RPSE

Summary of the Japan quake:

http://www.fema.gov/library/viewRecord.do?id=4620

A subduction fault - Pacific tectonic plate pushed underneath Japan. It was proceeded by 4 M6+ quakes two days before. Aftershocks: an M7, 50 M6, and 100s of M5.

Damage was limited (epicenter was almost 100 km from shore) mostly due to the building codes - more restrictive than the US. No reports of collapse of any engineered building