scholarly journals Comments on the generation mechanism of Seismic Electric Signals

2011 ◽  
Vol 11 (12) ◽  
pp. 3093-3096 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Power Law ◽  
Thermodynamic Model ◽  
Stress Drop ◽  
Lead Time ◽  
Generation Mechanism ◽  
Laboratory Measurements ◽  
Bulk Properties ◽  
Seismic Electric Signals ◽  
Electric Signals ◽  
Recent Laboratory

Abstract. Recent laboratory measurements on rocks under varying pressure lead to results which strengthen a model suggested by the author for the explanation of the power law relation that interconnects the lead time of Seismic Electric Signals and earthquake stress drop. In addition, recent applications of a thermodynamic model that interrelates the defect parameters in materials of geophysical interest and their bulk properties open a new window to further advance the aforementioned explanation.

scholarly journals Power law relationship between parameters of earthquakes and precursory electrical phenomena

2008 ◽  
Vol 8 (5) ◽  
pp. 977-983 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Power Law ◽  
Critical Exponents ◽  
Physical Meaning ◽  
Linear Relation ◽  
Stress Drop ◽  
Lead Time ◽  
Earthquake Magnitude ◽  
Seismic Electric Signals ◽  
Electric Signals ◽  
Fracture Processes

Abstract. A number of Seismic Electric signals data have been accumulated during the last two decades that also includes the signals observed before the magnitude 6 class earthquakes that occurred in Greece very recently i.e., the first two months of 2008. Using all the available data we investigate whether a possible interconnection exists between the lead time of Seismic Electric Signals and the stress drop of subsequent earthquakes. We show that for "non thrust" earthquakes a power law relation emerges with an exponent value around 0.29, the possible physical meaning of which is discussed. This value is very close to the range of critical exponents that govern the fracture processes and is also comparable with the value of the slope, found much earlier by the VAN group, in the linear relation between the logarithm of the SES amplitude and the earthquake magnitude.

scholarly journals Features of criticality in precursory seismic electric signals and earthquakes in Greece

2013 ◽  
Vol 20 (3) ◽  
pp. 411-416 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Power Law ◽  
Critical Exponents ◽  
Stress Drop ◽  
Lead Time ◽  
Northern Greece ◽  
Seismic Region ◽  
Seismic Electric Signals ◽  
The Stability ◽  
Electric Signals

Abstract. Very recently the recordings of precursory seismic electric signals (SESsf) in the island of Kozu-shima, Japan, have been reported, and their interrelation with subsequent earthquakes was shown to be beyond chance. Almost simultaneously, the recording of SES activity in northern Greece was also reported, which was followed by a magnitude 5.7 earthquake in northern Greece. These facts strengthen the aspects on the precursory nature of SESs and also enable the updating of a previously found power law relation between the earthquake stress drop and the lead time of SESs. They led to an exponent of 0.330, which falls in the range of critical exponents for fracture. The stability of this exponent, which results from a large amount of data during the last 30 yr, is remarkable and may thus confirm features of criticality in the pre-seismic region after the SES emission. The underlying physics are also discussed.

scholarly journals Brief Communication: The recent seismic activity in Central Greece in 2013 and its precursory electric signals in terms of criticality

2014 ◽  
Vol 21 (1) ◽  
pp. 149-153 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Power Law ◽  
Critical Exponents ◽  
Stress Drop ◽  
Seismic Activity ◽  
Lead Time ◽  
Dynamic Processes ◽  
Electric Signal ◽  
Central Greece ◽  
The Stability ◽  
Electric Signals

Abstract. Here, we check the obedience of new data, derived from the Mw = 5.4 earthquake on 7 August 2013 in Central Greece, to a previously found power law relation by the author between the stress drop of an earthquake and the lead time of its precursory seismic electric signal (SES). An exponent value α =0.329 has been found which is in excellent agreement with previous ones reported in a series of articles by the author. This value falls in the range of critical exponents suggested by various models for fracture and is very close to a reported one which interconnects the amplitude of the SES and the magnitude of the impending earthquake. The stability of this exponent confirms the credibility of the above-mentioned power law and probably implies that real physical dynamic processes evolving to criticality are present in the pre-focal area when the SES is emitted.

scholarly journals Testing the critical exponent in the relation between stress drop of earthquake and lead time of seismic electric signal

2012 ◽  
Vol 12 (8) ◽  
pp. 2603-2607 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Critical Exponent ◽  
Excellent Agreement ◽  
Power Law ◽  
Critical Exponents ◽  
Stress Drop ◽  
Lead Time ◽  
Dynamic Processes ◽  
Electric Signal ◽  
The One ◽  
Electric Signals

