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

Abstract

Very recently the recordings of precursory seismic electric signals (SESsf) in the island of K<span style="text-decoration: overline">o</span>zu-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

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

“…The introduction now of these values into the latest reported (Dologlou, 2013) power law relation σ B = 8.213 t −0.330 , which is under a continuous updating process by the author, leads to an exponent α = 0.329 ± 0.010 with a correlation coefficient R = 0.86 (see Fig. 2 and Table 1).…”

“…(Table 1, no. 23), while solid circles refer to the data sets reported in Table 2 of Dologlou (2013). The new derived power law relation along with its correlation coefficient R and the exponent α = 0.329 are displayed on the top of the diagram.…”

“…We remark that events nos. 11, 13, and 15 (Table 2 of Dologlou, 2013) are always excluded from this relation for reasons explained in detail elsewhere (Dologlou, 2008(Dologlou, , 2009). This new exponent 0.329 is in excellent agreement with the previously found one (i.e.…”

“…Here, we focus on the update of the power law between the lead time of the SES and the stress drop of the earthquake, by introducing the most recent data from 9 January 2013 to 23 September 2013 (see Dologlou, 2013 - Table 2). Two events with M w > 5.0 have been reported in the region (36)(37)(38)(39)(40)(41) • N (19-26) • E (EMSC, 2013) during this period.…”

“…A series of recent articles (Dologlou, 2008(Dologlou, , 2009(Dologlou, , 2010(Dologlou, , 2012(Dologlou, , 2013 showed an interconnection between dynamic parameters of large earthquakes and features of their precursory SES in terms of criticality. Precisely, a power law relation with an exponent falling in the range of critical values for fracture has been found between the lead time of the SES and the stress drop of the earthquake.…”