Articles | Volume 8, issue 5
Research article
05 Sep 2017
Research article |  | 05 Sep 2017

Earthquake static stress transfer in the 2013 Gulf of Valencia (Spain) seismic sequence

Lluís Saló, Tànit Frontera, Xavier Goula, Luis G. Pujades, and Alberto Ledesma

Abstract. On 24 September 2013, an Ml 3.6 earthquake struck in the Gulf of Valencia (Spain) near the Mediterranean coast of Castelló, roughly 1 week after gas injections conducted in the area to develop underground gas storage had been halted. The event, felt by the nearby population, led to a sequence build-up of felt events which reached a maximum of Ml 4.3 on 2 October.

Here, we study the role of static stress transfer as an earthquake-triggering mechanism during the main phase of the sequence, as expressed by the eight felt events. By means of the Coulomb failure function, cumulative static stress changes are quantified on fault planes derived from focal mechanism solutions (which act as both source and receiver faults) and on the previously mapped structures in the area (acting only as stress receivers in our modeling). Results suggest that static stress transfer played a destabilizing role and point towards an SE-dipping structure underlying the reservoir (or various with analogous geometry) that was most likely activated during the sequence. One of the previously mapped faults could be geometrically compatible, yet our study supports deeper sources. Based on this approach, the influence of the main events in the occurrence of future and potentially damaging earthquakes in the area would not be significant.

Short summary
Fault movement on the crust is governed by stress levels. Our study focuses on the effect of stress transfer between faults, a mechanism long known to have potential for generating earthquakes. Our results suggest that static stress transfer would have acted as a destabilizing trigger during the sequence and that the experienced events would not have shortened the occurrence of future damaging shakes. The study aims to provide insight on an issue related to energy resources management.