The Great Alaska Earthquake

March 27, 1964 a magnitude 9.2 earthquake hit Alaska its epicenter located in Prince William Sound, 75 miles east of Anchorage. This earthquake was and still is the second larges earthquake ever recorded (Christensen). The plates involved In this major earthquake were the Pacific plate and North American plate. This subduction zone is know as Aleutian-Alaska megathrust zone (Sokolowski). This region was known for its active plate tectonics, but this earthquake did come as a surprise to the public and scientists in the area. About 200-250,000 kilometers squared of the earths crust were vertically displaced during the 1964 earthquake reports Carla Cornibert (Cornibert). The dominant stress that caused that much crust to be displaced was compression of the Pacific plate subducting below the North American plate. As the Pacific plate subducted below the North American plate pressure started to build causing compression and finally so much compression had built up causing elastic strain like a rubber bad that can stretch to a certain point, but on march 27, 1964 the rocks elastic limit was hit and elastic rebound occurred causing the rocks to break in a brittle manner just like a rubber band snapping when it reaches its elastic limit. As I sated before this earthquake was a megathrust meaning a large portion of the Pacific plate slipped during the quake and it's after shocks. Along with a moment magnitude of 9.5 the earthquake was rated as a XI on the Mercalli scale which measures the damage caused by the earthquake.

While the Mercalli scale peeked at XI it ranged from IV-V in areas up to 50,000 square miles from the epicenter. The Mercalli scale ranges from I being not felt/ no damage to XII which is total destruction and many lives taken. In Alaska alone the earthquake took 115 peoples lives 106 of these being from the tsunamis created by the earthquake and its aftershocks (Sokolowski). The damage was estimated at about 300 million dollars most of the damage being in southern Alaska caused by landslides and avalanches. While this is extremely devastating and took many lives scientists learned a lot from this earthquake to help in projecting future megathrust earthquakes in the area. I believe there is most likely a definite chance for a future megathrust earthquake at the Aleutian-Alaska megathrust zone.

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