by Charmagne Jane Duyag

1. 2011 JAPAN EARTHQUAKE

2. The magnitude 9.0 Tohoku-Oki quake that occurred last March 11, 2011
was the most powerful earthquake known to hit Japan and the fifth-
most powerful quake ever recorded. The quake triggered a tsunami that
killed thousands of people.

3. The 2011 Tohoku Earthquake struck offshore of Japan, along a subduction zone
where two of Earth's tectonic plates collide. In a subduction zone, one plate
slides beneath another into the mantle, the hotter layer beneath the crust. The
great plates are rough and stick together, building up energy that is released as
earthquakes.

4. The epicenter of the
earthquake is along the
convergent margin where
the Pacific Plate is being
subducted beneath the
Okhotsk Plate. Earthquakes
are caused by breaking and
movement of rocks along
the faultline where the two
plates collide.

5. The earthquake struck the coast of Japan at a depth of about
17 miles below the earth's surface. Dozens of aftershocks,
some of magnitude 6.0 or greater, were felt after the quake.
The Japan Trench, a subduction zone, is where the Pacific plate beneath the Pacific
Ocean dives underneath North American plate beneath Japan. This violent
movement, called thrust faulting, forced the North American plate upward in this
latest quake.

6. The sudden horizontal and vertical thrusting of the Pacific Plate, which
has been slowly advancing under the Eurasian Plate near Japan,
displaced the water above and spawned a series of highly destructive
tsunami waves.