GEOG 361:Environmental Hazards, Research Project Presentation

VALDIVIA, CHILE MAY 22 1960: THE LARGEST EARTHQUAKE EVER RECORDED, RESULTS IN HAZARDOUS TSUNAMI & LANDSLIDES

Abstract

Definition of Earthquake: "The shaking of the Earth by seismic waves radiating away from a disturbance, most commonly a fault movement." The earthquake that happened off the coast of Chile was of tectonic origin at a subduction zone.

Plate Tectonics: "the description of the movements of plates and the effects caused by plate formation, collision, subduction, and sliding past one another." The theory explains that much of the earth's seismic activity occurs at boundaries of these plates. This is the most widely accepted theory for why we experience earthquakes.

 

CHARACTERISTICS OF THE LARGEST EARTHQUAKE EVER RECOREDED

Date: May 22nd, 1960
Time: 19h11m20s GCT
Location:

39.5º S Lat., 74.5º W Long.

Magnitude: 9.5 (revised)
Depth:

55 meters below the sea surface

Plates Involved: Nazca Plate & S. American Plate

 

The Nazca Plate has been colliding and subducting underneath the South American plate for thousands of years (long before the first humans roamed the earth). At a subduction zone, the piece of crust that is descending gets caught in the trench and tension builds up as it tries to descend further. When we feel an earthquake it is that tension releasing which sends seismic waves through the Earth's crust. (This figure will help you visualize what happens at a subduction zone: Figure #1). The 1960 Chile earthquake was caused by the Nazca plate releasing tension and descending 15 meters underneath the South American Plate. It happened 30.5 km off the Chilean coast. My reaserach focused on the nearest city to the epicenter; Valdivia, Chile (39.8º S Lat.,73.24º W Long.). Click on the links below to see how the earthquake effected the city.

 

MAIN EFFECTS OF THE QUAKE

 

Mitigation of the hazards decribed above are needed to protect the welfare of human kind. It is important to teach all humans the risks we are are subject to while living on this dynamic planet. I have provided a Hazard Map and some suggestions that I hope will explain what needs to be done in such regions as Chile to reduce/prevent loss. Socially and economically we can learn from the past to better our future.

 

Resources

Created by ~ Casey Farrell a UWEC Geography Major