Research output: Contribution to journal › Article › peer-review
Reduction of the vlf signal phase noise before earthquakes. / Nina, Aleksandra; Biagi, Pier Francesco; Mitrović, Srɖan T.; Pulinets, Sergey; Nico, Giovanni; Radovanović, Milan; Popović, Luka.
In: ATMOSPHERE, Vol. 12, No. 4, 444, 01.04.2021.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Reduction of the vlf signal phase noise before earthquakes
AU - Nina, Aleksandra
AU - Biagi, Pier Francesco
AU - Mitrović, Srɖan T.
AU - Pulinets, Sergey
AU - Nico, Giovanni
AU - Radovanović, Milan
AU - Popović, Luka
PY - 2021/4/1
Y1 - 2021/4/1
N2 - In this paper we analyse temporal variations of the phase of a very low frequency (VLF) signal, used for the lower ionosphere monitoring, in periods around four earthquakes (EQs) with magnitude greater than 4. We provide two analyses in time and frequency domains. First, we analyse time evolution of the phase noise. And second, we examine variations of the frequency spectrum using Fast Fourier Transform (FFT) in order to detect hydrodynamic wave excitations and attenuations. This study follows a previous investigation which indicated the noise amplitude reduction, and excitations and attenuations of the hydrodynamic waves less than one hour before the considered EQ events as a new potential ionospheric precursors of earthquakes. We analyse the phase of the ICV VLF transmitter signal emitted in Italy recorded in Serbia in time periods around four earthquakes occurred on 3, 4 and 9 November 2010 which are the most intensive earthquakes analysed in the previous study. The obtained results indicate very similar changes in the noise of phase and amplitude, and show an agreement in recorded acoustic wave excitations. However, properties in the obtained wave attenuation characteristics are different for these two signal parameters.
AB - In this paper we analyse temporal variations of the phase of a very low frequency (VLF) signal, used for the lower ionosphere monitoring, in periods around four earthquakes (EQs) with magnitude greater than 4. We provide two analyses in time and frequency domains. First, we analyse time evolution of the phase noise. And second, we examine variations of the frequency spectrum using Fast Fourier Transform (FFT) in order to detect hydrodynamic wave excitations and attenuations. This study follows a previous investigation which indicated the noise amplitude reduction, and excitations and attenuations of the hydrodynamic waves less than one hour before the considered EQ events as a new potential ionospheric precursors of earthquakes. We analyse the phase of the ICV VLF transmitter signal emitted in Italy recorded in Serbia in time periods around four earthquakes occurred on 3, 4 and 9 November 2010 which are the most intensive earthquakes analysed in the previous study. The obtained results indicate very similar changes in the noise of phase and amplitude, and show an agreement in recorded acoustic wave excitations. However, properties in the obtained wave attenuation characteristics are different for these two signal parameters.
KW - Acoustic and gravity waves
KW - Earthquakes
KW - Ionosphere
KW - Observations
KW - Signal processing
KW - VLF signal
UR - http://www.scopus.com/inward/record.url?scp=85104315898&partnerID=8YFLogxK
U2 - 10.3390/atmos12040444
DO - 10.3390/atmos12040444
M3 - Article
AN - SCOPUS:85104315898
VL - 12
JO - ATMOSPHERE
JF - ATMOSPHERE
SN - 1598-3560
IS - 4
M1 - 444
ER -
ID: 114329948