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. These combination faults are called oblique faults and include the Seattle fault, southern Whidbey Island fault zone, and DarringtonDevils Mountain fault zone. These sediments were laid down 20,000 to 60,000 years ago, before the last ice age. Photo from Pacific Northwest Seismic Network Seismo Blog. This fault produces some of the largest and most damaging earthquakes in the world (M9). In Seattle, the quake damaged buildings, weakened bridges, started fires and opened cracks in the earth. The April 1949 Tacoma earthquake measured 7.1 on the Richter Scale and caused damage from southern Oregon to British Columbia. And experts fear it could be even worse than The Big One.. Scientists are not sure how far east it goes. Larger crustal faults, such as the Seattle fault and southern Whidbey Island fault zone, can produce earthquakes up to magnitude 7.5. There are many other active faults in Washington and any of these could produce a large earthquake in the future. Kristin D. Morell 1 *, Christine Regalla 2, Lucinda J. Leonard 3, Colin Amos 4, Vic Levson 5. Evidence for Quaternary movement on the southern Whidbey Island fault includes (1) offset and disrupted upper Quaternary strata imaged on seismic-reflection profiles; (2) borehole data that suggests as much as 420 m of structural relief on the Tertiary-Quaternary boundary in the fault zone; (3) several meters of displacement along exposed faults in upper Quaternary sediments; (4) late Quaternary folds with limb dips of as much as ???9?? Earthquakes cause damage by moving and shaking the ground, sometimes for several minutes. %PDF-1.5 His team wanted to find the rate of sea level rise along the shore. Seconds later, its as if Whidbey Island is trapped in a cocktail shaker, lurching back and forth. The Mercalli Intensity scale is another historical way to measure the intensity of an earthquake. This new method allows geologists to see through trees and vegetation to find new faults. Lidar maps show the Earths surface without vegetation. " A lot of people are transplants, " Forson said. Liquefaction has caused significant damage during earthquakes in Washington. It can also make landslides that are much bigger than expected. The map is from a 2007 report (click here to download) on seismic design categories in Washington. But quiet period wont last, Strongest earthquake in 40 years rattle residents of Buffalo, NY, Is Istanbul next? An increase of 2 means that ~1,000 times more energy is released. Hover over a cluster of earthquakes to learn about the different types in the Pacific Northwest. Faults are features in the Earths crust where rock periodically breaks and moves, releasing seismic energy and creating an earthquake. Official websites use .gov This photo shows a fence that was offset about 8.5 feet during the 1906 Great San Francisco Earthquake on the San Andreas fault. Although we cannot predict exactly when the next earthquake will happen, we can predict the general distribution of earthquake sizes. This is similar to how sound is quieter when you move away from a speaker. At a downtown coffee shop, the mugs begin to chatter. The South Whidbey Island Fault is also dangerous. The 1949 earthquake near Tacoma triggered a landslide near the Tacoma Narrows that caused a local tsunami. It devastated the coast of the Pacific Northwest and sent an orphan tsunami to Japan. These faults and earthquakes usually occur at great depth (tens to hundreds of miles). 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. 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. A national credit rating service has improved its opinion of WhidbeyHealths financial future. Other types of seismic energy (S waves) also travel through the earth, but they move with a side-to-side (shearing) motion. Geologists have used the location of these shallow, intermediate, and deep earthquakes to learn about subduction zones throughout the world. That place is the Ocosta School. Higher risk areas are in orange and lower risk areas are in green. Whats up with the 50 US nuclear bombs stored at the Incirlik Air Base in Turkey, right on the same fault line California hasnt seen a catastrophic earthquake recently. The map is from a, This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. HomePrograms and ServicesGeologyGeologic Hazards. Another piece can be seen under the elevated lanes of northbound Interstate 5 in South Seattle not far from the Rainier brewery. Deep faults can occur where two tectonic plates collide and one of the plates is forced beneath the other. The crustal faults the Seattle Fault, the South Whidbey Island Fault, the Tacoma Fault those are less well known, said Forson. A baristas hand hovers over the bean grinder. 1 0 obj Still think well avoid Gods wrath, its not going to happen regardless of what the multi millionaire TV preachers tell you. Official websites use .gov 1 School of Earth and Ocean Sciences, University of Victoria, Victoria, British Columbia V8P 5C2, Canada 2 Department of Earth and Environment, Boston University, Boston, Massachusetts 02215, USA Know what to expect. Each of these aftershocks would be a significant earthquake if it happened on its own. Geologists do not yet know how often earthquakes happen on this fault. 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. Large and damaging earthquakes are inevitable in Washington, but no one knows exactly when they will happen. 