1.
Whole Lotta Shakin' Goin' On
Introduction
Download
Expedition Worksheet if you wish
(it is in your course workbook)
Objectives: Students will learn about the global distribution of earthquakes and volcanoes in both space and time, which is central to our understanding of plate tectonics, the formation of the seafloor, movement of the plates of lithosphere, and interactions at the boundaries between plates. The movement of the seafloor, caused by underwater earthquakes poses a significant threat to communities along coastal
California.This expedition serves as a good review of the material in some of the previous expeditions while the concepts presented in the following web pages are closely related to the dangers posed by undersea earthquakes and tsunamis, which will discuss in the next expedition.
Make sure that you read the accompanying worksheet as it also contains important information on this subject.
The
screens that follow will show the distribution of the surface locations
of earthquakes, or epicenters. We
will see that most of these earthquakes are located along the location of plate boundaries, mainly under the sea or along
the coast.
Earthquakes occur within the Earth down to a depth of 670 kilometers, in other words in the crust or upper mantle. In fact, earthquakes only occur in the lithosphere, the rigid outer layer of the earth that composes the tectonic plates. The diagram at the right, and in your worksheet, shows how the location of an earthquake within the earth is projected upwards, towards the Earth surface, to determine the location of the epicenter.
Contact Don Reed
Dept. of Geology
San José State University
©Copyright 2007
Last Updated on
September 24, 2007
Let's
examine the distribution of earthquakes
over the past 50 years