The INFREP Network: Present Situation and Recent Results
P. F. Biagi,Roberto Colella,Luigi Schiavulli,A. Ermini,Mohammed Y. Boudjada,Hans Eichelberger,Konrad Schwingenschuh,Konstantinos Katzis,Michael E. Contadakis,Christos Skeberis,Iren Adelina Moldovan,Mourad Bezzeghoud +11 more
- Vol. 08, Iss: 2, pp 101-115
TLDR
In this article, the authors presented the results obtained on the occasion of recent (2016-2017) seismic activities which occurred in the “sensitive” zone of the INFREP network are presented, that is: the location of the receivers, the locations of the VLF/LF transmitters whose signal is sampled, the daily download of the data collected by the receivers on the InfREP server and the method of data analysis used in order to identify possible radio precursors.Abstract:
VLF/LF (20 - 300 kHz) radio waves propagation is affected by different factors such as meteorological conditions, solar bursts and geomagnetic activity. At the same time, variations of some parameters in the ground, in the atmosphere and in the ionosphere occurring during the preparatory phase of earthquakes can produce disturbances in the propagation of the previous signals along their radio paths: these disturbances are the radio precursors. Since 2009, several VLF/LF radio receivers have been installed throughout Europe in order to realize a European (VLF/LF) radio network for studying the VLF/LF radio precursors of earthquakes, called the INFREP network. In this paper, at first the description of the present situation of the INFREP network is presented, that is: the location of the receivers, the location of the VLF/LF transmitters whose signal is sampled, the daily download of the data collected by the receivers on the INFREP server and the method of data analysis used in order to individuate possible radio precursors. Then the results obtained on the occasion of recent (2016-2017) seismic activities which occurred in the “sensitive” zone of the INFREP network are presented. The first case examined is the October 30, 2016 earthquake with Mw = 6.5, which occurred in Central Italy, near Norcia small town; this earthquake was preceded by a strong shock (Mw = 5.9) which occurred 4 days before. The second case presented is the strong (Mw = 6.7) offshore earthquake which occurred on July 20, 2017, near the coast of Turkey and Kos island (Greece) and the third case is the August 8, 2017 earthquake with Mw = 5.0, which also occurred near the coast of Turkey and Kos island (Greece). In all the previous cases radio anomalies were revealed in some radio signals collected by the receiver located in Cyprus. The influence of causes different from seismicity as geomagnetic activity and solar burst, meteorological conditions, malfunction of the receiver and/or the transmitters has been examined and none convincing connections appeared. So, the possibility that the previous anomalies are radio precursors of the earthquakes seems realistic. Finally, some discrepancy of some of these anomalies with respect to the general peculiarities of the radio precursors is presented and discussed.read more
Citations
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Journal ArticleDOI
Statistical and Criticality Analysis of the Lower Ionosphere Prior to the 30 October 2020 Samos (Greece) Earthquake (M6.9), Based on VLF Electromagnetic Propagation Data as Recorded by a New VLF/LF Receiver Installed in Athens (Greece).
Dimitrios Z. Politis,Stelios M. Potirakis,Yiannis Contoyiannis,Sagardweep Biswas,Sudipta Sasmal,Masashi Hayakawa +5 more
TL;DR: In this paper, a very recent, strong (M6.9), and shallow earthquake (EQ) that occurred on 30 October 2020, very close to the northern coast of the island of Samos (Greece).
Proceedings ArticleDOI
Studying the temporal variations of atmosphere physical properties at different spatial and temporal scales by VLF radio signals and space geodesy techniques
TL;DR: In this article, the temporal evolution of the amplitude of very low frequency (VLF) radio signals is used as a means to characterize the seasonal variations of atmosphere at different spatial and temporal scales.
Analysis of ground-based very low frequency signal recorded onboard CSES satellite
Mohammed Y. Boudjada,Hans Eichelberger,Xuemin Zhang,Werner Magnes,Valery V. Denisenko,Andreas Pollinger,Patrick H. M. Galopeau,Konrad Schwingenschuh,Bruno P. Besser +8 more
TL;DR: In this paper, the wave spectral intensity variations associated to very low frequency (VLF) signal observed during the minimum of solar cycle 25 were investigated and the authors analyzed the electric flux above those key regions and estimated the corresponding intensity levels.
Journal ArticleDOI
Satellite Measured Ionospheric Magnetic Field Variations over Natural Hazards Sites
Christoph Schirninger,Hans Eichelberger,Werner Magnes,Mohammed Y. Boudjada,Konrad Schwingenschuh,Andreas Pollinger,Bruno P. Besser,Pier Francesco Biagi,Maria Solovieva,Jindong Wang,Bingjun Cheng,Bin Zhou,Xuhui Shen,Magda Delva,Roland Lammegger +14 more
TL;DR: In this article, the authors investigate magnetic field variations measured at low Earth orbit (LEO) altitudes possibly associated with earthquakes, volcanic eruptions, and artificial outbursts.
References
More filters
Journal ArticleDOI
A Practical Guide to Wavelet Analysis.
TL;DR: In this article, a step-by-step guide to wavelet analysis is given, with examples taken from time series of the El Nino-Southern Oscillation (ENSO).
Journal ArticleDOI
A review on Hilbert‐Huang transform: Method and its applications to geophysical studies
Norden E. Huang,Zhaohua Wu +1 more
TL;DR: Hilbert-Huang transform, consisting of empirical mode decomposition and Hilbert spectral analysis, is a newly developed adaptive data analysis method, which has been used extensively in geophysical research.
Journal ArticleDOI
Estimation of the size of earthquake preparation zones
TL;DR: In this article, an approximate solution of the problem for a soft elastic inclusion in an elastic half-space is presented. But the authors assume that the moduli of the inclusion differ slightly from those of the surrounding medium (by no more than 30%).
Journal ArticleDOI
Subionospheric VLF signal perturbations possibly related to earthquakes
O. A. Molchanov,Masashi Hayakawa +1 more
TL;DR: In this paper, the authors analyzed similar data during periods around 10 other great earthquakes (magnitude M>6) in order to understand the main features of such an effect.
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