Toward the development of a multi parametric system for a short-term assessment of the seismic hazard in Italy

Abstract

With the aim to develop a multi-parametric system devote to improving our present capability to assess seismic hazard particularly in the short-medium term, the preliminary step is to identify those parameters that have demonstrated their non-casual relation with earthquake occurrences and whose anomalous variations can be associated to the complex seismic process. Since 80, fluctuations of Earth thermally emitted radiation, measured by satellite sensors in the Thermal InfraRed (TIR) spectral region, have been reported by several authors in some connection with the occurrence of earthquakes; they and can be considered as one of the possible parameters to include within a multi-parametric system. In this paper, the Robust Satellite Techniques (RST) approach has been exploited to highlight Significant Sequences of TIR Anomalies (SSTAs) possibly related to seismic events happened in Italy in the period June 2004 - December 2014. In particular, we evaluated the level of correlation between occurrence of earthquakes with M≥4 and RST-based TIR anomalies using two different spatial resolutions of MSG-SEVIRI (Meteosat Second Generation -Spinning Enhanced Visible and Infrared Imager) images. Results of the two RST analyses show that the 82% of the identified SSTAs does not disappear when downscaled spatial resolution SEVIRI TIR records were used. For both analyses, more than 60% of SSTAs is apparently in connection with the occurrence of M≥4 earthquakes; more than the 80% of them has tendency to anticipate the occurrence of earthquakes. Although about the 40% of SSTAs is not apparently related to documented seismic activity (false positives), results of random tests (i.e. Molchan’s error diagrams) indicate a non-casual correlation between SSTAs and earthquake occurrences. These results confirm that the parameter “RST-based satellite TIR anomalies” is one of the possible candidates to be included in a multi-parametric system for time-Dependent Assessment of Seismic Hazard (t-DASH).