GNGTS 2017 - 36° Convegno Nazionale

GNGTS 2017 S essione 2.1 315 2016 and reaching a peak a few days after the main shock in Norcia. Chieti Station data before and after the Amatrice earthquake occurring on August 24, 2016, M = 6 were lost. A near constant behaviour had the intensity of ELF oscillations recorded by tha N-S electrode. The Chieti Station has always recorded low ELF activity since 2011. The proposed model to explain electric oscillations (Fidani and Martinelli, 2015) seemed to justify such small values due to the symmetric charge distributions which were supposed to be the sources of the signals. This charged cloud model justified the disappearance of the electric field oscillations far from the source, consequently justifying the absence of correlations among signals recorded by different CIEN stations, as reported in past studies. Vertical conductivity variations recorded by a new instrument installed at several CIEN stations were possibly produced by variations in concentration of air ions (Fidani and Marcelli, 2017). The charged cloud model was in agreement with all the observations made by CIEN around the time of both seismic and meteorologic events. However, the use of this model lead us to test a new instrument. This new instrument, an air ion counter, was installed at the Fermo Station, see Fig. 2. DLY-6A2 Smart Air Ion Counter by Kilter is designed for measuring the concentration of positive and negative air ions per cubic centimeter. The instrument is mainly used to measure the small air ions. The ion collector and electrometer of this counter are designed in one set. This arrangement reduces the measurement noise greatly. The air ion concentration can be read out from the panel LCD display directly, or on a PC using both software and USB cable connection. Other surveys have been carried out by CIEN including the Schumann Resonance monitorings. Prior to this, several studies had reported that ionosphere resulted being influenced by strong seismic activity, for example, ion concentration (Pulinets et al. , 2010). These reported ion concentration variations might have moved the ionosphere boundary, therein disturbing the earth-ionosphere resonances. Electrode altitudes and sound card frequency responses condition the detection of Schumann Resonances. To this regard, the Camerino and Trasacco Stations Fig. 2 - A first recording of air ions made by the Fermo Station with the new instrument air ion counter DLY-6A2 by Kilter on September 21, 2017. Positive air ions are indicated by red lines, while negative ions are indicated by blue ones.