EGU21-12516
https://doi.org/10.5194/egusphere-egu21-12516
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

A new VLF radio receiver in Greece for the detection of lower ionosphere anomalies before strong seismic events and the preliminary results for a strong (6.7 Mw) earthquake that occurred in Samos (Greece) on 30/10/2020.

Dimitrios Politis1, Stelios Potirakis1, Sagardweep Biswas2, Sudipta Sasmal2, and Masashi Hayakawa3,4
Dimitrios Politis et al.
  • 1University of West Attica, Electrical and Electronics engineering, Greece (d.z.politis@uniwa.gr)
  • 2Indian Centre for Space Physics, Kolkata, India (sagar94m@gmail.com; meet2ss25@gmail.com)
  • 3Hayakawa Institute of Seismo Electromagnetics, Co.Ltd. (Hi-SEM), UEC Alliance Center #521, 1-1- Kojima-cho, Chofu-shi, Tokyo 182-0026, Japan (hayakawa@hi-seismo-em.jp)
  • 4University of Electro-Communications, Advanced Wireless & Communications research Center (AWCC), Chofu, Tokyo 182-8585, Japan (hayakawa@hi-seismo-em.jp)

A new VLF/LF (10 - 47.5 kHz) radio receiver has recently been installed in the University of West Attica, in Athens (Greece), and has been operating in trial mode since April 2020 for the study of sub-ionospheric propagation variations, mainly aiming at the identification of possible earthquake (EQ) precursors or signatures of other extreme geophysical phenomena. The receiver is monitoring signals from a number of transmitters. Most of them are located in Europe, while some are located in Asia, Australia and North America. The recorded data (amplitude and phase) from this receiver are sampled at a rate of 1 sample per second. In this paper we present information about the new VLF/LF receiver as well as preliminary results concerning a very recent, strong (Mw = 6.7), shallow (focal depth = 12 km), EQ that occurred in Greece (epicenter located in the Aegean Sea, off-coast of the Samos island, close to the Greece-Turkey borders) on 30/10/2020, hereafter referred to as Samos’ EQ. The subionospheric propagation data associated with two specific transmitters were analyzed. Τhe first transmitter, with call sign TBB, is located in Denizköy (Turkey) and the location of Samos’ EQ epicenter is within of 5th Fresnel zone of the corresponding propagation path. The second transmitter, with call sign ISR, is located in Negev (Israel) and the location of Samos’ EQ epicenter is in close distance to the borders of the 5th Fresnel zone, so that, considering the magnitude of the specific EQ, the corresponding propagation path could possibly be disturbed. In this paper we present the analysis of the receiver’s amplitude data by means of the Terminator Time Method (TTM) in order to reveal any possible pre-seismic anomaly in the lower ionosphere. Our preliminary results show that there are indications for disturbance of the lower ionosphere a few days before the EQ occurrence.

How to cite: Politis, D., Potirakis, S., Biswas, S., Sasmal, S., and Hayakawa, M.: A new VLF radio receiver in Greece for the detection of lower ionosphere anomalies before strong seismic events and the preliminary results for a strong (6.7 Mw) earthquake that occurred in Samos (Greece) on 30/10/2020., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12516, https://doi.org/10.5194/egusphere-egu21-12516, 2021.

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