STAY THERE until the shaking stops. You just need one person to crash or a power line to fall over the road, and the roads are unusable.. You have entered an incorrect email address! Graphic from IRIS. Stay away from glass, windows, outside doors and walls, and anything that could fall down. The crustal faults the Seattle Fault, the South Whidbey Island Fault, the Tacoma Fault those are less well known, said Forson. Maps. Sherrod remembers his son, age 5 at the time, playing with toy trucks on the mossy banks of the marsh while the scientists worked. Audio; Before and After Images; Images; Slideshows; Stereograms; Videos; Webcams; . Its significantly larger than the Seattle Fault, and South Whidbey could hand us a magnitude 7.5 earthquake. Electricity, water, natural gas, and phones may not work. 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. Although we cannot predict exactly when the next earthquake will happen, we can predict the general distribution of earthquake sizes. Like other faults, when enough stress builds up, the megathrust will rupture. One of the best views of SWIF should be from Grand Avenue Park in Everett. But they didnt document it hardly at all.. The Geologic Information Portal has a Natural Hazards theme that shows active faults and earthquakes. (360) 678-5111 Official websites use .gov #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. A national credit rating service has improved its opinion of WhidbeyHealths financial future. In much of Washington, dense vegetation covers the land and makes finding faults very difficult. View of the Sunset Lake liquefaction failure about three weeks after the earthquake. Faults often occur at and near the boundary of large tectonic plates because the plates are moving in different directions. The map is from a 2007 report (click here to download) on seismic design categories in Washington. Finding nothing of serious monetary value, the companies abandoned reams of information they had gathered through seismic surveys. Photo by G.K. Gilbert, from the Steinbrugge Collection of the UC Berkeley Earthquake Engineering Research Center. But the mapping offered geological clues that the newly found fault was indeed capable of future quakes. And being ready means being able to support yourself, your loved ones, your neighborhood for 2 weeks. Tsunamis and seiches can also be triggered by large slides, both on land and underwater. The southern Whidbey Island fault should be considered capable of generating large earthquakes (Ms ?? This fault produces some of the largest and most damaging earthquakes in the world (M9). Excavations across several LiDAR scarps show evidence for multiple post-glacial folding and faulting event on faults with reverse oblique sense of slip. 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. Moving inland, the Seattle Fault is capable of a magnitude 7. 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. Ground shaking is a hazard near the epicenter of an earthquake and also in areas far from the earthquake where amplification occurs. This is a very good example of a strike-slip fault. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). Know what to expect. This date was confirmed by records in Japan of an orphan tsunami and by many lines of geologic evidence. 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. A major southern Whidbey quake, on the other hand, could kill and injure many more, according to Murphy. Although we know much about active faults and earthquakes, there is much more to learn. In some areas getting up a hill to higher ground will be difficult. We do not encourage people to evacuate in vehicles. The marshy deposits are about a meter higher at Lake Hancock. Click the "Seismogenic Features" button in the Map Contents window to display faults and earthquakes. Secure .gov websites use HTTPS Prepare to be on your own for at least three days. 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. In the Puget Sound region, it takes a trained eye to recognize rocky outcrops and subtly raised ground as evidence of a fault. Landslide at Salmon Beach was triggered by the 1949 Tacoma earthquake and caused a tsunami. (1999 . This evidence can come from finding something younger than 12,000 years that has been deformed or moved by the fault. Photo courtesy of MOHAI (neg. Westport currently is the only location with a vertical evacuation structure designed for a tsunami. It can also make landslides that are much bigger than expected. 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. 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. Seconds later, its as if Whidbey Island is trapped in a cocktail shaker, lurching back and forth. Unlike The Big One, scientists who have studied the southern Whidbey fault have far less understanding of when the next sudden shift might hit. These include the: Southern Whidbey Island Fault (SWIF) Seattle Fault Devils Mountain Fault Strawberry Point fault Utsalady Point fault The map also shows potentially active faults from a separate 2014 report (click here to download). Most injuries occur when people inside change rooms or try to leave the building. 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. The southern Whidbey Island fault (SWIF) stretches from the vicinity of Victoria, B.C., across Puget Sound as far as the Cascade Range. Standing becomes almost impossible as the jolts turn to rolling waves. Gower (1980 #6229) showed and named the "southern Whidbey Island fault," and Gower and others (1985 #4725) showed this fault on their seismotectonic map of the Puget Sound region and briefly outlined its geologic relationships. Hover over a cluster of earthquakes to learn about the different types in the Pacific Northwest. Though it was not directly related to Johnsons work, he asked a friend working for Mobil Oil to pass along the information. Because they rupture at such great depth, their seismic energy is distributed over a large area. There are also many faults that have not been studied enough to know if they are active. 