Ray paths of VLF/LF transmitter radio signals in the seismic Adriatic regions
- 1Institut für Weltraumforschung, Extraterrestrial Physics, Graz, Austria (mohammed.boudjada@oeaw.ac.at)
- 2Department of Physics, University of Bari, Bari, Italy
- 3Institute for Applied Mathematics (IAC), National Research Council of Italy (CNR), Bari, Italy
- 4Institute of the Earth Physics, RAS, Moscow, Russia
- 5Department of Industrial Engineering, University of Tor Vergata, Rome, Italy
- 6National Institute of Earth’s Physics, Seismological Department, Bucharest, Romania
- 7Department of Surveying & Geodesy, University of Thessaloniki, Thessaloniki, Greece
- 8Institute of Physics Belgrade, University of Belgrade, Belgrade, Serbia
- 9Department of Computer Science and Engineering, European University Cyprus, Nicosia, Cyprus
- 10Geophysical Centre of Évora and Physics Department, ECT, University of Évora, Évora, Portugal
- 11LATMOS-CNRS, Université Versailles Saint-Quentin-en-Yvelines, Guyancourt, France
We analyze the radio wave propagations of VLF/LF transmitter signals along subionospheric paths using two different reception systems localized in the Graz seismo-electromagnetic facility (15.43E,47.06N). Those systems allow the simultaneous detection of more than fifteen transmitter signals emitting in the northern (i.e. France, Germany and United Kingdom) and southern (i.e. Italy and Turkey) parts of Europe. In this work, we investigate the transmitter radio wave propagations associated with two earthquakes (EQs) which occurred, at two occasions, in nearly the same Croatian regions (Geo. Long.=16°E; Geo. Lat.=45°N). The first and second EQs happened, respectively, on March 22 and December 29, 2020, with magnitudes Mw equal to 5.4 and 6.4. The use of two complementary reception systems, i.e. INFREP (Biagi et al., Open Journal of Earthquake Research, 8, 2019) and UltraMSK (Schwingenschuh et al., Nat. Hazards Earth Syst. Sci., 11, 2011), and the proximity to the epicenters lead us to characterize the behavior of the transmitter signal amplitudes particularly above the Croatian seismic regions. We analyze the amplitude variation for a given transmitter frequency starting few weeks before the earthquakes occurrences. We discuss the observed anomalies in the transmitter signals which may be considered as precursors due to the ionospheric disturbances of the transmitter ray paths above the earthquakes preparation zones.
How to cite: Boudjada, M. Y., Eichelberger, H. U., Biagi, P. F., Schwingenschuh, K., Nico, G., Solovieva, M., Ermini, A., Moldovan, I. A., Contadakis, M. E., Nina, A., Katzis, K., Bezzeghoud, M., Lammer, H., Galopeau, P. H. M., Besser, B., and Aydogar, Ö.: Ray paths of VLF/LF transmitter radio signals in the seismic Adriatic regions, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7659, https://doi.org/10.5194/egusphere-egu21-7659, 2021.