Pre-Seismic Electrical Signals (SES) generation and their relation to the lithospheric tidal oscillations K2, S2, M1 (T = 12hours / 14 days)

Medium - long term earthquake prediction by the use of the oscillating electric field (T = 365 days) generated due to Earth's orbit around the Sun and due to its consequent oscillating lithospheric deformation

We study the Earth's electric field monitored at PYR (Greece) monitoring site, for a period of more than six years (May 23rd, 2003 to September 7th, 2009). It is compared, in particular its oscillating component of T = 365 days, with the Perihelion - Aphelion dates of the Earth's orbit around the Sun, with the same component of the Earth's magnetic field, with the corresponding same period tidal oscillation and with the occurred large EQs of the same period of time. The obtained results suggest that the oscillating electric field component is generated by large scale piezoelectricity triggered…

The Andravida, Greece EQ (8/06/2008, Ms=7.0R). An "a posteriori" analysis for the determination of its location, occurrence time and magnitude parameters in terms of short-term predictability

The Andravida EQ, Greece (8/6/2008, Ms=7.0R) seismic parameters: location, time of occurrence and magnitude were determined "a posteriori" in an attempt to verify the predictability of the large EQs. The Earth's electric field, after its processing by de-noising techniques, was used, in conjunction with appropriate physical models, for the determination of the epicenter by triangulation. The time of occurrence was determined in very short-term mode by the use of the tidal waves (M1, K1) and the "strange attractor like" seismic electric precursor, while its magnitude was calculated by the appli…

Application of the Huang-Hilbert transform and natural time to the analysis of Seismic Electric Signal activities

The Huang-Hilbert transform is applied to Seismic Electric Signal (SES) activities in order to decompose them into a number of Intrinsic Mode Functions (IMFs) and study which of these functions better represent the SES. The results are compared to those obtained from the analysis in a new time domain termed natural time after having subtracted the magnetotelluric background from the original signal. It is shown that the instantaneous amplitudes of the IMFs can be used for the distinction of SES from artificial noises when combined with the natural time analysis.

On the recent large EQ of Karpathos, Greece (April 1st, 2011, Ms = 6.7R) and its similarities to the large EQ of the January 1st, 2006 (Ms = 6.9R) at East of Kythira, Greece

The recent large EQ that occurred in Greece (April 1st, 2011, Ms = 6.7R) is investigated as far as it concerns regional geophysical features of the Greek territory. In particular, the EQ location is compared to the deep lithospheric fracture zones and faults, derived from the analysis of the corresponding earth's gravity field; to the current seismic potential map determined from the study of the past seismicity, while its time of occurrence is compared to the peaks of the M1 and diurnal tidal waves. The detailed investigation of the earth's electric field that was recorded by the ATH monitori…

The precursory electric signals, observed before the Izmit Turkey EQ (Mw = 7.6, August 17th, 1999), analyzed in terms of a hypothetically pre-activated, in the focal area, large scale piezoelectric mechanism

The generated, prior to the Izmit Turkey large EQ, preseismic electric signals were recorded in Greece by the VOL Earth's electric field monitoring site. In order to explain their peculiar character and their generating mechanism, a large scale piezoelectric mechanism was assumed that was initiated in the Izmit seismogenic region long before the EQ occurrence time. The theoretical analysis of the adopted physical model justifies the generation of a number of specific electric signals that can be emitted from the focal area before the rock formation failure. The processing of the registered by …

Seismic Electric Signals: A physical interconnection with seismicity

By applying natural time analysis to the time series of earthquakes, we find that the order parameter of seismicity exhibits a unique change approximately at the date(s) at which Seismic Electric Signals (SES) activities have been reported to initiate. In particular, we show that the fluctuations of the order parameter of seismicity in Japan exhibits a clearly detectable minimum approximately at the time of the initiation of the SES activity observed almost two months before the onset of the Volcanic-seismic swarm activity in 2000 in the Izu Island region, Japan. To the best of our knowledge, …

Identification of Seismic Electric Signals upon significant data loss

When monitoring geophysical parameters, data from segments that are contaminated by noise may have to be abandoned. This is the case, for example, in the geoelectrical field measurements at some sites in Japan, where high noise -due mainly to leakage currents from DC driven trains- prevails almost during 70\% of the 24 hour operational time. We show that even in such a case, the identification of seismic electric signals (SES), which are long-range correlated signals, may be possible, if the remaining noise free data are analyzed in natural time along with detrended fluctuation analysis (DFA).

2018年希腊Mw6.8地震前的地电场与地震活动变化及后续活动

Geoelectric field and seismicity changes preceding the 2018 Mw6.8 earthquake and the subsequent activity in Greece

本研究分析2018年希腊Mw6.8地震前的地电异常信号，验证其为符合统计显著性的前兆SES活动，结合自然时间分析与地震临近预测方法得到震前80%的地震潜势评分，并补充了2023年的最新SES观测记录。

Additional information for the paper `Entropy of seismic electric signals: Analysis in natural time under time-reversal'

After the submission of the paper, three strong earthquakes with magnitude around 6.0-units occurred on October 17 and October 20, 2005, with epicenters in the Aegean Sea, at a distance {\em only} 100km from MYT station at which the intense signals $M_1$ to $M_4$ -analyzed in the main text- have been recorded. This confirms experimentally the proposed criterion we used for the classification of these signals as Seismic Electric Signals (SES). Moreover, we show that, if we follow the procedure described in [P.A. Varotsos, N. V. Sarlis, H. K. Tanaka and E. S. Skordas {\it Phys. Rev. E} {\bf 72},…

Preseismic oscillating electric field "strange attractor like" precursor, of T = 6 months, triggered by Ssa tidal wave. Application on large (Ms > 6.0R) EQs in Greece (October 1st, 2006 - December 2nd, 2008)

In this work the preseismic "strange attractor like" precursor is studied, in the domain of the Earth's oscillating electric field for T = 6 months. It is assumed that the specific oscillating electric field is generated by the corresponding lithospheric oscillation, triggered by the Ssa tidal wave of the same wave length (6 months) under excess strain load conditions met in the focal area of a future large earthquake. The analysis of the recorded Earth's oscillating electric field by the two distant monitoring sites of PYR and HIO and for a period of time of 26 months (October 1st, 2006 - Dec…