12/27/2023 0 Comments Alaska quake depthIn addition to local tsunamis caused by underground landslides, the earthquake triggered an enormous tectonic tidal wave.Īfter wreaking havoc on southeastern Alaskan coastal towns that had already endured local tsunamis, the tectonic tsunami made its way to British Columbia where it ravaged small villages along the coastline near Vancouver. The largest tsunami wave of the 1964 Alaska Earthquake measured over 200 feet in height and was recorded at Shoup Bay near the Valdez inlet. The delta slump triggered a local tsunami which destroyed almost anything left standing and ruptured the Union Oil Company’s oil tanks, igniting a massive fire. When the earthquake struck, seismic waves caused soil liquefaction and a portion of the delta slumped into Port Valdez, taking much of the port’s resources, living and otherwise, with it. The town of Valdez was originally built on sand and gravel. Reports of residual water sloshing (seiches) came in from the U.S. Thousands of strong aftershocks continued for weeks after the earthquake, some measuring greater than magnitude 6.2. Part of the of the Million Dollar Bridge at Copper River also crumpled. The control tower at Anchorage International Airport collapsed, killing an air traffic controller. In the Turnagain Heights area of Anchorage, soil liquefaction (when the ground behaves like a liquid) triggered a landslide which moved parts of a suburban bluff 2,000 feet into the bay, taking up to 75 homes with it. Local tsunamis also caused destruction in Kodiak, Whittier and Seward.ĭowntown Anchorage had the most property damage mainly due to immense landslides, one of which dropped the business district nine feet. Local Tsunamis and LandslidesĪs the tremors ended, local tsunamis sprung up almost immediately, leaving residents little to no time to flee for higher ground.Ī massive tidal wave crushed the small, coastal village of Chenega four minutes after the tremors subsided-the town lost a third of its population. Coastal forests plunged below sea level and were destroyed by salt water. Geological surveys taken immediately afterward showed parts of the Alaskan coast sank up to eight feet, other parts rose up to 38 feet and much of the coast moved 50 feet towards the ocean. 1964 Alaska Earthquake Changes the Coastlineįour minutes may not seem like a long time, but when it comes to earthquakes, it’s an eternity, and tremors during the Great Alaska Earthquake of 1964 lasted at least four minutes. The death toll reached 131 people: 15 died during the initial tremors and the rest in the subsequent tsunamis and landslides. The earthquake triggered a swell of devastating tsunamis, landslides and submarine slumps which caused massive property damage and loss of life. Seismic waves caused the earth to “ring like a bell.”Īs bad as the tremors were, the worst was yet to come. It effortlessly toppled telephone poles, buckled railroad tracks, split roads in half, uprooted buildings, cars and docks and tore homes apart. The violent shaking led to water, sewer and gas line breaks and widespread telephone and electrical failures. They recalled seeing asphalt roads rise and fall like waves and the ground opening and closing before them, water shooting up through the ensuing cracks. on March 27, 1964-Good Friday-the earth trembled just as many Alaskans were sitting down to dinner.Įyewitnesses described hearing a crunching, grinding noise as the earth shook. The event remains the strongest earthquake to have hit the US.At 5:36 p.m. The quake hit early in the morning local time.Īlaska was also the site of the 9.2 earthquake which caused a tsunami and killed 139 people in the sparsely populated state in 1964. The National Weather Service sent out an alert to cellphones in Alaska, reading: "Emergency Alert, Tsunami danger on the coast, Go to high ground or move inland."Īuthorities also issued a a lower-level "tsunami watch" warning for the entire US West Coast and Hawaii, which was lifted hours later as data from ocean buoys indicated no threat. The US Geological Survey previously measured the quake's magnitude at 8.2 before revising it to 7.9. Scientists located the epicenter of the earthquake some 280 kilometers (174 miles) southeast of Kodiak, Alaska, at a depth of 10 kilometers. "The first wave may not be the largest," the officials added. "Tsunami warnings mean that a tsunami with significant inundation is possible or is already occurring." "If you are located in this coastal area, move inland to higher ground," the Anchorage Office of Emergency Management said. Parts of Canada's British Columbia also issued a warning soon after the tremor. US authorities issued a tsunami warning for coastal areas of Alaska after an 7.9 earthquake hit the Gulf of Alaska on Tuesday, before withdrawing the alert several hours after the quake.
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