Natural time analysis: Important changes of the order parameter of seismicity preceding the 2011 M9 Tohoku earthquake in Japan

2019 ◽  
Vol 125 (6) ◽  
pp. 69001 ◽  
Author(s):  
P. A. Varotsos ◽  
N. V. Sarlis ◽  
E. S. Skordas
Keyword(s):  
Order Parameter ◽  
Tohoku Earthquake ◽  
Time Analysis ◽  
Natural Time ◽  
Natural Time Analysis

scholarly journals Natural Time Analysis: The Area under the Receiver Operating Characteristic Curve of the Order Parameter Fluctuations Minima Preceding Major Earthquakes

Entropy ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 583 ◽  
Author(s):  
Nicholas V. Sarlis ◽  
Efthimios S. Skordas ◽  
Stavros-Richard G. Christopoulos ◽  
Panayiotis A. Varotsos
Keyword(s):  
Order Parameter ◽  
Characteristic Curve ◽  
Activity Patterns ◽  
Space Physics ◽  
Operating Characteristics ◽  
Time Analysis ◽  
Natural Time ◽  
Natural Time Analysis ◽  
Electric Signals ◽  
Receiver Operating

It has been reported that major earthquakes are preceded by Seismic Electric Signals (SES). Observations show that in the natural time analysis of an earthquake (EQ) catalog, an SES activity starts when the fluctuations of the order parameter of seismicity exhibit a minimum. Fifteen distinct minima—observed simultaneously at two different natural time scales and deeper than a certain threshold—are found on analyzing the seismicity of Japan from 1 January 1984 to 11 March 2011 (the time of the M9 Tohoku EQ occurrence) 1 to 3 months before large EQs. Six (out of 15) of these minima preceded all shallow EQs of magnitude 7.6 or larger, while nine are followed by smaller EQs. The latter false positives can be excluded by a proper procedure (J. Geophys. Res. Space Physics 2014, 119, 9192–9206) that considers aspects of EQ networks based on similar activity patterns. These results are studied here by means of the receiver operating characteristics (ROC) technique by focusing on the area under the ROC curve (AUC). If this area, which is currently considered an effective way to summarize the overall diagnostic accuracy of a test, has the value 1, it corresponds to a perfectly accurate test. Here, we find that the AUC is around 0.95 which is evaluated as outstanding.

scholarly journals M W9 Tohoku earthquake in 2011 in Japan: precursors uncovered by natural time analysis

2017 ◽  
Vol 30 (4) ◽  
pp. 183-191 ◽  
Author(s):  
Panayiotis A. Varotsos ◽  
Nicholas V. Sarlis ◽  
Efthimios S. Skordas ◽  
Mary S. Lazaridou-Varotsos
Keyword(s):  
Tohoku Earthquake ◽  
Time Analysis ◽  
Natural Time ◽  
Natural Time Analysis

Statistical significance of the precursory minima of the order parameter fluctuations of seismicity by modern methods of Statistical Physics

2020 ◽  
Author(s):  
Panayiotis A. Varotsos ◽  
Nicholas V. Sarlis ◽  
Efthimios S. Skordas ◽  
Stavros-Richard G. Christopoulos
Keyword(s):  
Time Series ◽  
Order Parameter ◽  
Statistical Physics ◽  
Statistical Significance ◽  
Time Analysis ◽  
Seismic Electric Signals ◽  
Natural Time ◽  
Natural Time Analysis ◽  
Global Seismicity ◽  
Electric Signals

