A pre-earthquake regional seismic risk estimation methodology and a prioritization approach for regional risk assessment

The 2023 Kahramanmaras earthquakes highlighted the urgency of assessing and intervening in old, seismically deficient buildings. However, not all old buildings collapse during earthquakes despite noncompliance with current codes. Prioritizing buildings based on seismic risk offers a reasonable approach. This study analyzed 17 242 1–10 story pre-2000 RC buildings in Kahramanmaras, considering factors such as soil conditions, number of stories, construction year, fault proximity, and seismic demand, and their effects on structural damage distribution. Risk class distributions of these buildings are estimated by a pre-earthquake regional seismic risk estimation methodology developed based on the outcomes of performance-based rapid seismic risk assessment of pre-2000 buildings in Istanbul using PERA2019 methodology, and compared with actual earthquake damage. Results showed a strong correlation between “very high risk” buildings and those heavily damaged or collapsed. Finally, based on the results, a regional-scale prioritization strategy was proposed to efficiently identify high-risk buildings prone to excessive damage.