3-D crustal structure of the extensional Granada Basin in the convergent boundary between the Eurasian and African plates

Inmaculada Serrano, Dapeng Zhao, José Morales

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

Three-dimensional P and S wave velocity models of the crust under the Granada Basin in Southern Spain are obtained with a spatial resolution of 5 km in the horizontal direction and 2 to 4 km in depth. We used a total of 15407 P and 13704 S wave high-quality arrival times from 2889 local earthquakes recorded by both permanent seismic networks and portable stations deployed in the area. The computed P and S wave velocities were used to obtain three-dimensional distributions of Poisson's ratio (σ) and the porosity parameter (Vp x Vs). The 3-D velocity images show strong lateral heterogeneities in the region. Significant velocity variations up to ± 7% in P and S velocities are revealed in the crust below the Granada Basin. At shallow depth, high-velocity anomalies are generally associated with Mesozoic basement, while the low-velocity anomalies are related to the neogene sedimentary rocks. The south-southeastern part of the Granada Basin exhibits high σ values in the shallowest layers, which may be associated with saturated and unconsolidated sediments. In the same area, Vp x Vs is high outside the basin, indicating low porosity of the mesozoic basement. A low-velocity zone at 18-km depth is found and interpreted as a weak-ductile crust transition that is related to the cut-off depth of the seismic activity. In the lower crust, at 34-km depth, a clear slow Vp and Vs anomalous zone may indicate variations in lithology and/or with the rigidity of the lower crust rocks.

Original languageEnglish
Pages (from-to)61-79
Number of pages19
JournalTectonophysics
Volume344
Issue number1-2
DOIs
Publication statusPublished - 2002
Externally publishedYes

Keywords

  • Crustal earthquakes
  • Granada basin
  • Low-velocity layer
  • P waves
  • S waves
  • Seismic tomography

ASJC Scopus subject areas

  • Geophysics
  • Earth-Surface Processes

Fingerprint Dive into the research topics of '3-D crustal structure of the extensional Granada Basin in the convergent boundary between the Eurasian and African plates'. Together they form a unique fingerprint.

Cite this