Japan Geoscience Union Meeting 2023

Presentation information

Print

[J] Oral

S (Solid Earth Sciences ) » S-CG Complex & General

[S-CG60] Shallow Fault Zone Structure and Seismic Hazard Assessment

Sun. May 21, 2023 9:00 AM - 10:30 AM 301A (International Conference Hall, Makuhari Messe)

convener:Kimiyuki Asano(Disaster Prevention Research Institute, Kyoto University), Tanaka Shinya(Tokyo Electric Power Services Co., Ltd.), Ken Miyakoshi(Ohsaki Research Institute), Hiroe Miyake(Earthquake Research Institute, University of Tokyo), Chairperson:Kimiyuki Asano(Disaster Prevention Research Institute, Kyoto University), Tanaka Shinya(Tokyo Electric Power Services Co., Ltd.), Ken Miyakoshi(Ohsaki Research Institute), Hiroe Miyake(Earthquake Research Institute, University of Tokyo)


9:00 AM - 9:15 AM

[SCG60-01] Earthquake disaster and strong ground motion very close to surface fault - A very tentative draft for 2023 Turkey earthquake -

*Takao Kagawa1 (1.Tottori University, Faculty of Engineering)

Keywords:surface fault, strong ground motion, earthquake disaster, the 2023 Turkey earthquake

On February 6, 2023, a M7.8 earthquake with its epicenter near Nurdagi hit the southern Republic of Turkey. Surface faults were appeared along the East Anatolian Fault. The 1999 Kocaeli earthquake (M7.6) occurred in the northeastern part of Turkey, and surface faults were also confirmed. During the field survey, undamaged constructions that are expected not to be suffered by large seismic motions were found, in the vicinity of buildings that were collapsed by fault displacement. To confirm the similar phenomenon in this earthquake, a very tentative considerationwas made based on the evaluation of surface faults and damages based on satellite data. An attached figure is a base map of Google Earth Pro superimposed on the USGS estimated surface fault (red line) and the estimated damage by the Earth Observatory of Singapore. Observation site 4632 maintained by the Republic of Turkey which is the closest site to the estimated surface fault, is located northwest of the epicenter, epicentral distance 24.1 km. The observed value is not necessarily large. A horizontal PGA of 349.34 Gal and PGV of 43.02 cm/s were observed, but these values are not large among the records observed in this earthquake. In addition, the estimated damage and the surface fault are not aligned in this area. However, the digital data and plots at the site are not available at present, and the details are unknown. The attached figure also shows a news report by NHK on the outskirts of Nurdagi, where no major damage was seen in houses in the vicinity of the surface fault.
At present, we can only speculate based on limited information, but we would like to conduct a more detailed analysis including other sites based on the results of field surveys and accumulated information in near future.