Phenomena preceding major earthquakes interconnected through a physical model

Abstract

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.

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

“…Thus, it is highly likely that a preparation stage has already started even before the observation of the local β min at 5 January 2011. Interestingly, recent findings [8,37,99,100] based on the analysis of seismicity in natural time and non-extensive statistical mechanics [101][102][103] have revealed signs of critical behavior related with the preparation of a strong EQ around 22 December 2010 which lies between the date of the global and the regional β min . Fourth, p G 3 , that corresponds to the β min observed when analyzing the mid-scale global seismicity in natural time, is one order of magnitude smaller than p G 2 strengthening the importance of the mid-scale for EQ prediction (cf.…”

Natural Time Analysis: Results Related to Two Earthquakes in Greece during 2019

“…According to the VAN method of short-term earthquake prediction [3,4,6,7,[19][20][21], the electric signals that are emitted from the future focal area as the stress increases prior to the EQ due to the collective (re)orientation (cf. such a cooperativity is a hallmark showing that the region enters the critical stage) [22] of the pre-existing electric dipoles [23] in the ionic constituents of the rocks, e.g., see Figure 1 in [24], follow [7], conductive paths in the solid Earth crust and become detactable at certain (SES sensitive) sites on the Earth's surface giving rise to the so-called selectivity phenomenon [7,17,[25][26][27][28][29][30][31]. This means that an SES measuring station is capable of recording SESs emitted from certain EQ prone areas.…”

Seismic electric signals (SES) and earthquakes: A review of an updated VAN method and competing hypotheses for SES generation and earthquake triggering

“…Likewise, the magnitudes of the observed electric signals at the surface are high (with fields of about 2 x 10 -5 V m -1 ), and events at earthquake-focus depth might need to produce immense signals (10 5 A • m or more) to match observation (Honkura and Kuwata, 1993). Thus mechanisms that occur close to the surface are to be favored (Johnston, 1997;Park et al, 1993;Park, 1996), for example, fluctuations in groudnwater (Varotsos et al, 2019). Critical work was organized in 1993 (Tectonophysics,Volume 224) and 1996 (Lighthill, 1996), and highlights seven features of this VAN method that are problematic:…”