Recorded ground motion and estimated soil amplification for the May 11, 2011 Lorca earthquake.

Abstract : On May 11 2011 an earthquake of magnitude 5.2 (Mw) hit the Murcia region of Spain causing significant damage to buildings in the town of Lorca. Accelerograms were recorded by stations of the Instituto Geográfico Nacional and high-amplitude ground motions were observed at the Lorca station, with a PGA of 0.37g. The contribution of a near-field component of ground motion is shown in time histories and in elastic response spectra. Features of near-field ground motions such as directivity could have significantly enhanced the ground shaking caused by this event. Local amplification effects in Lorca were investigated by the H/V spectral ratio technique and an array method. Information obtained from the geophysical field survey allowed the definition of representative soil columns and site classifications according to Eurocode-8. Modelling of site response is conducted for an example location. The aftershocks recorded at different sites confirm the soil amplification at these locations.