Japans Earhtquake

A severe earthquake struck the north-east coast of Japan on 11 March, causing a major tsunami and serious damage across northern Japan.



Tokyo Electric Power Company has distributed a series of dramatic images showing Fukushima Daiichi Nuclear Power Station workers risking their health to repair the control room of reactors no. 1 and 2, heavily damaged by the devastating March 11  earthquake and tsunami in northeast Japan.

Earthquake Hazard in California

The first strong earthquake listed in earthquake annals for California occurred in the Los Angeles region in 1769, probably near the San Andreas Fault. Four violent shocks were recorded by the Gaspar de Portola Expedition, in camp about 30 miles southeast of Los Angeles center. Most authorities speculate, even though the record is very incomplete, that this was a major earthquake.


Forty persons attending church at San Juan Capistrano on December 8, 1812, were killed by a strong earthquake that destroyed the church. Many mission buildings were severely damaged there and at San Gabriel. The shock probably centered on a submarine fault offshore

http://www.conservation.ca.gov/cgs/rghm/pshamap/Pages/pshamain.aspx

Seismic Waves

A seismic wave is an elastic wave generated by an impulse such as an earthquake or an explosion.

Seismic waves are wavesof energy that travel through the earth, for example as a result of an earthquake explosion, or some other process that imparts low-frequency acoustic energy.

The P waves move in a compressional motion similar to the motion of a slinky, while the S waves move in a shear motion perpendicular to the direction the wave is travelling.