GNGTS 2019 - Atti del 38° Convegno Nazionale

GNGTS 2019 S essione 2.1 297 strong thunderstorms. Thus, a first comparison of measurements between electrode data and air ion counting rate was tested in these meteorological occurrences, see Fig.2. Charge density inversions were tested for the entire period when the air ion counter operated with continuity. Even with heating system, the air ion counter continuously recorded charge density during few periods. Analysing measured charge density in the occasion of electric oscillations detected at the same station, some case of charge density inversion was detected (Fig. 3). However, major charge density inversions appeared when electric oscillations were not detected. On the other hand, when electric oscillations were detected and air ion counter was operating this phenomenon occurred in 5% of the cases only. These results do not confirm the hypothesis of the presence of charged clouds when the electric field oscillations are measured. Finally, the air ion detectors were used at distances of 5 – 10 m from the electrodes measuring field oscillations: this because their delicacy. Thus, given the smallness of the clouds, the air ion detectors may not have been enveloped by the charged clouds. References Cinti F.R., Faenza L., Marzocchi W., Montone P.; 2004: Probability map of the next M ³ 5.5 earthquakes in Italy. Geochemistry Geophysics Geosystems, Volume 5, Number 11, 1-15. Fidani C. and Marcelli D.; 2017: Ten Years of the Central Italy Electromagnetic Network (CIEN) Continuous Monitoring, Open Journal of Earthquake Research, 6, 73-88. Fidani C.; 2018: An electric cloud model verify for the electric oscillations recorded by CIEN during intense seismic swarms, 37th GNGTS, Bologna. 64-67. Tennakone K.; 2011: Stable spherically symmetric static charge separated configurations in the atmosphere: Implications on ball lightning and earthquake lights. J. Electrostat., 69, 638-640. THE MAGNETIC NETWORK OF CIEN DETECTING ELF PULSES C. Fidani 1,2 , M. Orsini 1 1 Central Italy Electromagnetic Network, Fermo, Italy 2 “A. Bina” Seismic Observatory, Perugia, Italy Continuous long-term EM monitoring is necessary for obtaining reliable results regarding correlations with seismic activity (Uyeda et al. , 2009). Here, a simple and economical recording system for magnetic pulses is reported which is currently operative at the six stations of the Central Italy Electromagnetic Network (CIEN). CIEN was established in the area where a relevant probability of strong earthquake occurrence was assessed by Cinti et al. (2004). The network started to record the electric component of the EM field. This because, past experiences have shown that the pattern of magnetic records did not show a clear and unequivocal correlation with seismogenic activity (Fidani, 2005), despite of some encouraging evidence (Moore, 1964; Rikitake, 1968). Recently, a number of works demonstrated the possibility to detect ULF (Han et al. , 2014) and ELF (Schekotov et al. , 2015) magnetic signatures of earthquakes as well as ELF magnetic pulses measured hours before moderate and strong seismic activity (Bleier et al. , 2009, Scoville et al. , 2015). Similar observations were published for intense seismic events in Italy such as the L’Aquila earthquake M = 6.3 in 2009 (Orsini, 2011), the Emilia earthquake M = 6.0 in 2012 (Curcio, 2012) and the Norcia earthquake M = 6.5 in 2016 (Orsini and Fidani, 2017; 2018a; 2018b). CIEN that has been operating for more than thirteen years starting to record the electric component in 2006 with the first station at San Procolo, close to Fermo (Central Italy), reached a maximum extension of 16 stations in 2015 – 2017 and reduced its extension in the following