Earthquake along the Central Coast of Chile on February 27, 2010
On February 27, 2010, at 15:34 (JST) there was a Mw8.8 (JMA moment magnitude) earthquake along the central coast of Chile. The focal mechanism (CMT analysis) showed a reverse fault with a compression axis in an E-W direction. This event occurred at the plate boundary, with the Nazca plate subducting under the South American plate. This event caused tsunamis with heights over 2m observed close to the hypocenter in Chile, and tsunamis were recorded in countries around the Pacific, including Japan. This earthquake and its tsunamis caused damage with over 528 fatalities in Chile (USGS)
The seismic activity is a main shock - aftershock sequence. There have been aftershocks located within an area 600km in a north - south direction, centered on the main shock.
In Japan, tsunamis generated by the earthquake started to be seen in the afternoon of February 28. The largest tsunamis that were observed at tidal observatories in Japan had a height of 1.2m in Kuji Port and in Susaki Port. (Both are tidal observatories of the Ports and Harbors Bureau, Ministry of Land, Infrastructure, Transport and Tourism)
The western coast of South American, including coastal Chile, is a place where an oceanic plate (Nazca plate) is subducting under a continental plate (South American plate), similar to the Pacific coast of Japan. Therefore large earthquakes of M8 or greater have often occurred there. To the south of the recent event, the 1960 Chile Earthquake occurred (Mw9.5, the largest event in the past 100 years). Tsunamis generated by the 1960 Chile Earthquake reached Japan and caused damage with 142 fatalities (Comprehensive Bibliography of Destructive Earthquakes in Japan, Latest Edition)
Japan Meteorological Agency
[Seismic Activity for February 2010 (March 11, 2010)]