1:45 PM - 3:15 PM
[HDS08-P03] Utilization of various occurrence scenarios of Nankai Trough earthquakes for disaster Prevention Trainings and identification of issues
Keywords:Nankai Trough, Earthquake, Occurrence Scenarios, Diversity, Disaster Prevention Training, Aeon
1. Introduction
The National Research Institute for Earth Science and Disaster Prevention (NIED) is developing an earthquake disaster prevention simulator that can provide information on earthquake and tsunami hazards and the risks posed by such hazards, considering the time evolution after the occurrence of "unusual phenomena" as an example of the spatiotemporal diversity of earthquake occurrence. Until now, disaster prevention measures taken by companies have tended to avoid assuming earthquake scenarios other than the largest class. However, with the release of "Temporary Information on Nankai Trough Earthquakes," it is becoming increasingly important to assume a variety of earthquake scenarios when considering countermeasures. Therefore, in this study, Methods for utilizing the occurrence scenario information generated from research into understanding and predicting Nankai Trough earthquake activity, and identification of issues. We provided the AEON Group with earthquake scenarios as basic information on the occurrence of disasters, and conducted disaster Prevention Trainings on June, 2022 and November, 2022.
2. Extraction of occurrence scenarios
In this case, the source area set was created assuming a half-cracked case. The source region set for a subsequent earthquake that occurs after the first earthquake was created only for the portion that had not yet been destroyed at the time of the earthquake. As for the conditional hazard evaluation estimation after the occurrence of the first earthquake, we estimated the conditional hazard after the occurrence of the first earthquake. Based on the concepts of long-term assessment and probabilistic tsunami hazard assessment, we organized the possible combinations of earthquakes that could occur after the occurrence of the first earthquake and evaluated the weight of each combination. In addition, as a risk assessment considering prior evacuation after the occurrence of the first earthquake, an exposure population model considering prior evacuation and a risk assessment in the half-cracked case are conducted, referring to the case study for the half-cracked case for which the Temporary Information and Response Guidelines were established. The epicentral areas used were earthquakes occurring in the ABm/CEm area for the June disaster Prevention Training and the ZBm/CEm area, including the Hyuga Sea area, for the November disaster Prevention Training. Seismic motion and tsunami inundation depths were generated on a 250 m mesh.
3. Verification of information utilization methods and identification of issues
In the June disaster Prevention Trainings, the disaster response and business continuity in the affected areas were verified after the eastern half-crack (CEm) occurred. Later, the Nankai Trough earthquake contingency information (huge earthquake warning) was announced, and the response in the western area was discussed under the possibility of a western half-crack (ABm) occurring. The November disaster Prevention Training was conducted in the reverse order of earthquake occurrence. Considering the diversity of earthquake occurrence scenarios and using scientifically supported data for disaster Prevention Training s in semi-cracked cases that are different from the largest scale, realistic planning and trainings can be carried out. As a result of verification through disaster Prevention Trainings, it was found that one of the issues is the lack of assumed information that can be used to make agreements on what to do and when to continue until a subsequent earthquake occurs after the release of the Nankai Trough contingency information.
Acknowledgments: This study was conducted as part of the Nankai Trough Earthquake Research Project for Disaster Prevention Measures, a research project of the Ministry of Education, Culture, Sports, Science and Technology of Japan. We would like to express our sincere appreciation to all parties involved.
The National Research Institute for Earth Science and Disaster Prevention (NIED) is developing an earthquake disaster prevention simulator that can provide information on earthquake and tsunami hazards and the risks posed by such hazards, considering the time evolution after the occurrence of "unusual phenomena" as an example of the spatiotemporal diversity of earthquake occurrence. Until now, disaster prevention measures taken by companies have tended to avoid assuming earthquake scenarios other than the largest class. However, with the release of "Temporary Information on Nankai Trough Earthquakes," it is becoming increasingly important to assume a variety of earthquake scenarios when considering countermeasures. Therefore, in this study, Methods for utilizing the occurrence scenario information generated from research into understanding and predicting Nankai Trough earthquake activity, and identification of issues. We provided the AEON Group with earthquake scenarios as basic information on the occurrence of disasters, and conducted disaster Prevention Trainings on June, 2022 and November, 2022.
2. Extraction of occurrence scenarios
In this case, the source area set was created assuming a half-cracked case. The source region set for a subsequent earthquake that occurs after the first earthquake was created only for the portion that had not yet been destroyed at the time of the earthquake. As for the conditional hazard evaluation estimation after the occurrence of the first earthquake, we estimated the conditional hazard after the occurrence of the first earthquake. Based on the concepts of long-term assessment and probabilistic tsunami hazard assessment, we organized the possible combinations of earthquakes that could occur after the occurrence of the first earthquake and evaluated the weight of each combination. In addition, as a risk assessment considering prior evacuation after the occurrence of the first earthquake, an exposure population model considering prior evacuation and a risk assessment in the half-cracked case are conducted, referring to the case study for the half-cracked case for which the Temporary Information and Response Guidelines were established. The epicentral areas used were earthquakes occurring in the ABm/CEm area for the June disaster Prevention Training and the ZBm/CEm area, including the Hyuga Sea area, for the November disaster Prevention Training. Seismic motion and tsunami inundation depths were generated on a 250 m mesh.
3. Verification of information utilization methods and identification of issues
In the June disaster Prevention Trainings, the disaster response and business continuity in the affected areas were verified after the eastern half-crack (CEm) occurred. Later, the Nankai Trough earthquake contingency information (huge earthquake warning) was announced, and the response in the western area was discussed under the possibility of a western half-crack (ABm) occurring. The November disaster Prevention Training was conducted in the reverse order of earthquake occurrence. Considering the diversity of earthquake occurrence scenarios and using scientifically supported data for disaster Prevention Training s in semi-cracked cases that are different from the largest scale, realistic planning and trainings can be carried out. As a result of verification through disaster Prevention Trainings, it was found that one of the issues is the lack of assumed information that can be used to make agreements on what to do and when to continue until a subsequent earthquake occurs after the release of the Nankai Trough contingency information.
Acknowledgments: This study was conducted as part of the Nankai Trough Earthquake Research Project for Disaster Prevention Measures, a research project of the Ministry of Education, Culture, Sports, Science and Technology of Japan. We would like to express our sincere appreciation to all parties involved.