Japan Seismic Activity

In order to understand Japan's earthquakes activity, let's look up at this picture. The island of Japan is surrender by major tectonic plates like the Pacific Plate, the Philippine Plate, the Asian Plate (see attached bellow); making Japan one of the most active earthquakes zone in the world.


Just to have a wider idea of how active this island can be; Japan can registered up to 1,500 earthquakes per year. One of worst earthquakes ever registered in Japan was the 9.0 (March 2011) that triggered a tsunami that killed thousands of people and damaged some nuclear reactors. After a big earthquake it is completely normal to have after-shocks because the tectonic plates are readjusting the stress along the fault. After shocks depend on the quake intensity, in the event of a 9.0 earthquake, the aftershocks will range between 5.0-7.0 (on the Richter Scale).


According to the USGS (United States Geological Survey)"Plate tectonics tells us that the Earth's rigid outer shell (lithosphere) is broken into a mosaic of oceanic and continental plates which can slide over the plastic aesthenosphere, which is the uppermost layer of the mantle. The plates are in constant motion. Where they interact, along their margins, important geological processes take place, such as the formation of mountain belts, earthquakes, and volcanoes."

TectonicJapan.gif

http://www.usgs.gov

http://www.facts-about-japan.com

http://en.wikipedia.org/wiki/Earthquakes_in_Japan