Real-time estimation system for seismic-intensity exposed-population
Abstract
For an appropriate first-action to an earthquake, risk (damage) information evaluated in real-time are important as well as hazard (ground motion) information. To meet this need, we are developing real-time estimation system (J-RISQ) for exposed population and earthquake damage on buildings. We plan to open the web page of estimated exposed population to the public from autumn. When an earthquake occurs, seismic intensities are calculated at each observation station and sent to the DMC (Data Management Center) in different timing. For rapid estimation, the system does not wait for the data from all the stations but begins the first estimation when the number of the stations observing the seismic intensity of 2.5 or larger exceeds the threshold amount. Estimations are updated several times using all the available data at that moment. Spatial distribution of seismic intensity in 250 m meshes is estimated by the site amplification factor of surface layers and the observed data. By using this intensity distribution, the exposed population is estimated using population data of each mesh. The exposed populations for municipalities and prefectures are estimated by summing-up the exposures of included meshes for the area and are appropriately rounded taking estimation precision into consideration. The estimated intensities for major cities are shown by the histograms, which indicate the variation of the estimated values in the city together with the observed maximum intensity. The variation is mainly caused by the difference of the site amplification factors. The intensities estimated for meshes with large amplification factor are sometimes larger than the maximum value observed in the city. The estimated results are seen on the web site just after the earthquake. The results of the past earthquakes can be easily searched by keywords such as date, magnitudes, seismic intensities and source areas. The summary of the results in the one-page report of Portable Document Format is also available. This system has been experimentally operated since 2010 and has performed the estimations in real-time for more than 670 earthquakes by July of 2012. For about 75 % of these earthquakes, it takes less than one minute to send the e-mail of first estimation after receiving data from the first triggered station, and therefore, the rapidity of the system is satisfactory. To upload a PDF report form to the web site, it takes approximately additional 30 second.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.S41A2406A
- Keywords:
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- 7212 SEISMOLOGY Earthquake ground motions and engineering seismology;
- 7294 SEISMOLOGY Seismic instruments and networks