Abstract. The application of new data in the power law relation between the stress drop of the earthquake and the lead time of the precursory seismic electric signal led to an exponent which falls in the range of the values of critical exponents for fracture and it is in excellent agreement with a previous one found by (Dologlou, 2012). In addition, this exponent is very close to the one reported by Varotsos and Alexopoulos (1984a), which interconnects the amplitude of the precursory seismic electric signals (SES) and the magnitude of the impending earthquake. Hence, the hypothesis that underlying dynamic processes evolving to criticality prevail in the pre-focal area when the SES is emitted is significantly supported.

scholarly journals Power law relationship between parameters of earthquakes and precursory electrical phenomena revisited

2009 ◽  
Vol 9 (1) ◽  
pp. 17-23 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Critical Exponent ◽  
Power Law ◽  
Stress Drop ◽  
Lead Time ◽  
Additional Data ◽  
Ionian Sea ◽  
The Past ◽  
Earthquake Preparation ◽  
The One ◽  
Electric Signals

Abstract. The power law relation between the stress drop of "non thrust" earthquakes and the lead time of precursory Seismic Electric Signals (SES), obtained by Dologlou (2008a), has been tested by using additional data from the most recent earthquake that occurred on 8 June 2008, in Andravida, NW. Peloponnesus, Greece and from two other destructive earthquakes that occurred in the past in Ionian sea. A critical exponent α=0.33 is derived which is close to the one (e.g. 0.29) reported by Dologlou (2008a). The above preliminary result strengthens the hypothesis that probably signatures of criticality are present in the earthquake preparation and precursory SES processes and that both phenomena are governed by same physics.

scholarly journals Electrical precursors of earthquakes in Aegean Sea during the last decade (1997–2007)

2008 ◽  
Vol 8 (1) ◽  
pp. 123-128 ◽  
Author(s):  
E. Dologlou ◽  
V. Hadjicontis ◽  
C. Mavromatou
Keyword(s):  
Lead Time ◽  
Aegean Sea ◽  
Time Difference ◽  
Lead Times ◽  
Main Interest ◽  
Seismic Electric Signals ◽  
Precursors Of Earthquakes ◽  
Electric Signals ◽  
Large Earthquakes ◽  
Regional Tectonics

Abstract. The purpose of this study is to investigate some properties of the Seismic Electric Signals (SES) that preceded large earthquakes which occurred in the Aegean Sea (24–27)° E, (37–40)° N, during the last decade. Our main interest is focused on the important parameter of the lead time Δt, which is the time difference between the occurrence of the earthquake and the detection of the associated SES signal. Two groups of lead times, a short (i.e. Δt~ some weeks) and a long one (Δt~ some months) have been observed. We examine whether this difference could be related to the regional tectonics. Furthermore the property of SES selectivity is discussed.

scholarly journals Stability of a power law relation between characteristics of earthquakes and electric precursors

2012 ◽  
Vol 12 (5) ◽  
pp. 1783-1787 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Critical Exponent ◽  
Critical Phenomena ◽  
Power Law ◽  
Stress Drop ◽  
Lead Time ◽  
Dynamic Processes ◽  
Full Agreement ◽  
Focal Area

Abstract. New data were used to test the credibility of a previously reported power law relation between the stress drop of earthquakes and the lead time of precursory SES. Here, we found that the critical exponent of this power law is very sensitive and remains stable around 0.33 only for appropriate sets of data. This value is in full agreement with the reported one in literature for critical phenomena. That means this power law is not an artifact, but probably implies that real physical dynamic processes evolving to criticality are present in the pre-focal area when the SES is emitted. An attempt to advance the underlying physics of the interconnection of the stress drop and the lead time of the precursory SES is still in progress.

scholarly journals Power law relationship between parameters of earthquakes and precursory electrical phenomena revisited II

2010 ◽  
Vol 10 (7) ◽  
pp. 1403-1409 ◽  
Author(s):  
E. Dologlou
Keyword(s):  
Critical Exponent ◽  
Power Law ◽  
Stress Drop ◽  
Lead Time ◽  
Dynamic Processes ◽  
Electric Signal ◽  
Focal Area ◽  
Critical Dynamic ◽  
The Stability ◽  
The One

Abstract. The credibility of the power law relation, reported by Dologlou (2009) between the stress drop of an earthquake and the lead time of the preceded Seismic Electric Signal, SES, has been checked through additional new data from 9 June 2008 to 7 April 2010. Three earthquakes with Mw≥5.5 have been found in Greece during this period. A critical exponent α (e.g. 0.328) has been obtained which compares very well with the one reported (α=0.332) by Dologlou (2009). The stability of this exponent might imply that critical dynamic processes, of mechanical (earthquakes) and also of electromagnetic (SES) sense dominate the pre focal area when the SES signal of the impending earthquake is emitted.

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