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Earthquake and Tsunami Forecasting System Research Group

Earthquake and Tsunami Forecasting System Research Group

写真 Earthquake and Tsunami Forecasting System Research Group
Group Leader
Takane HORI

  • Research on improvement of forecasting of earthquakes using observation and research results, and monitoring data, etc.
  • Research on construction of a scenario database, and improvement of the accuracy of earthquake and tsunami simulation utilizing the database
  • Research and development of a data assimilation method for improving the accuracy of forecasting earthquakes
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Earthquake and Tsunami Forecasting System Research Group

Great earthquakes in subduction zones repeatedly occur at intervals of decades to centuries. Along the Nankai Trough, for example, a number of large-scale Tokai, Tonankai and Nankai earthquakes have occurred at intervals of 100 to 200 years. Such a repetition of earthquakes is called an earthquake generation cycle, and the method to estimate the shape and friction characteristics of a plate boundary interface and reproduce the earthquake generation cycle by mechanical calculation using computers is called earthquake generation cycle simulation. The Earthquake and Tsunami Forecasting System Research Group performs earthquake generation cycle simulation mainly for the Nankai Trough and the Japan Trench, examines the scenarios of possible occurrence of large earthquakes, and compares crustal movements and seismic activities predicted from models with actual observation data acquired from the GNSS Earth Observation Network System (GEONET, the Geospatial Information Authority of Japan) which monitors crustal movement with a high degree of accuracy and DONET that JAMSTEC deploys in the Nankai Trough and the source areas of the past Tonankai earthquake, thus conducting research to sophisticate the future trend forecast through data assimilation. As well as forecasting earthquakes, we also do research to improve the accuracy of simulation of strong motions and tsunamis both for real-time prediction when an earthquake occurs and for estimation of damages caused by strong motions and tsunamis before earthquake occurrence.


figure
Through seismic cycle simulations, we are trying to reproduce historical earthquake sequences and collect possible future earthquake patterns around the Japan Islands. The 4 panels show examples of earthquake scenarios along the Nankai Trough, southwest Japan.
In upper two panels, the eastern segment fi rstly ruptured, then the western segment followed with different time lags. Such metachronous ruptures resemble 1854 Ansei events or 1944 and 1946 Showa events. The lower left panel shows the concurrent rupture of the eastern and western segments like 1707 Hoei event.
The lower right is an example of possible scenarios. There, the western segment ruptured first and the eastern segment rupture followed with one year interval.