Human Losses and Damage Expected in Future Earthquakes on Faial Island – Azores

Abstract

Since the 15th century, the death toll due to large earthquakes has reached approximately 6300 in the Azores and 17 for Faial Island. The likely number of fatalities and injuries in future large earthquakes (M6+) in Faial Island is estimated using the software QLARM (Quake Loss Assessment for Response and Mitigation) and its dataset, validated at the regional scale. The current population for the 13 settlements on this island is extrapolated from the 2001 and 2011 census. The distribution of buildings into EMS-98 vulnerability classes is based on detailed census information and damage reports written after the 1980 (M7.2) and 1998 (M6.2) earthquakes. The most appropriate ground motion prediction equation (i.e. Shebalin in Regularities of the natural disasters (in Russian), Nauki o zemle, Znanie, vol 11, p 48, 1985) is selected and coupled with site amplification information to adjust calculated ground shaking with observed intensities for the aforementioned events. The good agreement of fatalities and injuries calculated by QLARM with the observed numbers in both earthquakes was the motivation for proposing two scenarios for likely future earthquakes of M6 and 6.9, offshore and inland, respectively. Based on these scenarios, fatalities, and injuries may range between 110–620 and 330–1750, respectively, depending on the likely large earthquake.