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http://hdl.handle.net/2122/1473
Authors: | Iannaccone, G.* Improta, L.* Capuano, P.* Zollo, A.* Biella, G.* De Franco, R.* Deschamps, A.* Cocco, M.* Mirabile, L.* Romeo, R.* |
Title: | A P-wave velocity model of the upper crust of the Sannio region (Southern Apennines, Italy) | Issue Date: | Oct-1998 | Series/Report no.: | 4/41 (1998) | URI: | http://hdl.handle.net/2122/1473 | Keywords: | southern Apennines upper crustal structure 2D P-wavw velocity model |
Subject Classification: | 04. Solid Earth::04.06. Seismology::04.06.09. Waves and wave analysis | Abstract: | This paper describes the results of a seismic refraction profile conducted in October 1992 in the Sannio region, Southern Italy, to obtain a detailed P-wave velocity model of the upper crust. The profile, 75 km long, extended parallel to the Apenninic chain in a region frequently damaged in historical time by strong earthquakes. Six shots were fired at five sites and recorded by a number of seismic stations ranging from 41 to 71 with a spacing of 1-2 km along the recording line. We used a two-dimensional raytracing technique to model travel times and amplitudes of first and second arrivals. The obtained P-wave velocity model has a shallow structure with strong lateral variations in the southern portion of the profile. Near surface sediments of the Tertiary age are characterized by seismic velocities in the 3.0-4.1 km/s range. In the northern part of the profile these deposits overlie a layer with a velocity of 4.8 km/s that has been interpreted as a Mesozoic sedimentary succession. A high velocity body, corresponding to the limestones of the Western Carbonate Platform with a velocity of 6 km/s, characterizes the southernmost part of the profile at shallow depths. At a depth of about 4 km the model becomes laterally homogeneous showing a continuous layer with a thickness in the 3-4 km range and a velocity of 6 km/s corresponding to the Meso-Cenozoic limestone succession of the Apulia Carbonate Platform. This platform appears to be layered, as indicated by an increase in seismic velocity from 6 to 6.7 km/s at depths in the 6-8 km range, that has been interpreted as a lithological transition from limestones to Triassic dolomites and anhydrites of the Burano formation. A lower P-wave velocity of about 5.0-5.5 km/s is hypothesized at the bottom of the Apulia Platform at depths ranging from 10 km down to 12.5 km; these low velocities could be related to Permo-Triassic siliciclastic deposits of the Verrucano sequence drilled at the bottom of the Apulia Platform in the Apulia Foreland. |
Appears in Collections: | Annals of Geophysics Manuscripts |
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