<p>An order parameter for seismicity was introduced in the frame of natural time analysis [1].  Recent studies of the fluctuations of this order parameter revealed the existence of minima preceding major earthquakes [2-7]. Here, we review the statistical significance of these minima by using recent methods of Statistical Physics, such as receiver operating characteristics [8] and event coincidence analysis [9,10]. These methods are also applied to the investigation [11] of the statistical significance of Seismic Electric Signals [12].</p><p>References</p><ol><li>Varotsos, P.A.; Sarlis, N.V.; Skordas, E.S. Natural Time Analysis: The new view of time. Precursory Seismic Electric Signals, Earthquakes and other Complex Time-Series; Springer-Verlag: Berlin Heidelberg, 2011.</li> <li>Sarlis, N.V.; Skordas, E.S.; Varotsos, P.A.; Nagao, T.; Kamogawa, M.; Tanaka, H.; Uyeda, S. Minimum of the order parameter fluctuations of seismicity before major earthquakes in Japan, Proc. Natl. Acad. Sci. USA 110 (2013) 13734–13738, dx.doi.org/10.1073/pnas.1312740110.</li> <li>Varotsos, P.A.; Sarlis, N.V.; Skordas, E.S. Study of the temporal correlations in the magnitude time series before major earthquakes in Japan. J. Geophys. Res.: Space Physics 119 (2014) 9192–9206, dx.doi.org/10.1002/2014JA020580.</li> <li>Sarlis, N.V.; Christopoulos, S.R.G.; Skordas, E.S. Minima of the fluctuations of the order parameter of global seismicity. Chaos 25 (2015) 063110, dx.doi.org/10.1063/1.4922300.</li> <li>Sarlis, N.V.; Skordas, E.S.; Christopoulos, S.-R.G.; Varotsos, P.A. Statistical significance of minimum of the order parameter fluctuations of seismicity before major earthquakes in Japan, Pure Appl. Geophys. 173 (2016) 165–172, dx.doi.org/10.1007/s00024-014-0930-8.</li> <li>Sarlis, N.V.; Skordas, E.S.; Mintzelas, A.; Papadopoulou, K.A. Micro-scale, mid-scale, and macro-scale in global seismicity identified by empirical mode decomposition and their multifractal characteristics. Scientific Reports 8 (2018) 9206, dx.doi.org/10.1038/s41598-018-27567-y.</li> <li>Mintzelas, A.; Sarlis, N. Minima of the fluctuations of the order parameter of seismicity and earthquake networks based on similar activity patterns. Physica A 527 (2019) 121293, dx.doi.org/10.1016/j.physa.2019.121293.</li> <li>Fawcett, T., An introduction to ROC analysis, Pattern Recognit. Lett. 27 (2006) 861–874, dx.doi.org/10.1016/j.patrec.2005.10.010.</li> <li>Donges, J.; Schleussner, C.F.; Siegmund, J.; Donner, R. Event coincidence analysis for quantifying statistical interrelationships between event time series. The European Physical Journal Special Topics 225 (2016) 471–487, dx.doi.org/10.1140/epjst/e2015-50233-y.</li> <li>Siegmund, J.F.; Siegmund, N.; Donner, R.V. CoinCalc - A new R package for quantifying simultaneities of event series. Computers & Geosciences 98 (2017) 64-72, dx.doi.org/10.1016/j.cageo.2016.10.004.</li> <li>Sarlis, N.V. Statistical Significance of Earth’s Electric and Magnetic Field Variations Preceding Earthquakes in Greece and Japan Revisited. Entropy 20 (2018) 561, dx.doi.org/10.3390/e20080561.</li> <li>Varotsos, P.; Lazaridou, M. Latest aspects of earthquake prediction in Greece based on seismic electric signals, Tectonophysics 188 (1991) 321–347, dx.doi.org/10.1016/0040-1951(91)90462-2.</li> </ol>

scholarly journals On the Statistical Significance of the Variability Minima of the Order Parameter of Seismicity by Means of Event Coincidence Analysis

2020 ◽  
Vol 10 (2) ◽  
pp. 662 ◽  
Author(s):  
Stavros-Richard G. Christopoulos ◽  
Efthimios S. Skordas ◽  
Nicholas V. Sarlis
Keyword(s):  
Critical Phenomena ◽  
Order Parameter ◽  
Eastern Mediterranean ◽  
Statistical Significance ◽  
Time Analysis ◽  
Strong Earthquakes ◽  
Natural Time ◽  
Natural Time Analysis ◽  
Recent Method ◽  
Global Seismicity

Natural time analysis has led to the introduction of an order parameter for seismicity when considering earthquakes as critical phenomena. The study of the fluctuations of this order parameter has shown that its variability exhibits minima before strong earthquakes. In this paper, we evaluate the statistical significance of such minima by using the recent method of event coincidence analysis. Our study includes the variability minima identified before major earthquakes in Japan and Eastern Mediterranean as well as in global seismicity.

