Insights on the role of local site effects on damage distribution in the Izmir metropolitan area induced by the October 30, 2020 Samos earthquake

Abstract

On the 30th of October 2020, a 6.6 magnitude earthquake occurred 14 km north of Samos Island, causing 119 casualties (117 in Izmir, Türkiye, and 2 in Samos, Greece) and significant damage in the 3rd biggest city of Türkiye, Izmir. Although the city is roughly 70 km far away from the epicenter, the damage was significant and concentrated in the city center settled on alluviums. This paper aims to analyze the distribution of damage in Izmir province, by crosschecking the recorded motions, the subsoil conditions and the evidence of damage as collected by an ad-hoc on-site reconnaissance. The intrinsic behavior of the Samos earthquake was investigated by employing three different ground-motion prediction equations. The results of the analyses revealed that site effects play a significant role in the amplification of ground motions, and valley effects are responsible for the concentration of damage. The damage in buildings was classified in terms of the intensity and structural typologies for the 30 districts of Izmir metropolitan area. In-depth analysis of the distribution of damages revealed that the earthquake caused damage all over the boundaries of Izmir province, and the concentration of damage in Bornova and Karşıyaka districts has a clear correlation with double resonance effects.