CRUSTAL STRUCTURE AND SEISMICITY OF SOUTHERN TYRRHENIAN BASIN

In this paper all the travel-time data from crustal earthquakes that o ccurred in the period 1978-1991 along the southern Tyrrhenian sea have been re-examined, In particular, 410 local earthquakes recorded at a minimum number of seven seismic stations and 52 shots fired on sea hav e been utilized to infer a tomographic image of the velocity model ben eath a region located in the domain 37 degrees 41'-39 degrees 10'N and 14 degrees 10'-16 degrees 44'E. These earthquakes are selected from a database containing about 1000 local earthquakes. The results from th e inversion of about 9000 travel-times confirm the strong lateral vari ations of the velocity model relative to compressional and shear waves . Below the volcanic center of the Aeolian Islands, in the upper crust , several low velocity bodies are found, in agreement with features in ferred from seismicity and other geophysical data. The 3-D velocity im ages also show a thickening of the crust from the center of the Tyrrhe nian sea towards the coasts of Sicily and Calabria. Finally hypocenter locations derived from inversion, which appear to be significantly le ss scattered than using 1-D velocity models, help to identify with som e accuracy two notable fault systems of the southern Tyrrhenian basin. (C) 1997 Elsevier Science B.V.