults are active. One model suggests it extends to about 30 miles east of Yakima. 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. 2 0 obj This kind of grouping gives us information about how common earthquakes might be and how large an area may be affected. Avoid stopping near or under buildings, trees, overpasses, or utility wires. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. But Forson says you also need to know what to do when the shaking happens. These sediments were laid down 20,000 to 60,000 years ago, before the last ice age. Once we got it, we were sort of shocked to see these big faults in the Puget lowlands, he said. Contact Us, Whidbey Office USA Earthquake Hazard Map. On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. 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. Finding faults and knowing how often they rupture is one of the most important tasks to keep society safe from these hazards. This northwest-trending fault zone extends more than 65 km across Possession Sound, southern Whidbey Island, Admiralty Inlet into the eastern Strait of Juan de Fuca. Unlike The Big One, scientists who have studied the southern Whidbey fault have far less understanding of when the next sudden shift might hit. Scientists are not sure how far east it goes. One model suggests it extends to about 30 miles east of Yakima. Reverse faults are usually steep and occur in regions of compression. The San Andreas fault in California is a good example of a very active 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. If they know theres data available that could help them in any way, they want to get it. Because Japan was so well prepared, mostretrofitted buildingsoutside of the tsunami zone survived. Secure .gov websites use HTTPS Another big one is expected, and it could be devastating. Depending on the type of fault, the ground can move laterally, vertically, or a combination of both. Part 2 will be full Martial Law and mandatory vaccines? 121 N East Camano Dr <> There are many other active faults in Washington and any of these could produce a large earthquake in the future. Sherrod remembers his son, age 5 at the time, playing with toy trucks on the mossy banks of the marsh while the scientists worked. California Department of Conservation. 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. Why is Strange Sounds focusing so much on disaster preps? A damaging earthquake is inevitable on this fault, but we do not know exactly when it will happen. The term active can have different meanings. Doorways do not provide protection from falling or flying objects and you may not be able to remain standing. However, seismic tomography studies (Brocher and others, 2001 #4718) reveal that only the northwestern end of the fault zone in the southeastern Strait of Juan de Fuca is associated with a strong velocity contrast. The Moment Magnitude Scale (M) measures the total amount of seismic energy (known as moment to engineers and seismologists) released by an earthquake. Click the "Seismogenic Features" button in the Map Contents window to display faults and earthquakes. One model suggests it extends to about 30 miles east of Yakima. Buildings could sustain extensive damage. Most faults in Washington are a mix of a strike-slip fault and a thrust or reverse fault. Liquefaction can be a big problem. Mudslides. We do know that it is active and will likely produce a large M67.5 earthquake when it next ruptures. The map is from a 2007 report (click here to download) on seismic design categories in Washington. Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. The evidence shows each lake rests on different free-floating jigsaw pieces of planetary crust, separated by the southern Whidbey Island fault. It is mandatory to procure user consent prior to running these cookies on your website. Photo by G.K. Gilbert, from the Steinbrugge Collection of the UC Berkeley Earthquake Engineering Research Center. It forms the northern boundary of the Everett basin and lies along a series of high-amplitude aeromagnetic anomalies that extend from the Cascade Mountains to Vancouver Island, B.C. In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. During site visits in 2005, Sherrods team found evidence of four SWIF earthquakes in the past 30,000 years. These maps are created by small planes that use a specific type of laser to measure the elevation of the ground. We also use third-party cookies that help us analyze and understand how you use this website. At a downtown coffee shop, the mugs begin to chatter. Most faults are considered active if they have evidence for movement (this includes earthquakes) within the past 12,000 years (the Holocene time period). These include the: Southern Whidbey Island Fault (SWIF) Seattle Fault Devils Mountain Fault Strawberry Point fault Utsalady Point fault Please visit our Geologic Information Portal and Geologic Hazard Maps page for the most up-to-date listing of all of our hazard maps. Then consider that the Seattle Fault is a complex of faults with various branches that run at or just below the surface. Finding and learning about faults requires many different aspects of geology and geophysics. Sensitive seismographs located throughout the state, and all over the world, measure this seismic energy. 