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. Seismic waves travel at hundreds to thousands of miles per hour and quickly reach the surface where they are felt or measured. During the shaking liquefaction occurred, the sand lost its strength, and the car sunk. Sensitive seismographs located throughout the state, and all over the world, measure this seismic energy. Maps. The bluff, where the cabins now sit, could have jutted up in the most recent Whidbey fault quake, Sherrod said. Photo courtesy of MOHAI (neg. There are also many faults that have not been studied enough to know if they are active. A drill rig left of the blockade is collecting data about the failure. Reverse faults are usually steep and occur in regions of compression. 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." Washington, Seattle, WA 98195 2 U.S. Geological Survey, 345 Middlefield Road, M/S . Sherrod remembers his son, age 5 at the time, playing with toy trucks on the mossy banks of the marsh while the scientists worked. Faults can also occur within a tectonic plate when the plate itself is deforming. The 1964 M9.2 Alaska earthquake created a large tsunami from the fault rupture, and many smaller tsunamis from on-land and underwater landslides. For example, in the open ocean a tsunami may be less than a few feet tall. This earthquake caused parts of Restoration Point near on Bainbridge Island to be lifted 35 feet straight up. 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. Oblique convergence and clockwise rotation along the continental margin are the inferred driving forces for ongoing deformation. Each year we map additional areas and learn more about existing faults and (or) discover new ones. 4 0 obj When this happens, even a very small slope can cause the ground to slide. 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. It is mandatory to procure user consent prior to running these cookies on your website. In places where there is little vegetation, different rock types and faults can be found with relative ease. In fact, until the 1980s, no one knew SWIF existed. If you are in bed: STAY there and COVER your head and neck with a pillow. Other faults are inactive and are left over from much older periods of deformation. Do you live or work near an area that could have liquefaction? It is capable of generating severe earthquakes that would impact the entire west coast. The Cascadia subduction zone last ruptured over 300 years ago on January 26, 1700. Fault Activity Map of California. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. Hold on to any sturdy shelter until the shaking stops. The below map shows that Seattle and its surroundings is constantly being rattled by small earthquakes and tremors. The last major earthquake was over 300 years ago. Some faults reach the surface and can be found by geologists. Liquefaction is when wet soil or sediment loses strength because it is being shaken during an earthquake. 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. Buildings could sustain extensive damage. Others, like the Seattle fault and southern Whidbey Island fault zone, cross under major cities and pose a significant hazard. Radiocarbon ages of macrofossils constrain uplift timing to 2.83.2 ka. A paleoseismologist will look for surface ruptures along faults and may use carbon-14 dating to learn when the rupture happened. Despite its location well offshore, a Cascadia quake would likely kill at least 10,000 and injure more than 30,000 in Washington, Murphy found. On an inactive fault, the sea would have risen at the same rate at both locations. Throughout the world shallow earthquakes generally refer to earthquakes that are less than ~45 miles deep. Contact Us, Whidbey Office For example, a building on soft soil will experience more shaking than the same building on bedrock. The Geologic Information Portal has a Natural Hazards theme that shows active faults and earthquakes. An earthquake along the southern Whidbey Island fault reshaped the land some 2,700 years ago. An official website of the United States government. 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). Shallow faults produce earthquakes in the upper 18 miles (30 kilometers) of the Earths crust. Many low-lying areas have wet soil or sediment beneath them that could liquefy during earthquakes. People stagger into the streets to avoid an avalanche of debris. Why is Strange Sounds focusing so much on disaster preps? Photo by G.K. Gilbert, from the Steinbrugge Collection of the UC Berkeley Earthquake Engineering Research Center. In 1985, with little concrete evidence of its existence, the pair included the possible fault on a geologic map published by the USGS. An earthquake occurs when rock inside the Earth moves or breaks. Part 2 will be full Martial Law and mandatory vaccines? Geologic maps show the types and ages of rocks and younger deposits that are found at or near the Earth's surface. Areas like these are also susceptible to liquefaction. Prepare to be on your own for at least three days. Scientists are not sure how far east it goes. 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. 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. One of the most important new technologies for finding faults (and landslides too) is called lidar. Even if the earthquake is too small to be felt by people, seismographs can detect it. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. Johnson and others . and the Red Cross will be there to care for them. On a brilliant November day, Sherrod took in the panorama from the parks bluff. The buildings sank when ground shaking weakened the underlying sediments. (1999 . 