TIME AND MAGNITUDE


This earthquake has been recognized for its destructiveness, its duration and its extraordinary range of damages inflicted. On that Good Friday evening at approximately 30 kilometers beneath the surface, the largest earthquake of that time struck Prince william Sound. It was triggered by massive fracturing of the sinking edge of the Northeastern Pacific Ocean plate where it descends beneath the rocky slab carrying the North American Continent.

Plate Tectonics Map

Photo modified courtesy of Tilling, Heliker, and Wright, 1987 and Hamilton, 1976. --Topinka, USGS/CVO 1999

The earthquake and the rupture in those rocks extended horizontally nearly 800 kilometers, roughly parallel to the Aleutian Trench. Measurements of the wave amplitudes put the magnitude of this quake at between 8.0 and 8.6 on the Richter Scale, making it one of the largest earthquakes ever recorded. Few, if any earthquakes of this magnitude have existed. Within minutes, thousands became homeless, and over 100 people lost their lives. Tsunamis raced across the Pacific Ocean to Antartica, British Columbia, California and Hawaii.

Table of Contents

Main

Abstract

Introduction

Time and Magnitude

Epicenter

Duration and Extent

Aftershocks

Deformation

Liquefaction

Tsunamis
References