Evaluation of ULF electromagnetic phenomena associated with the 2000 Izu Islands earthquake swarm by wavelet transform analysis

Han, Pu; Hattori, Katsumi; Huang, Qinghua; Hirano, Takuya; Ishiguro, Yuki; Yoshino, Chie; Febriani, Febty

doi:10.5194/nhess-11-965-2011

Cited by 47 publications

(25 citation statements)

References 20 publications

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“…In particular, the main frequency found in the analysed ULF seismomagnetic is around 0.01 Hz, a period of 100 s; however, this main frequency can change depending on the direction, the distance, and the magnitude of each EQ analysed (Chavez et al 2011). Similar periods of the ULF seismo-magnetic phenomena have been reported by Hayakawa et al (1996), Uyeda et al (2002), Hattori (2004), Hattori, Han, Yoshino, et al (2013), Hattori, Han, and Huang (2013), and Han et al (2011Han et al ( , 2014. …”

Section: St-music-based Geomagnetic Wave Analysissupporting

confidence: 67%

Novel ST-MUSIC-based spectral analysis for detection of ULF geomagnetic signals anomalies associated with seismic events in Mexico

Chavez

Amezquita-Sanchez

Valtierra-Rodríguez

et al. 2015

Geomatics, Natural Hazards and Risk

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(2016) Novel ST-MUSIC-based spectral analysis for detection of ULF geomagnetic signals anomalies associated with seismic events in Mexico, Geomatics, Natural Hazards and Risk, 7:3, 1162-1174, DOI: 10.1080/19475705.2015 Recently, the analysis of ultra-low-frequency (ULF) geomagnetic signals in order to detect seismic anomalies has been reported in several works. Yet, they, although having promising results, present problems for their detection since these anomalies are generally too much weak and embedded in high noise levels. In this work, a short-time multiple signal classification (ST-MUSIC), which is a technique with high-frequency resolution and noise immunity, is proposed for the detection of seismic anomalies in the ULF geomagnetic signals. Besides, the energy (E) of geomagnetic signals processed by ST-MUSIC is also presented as a complementary parameter to measure the fluctuations between seismic activity and seismic calm period. The usefulness and effectiveness of the proposal are demonstrated through the analysis of a synthetic signal and five real signals with earthquakes. The analysed ULF geomagnetic signals have been obtained using a tri-axial fluxgate magnetometer at the Juriquilla station, which is localized in Queretaro, Mexico (geographic coordinates: longitude 100.45 E and latitude 20.70 N). The results obtained show the detection of seismic perturbations before, during, and after the main shock, making the proposal a suitable tool for detecting seismic precursors.

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Section: St-music-based Geomagnetic Wave Analysissupporting

confidence: 67%

Novel ST-MUSIC-based spectral analysis for detection of ULF geomagnetic signals anomalies associated with seismic events in Mexico

Chavez

Amezquita-Sanchez

Valtierra-Rodríguez

et al. 2015

Geomatics, Natural Hazards and Risk

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“…Recognition of anomalous pre-earthquake phenomena has been reported for major earthquakes since 1990 (Fraser-Smith et al, 1990;Bernardi et al, 1991;Molchanov et al, 1992;Kopytenko et al, 1993;Lin and Zeng, 1992;Hayakawa et al, , 1999Hayakawa et al, , 2000Kawate et al, 1998;Gotoh et al, 2002;Hattori et al, 2002Hattori et al, , 2004aHattori, 2004;Liu et al, 2006;Molchanov and Hayakawa, 2008;Chen et al, , 2011Han et al, 2011;Wen et al, 2012). These reports indicate that geomagnetic anomalies prior to earthquakes are caused by either momentary existence of earthquake-related high conductivity materials or the movement of electric current along faults (Zeng et al, 1995;Merzer and Klemperer, 1997;Yen et al, 2004).…”

Section: Introductionmentioning

confidence: 88%

Evaluation of seismo-electric anomalies using magnetic data in Taiwan

Chen

Hsu

Wen

et al. 2013

Nat. Hazards Earth Syst. Sci.

