The research program titled “Earthquake and Volcano Hazards Observation and Research Program” was started in fiscal year (FY) 2014 as a new five-year project authorized and funded by the Council for Science and Technology of the Ministry of Education, Culture, Sports, Science and Technology. It included a new format of collaborative research called, “Core-to-Core Collaborative Research between Earthquake Research Institute, The University of Tokyo and Disaster Prevention Research Institute, Kyoto University.” In this format, two types of research, “Participation Type Research” and “Subject Proposal Type Research” were conducted from FY2015. A preliminary study was performed in FY2015 for “Integrated Research” of “Participation Type Research,” which developed a framework for seismic risk evaluation at prefectural offices of Osaka and Kochi for an earthquake occurring along the Nankai Trough, considering the epistemic uncertainty. The secondary study was performed from FY2016 through to FY2018, wherein the methodology for the seismic risk evaluation was improved on three aspects: i.e., revision in ground motion prediction models considering the saturation effect, revision in loss models in terms of the fatalities as well as the direct losses of buildings, and extension of target sites to the whole of Osaka and Kochi prefectures. The results suggest that the epistemic uncertainty in the ground motion prediction models is most sensitive to the overall uncertainty of seismic risk. Along with “Integrated Research,” a total of 14 “Research on Specific Topics” related to time-dependent risk analysis, economical risk evaluation, source characterization, structural damage estimation models, ground motion estimation models, soil amplification models, and disaster prevention planning considering the uncertainty of risk assessment, were studied during this period in order to improve the risk assessment studies for “Integrated Research.” With respect to “Subject Proposal Type Research,” a total of 27 individual research themes focused on research to understand hazards/risks by earthquakes and volcanic eruptions and to mitigate disasters by them.

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