1:45 PM - 3:15 PM
[O07-P22] On the study of Fukui Earthquake Fault Ⅸ
Keywords:Fukui Earthquake, fault, intensity of lower 5
The purpose of our research is identifying the main shock fault surface, which caused the M5.0 event on september 4 in 2020. The important point to understand this research is that there are a lot of reverse faults in
Japan. In addition, a character of the land-form by the fault is a straight structure. According to previous studies,a varied fault expected in the west side of Fukui plain. In this study we thought that the main shock might occured on the expected faults. We desided hypocenter of event by the Win-system. Win-system is a software to identify the hypocenters. With this system, we detected 44 hypocenters of the main shocks and aftershocks. We found that the decided epicenters concentrated on the west side of Fukui plain.Hypocenters of the first 13 aftershocks that occurred just after the main shock distributed like a plane. Therefore, these aftershocks occurred on the fault plane which had caused the main shock. We define this plane as a main shock fault surface. On the other hand, the other aftershocks were scattered outside from the main shock fault surface. We define these as extended type
aftershocks.From the initial 13 aftershocks distribution,it was found that the main shock surface runs from West-southwest to East-northeast and incline North-northwest. After 30 aftershock epicenters show the distribution from east to west more widely than aftershocks of mainshock fault surface.
Japan. In addition, a character of the land-form by the fault is a straight structure. According to previous studies,a varied fault expected in the west side of Fukui plain. In this study we thought that the main shock might occured on the expected faults. We desided hypocenter of event by the Win-system. Win-system is a software to identify the hypocenters. With this system, we detected 44 hypocenters of the main shocks and aftershocks. We found that the decided epicenters concentrated on the west side of Fukui plain.Hypocenters of the first 13 aftershocks that occurred just after the main shock distributed like a plane. Therefore, these aftershocks occurred on the fault plane which had caused the main shock. We define this plane as a main shock fault surface. On the other hand, the other aftershocks were scattered outside from the main shock fault surface. We define these as extended type
aftershocks.From the initial 13 aftershocks distribution,it was found that the main shock surface runs from West-southwest to East-northeast and incline North-northwest. After 30 aftershock epicenters show the distribution from east to west more widely than aftershocks of mainshock fault surface.