2. Global Distribution
Expedition Menu
1.
Introduction
2. Global Distribution
3. Earthquakes & Plate Boundaries
4. The Ring of Fire
5. Convergent Boundaries
6. Atlantic Ocean
7. Atlantic Ocean II
8. Alaska Earthquake
9. Vertical Slice
10. 3-D Look
11. California Plate Boundaries
Here is the global distribution of earthquakes overlain by a map of the global topography (shape of the earth's surface).
Now that is a lot of earthquakes...look at all of them!
Dots, upon dots, upon dots....each one marking the surface projection
of the earthquake location (epicenter).The large number of earthquakes, more than 50,000 since 1960 with magnitudes
greater than 5, and volcanoes are testaments to the dynamic nature of the
Earth
Earthquakes can only occur in "strong rock" where stresses (forces) can build up to the
point to cause the material to fracture, thereby sending seismic waves through the
Earth…..and strong rock only is found in the rigid lithosphere…deeper in the Earth the
temperatures are too high, thereby allowing the rocks to flow, rather than fracture.Take notice of the locations of the earthquake epicenters.
Contact Don Reed
Dept. of Geology
San José State University
©Copyright 1999
Last Updated on June 21, 1999
Is the worldwide pattern of earthquake epicenters distributed randomly about the earth's surface or does it exhibit a clear pattern, meaning located in specific regions?