Electromagnetic precursors to the 2004 Mid Niigata Prefecture earthquake

Hayakawa, Masashi; Ohta, Kenji; Maekawa, Shigeru; Yamauchi, Takeshi; Ida, Y.; Gotoh, T.; Yonaiguchi, N.; Sasaki, Haruo; Nakamura, Tohru

doi:10.1016/j.pce.2006.02.023

Cited by 50 publications

(31 citation statements)

References 15 publications

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“…Fraser-Smith et al (1990) reported ultra-low frequency (ULF) magnetic field activity in the frequency range 0.01-0.2 Hz that began around 12 days before the main shock of the Loma Prieta earthquake. Similar observations are also reported by Molchanov et al (1992) (M S = 6, Spitak), Hayakawa et al (2006) (M S = 8, Guam), and Prattes et al (2011) (M = 6.3, L'Aquila) amongst others. However, not all large earthquakes exhibit such phenomena.…”

Section: Introductionsupporting

confidence: 89%

Changes in the ultra-low frequency wave field during the precursor phase to the Sichuan earthquake: DEMETER observations

2013

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Abstract. Electromagnetic phenomena observed in association with increases in seismic activity have been studied for several decades. These phenomena are generated during the precursory phases of an earthquake as well as during the main event. Their occurrence during the precursory phases may be used in short-term prediction of a large earthquake. In this paper, we examine ultra-low frequency (ULF) electric field data from the DEMETER satellite during the period leading up to the Sichuan earthquake. It is shown that there is an increase in ULF wave activity observed as DEMETER passes in the vicinity of the earthquake epicentre. This increase is most obvious at lower frequencies. Examination of the ULF spectra shows the possible occurrence of geomagnetic pearl pulsations, resulting from the passage of atmospheric gravity waves generated in the vicinity of the earthquake epicentre.

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Section: Introductionsupporting

confidence: 89%

Changes in the ultra-low frequency wave field during the precursor phase to the Sichuan earthquake: DEMETER observations

2013

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“…In addition, variations of some parameters in the ground, atmosphere and ionosphere during the preparatory phase of an earthquake can produce disturbances in the VLF/LF signals. As reported in many previous studies (Biagi et al, 2001a,b;Biagi and Hayakawa, 2002;Biagi et al, 2004Biagi et al, Q2 , 2005, 2008Hayakawa and Sato, 1994;Hayakawa et al, 1996Hayakawa et al, , 20062010;Morgounov et al, 1994; 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 Molchanov et al, 2006;Rozhnoi et al, 2004Rozhnoi et al, , 2005, 20072009), these disturbances are classified as anomalies; different analysis methods such as the residual dA/dP (Rozhnoi et al, 2004), terminator time TT (Hayakawa et al, 1996), Wavelet spectra and Principal-Component Analysis have been used (Biagi et al, , 2008. In this paper, we analyse some sampled LF signals in the framework of the European radio network, and using the Wavelet analysis, we investigate possible connections between anomalies in the radio signals and the M w ¼ 6.5 earthquake in Crete on October 12, 2013.…”

Section: Introductionsupporting

confidence: 71%

The LF radio anomaly observed before the M w = 6.5 earthquake in Crete on October 12, 2013

Maggipinto

Biagi

Colella

et al. 2015

Physics and Chemistry of the Earth, Parts A/B/C

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a b s t r a c tOn October 12, 2013, an earthquake with M w ¼ 6.5 occurred in the southern Hellenic Arc, approximately 20 km off the west coast of Crete. The main shock, the focal depth of which is on the order of 40 km, was followed by aftershocks felt in the nearby cities and villages, although the aftershock sequence was poor. The epicentre was located at approximately 60 km from a radio receiver in Crete (CRE), which belongs to the European VLF/LF Radio Network. Several days before the earthquake, a clear disturbance occurred in one of the ten radio signals that the CRE receiver sampled. The disturbance, which can be considered an anomaly, appeared in the 216 kHz radio signal radiated by the Radio Monte Carlo (MCO) transmitter. The radio path MCO-CRE crossed directly over the epicentre area of the aforementioned earthquake. In this work, we present a detailed analysis of the MCO signal anomaly using spectral tools. We also investigate the behaviour of other radio signals sampled by the CRE receiver and consider other possible causes of disturbances on the MCO radio signal. We conclude that the disturbance in the MCO radio signal is a convincingly possible precursor of the earthquake in Crete. Emission of electromagnetic waves with a frequency band that includes 216 kHz from the focal zone of the earthquake can provide a satisfactory explanation of the radio anomaly.

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“…Even though Hayakawa et al (2006) have already presented the convincing results on the presence of precursory ionospheric perturbations for this Niigata-chuetsu EQ, we repeat in Fig. 2 the seismo-ionospheric perturbations on the most favorable propagation path of JJY-KCH as shown in Fig.1.…”

Section: Analysis Methods and Analysis Resultsmentioning

confidence: 57%

An evidence on the lithosphere-ionosphere coupling in terms of atmospheric gravity waves on the basis of a combined analysis of surface pressure, ionospheric perturbations and ground-based ULF variations

Nakamura

Korepanov

Kasahara

et al. 2013

JAE

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One major candidate of lithosphere-atmosphere-ionosphere (LAI) coupling mechanism is through atmospheric oscillations triggered near Earth's surface due to some pre-earthquake (EQ) effect, and this channel has been extensively proved by using meteorological disturbances much more easily treated than pre-EQ effects (Korepanov et al., 2009). In the present paper this channel is challengingly studied, for the first time, for pre-EQ phenomena, and we take a rather strong EQ named Niigata-chuetsu EQ on 23 October, 2004 (with magnitude of 6.8 and with depth of 13 km) for which we already know that the ionospheric perturbation did take place prior to the EQ . In this paper the LAI coupling has been intensively studied by means of coordinated observational data (surface atmospheric pressure data as an indicator of atmospheric gravity waves (AGWs), our own subionospheric VLF/LF data as a measure of ionospheric perturbations and the ground-based ULF data as a measure to monitor the modulation in the ionospheric dynamic region). The wavelet analyses for these parameters in different spatial regions have all indicated the enhancements of fluctuations in the wave frequency of 10 ~ 100 min (in the frequency range of AGWs). The correlation of wavelet spectra between the atmospheric pressure and VLF/LF amplitude has yielded a high value with the delay of a few hours, while there is nearly no distinct delay of the wavelet spectra between the ionospheric perturbation and the ground-based ULF fluctuation. These observational facts are compared with the theoretical estimation of AGW hypothesis, which may provide a convincing support to the AGW channel of the LAI coupling.

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Electromagnetic precursors to the 2004 Mid Niigata Prefecture earthquake

Cited by 50 publications

References 15 publications

Changes in the ultra-low frequency wave field during the precursor phase to the Sichuan earthquake: DEMETER observations

Changes in the ultra-low frequency wave field during the precursor phase to the Sichuan earthquake: DEMETER observations

The LF radio anomaly observed before the M w = 6.5 earthquake in Crete on October 12, 2013

An evidence on the lithosphere-ionosphere coupling in terms of atmospheric gravity waves on the basis of a combined analysis of surface pressure, ionospheric perturbations and ground-based ULF variations

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