Using Internet reports for early estimates of the final death toll of earthquake-generated tsunami: the March 11, 2011, Tohoku, Japan, earthquake

A retrospective case study was conducted for the March 11, 2011, earthquake that occurred off the east Pacific coast of Tohoku, Japan, with reference to the Sumatra-Andaman earthquake and Indian Ocean tsunami on December 26, 2004. The regularities of the temporal variations of the number of deaths reported through the Internet is used to make an early stage quick-and-rough estimate to assist in the emergency decision making, and to continue the revision of the estimate as new data comes in. The quick-and-rough estimate of the final fatalities that was obtained on the second day after the earthquake is shown to agree with the final reported fatalities to within an order of magnitude. This also has an added advantage over other estimation models, in that the estimates can be updated with new data as they become available