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. Faults often occur at and near the boundary of large tectonic plates because the plates are moving in different directions. The southern Whidbey Island fault (SWIF) stretches from the vicinity of Victoria, B.C., across Puget Sound as far as the Cascade Range. Landslides can be caused by strong ground shaking during an earthquake. Learn about at-risk areas and become prepared. Small talk stops. Stay away from glass, windows, outside doors and walls, and anything that could fall down. A strike-slip fault occurs when two blocks move past each other. Read more below to learn about how and where earthquakes occur, what to do before, during, and after an earthquake, and what scientists are doing to learn more about them. When the ground shakes during an earthquake, it moves up and down, acting like additional gravity. The buildings sank when ground shaking weakened the underlying sediments. The DNR team found that the Seattle fault is intercepted by the southern Whidbey Island fault zone in the vicinity of Fall City. 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. Emergency planners all had a simple message: Its not IF a disaster will happen, its WHEN. Seconds later, its as if Whidbey Island is trapped in a cocktail shaker, lurching back and forth. Some faults reach the surface and can be found by geologists. Once in the open, Drop, Cover, and Hold On. Johnsons curiosity changed the course of his career. America is going to be punished just like the rest of the world. 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. This map shows different seismic design categories that correlate with amount of seismic risk. <>>> An earthquake along the southern Whidbey Island fault reshaped the land some 2,700 years ago. This photo shows a fence that was offset about 8.5 feet during the 1906 Great San Francisco Earthquake on the San Andreas fault. Along the coast residents may have between 20 and 30 minutes to get to higher ground. 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. Learn how your comment data is processed. Along the water at Cama Beach State Park, cabins on a bluff overlook Saratoga Passage, facing the general direction of Lake Hancock on Whidbey Island. 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. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. The Straight Creek fault in the Cascade Range is an example of this kind of fault and has ~5060 miles of movement across it. The Flying Squirrel and Mountain Beaver trenches cross the Cottage Lake lineament. These large underwater slides only occur during very large earthquakes and are one way to learn about earthquakes that happened thousands of years ago. 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. Strabge sounds very good report thanks a lot. Though it was not directly related to Johnsons work, he asked a friend working for Mobil Oil to pass along the information. Seismic waves travel at hundreds to thousands of miles per hour and quickly reach the surface where they are felt or measured. This map of gravity residuals measured over the puget lowland reveals a pattern of deep, fault bounded basins (cool colors) and uplifts (warm colors). It may not be possible to find water, fuel, or food until services are restored days or even weeks after the event. 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. For example, it is unlikely that you will be able to use electricity, cell phones, or the internet. Watch the video below to learn how you can be ready for the next earthquake. An official website of the United States government. Do you know what to do if there is an earthquake? They knew something was there, said Sam Johnson, a retired USGS geologist who would follow up on their work. A 2014 map shows what we know about the age of faults in Washington. On a brilliant November day, Sherrod took in the panorama from the parks bluff. You also have the option to opt-out of these cookies. 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 . Many faults have not been studied enough to know if they are active. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. In some areas getting up a hill to higher ground will be difficult. What are the most dangerous fault lines for Seattle? STAY THERE until the shaking stops. Both of these things can cause equal or greater damage than the actual earthquake. There must be tsunami deposits of the same age along much of the Oregon and Washington coast in order to qualify as an earthquake. 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. Many landslide-prone areas of Washington are also located near active faults. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Ground shaking is a hazard near the epicenter of an earthquake and also in areas far from the earthquake where amplification occurs. Beef Barley and French Onion trenches cross the Little Bear Creek lineament. It startled Johnson that such massive faults had gone undetected for so long. Sometimes there may be a layer of volcanic ash or charcoal that has been deformed by the fault. Bookcases and china cabinets topple, trapping people beneath. Drop, Cover, and Hold On whenever you feel shaking. Deep faults can occur where two tectonic plates collide and one of the plates is forced beneath the other. HomePrograms and ServicesGeologyGeologic Hazards. They havent dug up enough history to estimate. The risk is complicated, but there are millions of people who live in the Seattle area, said Forson. 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. 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. Scientists have also dated large underwater landslides and turbidites that travel from the continental edge far out into the ocean basin. But opting out of some of these cookies may affect your browsing experience. Because they rupture at such great depth, their seismic energy is distributed over a large area. Below you will find links to view and download hazard maps created for each jurisdiction included in the current mitigation planning process. Higher risk areas are in orange and lower risk areas are in green. Sherrod shrugged his shoulders. Photo courtesy of National Center for Tsunami Research, NOAA. The shaking can damage or destroy buildings and other infrastructure. 