Dr. George Pararas-Carayannis, one of the nation's foremost authorities on earthquakes and tsunamis, states "The Pacific tectonic plate movement caused 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. At time intervals ranging from tens to hundreds of years, this compression is 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." In short, the Pacific plate was being pushed under the North American plate.
The Epicenter, location on the earths surface directly above focus, of the '64 earthquake is located in the northern part of the Prince William Sound; specifically 61.04º N- 147.73º W, approximately 75 miles east of Anchorage. The focus, or depth of the earthquake, is estimated at 25 miles below the epicenter. In general, the lower the earthquake occurs below the surface of the earth, the weaker it is; 25 miles is relatively close to the surface compared to most earthquakes that occur in …show more content…
The lack of seismic instruments in Alaska at the time has resulted in the length of the earthquake to be estimated from a variety of personal accounts. Although most early accounts of the earthquake range from 2 to 6 minutes, recent research has concurred that the earthquake lasted about 4 minutes (240 sec.) from beginning to end. One survivor who was wintering at the Ward Cannery in Kenai estimated the duration of the earthquake at half an hour; however, this may be due to the several immense aftershocks that followed. Of the 52 large aftershocks, the first 11 rated 6.0 or higher on the Richter scale during the first 24 hours after the main earthquake. During the next three weeks, nine earthquakes of the same magnitude followed. Thousands of smaller earthquakes pursued for a year in the same 250 kilometer area where the main earthquake took