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Robust satellite techniques (RST) for the thermal monitoring of earthquake prone areas: the case of Umbria-Marche October, 1997 seismic events
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Abstract
Several authors claim a space-time correlation between increases in Earth’s emitted Thermal Infra-Red (TIR) radiation
and earthquake occurrence. The main problems of such studies regard data analysis and interpretation,
which are often done without a validation/confutation control. In this context, a robust data analysis technique
(RST, i.e. Robust Satellite Techniques) is proposed which permits a statistically based definition of TIR «anomaly
» and uses a validation/confutation approach. This technique was already applied to satellite TIR surveys in
seismic regions for about twenty earthquakes that occurred in the world. In this work RST is applied for the first
time to a time sequence of seismic events. Nine years of Meteosat TIR observations have been analyzed to characterize
the unperturbed TIR signal behaviour at specific observation times and locations. The main seismic
events of the October 1997 Umbria-Marche sequence have been considered for validation, and relatively unperturbed
periods (no earthquakes with Mb ≥ 4) were taken for confutation purposes. Positive time-space persistent
TIR anomalies were observed during seismic periods, generally overlapping the principal tectonic lineaments
of the region and sometimes focusing on the vicinity of the epicentre. No similar (in terms of relative intensity
and space-time persistence) TIR anomalies were detected during seismically unperturbed periods