6 February 2023 Kahramanmaras, Turkey Earthquakes: Microtremor Measurement, Extensive Field Survey On Seismic Intensity And Structural Damage Correlations To Develop The New Intensity Formula For The Region
- 1Kandilli Observatory and ERI, Bogazici University, Geophysics, Istanbul, Türkiye (ozeln@boun.edu.tr)
- 2Graduate School of Science and Engineering, Ehime University, Matsuyama
- 3Graduate School of Science and Technology for Innovation, Yamaguchi University, Ube, Japan
- 4River Basin Research Center, Gifu University, Gifu, Japan
- 5Yeditepe University, Istanbul, Turkiye
- 6The University of Tokyo, Tokyo, Japan
- 7Disaster Prevention Research Institute, Kyoto University, Kyoto, Japan
- 8Soil Research, Tokyo, Japan
- 9Advanced Technology Research Institute, Chiba Laboratory, Asia Air Survey, Tokyo, Japan
- 10NEWJEC, Osaka, Japan
- 11Building Research Institute, Tsukuba, Japan
- 12Graduate School of Disaster Resilience and Governance, University of Hyogo, Kobe, Japan
The research conducted on the 6th of February 2023 Mw7.8 Kahramanmaraş earthquake represents
a comprehensive study aimed at understanding the distribution of seismic intensity in the affected
areas and developing a novel intensity calculation formula for Eastern-Southeastern Turkey. This
seismic event, the most catastrophic in Turkey's last century, was initiated on the Narli splay fault
and propagated bilaterally along the East Anatolian Fault (EAF). The rupture extended over a
significant seismic gap of the EAF and the Amanos Fault, affecting 11 provinces in Turkey's Southeast
region and bordering areas of Syria, resulting in a total rupture length exceeding 300 km and causing
over 50,000 fatalities.
The study evaluates seismic intensity distribution across seven cities: Hatay, Gaziantep,
Kahramanmaraş, Adıyaman, Malatya, Osmaniye, and Şanlıurfa. An online intensity questionnaire
survey was distributed to educational institutions in these provinces. In October 2023, a Turkish-
Japanese reconnaissance team collaborated with the National Education Directorate of the seven
provinces to disseminate the questionnaire format and URL link to all public high schools, middle
schools, and elementary schools, garnering responses from 14,739 participants. Geocoordinate
inputs were accurately assigned using the ArcGIS survey123 system, contributing to the preliminary
survey results which included damage observations.
Microtremor observations were conducted in Hatay, Gaziantep, Kahramanmaraş, and Adıyaman
using the Kinkei seismic measuring device developed in Japan. The research involved single-point
microtremor measurements at 20 locations within the earthquake zone, fault-fracture zones,
damaged residential areas, particularly near the AFAD seismic stations. Additionally, array
microtremor measurements were made at 31 AFAD station locations with strong motion records.
The analysis of 39 microtremor measurements revealed preliminary results indicating a correlation
between heavily damaged buildings and areas where the Vs30 values are less than 180 m/s. The
finding suggests that areas with lower Vs30 values may be more susceptible to damage during
earthquakes.
These observations, combined with the result of the online intensity questionnaire surveys and local
soil amplifications, are utilized to assess the correlation between microtremor amplification and
seismic damage. The objective is to formulate a new intensity calculation formula tailored to the
Eastern-Southeastern part of Turkey. This research's findings are anticipated to offer significant
contributions to earthquake intensity assessment methodologies, particularly in regions with distinct
geological and seismic profiles. The collaboration between Turkish and Japanese experts adds an
international dimension to the study, potentially leading to improved seismic risk assessment,
preparedness strategies, and recovery measures on a broader scale in the future.
How to cite: Meral Ozel, N., Mori, S., Murakami, H., Koyama, M., Kepekçi, D., Polat, G., Korkusuz Ozturk, Y., Yotsui, S., Goto, H., Osato, S., Chiba, T., Hada, K., Yamada, M., Hayashida, T., and Sakamoto, M.: 6 February 2023 Kahramanmaras, Turkey Earthquakes: Microtremor Measurement, Extensive Field Survey On Seismic Intensity And Structural Damage Correlations To Develop The New Intensity Formula For The Region, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18974, https://doi.org/10.5194/egusphere-egu24-18974, 2024.
