Finite Fault Analysis and Near Field Dynamic Strains and Rotations due to the 11/05/2011 (Mw5.2) Lorca Earthquake, South-Eastern Spain

TL;DR

This study analyzes the finite fault and near-field dynamic strains and rotations caused by the 2011 Lorca earthquake, combining waveform inversion and finite difference methods to assess their impact on local structures.

Contribution

It introduces a comprehensive approach combining waveform inversion and finite difference modeling to evaluate dynamic deformations from a moderate earthquake.

Findings

Dynamic deformations were quantified at the Lorca station.

The influence of near-field deformations on surface structures was assessed.

Finite fault slip distributions were successfully estimated.

Abstract

The 11/5/2011 Lorca, Spain earthquake (Mw5.2) and related seismicity produced extensive damage in the town of Lorca and vicinity. During these earthquakes, evidence of rotations and permanent deformations in structures were observed. To analyze these aspects and study the source properties from the near field, the displacement time histories were obtained including the static component at Lorca station. Displacement time histories were computed by an appropriate double time integration procedure of accelerograms. Using these data, the foreshock and mainshock slip distributions were calculated by means of a complete waveform kinematic inversion. To study the dynamic deformations, the 3D tensor of displacement gradients at Lorca station was first estimated by a single station method. Using the finite fault inversion results and by means of a first order finite difference approach, the dynamic deformations tensor at surface was calculated at the recording site. In order to estimate the distribution of the peak dynamic deformations, the calculation was extended to the close neighboring area of the town. The possible influence of the near-field deformations on the surface structures was analyzed.