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. Many faults have not been studied enough to know if they are active. This scenario was modeled on the part of the SWIF from Woodinville to just west of Whidbey Island. Radiocarbon ages of macrofossils constrain uplift timing to 2.83.2 ka. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. A strike-slip fault occurs when two blocks move past each other. Because Japan was so well prepared, mostretrofitted buildingsoutside of the tsunami zone survived. The southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. South Whidbey Island Fault Zone. 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. 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. Consider a magnitude 7.4 quake with Whidbey Island at or near the epicenter. Scientists have also dated large underwater landslides and turbidites that travel from the continental edge far out into the ocean basin. 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. This movement happens because stress builds up as tectonic plates move. 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. Then consider that the Seattle Fault is a complex of faults with various branches that run at or just below the surface. As of January 12, 2017, the USGS maintains a limited number of metadata fields that characterize the Quaternary faults and folds of the United States. People stagger into the streets to avoid an avalanche of debris. What are the most dangerous fault lines for Seattle? This category only includes cookies that ensures basic functionalities and security features of the website. <> The threat to Puget Sound from a quake along the Cascadia Subduction Zone, off the coast of Washington, Oregon and California, is well documented. Earthquakes occur nearly every day in Washington. 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. It is a qualitative scale that ranges from IXI (1-11) and measures the amount of damage caused by an event. The strength of ground shaking (called strong motion by seismologists) usually decreases with distance from the earthquake source. 121 N East Camano Dr We just dont know when.. Experts have warned that UK outbreak may be around two weeks behind Italys. They didnt recognize the significance of what they found. The Survey works to increase public and scientific understanding of fault and earthquake hazards in our state. At a downtown coffee shop, the mugs begin to chatter. Photo from, Liquefaction can be a big problem. The Seattle Fault is also likely to create a tsunami that would inundate Harbor Island and much of SODO, Interbay, and the waterfront. These faults and earthquakes usually occur at great depth (tens to hundreds of miles). The last time was 1,000 years ago between 900 and 903 A.D., said Forson. Once the shaking has stopped, exit the building if it is safe to do so. Story telling is an important part of the Native tradition and is how their history is passed down to the next generation. Faults can be grouped based on their relative movement into three types. This part of the Japanese coast had not seen this type of seismic rupture in some 800 years, and what failed was that walls built to keep tsunami waves were not high enough. This means that a large area feels the shaking, but the intensity is less than a similar shallow earthquake. Since the last ice age, the southern Whidbey Island fault zone has probably spawned several highly destructive shallow earthquakes. This is called liquefaction and is discussed in the next section. PO Box 5000 The more you know what to expect, the better prepared you will be to help yourself, your family, and others around you. We use the term deep to talk about faults and earthquakes deeper than about 18 miles. This map is from a 2007 report on the seismic design categories in Washington. Even if the earthquake is too small to be felt by people, seismographs can detect it. These and other problems led to the search for a scale that was based on the physical processes that happen during an earthquake. Each year we map additional areas and learn more about existing faults and (or) discover new ones. Stay inside until the shaking stops and it is safe to go outside. Its a natural curiosity.. One or possibly two of the unconformities are interpreted as event horizons. It startled Johnson that such massive faults had gone undetected for so long. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. Learning earthquake faults around where we live is a first good way to prepare the next devastating earthquake. There are also tsunami evacuation signs on the highways. Why is Strange Sounds focusing so much on disaster preps? By sampling sediment from the marsh to the beach berm, Sherrod and his research partner, Harvey Kelsey, developed a timeline of the oceans climb. 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). We do know that it is active and will likely produce a large M67.5 earthquake when it next ruptures. and the Red Cross will be there to care for them. In the Pacific Northwest we use the term shallow to talk about faults and earthquakes less than 18 miles deep. Johnson and others (1996 #4751) described the structure and stratigraphy of the southern Whidbey Island fault zone. The faults length depends on whom you ask, Sherrod said. 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). Seismologists estimate that such quakes and tsunami waves occur roughly every 500 years on average on the Cascadia Subduction Zone. If they know theres data available that could help them in any way, they want to get it. Official websites use .gov 3 0 obj The most important thing you can do before the next earthquake is to prepare. Never use a lighter or match near damaged areas. This map shows different seismic design categories that correlate with amount of seismic risk. For example, a M7 earthquake releases 32 times more energy than a M6 earthquake, and 1,000 times more than a M5 earthquake. The Pacific Tsunami Warning Center is located in Hawaii and is responsible for issuing alerts to all the countries that border the Pacific Ocean.
Kinchen Funeral Home Obituaries,
Houses For Rent No Credit Check Temple, Tx,
Articles S