The 16 September 2015 Illapel Earthquake and Tsunami: Post-Event Tsunami Inundation, Building and Infrastructure Damage Survey in Coquimbo, Chile

Abstract

The 16 September 2015 MW8.3 Illapel Earthquake generated a tsunami that caused severe building and infrastructure damage in Coquimbo, Chile. Initial reports indicated numerous buildings, transport, energy, water and coastal protection structures sustained varying levels of damage in response to tsunami exposure. A digital ‘census style’ survey was carried out in Coquimbo to measure and record tsunami hazard characteristics and associated buildings and infrastructure network component damage. Flow depths measured from 655 watermarks ranged from 0.1 to 4.7 m, with a 1.47 m mean and 1.02 m standard deviation. Over 3000 damage samples were recorded for tsunami exposed buildings and infrastructure components. Damage levels for 545 buildings showed most sustained partial but repairable damage at tsunami flow depths up to 2 m. A further 2544 damage samples were collected for transport, energy, water infrastructure network components and coastal protection structures. We observed undamaged infrastructure components in high proportions and observed that complete component damage was often caused by secondary hazards (e.g. debris) or cascading impacts where seawall and stormwater culvert failures damaged co-located roads, pathways and utility poles. Future investigations of the hydrodynamic tsunami characteristics influencing infrastructure component fragility will support the analysis of physical damage to single components and cascading impacts across multiple infrastructure networks.