Electric and magnetic phenomena observed before the volcano-seismic activity in 2000 in the Izu Island Region, Japan
Seiya Uyeda,Masashi Hayakawa,Toshiyasu Nagao,O. A. Molchanov,Katsumi Hattori,Yoshiaki Orihara,Kaoru Gotoh,Y. Akinaga,Hiroyuki Tanaka +8 more
TLDR
Significant anomalous changes in the ultra low frequency range were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan.Abstract:
Significant anomalous changes in the ultra low frequency range (≈0.01 Hz) were observed in both geoelectric and geomagnetic fields before the major volcano-seismic activity in the Izu Island region, Japan. The spectral intensity of the geoelectric potential difference between some electrodes on Niijima Island and the third principal component of geomagnetic field variations at an array network in Izu Peninsula started to increase from a few months before the onset of the volcano-seismic activity, culminating immediately before nearby magnitude 6 class earthquakes. Appearance of similar changes in two different measurements conducted at two far apart sites seems to provide information supporting the reality of preseismic electromagnetic signals.read more
Citations
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Long-range correlations in the electric signals that precede rupture: further investigations.
TL;DR: The correlations within the time series of the seismic electric signal (SES) activities have been studied and certain power spectrum characteristics seem to distinguish SES activities from "artificial" (man-made) electric noises.
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Investigation of seismicity after the initiation of a Seismic Electric Signal activity until the main shock.
TL;DR: Analysis of the time series of small earthquakes, the concept of natural time chi was used and the results revealed that the approach to criticality itself can be manifested by the probability density function (PDF) of kappa(1) calculated over an appropriate statistical ensemble.
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Seismic Electric Signals: An additional fact showing their physical interconnection with seismicity☆
TL;DR: In this paper, the authors apply natural time analysis to the time series of earthquakes and find that the order parameter of seismicity exhibits a unique change approximately at the date(s) at which Seismic Electric Signals (SES) activities have been reported to initiate.
References
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Low‐frequency magnetic field measurements near the epicenter of the Ms 7.1 Loma Prieta Earthquake
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