Evaluation of the February 6, 2023 Earthquakes (Mw 7.7 and Mw 7.6) in Adıyaman by Deterministic Seismic Hazard Analysis

On February 6, 2023, at 04.17 and 13.24  local time in Turkey, two earthquakes with an instrumental magnitude (Mw) of 7.7 and 7.6 with epicenters in Pazarcık (Kahramanmaraş) and Elbistan (Kahramanmaraş) occurred 9 h apart. It caused great destruction, damage, and many casualties in Adıyaman and neighboring provinces. This study aims to compare the probabilistic earthquake hazard assessment (PSHA) with the scenario-based deterministic seismic hazard assessment (DSHA) for Adıyaman. The impact of both earthquakes on Adıyaman province was analyzed deterministically using OpenQuake software. Scenario-based analysis is performed by using the earthquake information such as magnitude, longitude, latitude, dip angle, and rake angle and Chiou and Youngs 2014 attenuation relationship, by taking into account the soil conditions in the region. Earthquake intensity distribution were evaluated. The intensity distribution on Adıyaman derived from scenario analysis is compared with PSHA results. Based on PSHA results for 475 and 2475 years return period ground motion level of approximately 0.6 g and 0.8 g PGA level is predicted, respectively at the center of the Adıyaman. PGA value at the center of the Adıyaman for the Pazarcık and Elbistan earthquakes are calculated as 0.8 g and 0.7 g respectively, through scenario analysis of both earthquakes. Site-specific scenario-based DSHA analysis is in good agreement with PSHA results from the ESHM20 model. The computational results from this study can help provide a reference for seismic hazard assessment around any region under any probable earthquake scenario. DSHA results will be used to compare observed damage and predicted damage around Adıyaman.