Fracto-emissions and statistical seismic precursors: The case-study of Murisengo gypsum mine (January 2018 - June 2019)

In recent decades, a large number of laboratory tests and experimental observations have shown that acoustic, electromagnetic and neutron emissions are phenomena closely related to seismic activity. Through these tests it was demonstrated how, by subjecting brittle or quasi-brittle materials to mechanical stress, it is possible to observe ultrasonic acoustic emissions (AE), electromagnetic emissions (EME) and neutron emissions (NE) during the fracture process. These three forms of energy are called Fracto-emissions and, if analysed simultaneously in specific monitoring sites, can provide important information in terms of environmental protection against seismicity. Beside the Fracto-emissions, the temporal variation of the b-value, a statistical precursor deriving from the Gutenberg-Richter's law for the magnitude-frequency distribution, is proposed as a further parameter for seismic prevention. For the detection of the above-mentioned forms of energy, a specific monitoring platform has been installed at the “San Pietro - Prato Nuovo” gypsum mine located in Murisengo (Alessadria, Italy). In order to reduce interference due to environmental noise, the instrumental control unit has been placed at a depth of about 100 meters. After a brief summary of the experimental evidence observed during the nine semesters of monitoring between June 2013 - December 2017, the following work shows the results relating to the analysis of data acquired in the period January 2018 - June 2019. The purpose of this thesis is to confirm the close temporal correlation between acoustic, electromagnetic and neutron emissions and the seismic events, as already highlighted in the previous works, and to demonstrate how also the temporal variation of the b-value is an important parameter for seismic prevention. In addition, a possible connection between earthquakes and lunar phases has been investigated.