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. Image from the, Aquatic Lands Habitat Restoration Program, South Lake Washington Restoration Project, Scientific and Technical Support to Aquatic Programs, Washington Geologic Survey Publications Catalog, Washington Geologic Survey Photograph Collection, Wetlands of High Conservation Value Map Viewer, Timber Sale Remaining Volume by Purchaser Reports, Spanish - Brocha, Salal y Otros Productos Forestales, Complete: Baker to Bellingham Non-Motorized Recreation Plan, Community Wildfire Resilience and Preparedness, Utility Wildland Fire Prevention Advisory Committee, Blanchard, Reiter, Walker Valley and Nearby Islands, Teanaway Community Forest Advisory Committee, Teanaway Community Forest Advisory Committee Past Meetings, Faults and Earthquakes in Washington State, Pacific Northwest Seismic Network Seismo Blog, https://buildingfailures.files.wordpress.com/2014/02/tiltedbuilding.jpg, Pacific Geoscience Center of the Natural Resources of Canada. This northwest-trending fault comprises a broad (as wide as 6-11 km), steep, northeast-dipping zone that includes several splays with inferred strike-slip, reverse, and thrust displacement. Later movement on this long-term active fault zone cut the volcano. Washington has dozens of active faults and fault zones. Notable earthquakes in bold happened in Washington. A few miles southeast across the white-capped waves of Admiralty Bay, Lake Hancock rises and falls with the tides. Necessary cookies are absolutely essential for the website to function properly. Across the northern portion of Bainbridge Island, light radar or lidar images taken from airplanes clearly show the Seattle Fault running right on the surface. In the area of North Bend, the fault zone is 4 miles wide and consists of a series of parallel faults. Mudslides. 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. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. 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. Emergency planners all had a simple message: Its not IF a disaster will happen, its WHEN. Hundreds could die, with thousands more injured. Tsunami waves can travel over 500 miles per hour in the open ocean. of Earth and Space Sciences, Box 351310, Univ. Many faults have not been studied enough to know if they are active. The southern Whidbey Island fault (SWIF) stretches from the vicinity of Victoria, B.C., across Puget Sound as far as the Cascade Range. This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. Finding and learning about faults requires many different aspects of geology and geophysics. This can cause landslides to occur where they wouldnt normally happen. Each type has different kinds of earthquakes. In the early 2000s, USGS scientists including Brian Sherrod set out to further Johnsons work and better understand the slumbering fissure. Tsunamis are a common result of large earthquakes in Washington. A pair of scientists with the U.S. Geological Survey first theorized that a fissure between two major blocks of the earths crust might run through this slice of Puget Sound. For example, the Cascadia subduction zone has had between 15 to 19 earthquakes over the past 10,000 years. Were working on pedestrian evacuation maps that show the best routes for pedestrians to take to evacuate, said Forson. The next earthquake is inevitable, but the variability makes it difficult to know exactly when. The ground shaking from these earthquakes can last for several minutes. A low-angle fault, which is not conclusively earthquake related, separates a diamicton from the overlying recessional outwash deposit. There must be tsunami deposits of the same age along much of the Oregon and Washington coast in order to qualify as an earthquake. Until much more recently, no one really understood what it could do to a region of over 4 million people. 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. 2 0 obj These types of faults are common, but usually small. Bending of the fault and transpressional deformation began during the late middle Eocene and continues to the present. Excavations across several LiDAR scarps show evidence for multiple post-glacial folding and faulting event on faults with reverse oblique sense of slip. This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. endobj In the month after the main earthquake there were about 60 M7 and M6 earthquakes. In some areas getting up a hill to higher ground will be difficult. You also have the option to opt-out of these cookies. Coupeville, WA 98239, Camano Office Expect and help to extinguish fires. So they dont necessarily know the threats they face.. Armentrout, J. J. Miller, C. Finn, C. S. Weaver. Stories from tribes near Seattle have also helped us to learn that the last earthquake on the Seattle fault was about AD 900950. Each of the earthquakes listed on the bottom of the screen is capable of significant damage. If they know theres data available that could help them in any way, they want to get it. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. The shaking can damage or destroy buildings and other infrastructure. Small talk stops. The study of seismic waves is called seismology and has allowed scientists to learn much about the internal structure of the Earth. ; (5) large-scale liquefaction features in upper Quaternary sediments within the fault zone; and (6) minor historical seismicity.