Criticality features in ULF magnetic fields prior to the 2011 Tohoku earthquake

Hayakawa, Masashi; Schekotov, A.; Potirakis, Stelios M.; Eftaxias, K.

doi:10.2183/pjab.91.25

Cited by 58 publications

(57 citation statements)

References 14 publications

(23 reference statements)

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“…see Refs. [63][64][65][66] for such phenomena observed before t he M = 9 Tohoku mega-earthquake on 11 March 2011) show that the main characteristics (e.g., amplitude, frequency range, lead time) of these precursory changes are similar to those discussed above for SES (which, as mentioned, for strong impending earthquakes are accompanied by detectable magnetic field variations). This observation has prompted the application [67] of the aforementioned criteria (Eq.…”

Section: Results For the Electric And Magnetic Signals That Precede Rsupporting

confidence: 63%

Entropy in Natural Time and the Associated Complexity Measures

Sarlis¹

2017

Preprint

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Natural time is a new time domain introduced in 2001. The analysis of time series associated with a complex system in natural time may provide useful information and may reveal properties that are usually hidden when studying the system in conventional time. In this new time domain, an entropy has been defined and complexity measures based on this entropy as well as its value under time-reversal have been introduced and found applications in various complex systems. Here, we review these applications in the electric signals that precede rupture, e.g., earthquakes, in the analysis of electrocardiograms, as well as in global atmospheric phenomena like the El Niño/La Niña Southern Oscillation.

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Section: Results For the Electric And Magnetic Signals That Precede Rsupporting

confidence: 63%

Entropy in Natural Time and the Associated Complexity Measures

Sarlis¹

2017

Preprint

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“…However, we have to mention that the mechanisms for both phenomena are not well understood, and require further investigation [30]. Our non-conventional analysis based on critical analysis has yielded the presence of lithospheric ULF radiation for the 2011 Tohoku EQ [26], even though no clear signature in lithospheric ULF radiation was found by the conventional statistical analysis for this EQ. The lithospheric ULF radiation is again not so evident for this Kumamoto EQ event, but our future paper [29] will indicate a possibility of finding out criticality even for this Kumamoto EQ event.…”

Section: Discussionmentioning

confidence: 94%

“…But, we cannot come to any definite conclusion on the presence of precursory ULF radiation with this conventional statistical analysis. So that, we have to proceed to the non-conventional analysis such as the application of natural time to these ULF data (e.g., [26] [27] [28]), and those national time results will be published elsewhere [29].…”

Section: A Schekotov Et Al Open Journal Of Earthquake Researchmentioning

confidence: 99%

Electromagnetic Precursors to the 2016 Kumamoto Earthquakes

Schekotov¹,

Izutsu²,

Asano³

et al. 2017

OJER

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The Kumamoto area of Kyusyu Island was attacked by a series of large earthquakes (EQs) in April, 2016. The first two foreshocks had the magnitudes of 6.5 and 6.4, and about 1 day later there was the main shock on 15 April (UT) with magnitude 7.3. These are fault-type EQs, and so we would expect a variety of electromagnetic precursors to these EQs because we had detected different phenomena for the 1995 Kobe EQ, same fault-type EQ. As for the lithospheric effect, the ULF data at Kanoya observatory (about 150 km from the EQ epicenters) are used, but the simple statistical analysis could not provide us with any clear evidence of ULF radiation from the lithosphere. However, our conventional analyses indicated clear signatures in the atmosphere as ULF/ELF impulsive emissions and also in the ionosphere as observed by means of VLF propagation anomalies and ULF depression. ULF/ELF radiation appeared on 8-11 April (in UT) (maximum on 10 and 11 April (UT)), while ULF depression took place on 8 and 10 April (in UT), so that both atmospheric radiation and ionospheric perturbation took place nearly during the same time period.

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“…In addition, as the radial component of the Earth's magnetic field can be used as a measure of the variations in the CMB in periods of time of several months or years, we looked for significant variations in the geomagnetic spectra associated with other major geological events in the Chilean margin, as the latest research shows a statistically significant relation between geomagnetism and earthquakes (Hayakawa and Molchanov, 2002;Pulinets and Boyarchuk, 2004;Varotsos, 2005;Hayakawa et al, 2007Hayakawa et al, , 2015; Molchanov and Hayakawa, 2008;Liu, 2009;De Santis et al, 2015Contoyiannis et al, 2016;Potirakis et al, 2016a, b).…”

Section: Introductionmentioning

confidence: 99%

“…Despite this, there is a great amount of recent and rigorous research that has shown a statistical relation between magnetism and earthquakes, and thus, this effect could not be negligible in other magnetic properties, such as the Rc or the study of particle flux at Earth's ground level (Hayakawa et al, 2015;Contoyiannis et al, 2016;Potirakis et al, 2016a, b;De Santis et al, 2017;Oikonomou et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Latitudinal variation rate of geomagnetic cutoff rigidity in the active Chilean convergent margin

2018

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Abstract. We present a different view of secular variation of the Earth's magnetic field, through the variations in the threshold rigidity known as the variation rate of geomagnetic cutoff rigidity (VRc). As the geomagnetic cutoff rigidity (Rc) lets us differentiate between charged particle trajectories arriving at the Earth and the Earth's magnetic field, we used the VRc to look for internal variations in the latter, close to the 70 • south meridian. Due to the fact that the empirical data of total magnetic field BF and vertical magnetic field Bz obtained at Putre (OP) and Los Cerrillos (OLC) stations are consistent with the displacement of the South Atlantic magnetic anomaly (SAMA), we detected that the VRc does not fully correlate to SAMA in central Chile. Besides, the lower section of VRc seems to correlate perfectly with important geological features, like the flat slab in the active Chilean convergent margin. Based on this, we next focused our attention on the empirical variations of the vertical component of the magnetic field Bz, recorded in OP prior to the Maule earthquake in 2010, which occurred in the middle of the Chilean flat slab. We found a jump in Bz values and main frequencies from 3.510 to 5.860 µHz, in the second derivative of Bz, which corresponds to similar magnetic behavior found by other research groups, but at lower frequency ranges. Then, we extended this analysis to other relevant subduction seismic events, like Sumatra in 2004 and Tohoku in 2011, using data from the Guam station. Similar records and the main frequencies before each event were found. Thus, these results seem to show that magnetic anomalies recorded on different timescales, as VRc (decades) and Bz (days), may correlate with some geological events, as the lithosphereatmosphere-ionosphere coupling (LAIC).

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Criticality features in ULF magnetic fields prior to the 2011 Tohoku earthquake

Cited by 58 publications

References 14 publications

Entropy in Natural Time and the Associated Complexity Measures

Entropy in Natural Time and the Associated Complexity Measures

Electromagnetic Precursors to the 2016 Kumamoto Earthquakes

Latitudinal variation rate of geomagnetic cutoff rigidity in the active Chilean convergent margin

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