Image characteristics of deep seismics in Calabria (S. Italy) using
tomography and ray-tracing
Günay Çifçi and Derman Dondurur
Dokuz Eylül Univ., Engineering Faculty, Department of Geophysics, 35100 Bornova-Izmir, Turkey
(Received 5 April 2001; accepted 24 August 2001)
Abstract:The seismic characteristics of the lower crust of Serre Mountains, South Calabria (Southern Italy) were investigated by a Deep Seismic Sounding experiment along the main profile of about 30 km long. In this profile, 31 dynamite shots (10-95 kg) recorded by five recording units and three-component receivers. For the upper 2 km of the sections, the first breaks were used as input for tomographic inversion calculations. Modeling evaluations were based on the shot gathers. Both these and velocity data for deeper layers, were used for the ray-tracing modeling. Later, the section was extended to obtain 3D models and ray-tracing was again performed using actual geophone and shot positions. The shot gather ray-tracing was conducted on these models. Field and synthetic sections show good correlations with the seven layers such as low velocity zone, the Hercynian lower crust reflections, the strongly reflective Calabrian crust and the crust-Moho boundary. The Moho, which dips to the south, can be seen between 6.5 and 8 s corresponding to the depths of 19-24 km. A low velocity zone probably marks the contact between the Hercynian lower crust and the upper crust in the region (1.5-4.5 s). The gravity modeling also confirmed these layers evidently.
Key Words: Deep Seismic Experiment, Tomography, 3-D Ray-Tracing Modeling.