South Whidbey fault has potential for major quake This might include flammable appliances like a water heater, tall items like book cases, or heavy pictures. For example, the Cascadia subduction zone has had between 15 to 19 earthquakes over the past 10,000 years. 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. Using the stratigraphic column from the Freeport quadrangle map, confirm that you can recognize . In fact, until the 1980s, no one knew SWIF existed. And experts fear it could be even worse than The Big One.. Because they can travel great distances, tsunamis generated from earthquakes across the ocean can still cause damage. <> When this happens, even a very small slope can cause the ground to slide. Its just the way scientists work, he said. California Department of Conservation. Faults can be grouped based on their relative movement into three types. South Whidbey Island Fault Zone. 2 0 obj This map shows areas of seismic risk from high (red) to low (grayish-green). A reverse fault occurs when two blocks are pushed together and one moves up and over the other. Sometimes there may be a layer of volcanic ash or charcoal that has been deformed by the fault. Then the world rattles up and down. Within minutes, he spotted something groundbreaking. Beef Barley and French Onion trenches cross the Little Bear Creek lineament. Another big one is expected, and it could be devastating. If the epicenter is Everett, the SWIF could cause. Some parts of major cities (including Seattle, Tacoma, and Olympia) have been built on land that was reclaimed from soft and wet tidal ocean areas. The material becomes so weak that it behaves more like a liquid than a solid. On a frigid, blustery day in December 2018, Sherrod revisited the site where he conducted much of his field work. When an earthquake happens there will not be time to google what you are supposed to do. The moment magnitude scale replaced the Richter scale in the late 1970s. This is sometimes called "The Big One" by news media. Photo from Pacific Northwest Seismic Network Seismo Blog. Within this rich oral history there are many references to events like earthquakes and tsunamis. The Flying Squirrel and Mountain Beaver trenches cross the Cottage Lake lineament. 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. The crustal faults the Seattle Fault, the South Whidbey Island Fault, the Tacoma Fault those are less well known, said Forson. Some faults reach the surface and can be found by geologists. Each year we map additional areas and learn more about existing faults and (or) discover new ones. 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. Ground shaking is a hazard near the epicenter of an earthquake and also in areas far from the earthquake where amplification occurs. 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 . 121 N East Camano Dr This means that when the Seattle fault ruptures the south side of the fault moves up relative to the north side. 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. Plate Tectonics | Pacific Northwest Seismic Network document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. Be prepared and read more on DNR, USGS, King5, Strange Sounds and Steve Quayle. Each of these aftershocks would be a significant earthquake if it happened on its own. If folding on the Little Bear Creek lineament resulted in one or two of unconformities, the poorly constrained timing of the earthquakes is younger than 12,000 yr BP and older than about 2,850 cal yr BP. The Cascadia subduction zone off the Washington and Oregon coast is capable of some of the largest earthquakes in the world. Excavations across several LiDAR scarps show evidence for multiple post-glacial folding and faulting event on faults with reverse oblique sense of slip. Save my name, email, and website in this browser for the next time I comment. Geologists and geophysicists at the Washington Geological Survey map out these areas of amplification to help reduce damage during an earthquake. Cover your head and neck with your arms to protect against falling debris. PO Box 5000 It usually also means that there are earthquakes (even small ones) on the fault. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Doorways do not provide protection from falling or flying objects and you may not be able to remain standing. Some events appear to be only 200 years apart, and others are more than 1,000. One model suggests it extends to about 30 miles east of Yakima. Official websites use .gov 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 is a hypothetical scenario created by Mark Murphy of the Snohomish County Department of Emergency Management. People stagger into the streets to avoid an avalanche of debris. A few miles southeast across the white-capped waves of Admiralty Bay, Lake Hancock rises and falls with the tides. Faults often occur at and near the boundary of large tectonic plates because the plates are moving in different directions. The best thing you can do is to become prepared. Surface Geology | WA - DNR southern Whidbey Island fault zone (Class A) No. These types of faults are common, but usually small. Photo by Steve Palmer. When the ground shakes during an earthquake, it moves up and down, acting like additional gravity. Because after a region-wide event, it could take that long for help to come from the rest of the country and world. Johnsons curiosity changed the course of his career. Large and damaging earthquakes are inevitable in Washington, but no one knows exactly when they will happen. Earthquakes occur nearly every day in Washington. Washington State Earthquake Hazard Map. By finding the age of the deformed layer, a paleoseismologist can determine the minimum age of the fault. Click the "Seismogenic Features" button in the Map Contents window to display faults and earthquakes. 