Earthquake relocation and seismotectonics using a new 3D crustal model in the Alhama de Murcia Fault area (SE Iberia)
Abstract
The Eastern Betics shear zone comprises one of the most active tectonic areas in the Iberian peninsula due to the convergence between Eurasian and Africa plates since late Neogene. We focus our study in the Alhama de Murcia Fault and other nearby faults, that are the source of large paleoseismic events and some damaging seismic series in the historical period, the last one was the Mw 5.2 (2011) Lorca earthquake. The aim of this study is to give more accurate locations of h y pocentres in the region around these faults. We started with M>2.0 events in the period of 2015.01-2018.12 (123 events matched the requirements in the Spanish Seismic Catalogue - IGN). This was accomplished, firstly, by adding data recorded by the Andalusian Seismic Institute (IAG) stations and a local temporal seismic network installed in 2015 to the one used in the Spanish Catalogue and computing a relocation of these events in SeisComP3 (after performing a manual phase picking). After this manual relocation, we used the Nonlinloc software with a new 3D crustal model of the region that we created combining recent regional and local data from seismic wave tomography, gravimetry, seismic exploration surveys, Miocene basins thickness, and heat flow. The improvement of the location of the events allow s the unequivocal relation between seismic series and mapped structures. In addition, the cluster of early 2018, with around 250 events with M 0.5-4 is clearly differentiated, and located at 8-14 km depth. We calculated the focal mechanism for ML>3 earthquakes using mainly polarities and tensor inversion when possible to analyze the kinematics and rupture process of these seismic series.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T33D0400S
- Keywords:
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- 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICS