Seismic refraction imaging of the southern Corinth Rift shoulder at Derveni
Résumé
Two land seismic spreads installed on the shoulders of the Corinth Rift during the July 2001 R/V Maurice Ewing seismic reflection campaign provide records of waves that probe the shallow structure of the southern flank of the graben. The direct waves converted at the southern coast propagate in the shallow block faulted carbonates beneath the Derveni array at a velocity of 4.3 km s−1. The first-arrivals at the Galaxidi array indicate a basement velocity of 6 km s−1. The first-arrival times at the Derveni array are fitted for waves refracted along a north-dipping interface between the carbonate layer and the basement. The average dip of the interface beneath the southern shoulder and the basin part of the rift is 15°. A migration of the traces down to the emergence point of the refracted waves beneath the Derveni array shows a short wavelength undulation of the interface superposed to the regional 15° dip. The arrival times and the amplitudes of the waves are consistent with block faulting above a shallow detachment structure beneath the southern Corinth Rift shoulder at Derveni.