Natural time analysis: Estimation of the occurrence time of a major earthquake from the entropy changes of the preceding seismicity.

2020 ◽  
Author(s):  
Efthimios S Skordas ◽  
Nicholas V. Sarlis ◽  
Mary S Lazaridou-Varotsos ◽  
Panayiotis A Varotsos
Keyword(s):  
Time Reversal ◽  
Tohoku Earthquake ◽  
Entropy Change ◽  
Time Analysis ◽  
Occurrence Time ◽  
Remarkable Change ◽  
Major Earthquake ◽  
Entropy Changes ◽  
Natural Time ◽  
Natural Time Analysis

<p>By analyzing the seismicity in the new time domain termed natural time [1],  the entropy changes of seismicity before major earthquakes have been studied. It was found [2-5] that the key quantity is the entropy change ΔS under time reversal, which is minimized a few months before major earthquakes such as the M9.0 Tohoku earthquake [2] on 11 March 2011 and the M8.2 Chiapas earthquake [3] in Mexico on 7 September 2017; accompanied by an abrupt increase of its fluctuations [4,5]. Here we discuss how these fluctuations may lead to a procedure through which the occurrence time of an impending mainshock can be estimated [6].</p><p>References</p><p>1. Varotsos P.A., Sarlis N.V. and Skordas E.S., <em>Natural Time Analysis: The new view of time. Precursory Seismic Electric Signals, Earthquakes and other Complex Time-Series</em> (Springer-Verlag, Berlin Heidelberg) 2011.</p><p>2. N. V. Sarlis, E. S. Skordas, and P. A. Varotsos, "A remarkable change of the entropy of seismicity in natural time under time reversal before the super-giant M9 Tohoku earthquake on 11 March 2011", EPL (Europhysics Letters), 124 (2018), 29001.</p><p>3. N. V. Sarlis, E. S. Skordas P. A. Varotsos, A. Ramírez-Rojas, E. L. Flores-Márquez, "Natural time analysis: On the deadly Mexico M8.2 earthquake on 7 September 2017", Physica A 506 (2018), 625-634.</p><p>4. P. A. Varotsos, N. V. Sarlis and E. S. Skordas, "Tsallis Entropy Index q and the Complexity Measure of Seismicity in Natural Time under Time Reversal before the M9 Tohoku Earthquake in 2011", Entropy 20 (2018), 757.</p><p>5. A. Ramírez-Rojas, E. L. Flores-Márquez, N. V. Sarlis and P. A. Varotsos, "The Complexity Measures Associated with the Fluctuations of the Entropy in Natural Time before the Deadly México M8.2 Earthquake on 7 September 2017", Entropy 20 (2018), 477.</p><p>6. E. S. Skordas, N. V. Sarlis and P. A. Varotsos “Identifying the occurrence time of an impending major earthquake by means of the fluctuations of the entropy change under time reversal”, EPL (Europhysics Letters), <em>in press</em>.</p>

scholarly journals Identifying the Occurrence Time of the Deadly Mexico M8.2 Earthquake on 7 September 2017

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 301 ◽  
Author(s):  
Nicholas Sarlis ◽  
Efthimios Skordas ◽  
Panayiotis Varotsos ◽  
Alejandro Ramírez-Rojas ◽  
Elsa Flores-Márquez
Keyword(s):  
Order Parameter ◽  
Earthquake Occurrence ◽  
Dynamic Features ◽  
Time Analysis ◽  
Occurrence Time ◽  
Dynamic Phase ◽  
Natural Time ◽  
Natural Time Analysis ◽  
Dynamic Phase Transition ◽  
System Approaches

