Recent seismicity of the «Acque Albule» travertine basin

The seismic period which occurred in a portion of Guidonia Montecelio and Tivoli territory, two towns situated about twenty kilometres NE of Rome, affected four areas with a high density of population: Guidonia, Collefiorito, Villalba and Bagni di Tivoli. Even though the events had a very low magnitude (less than 3.0), local phenomena, like rumbles and strong vibrations of the ground, frightened inhabitants also because some months before (January 26, 2001) in a village named Marcellina situated a few kilometres away from Guidonia, a large sinkhole (600 m) had appeared without fore signals. The «Istituto Nazionale di Geofisica e Vulcanologia» (INGV) installed some digital stations that monitored the seismic phenomena. This paper has the aim to process all the information acquired during the period, both from the micro and macro seismic point of view, in order to explain the phenomenology that involved the area. The synergy of the two methodologies lead us to the conclusion that two different seismotectonic structures originated the events, one in an anti-apenninic direction, the other in a N-S direction

Analisi dei parametri ipocentrali del terremoto del Friuli del 6 maggio 1976

The hypocentral parameters to t0, φ0, λ0, h0, for the main shock occurred in Friuli on May 6th 1976 and itsfore shock were determined by the first arrival method. The computation was tried employing travel-time curves for different crustal models. The results show a very low influence of the travel-time curves on epicentral coordinates, whose error is essentially dependent on the precision of station data. The focal depth, on the contrary, is a parameter directly connected to the model used in the computation, so, if the model is not accurately known, the indetermination can be of the same order of magnitude as the crust thickness, even using very precise recorded data

The uncertainty and ambiguity of isoseismal maps

The problem of defining objective maps is as yet unresolved. The aim of the work, here presented, is to show how the studies of different authors and eras can produce contrasting, even contradictory, interpretations of the macroseismic data set for the same earthquakePublished509-5232SR TERREMOTI - Gestione delle emergenze sismiche e da maremotoN/A or not JC