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Crustal velocity structure in Italy from analysis of regional seismic waveforms
Bulletin of the Seismological Society of America, 97 (6): 2024--2039 (01.12.2007)
DOI: 10.1785/0120070071
Аннотация
In this article, we use regional seismic waveforms recorded by the
recently installed Istituto Nazionale di Geofisica e Vulcanologia
(INGV) national network and the Mediterranean Very Broadband Seismographic
Network (MedNet) stations to develop 1D crustal velocity models for
the Italian peninsula. About 55,000 P-wave and 35,000 S-wave arrival
times from 4727 events are used to derive average seismic parameters
in the crust and uppermost mantle. We define four regions, according
to geological constraints and recent travel-time tomography results.
Based on the average seismic parameters, we combine broadband seismic
waveforms and travel times of regional phases to model crustal structures
for the four regions by applying the genetic algorithm. Our results
indicate smooth velocity gradients with a depth beneath the Apennines
and a deep Moho beneath the central Alps. Green's functions from
the regionalized 1D velocity models are used to determine source
depths and focal mechanisms for 37 events with a magnitude larger
than 3.5 by a grid search technique. Our results show that normal
and strike-slip faulting source mechanisms dominate the Apenninic
belt and that most thrust faulting events occur in the Adriatic Sea
and the outer margin of the northern Apennines. 10.1785/0120070071
