Essay about Earthquakes: Earthquake and Prince William Sound

Submitted By NikelvrMoney
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Pages: 5


The Prince William Sound Earthquake in Alaska, accord on March 27, 1964 with a magnitude of 9.2. This earthquake is the second largest earthquake ever recorded in the world, with a duration rupture of four minutes. This earthquake took many lives, damaged a mass area of the earthquake, and created a devastating tsunami following the earthquake. This earthquake was not only felt in Alaska, but also in parts of Yukon, some parts of Canada, Texas, and Florida (Stover C, 2011). The epicenter of this major earthquake was about 10 km east of the College of Fiord, approximately 90 km west of Valdez and 120 km east of Anchorage.

REGION- The region that this earthquake occurred was in Anchorage, Alaska. In Anchorage, the epicenter, sustained the most severe damage to property. Anchorage sits at the base of the Chugach Mountains along the coast of Cook Inlet in southern Alaska. There are approximately 100,000 glaciers in Alaska, 60 of which are within 50 miles of Anchorage (Lovgren S, 2005). Anchorage is the northernmost city in the United States with a population of 295,570 in 2011. The city's seacoast consists mostly of treacherous mudflats. Large portions of the local economy depend on Anchorage's geographical location and surrounding natural resources. Anchorage's economy traditionally has seen steady growth, though not quite as rapid as many places in the lower 48 states (Drye W, 2005).

TECTONIC PLATES- The tectonic history of the region shows that the Pacific plate moves in a northwestern direction at about five to seven centimeters per year. This Pacific tectonic plate movement causes the crust of southern Alaska to be compressed and warped, with some areas along the coast being depressed while other areas inland are being uplifted. Because of intervals ranging from ten to a hundred years, this compression was relieved by the sudden motions of large portions of the coastal portion of Alaska moving back in a southeastern direction over the subducting Pacific plate. Another cause because of tectonic plates was because, the Latouche Island area moved about 18 meters to the southeast. Also, the patterns of uplift and subsidence which had been slowly developing prior to the earthquake were suddenly reversed, with areas around Montague Island being uplifted 4-9 meters and areas around Portage down-dropped as much as 3 meters. The hinge line extended from near the epicenter in Prince William Sound to the SE coast of Kodiak Island. The end result was the movement of the Pacific plate under the North American plate by about 9 meters on average (Hansen W, 1967).

EFFECTS- The effects of the earthquake were very devastating, causing many deaths and destruction of land. This great earthquake and tsunami took a total of 128 lives (tsunami 113, earthquake 15), and caused about $311 million in property loss (Stover C, 2011). Structural damage was seen in many cities in Alaska, the most damage in Anchorage. In Anchorage, total destruction to buildings and houses over a large area of 30 city blocks, mostly in the downtown area. All services were disturbed throughout the city and the suburbs. This earthquake also caused many landslides which contributed to heavy damage in the downtown business section. Another huge landslide, the largest, at Turnagain Heights devastated about 130 acres of residential property destroying about 75 houses. All schools in Anchorage were nearly demolished by this landslide (Cohen S, 1995).

AFTERSHOCKS AND TSUNAMI This shock generated a tsunami that devastated many towns along the Gulf of Alaska, and left serious damage at Alberni and Port Alberni, Canada, along the West Coast of the United States (15 killed), and in Hawaii. The maximum wave height recorded was 67 meters at Valdez Inlet (Kanamori H, 1970). It also caused action in rivers, lakes, protected harbors, and waterways along the Gulf Coast of Louisiana and Texas caused minor…