GNGTS 2014 - Atti del 33° Convegno Nazionale

26 GNGTS 2014 S essione 2.1 Radon is a heavy gas, so it can be pushed up by warmer gases, or by underground water. At this day, we have noted that an increase of Radon mean values can forewarn a seismic period, not always immediately, but a sudden increasing of Radon emission is always accompanied by a temperature rise and by a rise in frequency of rumble events, with or without earthquakes. The sudden increasing to the high value of 1517 Bq/m 3 on December 2, 2013, was simultaneous with an increase in temperature (over 5° the mean) in SPSC basement and was preceded by several rumbles, similar to underground rolls of timbals, and to far gun shots, but acoustically stifled. The “brontides”, similar to a closing of a big underground door were numerous, especially at the beginning of the Radon increasing. They remind some kind of floating pistons, tossed by underground water. These brontides, in fact, at the beginning of the long sequence of rumbles, are rhythmical enough, with short period of constant intervals of events. Actually, on December 3, 2013, a little earthquakes happened in Cuneo’s area, with a magnitude of 2.6 Richter. But we must not think that there can be a possible correlation between high average values of Radon emission and high values of magnitude of the future earthquake, because the valuations based on graphic analysis do not confirm this. In Fig. 3, rumbles happened just before every sudden increase in mean values, with animal alarms 50-80 second before every rumble. Conclusion. We can resume the following: a- The interesting geological structure of Valle Pellice, especially of Vandalino Mountain and Castelluzzo Peak presents good opportunities of development to the research on seismic precursors; b- During pre-seismic phase, the increases in Radon emission, in temperature values and in the frequency of rumble events are connected together; the future earthquakes can happen not always soon, but these parameters can be good precursors, with short, medium and long forecast period; c- Always with a sudden increase in Radon emission and in soil temperature there are rumbles of different typology: 1- underground rumbles similar to underground thunders, to underground rolls of timbals, to an underground landslide of big rolling stones; there are also “mistpoeffers” similar to far gun shots, but acoustically stifled, “brontides”, similar to a close of a big underground door; 2 - rumbles in the air similar to single blows in air, without echo, or wind blows, with a temporal long term, or to far gun shots (rarer); d- Animals always give alarms before rumbles, with or without following earthquakes; Fig. 3 – Radon 222 emission in SPSC, October-December, 2013.