HR: 1340h
AN: S43C-1019    [Abstracts]
TI: Seismogenic Fault Detection by Different Hypocenter Location Algorithms in the Southern Tyrrhenian Sea, Italy
AU: * Neri, G
EM: geoforum@unime.it
AF: Dipartimento di Scienze della Terra, Messina University, Salita Sperone, 31, Messina, 98166 Italy
AU: Presti, D
EM: dpresti@unime.it
AF: Dipartimento di Scienze della Terra, Messina University, Salita Sperone, 31, Messina, 98166 Italy
AU: De Natale, G
EM: pino@ov.ingv.it
AF: Osservatorio Vesuviano-INGV, Via Diocleziano, 328, Naples, 80124 Italy
AU: Troise, C
EM: troise@ov.ingv.it
AF: Osservatorio Vesuviano-INGV, Via Diocleziano, 328, Naples, 80124 Italy
AB: We investigated the seismicity occurring in the last few decades along the continental margin of the southern Tyrrhenian region. In this portion of the Nubia-Europe contact belt the Tindari fault (TF) is a regional structure capable of up to 6 magnitude earthquakes linking the ongoing contractional and extensional crustal compartments of Western and Eastern Sicily, respectively. According to several investigators, TF represents the northwestward propagation of the Malta escarpment, a normal fault linking Eastern Sicily to Malta island which produced magnitude 7 earthquakes in the last centuries. West of TF in the Tyrrhenian sea the Sisifo fault crosses the compressional compartment and generates seismicity of maximum magnitude over 6. The prevailing off-shore location of these faults has made the data acquisition slow and the definition of the geophysical and geological features of these structures quite problematic. We applied several hypocenter location algorithms to seismometric data collected in the study region by the national and local seismic networks in the last 25 years with the main purpose of improving the accuracy of the local fault detection. Clear improvement in the knowledge of the fault geometry has been obtained applying the Bayesian location method by Presti et al. (BSSA, 2004) to earthquake sequences and swarms recorded between 1978 and 2003. In our investigation of hypocenter locations, we also performed synthetic earthquake simulations to test the significance of the main hypocenter trends found, i.e. we established whether a seismolineament or cluster really reflects fault activity or is a fictitious product of the recording network geometry. The results have been evaluated in the light of the geophysical and geological information available in the literature for the study region.
DE: 9335 Europe
DE: 7230 Seismicity and seismotectonics
DE: 7215 Earthquake parameters
SC: Seismology [S]
MN: 2004 AGU Fall Meeting