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. Most damage and loss of life in earthquakes is a result of ground shaking. 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. The Safe America Foundation suggests texting as a way of communication. Areas like these are also susceptible to liquefaction. A national credit rating service has improved its opinion of WhidbeyHealths financial future. 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. Devastating wind storms. In fact, until the 1980s, no one knew SWIF existed. 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 By Human Capital March 19, 2019. sw_whidbeyfault_rev122706.pdf (28.68 KB) 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. They didnt recognize the significance of what they found. 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. You can look at different geological hazard mapson the website of the Department of Natural Resources. Other types of seismic energy (S waves) also travel through the earth, but they move with a side-to-side (shearing) motion. A major southern Whidbey quake, on the other hand, could kill and injure many more, according to Murphy. @\;L;=}%FC*l $@ 4x: 888O~xrsxx'/*rGRF\gI%~x(G-^-hjjq kx/V ou0hyegy0;ei`Tx&ilZ )TmZ$vb,`bQm|DR5x/ Other faults may lie entirely underground, or could be covered by vegetation and (or) sediment. The shaking usually lasts less than a minute and doesnt generally cause a tsunami or have many aftershocks. These types of faults are common, but usually small. A magnitude 7.4 along the southern Whidbey fault would rattle 18 counties in Washington, according to a federal projection . 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). The fault, not so much. Earthquakes can be measured in many ways, but the most accepted method is called moment magnitude. Consider subscribing to our blog, Washington State Geology News, to receive notifications when new information is published. This means that when the Seattle fault ruptures the south side of the fault moves up relative to the north side. endobj Sherrods son has since completed graduate school in applied geosciences. The Survey works to increase public and scientific understanding of fault and earthquake hazards in our state. 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 Within minutes, he spotted something groundbreaking. Radiocarbon ages of macrofossils constrain uplift timing to 2.83.2 ka. 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. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Johnson et al. The shaking can also cause landslides, surface ruptures, ground cracks, liquefaction, tsunamis, and seiches (standing waves). A paleoseismologist will look for surface ruptures along faults and may use carbon-14 dating to learn when the rupture happened. Recent geologic mapping by Washington State Department of Natural Resources (DNR) geologists reveals that this major fault zone extends through the Snoqualmie River valley in the vicinity of Carnation, Fall City, and North Bend. 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. Maps. 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. But it didnt. Although we cannot predict exactly when the next earthquake will happen, we can predict the general distribution of earthquake sizes. After the earthquake, many things you count on may not be available. An earthquake occurs when rock inside the Earth moves or breaks. The biggest one is called the South Whidbey Island fault, and it's thought to run from Victoria, B.C., through Woodinville and possibly beyond. Tohoku killed nearly 16,000 people; most died as a result of drowning or being crushed in the tsunami. While the intensity of this seismic event has now decreased, a big earthquake is overdue in the region. In the late 1960s, speculators considered the Puget Sound region a frontier for petroleum exploration. However, we can learn which faults are active and which are inactive. This uplift creates a very broad wave called a tsunami. . Like other faults, when enough stress builds up, the megathrust will rupture. A special type of shallow fault, called a subduction zone or megathrust, occurs where an oceanic plate moves beneath a continental plate. Liquefaction has caused significant damage during earthquakes in Washington. Expect aftershocks. Photo courtesy of MOHAI (neg. Over time, fault movement has created some interesting geologic features. Tsunamis are a common result of large earthquakes in Washington. Earthquakes occur nearly every day in Washington. 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 This is similar to how sound is quieter when you move away from a speaker. Unlike sound, ground shaking can be amplified or attenuated (made less) depending on the type of material at the Earths surface. This date was confirmed by records in Japan of an orphan tsunami and by many lines of geologic evidence. Its a natural curiosity.. Also, very large earthquakes were difficult to measure accurately. In effect, the wave energy is trapped by the edges of the body of water. That could spell trouble not only for its namesake island but for south and north King County and further west. It will happen; we dont know when.. The moment magnitude scale replaced the Richter scale in the late 1970s. And what were looking at is water.. The Seattle fault last ruptured about 1,100 years ago in AD 900950. In much of Washington, dense vegetation covers the land and makes finding faults very difficult. By sampling sediment from the marsh to the beach berm, Sherrod and his research partner, Harvey Kelsey, developed a timeline of the oceans climb. 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. The South Whidbey Island Fault is also dangerous. 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 .