1. Ray paths of VLF/LF transmitter radio signals in the seismic Adriatic regions
- Author
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A. Ermini, Patrick H. M. Galopeau, Konstantinos Katzis, Michael E. Contadakis, Pier Francesco Biagi, Mourad Bezzeghoud, Özer Aydogar, Konrad Schwingenschuh, Giovanni Nico, Iren Adelina Moldovan, Aleksandra Nina, Helmut Lammer, Maria Solovieva, Hans Eichelberger, Bruno P. Besser, Mohammed Y. Boudjada, Institut für Weltraumforschung [Graz] (IWF), Osterreichische Akademie der Wissenschaften (ÖAW), Department of Physics [Bari], Università degli studi di Bari Aldo Moro (UNIBA), Istituto per le Applicazioni del Calcolo [Bari] (IAC), Consiglio Nazionale delle Ricerche (CNR), Schmidt United Institute of Physics of the Earth [Moscow] (IPE), Russian Academy of Sciences [Moscow] (RAS), Dipartimento di Ingegneria Industriale [Roma], Università degli Studi di Roma Tor Vergata [Roma], National Institute for Earth Physics [Bucharest] (NIEP), Department of Geodesy and Surveying [Thessaloniki], Aristotle University of Thessaloniki, Institute of Physics [Belgrade], University of Belgrade [Belgrade], European University of Cyprus, Centre of Geophysics of Evora (CGE), Universidade de Évora, HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), and Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
- Subjects
VLF/LF radio signals ,Ray paths ,Adriatic region ,13. Climate action ,[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] ,Settore FIS/07 ,Transmitter ,Geology ,Seismology - Abstract
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.
- Published
- 2021