[O-10] 30 years from the Great Hanshin-Awaji Earthquake - Achievements for a safe society [Co-host:JANDR]

[O10-01] Progress of the active fault studies in Japan since the 1995 Kobe Earthquake

★Invited Papers

*Takashi Azuma¹ (1.National Institute of Advanced Industrial Science and Technology)

Keywords:The 1995 Kobe Earthquake, active fault, paleoseismological survey, long-term evaluation of active fault

The 1995 Kobe Earthquake (M 7.3) caused severe damages in the Hanshin area and Awaji Island in the Kinki area in Japan. After this earthquake, active fault studies were changed. Japanese government founded the Headquarters of Earthquake Research Promotion (HERP) including the Earthquake Research Committee (ERC) and conducted the project of the survey and observation for major active faults in Japan. Lots of paleoseismological data were collected and new techniques have taken into survey. The Earthquake Research Committee of HERP conducted a long-term evaluation of major active fault zones in Japan based on the results of these active fault surveys. Furthermore, based on results of these survey and evaluation, HERP created a probabilistic seismic hazard map and a strong ground motion evaluation map for the major active fault zones. These results achieved 10 years after the Kobe Earthquake are the culmination of cutting-edge research in academic fields such as seismology and earthquake engineering, and also represent a world-leading national earthquake disaster prevention policy. On the other hand, there are still issues. One of them is the difference in the quantity and quality of information on active faults. It is said that most of the major active faults distributed throughout the country have been surveyed, but there are large differences in the number of surveys conducted and the accuracy and reliability of the information obtained as a result of the surveys. When the active fault survey and observation project was first started, active fault research committees were set up in the local government to promote the survey and compile the results, but the quality of contents were not uniform. Another issue is that it is not clear how to utilize the obtained information on active faults. One of the goals of HARP is the publication and update of the national seismic hazard map of Japan, and they prepared a detailed manuals for its creation. But clear guidelines are needed on how to handle information on active faults for disaster prevention plans of local governments. In addition, not only the strong ground motion, the preparedness against earthquake disasters caused by active faults also requires fault displacement. Furthermore preliminary assessments of liquefaction phenomena and slope disasters caused by strong earthquake motion are also essential. We need to continue to have dialogue with earthquake countermeasures from the perspectives of engineering and sociology regarding how to utilize the information provided by researchers investigating active faults.