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. Until much more recently, no one really understood what it could do to a region of over 4 million people. For earthquakes that occurred before seismographs were invented, the Mercalli Intensity scale was used to make maps of damage and determine the size and location of an earthquake. Disoriented drivers wonder whats wrong with their cars, then realize something much bigger is amiss. This movement created a tsunami in Puget Sound and triggered a large landslide into Lake Washington. The map also shows potentially active faults from a separate 2014 report (click here to download). An earthquake can be a scary event. There are also tsunami evacuation signs on the highways. and the Red Cross will be there to care for them. Liquefaction can be a big problem. The DNR team found that the Seattle fault is intercepted by the southern Whidbey Island fault zone in the vicinity of Fall City. We pray for people of WA and our all north Americans as well. 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. Expect and help to extinguish fires. With Medical Martial Law imposed in Washington state. But opting out of some of these cookies may affect your browsing experience. Emergency Management Maps - Island County, Washington Most damage and loss of life in earthquakes is a result of ground shaking. One model suggests it extends to about 30 miles east of Yakima. Earthquakes on faults like these may cause tsunamis in the Puget Sound region. This new method allows geologists to see through trees and vegetation to find new faults. And what were looking at is water.. These quakes are capable of magnitudes from 7 to over 9. Some people in places like SODO and Harbor Island may have to flee to higher floors in a building. 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. The shaking usually lasts less than a minute and doesnt generally cause a tsunami or have many aftershocks. You have entered an incorrect email address! The Seattle fault last ruptured about 1,100 years ago in AD 900950. The southern Whidbey Island fault represents a segment of a boundary between two major crustal blocks. Theres approximately a 14% chance of another approximately M9 earthquake occurring in the next 50 years. The Port of Coupeville will apply for a grant to fund two electric vehicle charging stations. Westport currently is the only location with a vertical evacuation structure designed for a tsunami. Higher risk areas are in orange and lower risk areas are in green. Devils Mountain Fault -- Online Professional Paper - USGS We also use third-party cookies that help us analyze and understand how you use this website. This scenario was modeled on the part of the SWIF from Woodinville to just west of Whidbey Island. <> Even when an earthquake happens on a fault that doesnt reach the surface, the ground can still show signs of cracking. Seattle's Faults: Maps That Highlight Our Shaky Ground As an example, parts of Seattle and certain areas of downtown Olympia are built on softer ground that will amplify ground shaking during an earthquake. 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. Often this cracking happens because a soft part of the ground liquefies during the shaking. from Whidbey Island to Vancouver Island (Figure 1). Armentrout, J. J. Miller, C. Finn, C. S. Weaver. Scientists have also dated large underwater landslides and turbidites that travel from the continental edge far out into the ocean basin. The threat to Puget Sound from a quake along the Cascadia Subduction Zone, off the coast of Washington, Oregon and California, is well documented. The most recent hit roughly 2,700 years ago. Small talk stops. Mudslides. But scientists theorize that the area has suffered only four . These faults and earthquakes usually occur at great depth (tens to hundreds of miles). The average time between large earthquakes is about 535 years, but has been as little as 200 years, and more than 1,000 years. 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. The Safe America Foundation suggests texting as a way of communication. The moment magnitude scale is a type of logarithmic scale, where each increase of 1 means ~32 times more energy is released. Avoid stopping near or under buildings, trees, overpasses, or utility wires. After the shaking stopped the sand regained its strength. The Darrington-Devils Mountain fault zone is located in southern Skagit County and northern Snohomish County. Get On The List To Receive Your Daily Dose Of Weird News And Amazing Phenomena. Black lines show the South Whidbey Island Fault Zone, the Seattle Fault Zone and the Tacoma Fault Zone. Here, were looking at one of the bigger faults in the region, he said. The video is also available in Spanish and there is a fun activity/coloring book that can be found here. The fault has at least three almost parallel strands within a 4- to 7-mile-wide band, stretching eastward from Vancouver Island. Snohomish, King and Island counties would be expected to see the. If everyone tries to use their cell phones, it can overload the system. One model suggests it extends to about 30 miles east of Yakima. Bending of the fault and transpressional deformation began during the late middle Eocene and continues to the present. 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). Southeast Extension of the Southern Whidbey Island Fault By Human Capital March 19, 2019. sw_whidbeyfault_rev122706.pdf (28.68 KB) He said he believes dramatic shifts from that quake also may be visible on the western edge of Camano Island. Other faults may lie entirely underground, or could be covered by vegetation and (or) sediment. 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. 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. Other faults are inactive and are left over from much older periods of deformation. These include the: Southern Whidbey Island Fault (SWIF) Seattle Fault Devils Mountain Fault Strawberry Point fault Utsalady Point fault Johnson et al. 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. It will happen; we dont know when.. USA Earthquake Hazard Map. Contact Us, Whidbey Office A baristas hand hovers over the bean grinder.

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