GNGTS 2015 - Atti del 34° Convegno Nazionale

GNGTS 2015 S essione 1.3 167 data recorded during the period 1981-2014 by the INGV permanent seismic network (http:// iside.rm.ingv.it; http://bollettinosismico.rm.ingv.it/ ). We considered a roughly NW-SE oriented sector with coordinates of vertices: lat. 37.05 – long. 10.09, lat. 38.34 – long. 11.24, lat. 35.81 – long. 16.60, lat. 33.73 – long. 14.91. We compiled a catalogue of 575 earthquakes in the time span 1983-2014 (Fig. 3a), although it should be noted that often hypocentres, with large vertical and horizontal errors, are not well constrained because of the few recording stations and unsatisfactory azimuthal coverage of the network. Daily earthquake rate and the associated cumulative seismic strain release (Fig. 3b) was fairly low from 1983 to 2005, except for 1990 and 1992. From mid-2005 to 2013, an increase both in the daily rate of earthquakes and Fig. 2 – Waveform (left) of the local earthquake recorded by PAN2 station (30/12/2006 – 00:02 UTC) and relative spectrogram (right) obtained by 256-points FFT. Fig. 3 – Earthquake density map during the period 1983- 2014 using the algorithm ZMAP (Wiemer, 2001). The inset shows daily number of earthquakes and associated cumulative strain release in Sicily Channel between 1983 and 2014.