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

Varotsos, P.; Sarlis, N. V.; Skordas, E. S.; Lazaridou-Varotsos, Mary S.

doi:10.1007/s11589-017-0189-0

Cited by 8 publications

(5 citation statements)

References 42 publications

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“…The figure displays the two main types of serrations: large primary serrations and small, interspersed secondary serrations. Serrations have also been observed in different phenomena, such as the Barkhausen noise in magnetic materials [8,[71][72][73][74] (see Figure 5), crackling noise during earthquakes [75][76][77][78], discrete strain bursts in nanocrystals [76], various economic indices [79][80][81][82][83], and neuronal avalanches that occur during the operation of the brain's network (see Figure 6) [84][85][86][87][88][89][90][91][92]. Endurance limits of the Al0.5CoCrCuFeNi HEA as a function of the ultimate tensile strength, compared with other structural materials and bulk metallic glasses (BMGs) (reproduced from Reference [68] with permission).…”

Section: The Serrated-flow Phenomenonmentioning

confidence: 99%

A Review of the Serrated-Flow Phenomenon and Its Role in the Deformation Behavior of High-Entropy Alloys

Brechtl

Chen

Lee

et al. 2020

Metals

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High-entropy alloys (HEAs) are a novel class of alloys that have many desirable properties. The serrated flow that occurs in high-entropy alloys during mechanical deformation is an important phenomenon since it can lead to significant changes in the microstructure of the alloy. In this article, we review the recent findings on the serration behavior in a variety of high-entropy alloys. Relationships among the serrated flow behavior, composition, microstructure, and testing condition are explored. Importantly, the mechanical-testing type (compression/tension), testing temperature, applied strain rate, and serration type for certain high-entropy alloys are summarized. The literature reveals that the serrated flow can be affected by experimental conditions such as the strain rate and test temperature. Furthermore, this type of phenomenon has been successfully modeled and analyzed, using several different types of analytical methods, including the mean-field theory formalism and the complexity-analysis technique. Importantly, the results of the analyses show that the serrated flow in HEAs consists of complex dynamical behavior. It is anticipated that this review will provide some useful and clarifying information regarding the serrated-flow mechanisms in this material system. Finally, suggestions for future research directions in this field are proposed, such as the effects of irradiation, additives (such as C and Al), the presence of nanoparticles, and twinning on the serrated flow behavior in HEAs.

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Section: The Serrated-flow Phenomenonmentioning

confidence: 99%

A Review of the Serrated-Flow Phenomenon and Its Role in the Deformation Behavior of High-Entropy Alloys

Brechtl

Chen

Lee

et al. 2020

Metals

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“…By considering the standard deviation 3(f) of ref. [35] where one can read that the mean value is 0.55 while the standard deviation is 0.23. In view of the fact that the maximum value attained on 22 December 2010 is around 1.35, we find that this maximum corresponds to a fluctuation of around 3.5 standard deviations.…”

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confidence: 99%

“…The precursory change on 22 December 2010 discussed for the first time in this paper is shown with an arrow. The descriptive statistics of β300 have been presented in fig.3(f) of ref [35]. where one can read that the mean value is 0.55 while the standard deviation is 0.23.…”

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confidence: 99%

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

Varotsos¹,

Skordas²

2019

EPL

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Applying the natural time analysis to the Japanese seismic data, we find that almost three months before the 11 March 2011 M9 Tohoku earthquake the order parameter fluctuations of seismicity exhibited an abrupt increase with a natural time scale dependence that has a functional form strikingly reminiscent of the one discussed by Penrose and coworkers in computer simulations of phase transition kinetics using the ideas of Lifshitz and Slyozov. This increase on 22 December 2010, which is shown to be of profound statistical significance by employing the recent method of event coincidence analysis, accompanies increased fluctuations of the entropy change of seismicity under time reversal that obey the Lifshitz-Slyozov-Wagner theory for phase transitions. On the same date the entropy change of seismicity under time reversal is minimized, while the order parameter fluctuations of seismicity exhibit a minimum almost two weeks later.

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“… 37 ). Later studies of this order parameter have shown 18 , 42 – 44 that its fluctuations β W ( κ 1 ) when studied within excerpts of the EQ catalog comprising W consecutive EQs, they exhibit characteristic minima that almost coincide 17 , 45 , 46 with the observation of Seismic Electric Signals (SES) activities 47 , 48 which are series of low-frequency (≤1 Hz) variations of the electric field of the Earth that appear a few weeks up to six months before EQs in Greece 48 – 53 and Japan 36 , 54 – 57 . Interestingly, the average lead time of SES activities corresponds to the average time for the observation of the precursory minima of β W ( κ 1 ), thus showing the existence of a characteristic time scale of the order of a few months that dominates the last stage of the preparation of a strong EQ.…”

Section: Introductionmentioning

confidence: 99%

Micro-scale, mid-scale, and macro-scale in global seismicity identified by empirical mode decomposition and their multifractal characteristics

Sarlis

Skordas

Mintzelas

et al. 2018

Sci Rep

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The magnitude time-series of the global seismicity is analyzed by the empirical mode decomposition giving rise to 14 intrinsic mode functions (IMF) and a trend. Using Hurst analysis one can identify three different sums of these IMFs and the trend which exhibit distinct multifractal behaviour and correspond to micro-, mid- and macro-scales. Their multifractal detrended fluctuation analysis reveals that the micro-scale time-series exhibits anticorrelated behaviour in contrast to the mid-scale one which is long-range correlated. Concerning the mid-scale one, in the range of 30 to 300 consecutive events the maximum entropy method power spectra indicates that it exhibits an 1/fα behaviour with α close to 1/3 which is compatible with the long-range correlations identified by detrended fluctuation analysis during periods of stationary seismicity. The results have been also verified to hold regionally for the earthquakes in Japan and shed light on the significance of the mid-scale of 30 to 300 events in the natural time analysis of global (and regional) seismicity. It is shown that when using the mid-scale time-series only, we can obtain results similar to those obtained by the natural time analysis of global seismicity when focusing on the prediction of earthquakes with M ≥ 8.4.

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

Cited by 8 publications

References 42 publications

A Review of the Serrated-Flow Phenomenon and Its Role in the Deformation Behavior of High-Entropy Alloys

A Review of the Serrated-Flow Phenomenon and Its Role in the Deformation Behavior of High-Entropy Alloys

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

Micro-scale, mid-scale, and macro-scale in global seismicity identified by empirical mode decomposition and their multifractal characteristics

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