GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 2.1 - POSTER GNGTS 2023 Fig. 2. The set of monitored sub-ionospheric channels from the Mefite Station, VLF in red and LF in yellow, are depicted on a Google Earth map. Ten epicenters of moderate earthquakes in the Mediterranean region and one for a seismic event in Iran are also reported for comparison, with the circle dimensions proportional to the respective magnitudes. The use of far VLF transmitters to study strong earthquakes has been presented by several authors over the last three decades. International cooperation includes a network that covers the whole Europe (Biagi et al., 2011). The sub-ionospheric channels, which are above the preparation zone of a future strong earthquake, are expected to influence the power signal. This kind of phenomenon was observed in several cases (Molchanov and Hayakawa, 1998; Clivered et al., 1999; Maekawa et al., 2006) preventing the transmissions several days before the main shocks. The set of sub-ionospheric channels was defined as the set of paths from the transmitter locations (Loudet, 2019) to the Mefite site. The paths were reported in the Google Map of Fig. 2, together with the red circles representing the epicentral areas of moderate earthquakes that occurred from half of November 2022 (downloaded by INGV catalogue http://terremoti.ingv.it/ ). The considered earthquakes are reported in Table 2. Table 2. The earthquake list that interested the Mediterranean region from half of November 2022. Time Latitude Longitude Depth Magnitude EventLocationName 20/11/2022 05:20 43.9027 13.2642 10.3 4.2 Costa Marchigiana Pesarese (Pesaro-Urbino) 20/11/2022 23:25 35.9033 26.3518 83.4 5.4 Crete, Greece [Sea: Greece] 22/11/2022 12:40 36.034 14.1937 17.4 4.3 Malta (MALTA) 23/11/2022 01:08 40.8498 31.0425 10 6.1 Turkey 27/11/2022 03:57 40.9061 31.1938 10 4.8 Turkey 28/11/2022 07:49 44.456 17.8333 10.1 4.3 Bosnia and Herz, [Land] 29/11/2022 20:06 38.2553 24.2424 10 5.0 Greece [Land]