CORRELATION BETWEEN INTENSITY MEASURES AND DAMAGE CAUSED BY THE 2023 TÜRKİYE EARTHQUAKES

This article presents comparisons between different ground-motion intensity measures and damage frequencies observed following the Pazarcık (Mw7.8) and Elbistan (Mw7.5) earthquakes that struck Türkiye in February 2023. Various intensity measures were examined including peak ground acceleration (PGA), peak ground velocity (PGV), and spectral ordinates (e.g., S_a0.3, S_a1, S_d1). Two data sources were used to quantify damage frequency: a survey conducted by the team deployed by ACI 133 Reconnaissance Committee involving more than 200 reinforced concrete buildings, and surveys published by the Ministry of Environment, Urbanization, and Climate Change of Türkiye. The differences and commonalities between the two surveys are discussed, and plausible correlations between damage and intensity measures are examined. It is concluded that, relative to other intensity measures, peak ground velocity (PGV) and spectral displacement at a fundamental period of 1.0 second (S_d1) had better correlations with the damage observed from Antakya to Malatya. This observation is consistent with two previously published ideas: a) in the absence of structural damage, drift demand can be expressed as a linear function of PGV, and b) seismic design ought to be focused on drift (and PGV) instead of force (and PGA).