3D crustal structure of a neotectonic basin (Saronikos gulf, Greece)
Abstract
3-D velocity model was constructed for the neotectonic basin of Saronikos Gulf, near Attica, Greece. 3-D linearised tomography algorithm inverted 3487 P-wave arrivals from 374 located earthquakes in the area. The data were acquired after the installation of a local network of 10 ocean bottom seismographs (OBS) and 29 stand-alone land-stations for a time period of fifty (50) days, in the summer of 2001. Since linearised inversion is sensitive to the selection of the initial model, we based the analysis on a reliable initial model originated from a 2-D wide-angle seismic profile passing through the investigated area. The resulted velocity distribution showed that the Saronikos Gulf, which lies along the Hellenic volcanic arc, is divided by a central platform in two parts, at least to the depth of 12 km. This implies the existence of a rupture zone trending in a NNE SSW direction. Probably this zone is the extension off shore of a large thrust belt which dominates the adjacent on shore areas. Due to their different structure, the two parts are predominant by lower velocities compare to the central platform. The western part is characterized by higher seismic activity than the eastern one. Moreover, the western Saronikos Gulf is divided in northern and southern parts by a well defined rupture zone of E-W direction. This zone seems to be the extension of the extended Corinthiakos Gulf rupture zone. At the depth of 17 km the velocity increases considerably and the crustal thickness is restricted up to 20 km. This ‘unexpected’ low thickness in the region of Saronikos Gulf could be the result of the extensional stress field which dominates the region, as well as of the emergence of the mantle material along the volcanic arc.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....5584D