Publication Date:
2018-12-11
Description:
Although the deep structure of the western Mediterranean has been extensively studied (i.e. global tomography, receiver function analysis or full-waveform inversion), the crustal and upper mantle structure of the Alboran Basin (westernmost Mediterranean) remains inadequately imaged, as the resolution of these models in the crust is limited by data availability and is not precise enough to characterize the crust under the basin. To understand the regional deep structure, a wide-angle seismic study across the basin is needed. The crustal structure of this basin has important implications for seismogenic and tsunamigenic potential estimations, as the main faults in the area are located at the boundaries between different crustal domains.
In order to characterize the entire crust and the boundaries between the different crustal domains coexisting in the area, we propose to combine Wide Angle Seismic (WAS) data and Multichannel Seismic (MCS) profiles. In this study we present the velocity and density model obtained from the only WAS study focus on the area, the WESTEMED project. In particular, we performed the inversion of profile P01, running from the south of Iberia (Almeria) to the north African margin (east of Nador). This profile includes 24 offshore obh/obs with a spacing 〈2.5km, and 13 onshore geophones located at both margins. Modelling have been carried out using the Korenaga inversion method. Result is a high horizontal resolution profile that delineate the crustal structure and the Moho depths across the Alboran Basin, and under the south Iberian and North African margins. This profile runs coincident with a crustal-scale MCS profile from the TOPOMED cruise, allowing the association of the velocity variations and anomalies with their tectonic origin.
Main finding concerns the unequivocal characterization of the crust under the Alboran Basin. Along this profile, a two layers crust is observed under the East Alboran Basin, limited by tectonic structures, that changes abruptly towards the basin margins. In addition, due to the close spacing of the obh/obs, we are able to correlate the observed velocity anomalies with their geologic origin, as is the case of the high velocity anomalies related with volcanic intrusions or the low velocity anomalies in relation with deeper sedimentary basins.
Type:
Conference or Workshop Item
,
NonPeerReviewed
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