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

On September 24^th, 2013, a M_L 3.6 earthquake struck in Valencia Gulf (Spain), near the Mediterranean coast of Castellon, roughly a week after the gas injections conducted in the area to develop an 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 M_L 4.3 on October 2^nd. Here, we study the role of static stress change as an earthquake triggering mechanism during the sequence, and provide quantitative assessment of the known faults final stress state. By means of the Coulomb Failure Function, the evolution of static stress is quantified both on fault planes derived from focal mechanism solutions (which act as source and receiver faults), and on the previously mapped structures in the area (receiver faults). Results show that static stress transfer could have acted as a partial trigger, and point towards an ESE-dipping structure as the most likely to have been activated during the sequence. Based on this approach, the influence of the studied events in the occurrence of future and potentially damaging earthquakes in the area would be, at most, of second order. [ABSTRACT FROM AUTHOR]