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The Parkinson vectors derived from 3-component geomagnetic data via the magnetic transfer function are discussed with respect to epicentre locations and hypocentre depths of 16 earthquakes (M ≥ 5.5) in Taiwan during a period of 2002–2005. To find out whether electric conductivity changes would happen particularly in the seismoactive depth ranges, i.e. in the vicinity of the earthquake foci, the frequency dependent penetration depth of the electromagnetic waves (skin effect) is taken into account. The background distributions involving the general conductivity structure and the coast effect at 20 particular depths are constructed using the Parkinson vectors during the entire study period. The background distributions are subtracted from the time-varying monitor distributions, which are computed using the Parkinson vectors within the 15-day moving window, to remove responses of the coast effect and underlying conductivity structure. Anomalous depth sections are identified by deviating distributions and agree with the hypocentre depths of 15 thrust and/or strike-slip earthquakes with only one exception of a normal fault event

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“…Hattori, et al [4] reported that the best frequency to observe seismogenic activity is 0.01 Hz. This was supported by Hirano and Hattori [15] and Han, et al [16] who studied earthquakes in the Izu and Baso Peninsulas during the year of 2000 using a periodogram to analyze the magnetometer network with a sampling rate of 50 Hz. They also found that a spectrum frequency similar to the one stated above to be a suitable frequency to analyze the polarization ratio to indicate anomalous ULF emissions.…”

Section: Relevant Methods In Previous Researchesmentioning

confidence: 99%

“…Other research that also used the spectrum frequency in a similar range, below 0.1 Hz, was conducted by Hattori, et al [20]. Hattori, et al [21][22] and Han, et al [16] also reported anomalies associated with the seismogenic ULF emission spectrum to be at f = 0.01 Hz, based on research executed on the Izu and Baso Peninsulas in the Kanto region of Japan.…”

Section: Relevant Methods In Previous Researchesmentioning

confidence: 99%

Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012

et al. 2015

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Abstract. Eleven strong Sumatran earthquakes, with their epicenter less than 550 km away from the Kototabang (KTB) geomagnetic station (2007)(2008)(2009)(2010)(2011)(2012), were studied to examine the occurrence of anomalous ultra-low frequency emissions (ULF-EM). Anomalous ULF signals, possibly associated with the earthquake's precursors, were determined by the Welch ratio S Z /S H at 0.06 Hz at the KTB station. These ULF anomalies were then compared with geomagnetic data observed from two reference stations in Darwin and Davao, to prevent misinterpretation of global geomagnetic disturbances as precursors. This study aims to analyze the relationship between earthquake magnitude and hypocenter radius, and seismic index against lead time during ULF-EM anomalies. We used the polarization ratio Welch method in terms of power spectrum density to evaluate the geomagnetic data by overlapping windows and applying fast Fourier transform (FFT). The results showed anomalous variations in onset and lead time, determined using the standard deviation controlling the S Z /S H power pattern. Our positive correlation between lead time of ULF emission and earthquake magnitude as well as between lead time and seismic index. It shows a negative correlation between hypocenter distances to KTB station against lead time.

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Evaluation of ULF electromagnetic phenomena associated with the 2000 Izu Islands earthquake swarm by wavelet transform analysis

Cited by 47 publications

References 20 publications

Novel ST-MUSIC-based spectral analysis for detection of ULF geomagnetic signals anomalies associated with seismic events in Mexico

Novel ST-MUSIC-based spectral analysis for detection of ULF geomagnetic signals anomalies associated with seismic events in Mexico

Evaluation of seismo-electric anomalies using magnetic data in Taiwan

Anomalous ULF Emissions and Their Possible Association with the Strong Earthquakes in Sumatra, Indonesia, during 2007-2012

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