Comparative seismic risk assessment of the residential buildings for a strong earthquake scenario in Iceland using local vs. global models

Abstract

Iceland is the most seismically active region in northern Europe and damaging earthquakes repeatedly occur in the South Iceland Seismic Zone (SISZ), a relatively densely populated region accommodating all critical infrastructures and lifelines. The most recent damaging earthquake in the SISZ was the Mw6.3, 29-May-2008 Ölfus earthquake that occurred in close vicinity of the Hveragerði town. The town experienced intense near-fault strong-motion recorded on a strong-motion array (ICEARRAY I). To understand the consequences that a strong earthquake can cause in a high seismic region in terms of damage probability and damage-to-cost ratio, and to identify the most vulnerable building typologies, we perform seismic risk analyses for the Ölfus earthquake scenario across Hveragerði. Having detailed ground-motion data and a complete building exposure database give the unique opportunity to perform loss estimation in a high geographical resolution of building-by-building, contrary to the common municipality-based resolution. To this end, we employed the Empirical Bayesian Kriging method to estimate the intensity measures at building locations as well as account for the impact of their variability on the expected seismic loss. Finally, the risk metrics resultant from the global fragility curves developed as part of the global seismic risk model are compared with the most recent local models.