Earthquake damage assessment for deterministic scenarios in Iquique, Chile

Abstract

Risk evaluation and loss analysis is key in foreseeing the impact of disasters caused by natural hazards, and may contribute effectively in improving resilience in a community through the pre-evaluation of preparedness and mitigation actions. The pilot study considered herein is the city of Iquique, located in north Chile where a large megathrust earthquake and tsunami is expected to eventually cover the south of Peru and north of Chile. Although the region was recently hit by an MW 8.2 earthquake April 1st 2014, damage caused was only moderate. Geophysical evidence suggests that there is still a potential for a much larger event in the region. Therefore, a thorough risk assessment is key to anticipate its possible physical, social, and economic consequences. Consequently, HAZUS-MH was used to simulate a set of earthquake hazard scenarios generated from estimates of plate interlocking and the residual slip potential remaining from the April 1st 2014 rupture fault mechanism. Successful application of the HAZUS-MH methodology relies on the construction of a comprehensive exposure model that takes into account regional features and a good characterization of the physical vulnerabilities. For Iquique we have used a large body of public and local data to develop a detailed inventory of physical and social assets including an aggregated building count, demographics, essential facilities, infrastructure, and lifelines. To characterize the response of the built environment to seismic demand, HAZUS fragility curves and downtime models were applied, and outputs were calibrated using the observed damage after the April 1st 2014 earthquake. Using such calibration, a deterministic seismic risk assessment for the collection of generated scenarios and their expected impacts on all physical assets, population, and essential facilities were estimated. This analysis sets a basis for the simulation and evaluation of different physical and social mitigation measures for the city in the future.