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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy<br />

(S) - <strong>IASPEI</strong> - International Association of Seismology and Physics of the Earth's<br />

Interior<br />

JSS011 Poster presentation 2164<br />

Seismotectonics of the southern Tyrrhenian compressive region, Italy<br />

Dr. Debora Presti<br />

Earth Science Dept. University of Messina <strong>IASPEI</strong><br />

Andrea Billi, Claudio Faccenna, Giancarlo Neri, Barbara Orecchio<br />

The application of a new technique of earthquake location (Bayloc) and the evidences inferred by<br />

structural data in the south-Tyrrhenian area have contributed to the definition of the tectonic<br />

architecture and active kinematics of the seismogenic apparatus of the plate compressive margin in this<br />

region. Compressional displacements have resumed at the rear of the Maghrebian orogenic wedge since<br />

about 700-500 ka and are presently accommodated along a seismic belt in the south-Tyrrhenian area,<br />

where a passive margin has developed during late Neogene-Quaternary times. Main seismological<br />

results show that the studied compressive belt is characterized by spatially-discontinuous epicentral<br />

clusters with major NW-SE and SW-NE trends and by hypocentral clusters dipping toward the north at<br />

angles greater than 60. These seismic clusters are here interpreted as high-angle, S-verging, reverse<br />

fault zones constituting an early tectonic architecture of the recently-inverted (i.e. younger than about<br />

700-500 ka) passive margin, which developed during late-Neogene-Quaternary time at the border of the<br />

Tyrrhenian backarc basin. Brittle deformations in the Quaternary volcanic island of Usticaare consistent<br />

with the geometry and kinematics of the seismic belt as deduced from the seismological data. The<br />

south-Tyrrhenian active belt may constitute an early stage of subduction of the Tyrrhenian oceanic crust<br />

beneath Sicily. A similar scenario has been hypothesized also for the westward prolongation of the<br />

south-Tyrrhenian belt off . On the basis of instrumental and historical seismic data, combined with<br />

tectonic and morphological information, a maximum seismic potential corresponding to magnitudes<br />

between 6.0 and 7.0 is proposed for the south-Tyrrhenian seismic belt as the most likely scenario. The<br />

segmented geometry of this belt should prevent from the occurrence of stronger earthquakes. These<br />

data may result important for mitigating the seismic and tsunamic hazards in such a densely populated<br />

region.<br />

Keywords: seismicity, tectonics, dynamics

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