It has been shown that some dynamic features hidden in the time series of complex systems can be unveiled if we analyze them in a time domain termed natural time. In this analysis, we can identify when a system approaches a critical point (dynamic phase transition). Here, based on natural time analysis, which enables the introduction of an order parameter for seismicity, we discuss a procedure through which we could achieve the identification of the occurrence time of the M8.2 earthquake that occurred on 7 September 2017 in Mexico in Chiapas region, which is the largest magnitude event recorded in Mexico in more than a century. In particular, we first investigated the order parameter fluctuations of seismicity in the entire Mexico and found that, during an almost 30-year period, i.e., from 1 January 1988 until the M8.2 earthquake occurrence, they were minimized around 27 July 2017. From this date, we started computing the variance of seismicity in Chiapas region and found that it approached the critical value 0.070 on 6 September 2017, almost one day before this M8.2 earthquake occurrence.

Remote sensing natural time analysis of heartbeat data by means of a portable photoplethysmography device

2020 ◽  
Vol 42 (6) ◽  
pp. 2292-2302
Author(s):  
G. Baldoumas ◽  
D. Peschos ◽  
G. Tatsis ◽  
V. Christofilakis ◽  
S. K. Chronopoulos ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Time Analysis ◽  
Natural Time ◽  
Natural Time Analysis

Natural-time analysis of critical phenomena: The case of seismicity

2010 ◽  
Vol 92 (2) ◽  
pp. 29002 ◽  
Author(s):  
P. A. Varotsos ◽  
N. V. Sarlis ◽  
E. S. Skordas ◽  
S. Uyeda ◽  
M. Kamogawa
Keyword(s):  
Critical Phenomena ◽  
Time Analysis ◽  
Natural Time ◽  
Natural Time Analysis

Natural Time Analysis of Seismic Time Series

2018 ◽  
pp. 199-235 ◽  
Author(s):  
Nicholas V. Sarlis ◽  
Efthimios S. Skordas ◽  
Panayiotis A. Varotsos
Keyword(s):  
Time Series ◽  
Time Analysis ◽  
Natural Time ◽  
Natural Time Analysis

scholarly journals Phenomena preceding major earthquakes interconnected through a physical model

2019 ◽  
Vol 37 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Panayiotis A. Varotsos ◽  
Nicholas V. Sarlis ◽  
Efthimios S. Skordas
Keyword(s):  
Time Series ◽  
Physical Model ◽  
Order Parameter ◽  
Tohoku Earthquake ◽  
Entropy Change ◽  
Natural Time ◽  
Earth Magnetic Field ◽  
Preceding Period ◽  
Magnetic Field Variations

Abstract. The analysis of earthquake time series in a new time domain termed natural time enables the uncovering of hidden properties in time series of complex systems and has been recently employed as the basis of a method to estimate seismic risk. Natural time also enables the determination of the order parameter of seismicity, which is a quantity by means of which one can identify when the system approaches the critical point (the mainshock occurrence is considered the new phase). Applying this analysis, as an example, to the Japanese seismic data from 1 January 1984 until the super-giant M 9 Tōhoku earthquake on 11 March 2011, we find that almost 3 months before its occurrence the entropy change of seismicity under time reversal is minimized on 22 December 2010, which signals an impending major earthquake. On this date the order parameter fluctuations of seismicity exhibit an abrupt increase. This increase is accompanied by various phenomena; e.g., from this date the horizontal GPS azimuths start to become gradually oriented toward the southern direction, while they had random orientation during the preceding period. Two weeks later, a minimum of the order parameter fluctuations of seismicity appears accompanied by anomalous Earth magnetic field variations and by full alignment of the orientations of GPS azimuths southwards leading to the most intense crust uplift. These phenomena are discussed and found to be in accordance with a physical model which seems to explain on a unified basis anomalous precursory changes observed either in ground-based measurements or in satellite data.

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