HR: 1340h
AN: OS23D-1348    [Abstracts]
TI: Tsunami Hazard Assessment for Tsunamis of Tectonic Origin: a new Method Applied to South-West Italy
AU: * Tinti, S
EM: steve@ibogfs.df.unibo.it
AF: Dipartimento di Fisica, Settore di Geofisica, Univers. di Bologna, Viale Carlo Berti Pichat, 8, Bologna, 40127 Italy
AU: Armigliato, A
EM: armigliato@ibogfs.df.unibo.it
AF: Dipartimento di Fisica, Settore di Geofisica, Univers. di Bologna, Viale Carlo Berti Pichat, 8, Bologna, 40127 Italy
AU: Tonini, R
EM: rtonini@ibogfs.df.unibo.it
AF: Dipartimento di Fisica, Settore di Geofisica, Univers. di Bologna, Viale Carlo Berti Pichat, 8, Bologna, 40127 Italy
AU: Maramai, A
EM: maramai@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia (INGV), Via di Vigna Murata, 605, Rome, 00143 Italy
AU: Graziani, L
EM: graziani@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia (INGV), Via di Vigna Murata, 605, Rome, 00143 Italy
AB: Italy has been affected by large tsunamis in the past. From historical catalogues the occurrence rate of tsunamis in the Italian seas is about 15 events per century, which shows that tsunamis are very rare phenomena and that probabilistic techniques cannot be applied with confidence, especially if interest is not nation-wide but is focussed on regional coastal areas. Here a method is presented that derives tsunami potential from the assessment of the occurrence rate of tsunamigenic earthquakes, and that, therefore, makes use of seismic catalogues as the primary source of information. The method is restricted to tsunamis of seismic origin, and nothing can tell on tsunamis generated by volcanic activity and by mass movements. Improving a methodology originally used for a preliminary evaluation of tsunami hazard in Italy more than one decade ago (Tinti, 1991), this paper applies probabilistic seismic hazard techniques focussing on south-west Italy, namely on Calabria and Sicily, that are among the most active seismic regions in Italy. The analysis is based on the Italian seismic catalogue known as CPTI2, that was recently released (2004) and that is integrated with the INGV catalogue, spanning a time period longer than 2000 years. The main steps of the procedure are: 1) estimating the occurrence rate of tsunamigenic earthquakes; 2) assessing the initial disturbance of the sea, with the aid of appropriate relationships between the earthquake size and the ensuing tsunami size; 3) evaluating the expected maximum tsunami height on the coast, on the basis of the known propagation properties of tsunamis. As the result of the analysis, estimated return periods of earthquake-induced tsunamis capable of producing coastal wave heights exceeding a given threshold are computed and shown in the form of suitable maps.
DE: 7223 Seismic hazard assessment and prediction
DE: 4564 Tsunamis and storm surges
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting