25 October 2010, Mw 7.7, Mentawai Region, Indonesia

Summary, as of 1 November 2010 

The 25 October 2010 magnitude 7.7 Mentawai, Indonesia earthquake and tsunami caused damage and over 450 deaths in the Mentawai Islands off the western coast of Sumatra, Indonesia.  Five minutes after the earthquake, the Indonesia Meteorological, Climatological and Geophysical Agency (Badan Meteorologi Klimatologi dan Geofisika) issued a national warning for a local tsunami, and the Pacific Tsunami Warning Center and Japan Meteorological Agencies issued local tsunami watches seven and nineteen minutes after the earthquake, respectively, to Indian Ocean countries; national authorities are then responsible for issuing warnings to their populations on the tsunami threat to their coasts.

The highest measured tsunami amplitude locally was 0.35 m in Padang, Sumatra, Indonesia, and the highest measured amplitude overall was 0.4 m in Rodrigues Islands, Mauritius.  The highest tsunami waves were reported to be 3-6 m high by eyewitnesses

According to the World Data Center for Marine Geology and Geophysics / US National Geophysical Data Center (http://www.ngdc.noaa.gov/hazard/) Global Historical Event databases, over 121 tsunamis have been generated in the Indian Ocean since 326 B.C.  These include the 2004 magnitude 9.1 Sumatra earthquake and tsunami that killed almost 230,000 people. Since the 2004 event, two tsunamis in the Sumatra region have caused deaths, in addition to the 25 October 2010 tsunami; these were the 2005 magnitude 8.7 Nias earthquake caused 1303 deaths and an additional 10 deaths due to the tsunami, and the 2006 magnitude 7.7 Java earthquake generated a tsunami that caused 664 deaths. In addition, non-fatal tsunamis were generated by the 2007 magnitude 8.4 Bengkulu earthquake that caused 25 deaths and the 2009 magnitude 7.5 Padang earthquake that resulted in 1,117 deaths.  Eruptions from three Indonesia volcanoes also caused fatalities since the Sumatra event: in 2005 Karthala caused one death, in 2006 Merapi (Java) caused two deaths, and in 2010 Sinabung (Sumatra) caused two deaths and Merapi has caused more than 30 deaths.   

Casualties and Damage
BNPB, National Disaster Management Agency, 3 Nov 10

BNPB, National Disaster Management Agency, 1 Nov 10