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[MIS17-06] Importance of organizing historical earthquake archives using GIS
Keywords:historical earthquakes, GIS, Nankai trough
In order to consider the rupture process of historical large earthquakes, it is necessary to understand the information written in the historical documents on a map. Here, we started to organize the historical earthquake archives using GIS. We have organized the information into major categories such as damage caused by shaking, tsunami, crustal deformation, and other information, with different markings. As for shaking and tsunami damage, we have changed the intensity of the color into three levels depending on the level of the damage. The color of the mark was changed for each earthquake. The GIS-based compilation began in Mie Prefecture, and is now underway in Aichi, Shizuoka, Wakayama, and Kochi Prefectures.
Advantages of organizing historical earthquake archives using GIS
1. It is easy to compare damage from earthquakes that occurred in the same region over different ages. For example, we compare the arrival times of tsunamis from the Hoei and Ansei-Tokai earthquakes. In the area south of Kihoku, Mie Prefecture, there was enough time to cook rice before the tsunami arrived after the shaking subsided in the Hoei earthquake, but it arrived immediately in the Ansei earthquake.
2. The ability to read historical documents in conjunction with various geospatial information such as site amplification factor, topography, active faults, and old edition topographic maps makes it easier to consider the triggers of disasters.
3. It is also possible to understand historical documents in conjunction with recent observational and analytical results. For example, recent observations of seafloor crustal deformation have revealed the distribution of asperities in the Nankai Trough. Using information on asperity distribution, it may be possible to estimate which asperities have slipped in past earthquakes.
Advantages of organizing historical earthquake archives using GIS
1. It is easy to compare damage from earthquakes that occurred in the same region over different ages. For example, we compare the arrival times of tsunamis from the Hoei and Ansei-Tokai earthquakes. In the area south of Kihoku, Mie Prefecture, there was enough time to cook rice before the tsunami arrived after the shaking subsided in the Hoei earthquake, but it arrived immediately in the Ansei earthquake.
2. The ability to read historical documents in conjunction with various geospatial information such as site amplification factor, topography, active faults, and old edition topographic maps makes it easier to consider the triggers of disasters.
3. It is also possible to understand historical documents in conjunction with recent observational and analytical results. For example, recent observations of seafloor crustal deformation have revealed the distribution of asperities in the Nankai Trough. Using information on asperity distribution, it may be possible to estimate which asperities have slipped in past earthquakes.