EARTHQUAKE, TSUNAMI AND NUCLEAR CRISIS

On March 11, 2011, an earthquake struck off the coast of Japan, churning up a devastating tsunami that swept over cities and farmland in the northern part of the country and set off warnings as far away the west coast of the United States and South America. Recorded as 9.0 on the Richter scale, it was the most powerful quake ever to hit the country. As the nation struggled with a rescue effort, it also faced the worst nuclear emergency since Chernobyl; explosions and leaks of radioactive gas took place in three reactors at the Fukushima Daiichi Nuclear Power Station that suffered partial meltdowns, while spent fuel rods at another reactor overheated and caught fire, releasing radioactive material directly into the atmosphere. Japanese officials turned to increasingly desperate measures, while their American counterparts gave a far more dire appraisal of the dangers.
As of March 24, the official death toll had been raised to more than 9,500, and more than 16,000 people are listed as missing, although there may be some overlap between the two groups. The final toll is expected to reach nearly 20,000.

Earthquake hazards 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.

Seismic Waves

Seismic waves are waves of 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. Many other natural and anthropogenic sources create low amplitude waves commonly referred to as ambient vibrations. Seismic waves are studied by seismologists and geophysicists. Seismic wavefields are measured by a seismograph, geophone, hydrophone (in water), or accelerometer.