Seismic electric signals in seismic prone areas

Statistical Significance of Earth’s Electric and Magnetic Field Variations Preceding Earthquakes in Greece and Japan Revisited

“…As for the SES transmission, the following model has been put forward [ 5 ] by considering that EQs occur near faults and in addition the electric conductivity of faults is usually orders of magnitude larger than the average conductivity of the surrounding medium (host rock), thus they constitute highly conductive paths: When the SES is emitted from the EQ preparation area, most of the current follows the highly conductive channel which may terminate below the Earth’s surface say at epicentral distances of the order of 100 km. By applying either numerical solutions of Maxwell’s equations [ 11 ] or analytical models [ 12 ], we find that the electric field E at a measuring site lying at the Earth’s surface, very close to the termination point is of the order of 5–10 mV/km which agrees with the experimental values (reported from various countries, e.g., Japan [ 13 , 14 , 15 , 16 , 17 ], China [ 18 , 19 , 20 ], Mexico [ 21 , 22 ], Kyrgyzstan [ 23 ] etc.) if we assume a current dipole source of the order of Am which corresponds to an EQ of magnitude (e.g., [ 11 , 12 ]).…”

Study in Natural Time of Geoelectric Field and Seismicity Changes Preceding the Mw6.8 Earthquake on 25 October 2018 in Greece

“…Geoelectric field continuous monitoring is operating in Greece by the Solid Earth Physics Institute [ 4 , 5 , 6 ] at nine measuring field stations (see the blue circles in Figure 1 ) aiming at detecting Seismic Electric Signals (SES). SES are low frequency (≤1 Hz) variations of the electric field of the Earth that have been found to precede strong EQs in Greece [ 7 , 8 , 9 , 10 , 11 ], Japan [ 12 , 13 , 14 ], China [ 15 , 16 , 17 , 18 ], Mexico [ 19 , 20 ], and elsewhere [ 21 ]. They are emitted due to the cooperative orientation of the electric dipoles [ 5 , 22 , 23 ] (that exist anyhow due to defects [ 24 , 25 ] in the rocks) of the future focal area when the gradually increasing stress before the strong EQ reaches a critical value [ 10 ].…”

Study of Geo-Electric Data Collected by the Joint EMSEV-Bishkek RS-RAS Cooperation: Possible Earthquake Precursors

“…Preliminary results of this cooperation have been presented [29]. The present paper is a continuation of that study.…”

“…Data from a longer period are examined. In particular, while only one case was briefly presented previously [29], here we examine the whole period 30 June 2014-10 June 2015 and identify a total of 32 electrical disturbances, of which three are possibly found to be SES activities. In the next section, a brief description of the methods used is provided.…”