Proceed cautiously once the earthquake has stopped. Map by And while scientists keep digging for more information and more situational awareness of what we face, the other problem is human. 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. Earthquakes occur nearly every day in Washington. Strabge sounds very good report thanks a lot. When a fault with vertical movement ruptures the ocean floor, it lifts up part of the ocean. 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 . #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 low-angle fault, which is not conclusively earthquake related, separates a diamicton from the overlying recessional outwash deposit. The tsunamis can travel far inland and deposit layers of sand and organic material. 121 N East Camano Dr The fault's length depends on whom you ask, Sherrod said. You just need one person to crash or a power line to fall over the road, and the roads are unusable.. Geologists at the Survey spend time mapping the geology of the state, looking for faults, folds, landslides, and different rock types. The coast is now the home of one of the states largest network of warning sirens called All Hazard Alert Broadcast (AHABs). PDF Seismic Characterization of the Seattle and Southern Whidbey Island Scientists are not sure how far east it goes. District Court: (800) 946-9765, South Whidbey Island Fault (SWIF) M7.4 Earthquake Scenario. The largest active fault that will affect Washington (and the whole Pacific Northwest) is the Cascadia subduction zone. Surface Geology | WA - DNR This scenario was modeled on the part of the SWIF from Woodinville to just west of Whidbey Island. . On Dec. 15th, a small swarm even hit near Bremerton, a few miles away from downtown. This kind of grouping gives us information about how common earthquakes might be and how large an area may be affected. This might include flammable appliances like a water heater, tall items like book cases, or heavy pictures. Ground shaking is a hazard near the epicenter of an earthquake and also in areas far from the earthquake where amplification occurs. Even places that are far from active faults are still at risk during a large Cascadia subduction zone earthquake. If you are in bed: STAY there and COVER your head and neck with a pillow. 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. Landslide at Salmon Beach was triggered by the 1949 Tacoma earthquake and caused a tsunami. 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. These large underwater slides only occur during very large earthquakes and are one way to learn about earthquakes that happened thousands of years ago. These faults and earthquakes occur in oceanic crust as it is subducted beneath the continent. These quakes are capable of magnitudes from 7 to over 9. It usually also means that there are earthquakes (even small ones) on the fault. It is capable of generating severe earthquakes that would impact the entire west coast. When earthquakes occur on faults that reach the Earths surface, the ground may rupture. Armentrout, J. J. Miller, C. Finn, C. S. Weaver. Finding and learning about faults requires many different aspects of geology and geophysics. Clicking on the map will download the publication. The process of breaking and moving rock releases a large amount of energy that travels through the Earth as seismic waves. Never use a lighter or match near damaged areas. These sediments were laid down 20,000 to 60,000 years ago, before the last ice age. Scientists are not sure how far east it goes. Earthquakes on faults like these may cause tsunamis in the Puget Sound region. 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. 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 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. The Flying Squirrel and Mountain Beaver trenches cross the Cottage Lake lineament. 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. There are also tsunami evacuation signs on the highways. During site visits in 2005, Sherrods team found evidence of four SWIF earthquakes in the past 30,000 years. A .gov website belongs to an official government organization in the United States. The evidence shows each lake rests on different free-floating jigsaw pieces of planetary crust, separated by the southern Whidbey Island fault. For example, it is unlikely that you will be able to use electricity, cell phones, or the internet. Its just the way scientists work, he said. Then consider that the Seattle Fault is a complex of faults with various branches that run at or just below the surface. 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. The Seattle fault last ruptured about 1,100 years ago in AD 900950. Another piece can be seen under the elevated lanes of northbound Interstate 5 in South Seattle not far from the Rainier brewery. 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. 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. This website uses cookies to improve your experience while you navigate through the website. For some active faults, such as the Seattle fault or Cascadia subduction zone, we can also learn how often large earthquakes have happened in the past. The San Andreas fault in California is a good example of a very active strike-slip fault. After the shaking stopped the sand regained its strength. This map of Puget Sound shows the location of the methane plumes (yellow and white circles) detected along the ship's path (purple). For more information about earthquakes, faults, and emergency preparation, consider visiting the following sites: This map shows areas of seismic risk from high (red) to low (grayish-green). The term active can have different meanings. Radiocarbon dating and other paleoseismic methods have also confirmed this date. Tsunami waves can travel over 500 miles per hour in the open ocean. This car was parked on sand during the 2011 earthquake in Christchurch, New Zealand. Others, like the Seattle fault and southern Whidbey Island fault zone, cross under major cities and pose a significant hazard. 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. By finding the age of the deformed layer, a paleoseismologist can determine the minimum age of the fault. Washington has the second highest risk in the U.S. of these large and damaging earthquakes because of its geologic setting. But the mapping offered geological clues that the newly found fault was indeed capable of future quakes. Around Puget Sound, it seems everyone knows about The Big One, the potential magnitude 9.0 Cascadia Subduction Zone megaquake some scientists say is due any day. The bluff, where the cabins now sit, could have jutted up in the most recent Whidbey fault quake, Sherrod said. Dishes jitter off tables, shattering on the floor. The faults length depends on whom you ask, Sherrod said. We use the term deep to talk about faults and earthquakes deeper than about 18 miles. When the landslide hit the water it may have created a tsunami. The buildings in this photo were built on soft materials that liquefied during the 1964 Niigata earthquake in Japan. When an earthquake happens there will not be time to google what you are supposed to do. These and other problems led to the search for a scale that was based on the physical processes that happen during an earthquake. In the month after the main earthquake there were about 60 M7 and M6 earthquakes. Latest earthquakes map and list (past 24 hours, M2.5+) from the ANSS (Advanced National Seismic System). Close to shore, this same wave could reach heights of 30100 feet or more. Each year we map additional areas and learn more about existing faults and (or) discover new ones. These combination faults are called oblique faults and include the Seattle fault, southern Whidbey Island fault zone, and DarringtonDevils Mountain fault zone. The more you know what to expect, the better prepared you will be to help yourself, your family, and others around you. Lidar maps show the Earths surface without vegetation. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. Stay inside until the shaking stops and it is safe to go outside. Check out the liquefaction susceptibility and NEHRP site class maps on the Geologic Hazard Maps page. Floods. An official website of the United States government. South Whidbey fault has potential for major quake The map also shows potentially active faults from a separate 2014 report (click here to download). Seattle Fault and Whidbey Faults 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.