GNGTS 2018 - 37° Convegno Nazionale

GNGTS 2018 S essione 2.1 339 3-de Liso G., Fidani C., Viotto A.: “Multiple-parameter and seismic precursory phenomenology in unusual animal behaviour in Western Piedmont “, 32° Convegno GNGTS di Trieste 2013, Tema 2, pag. 60-66. 4-de Liso G., C. Fidani C.: “ Seismic Precursory Phenomenology in Unusual Animal Behaviour in Val Pellice, Western Piedmont, in Comparison with Anomalies of Some Physical Parameters ”, Open Journal of Earthquake Research, 2014, n°3, pp. 30-42 Published Online February 2014 5-de Liso G., Fidani C., ViottoA.: “Unusual animal behaviour before earthquakes and multiple parameter monitoring in Western Piedmont ”, SDI PAPER, Original Research Article AN ELECTRIC CLOUD MODEL VERIFY FOR THE ELECTRIC OSCILLATIONS RECORDED BY CIEN DURING INTENSE SEISMIC SWARMS C. Fidani Central Italy Electromagnetic Network, Fermo, Italy “A. Bina” Seismic Observatory, Perugia, Italy The Central Italy Electromagnetic Network (CIEN) was realised where a relevant probability of strong earthquake occurrence was calculated in recent studies (Cinti et al. , 2004) and, in fact, three periods of major earthquakes have occurred throughout three different regions of Central Italy over the last decade, leading to deaths and extensive damage. The April 6 L’Aquila earthquake in 2009, the May 20 Modena earthquake in 2012 and the Amatrice – Norcia – Capitignano sequence which occurred August 24, October 30 in 2016 and January 18 in 2017, respectively. Four earthquakes occurred at these times having reached the magnitude of 6: L’Aquila Mw = 6.3, Modena Mw = 6.0, Amatrice Mw = 6.0 and Norcia Mw = 6.6. Whereas, 14 earthquakes overcame magnitude 5 in Central Italy during the same period, including the July 23 Ancona earthquake in 2013 with Mw = 5.0 and the October 26 Castelsantangelo sul Nera earthquakes in 2016 with Mw = 5.9 and Mw = 5.4. Oscillations in electric amplitudes were recorded by CIEN during all these three periods with amplitudes greater than normally measured. These oscillations are well discriminated from other natural signals and of anthropic origin in spectrograms (Fidani, 2011). Patterns recorded during all three periods were generally the same: they lasted from a few minutes up to two hours, and concerned frequencies between 40 Hz and 350 Hz. The electrical oscillation intensities observed during strong seismic activity in all the CIEN stations ranged between 100 nV/m and 10 μV/m. Usually, electric oscillation intensities started to increase weeks or months before the main shocks, reached a maxim around the main shocks which were maintained for days or weeks, and then started to decrease returning to normal values in few weeks. CIEN that has been operating for more than twelve years starting to record in 2006 with the first station at San Procolo, Fermo, reached a maximum of 16 stations in 2015 – 2017, and is presently composed of 8 stations. The active CIEN stations are Fermo, Chieti, Camerino, Colfiorito, Avigliano Umbro, Trasacco, Faenza and Narni. The recent decreasing number of active stations was due to the need to publish the results of the first phase of the experiment, to build physical models and waiting to install new detectors. The first phase of the experiment consisted in verifying the presence of electromagnetic radiation in connection with strong earthquakes using electric detectors. In fact, occasional observations centuries ago up until today of earthquake lights in Central Italy suggested the occurrence of electric phenomena in the atmosphere (Fidani, 2005). Measurements by CIEN suggested localised floating sources in the atmosphere of limited dimensions able to generate local horizontal electric fields. Recordings of electric oscillations shown relatively stable phenomena the duration of which go on for up to several hours. For