Evaluation of maximum horizontal near-surface stress (SHmax) azimuth and its distribution along Narmada-Son Lineament, India by geogenic Electromagnetic Radiation (EMR) technique

Application of Fracture Induced Electromagnetic Radiation (FEMR) technique to detect landslide-prone slip planes

“…The generation of the fracture-induced electromagnetic radiation (FEMR) owes its existence to the incremental increase in stress subjected to the brittle rock bodies in the near surface of the Earth's crust. This phenomenon leads to the occurrence of fracturing in the rock bodies which, in turn, leads to the generation of FEMR pulses having a frequency range of MHz to kHz (Mallik et al 2008;Rabinovitch et al 2007Rabinovitch et al , 2017Rabinovitch et al , 2018Das et al 2020). The FEMR pulses emanate from microcracks/nanocracks present in the brittle rock bodies.…”

“…With the gradual increase in stresses that are concentrated anomalously at the crack tip, it eventually leads to a macro-failure due to the propagation and coalescence of the microcracks in the "process zone" (Fig. 4a) (Bahat et al 2005;Mallik et al 2008;Rabinovitch et al 2017;Das et al 2020). In terms of FEMR intensity, an increase in the number of microcracks/nanocracks leads to an increase in the magnitude of the FEMR signals.…”

“…In terms of FEMR intensity, an increase in the number of microcracks/nanocracks leads to an increase in the magnitude of the FEMR signals. However, these signals damp down and cease to exist when the macro-fractures coalesce, resulting in the formation of a fault plane (Kuksenko et al 1982;Petrov and Gorobetz 1987;Teisseyre 1992;Gueguen and Palciauskas 1994;Bahat et al 2005;Mallik et al 2008;Das et al 2020). This has been explained in detail with the aid of the Reches-Lockner model in the section below (Reches and Lockner 1994).…”

“…perpendicular to the FEMR pulses due to the vibration of the longitudinal dipoles) or a transverse polarization (microcrack surface parallel to the FEMR pulses due to the vibration of the transverse dipoles), resulting in the emanation of FEMR pulses ( Fig. 4b, c; Khatiashvili 1988;Molchanov and Hayakawa 1998;Mognaschi 2002;Bahat et al 2005;Mallik et al 2008;Das et al 2020). Rabinovitch et al (2017) explained the mechanism of a propagating FEMR pulse in terms of fracture growth that can be broadly classified into five stages ( Fig.…”

“…4a). Along with an increase in the fracture length, it has been depicted that the amplitudes of the surface dipoles also change from the crack tip along the entire crack surface indicative of a time-dependent decay of amplitude of the surface dipoles from the crack tip to the entire crack length (Bahat et al 2005;Rabinovitch et al 2017;Mallik et al 2008;Das et al 2020).…”