Sensitivity of Structural Damage to Earthquake Ground Motion Scenarios. The Torrevieja Earthquake Case Study

Structural damage computation using analytical methods requires the knowledge of the ground motion distribution in the urban area caused by a given earthquake. In this manuscript, the ground motion estimates (i.e. PGA and spectral acceleration values) are obtained through simulation of the 1829 Torrevieja earthquake using the NGA ground motion prediction equations (GMPE). The building stock under consideration has been classified according to the methodology presented in RISK-UE. The computations have been done using the last version of the software SELENA. The epistemic uncertainties of the analysis are accounted for by means of a logic tree computation scheme. The logic tree has two branches for the uncertainty in the earthquake scenario, two branches for the GMPEs and three branches to consider the uncertainties in average shear wave velocity Vs30 (soil conditions). Results indicate large differences derived for the different earthquake loss scenarios (ELE) obtained following each branch of the logic tree.

The greatest structural damages and losses are obtained when the earthquake is located in the Bajo Segura fault zone, using Campbell and Bozorgnia GMPE and for soft soil conditions. This article has allowed us to see how the different possible input parameters for ELE should be carefully analyzed for each case study and the importance of providing ELE results in terms of mean values with corresponding uncertainty ranges.