An Integrated Study of the Dynamics of Electromagnetic and Acoustic Regimes During Failure of Complex Macrosystems Using Rock Blocks

On the puzzling feature of the silence of precursory electromagnetic emissions

“…As already noted in Sect. 2.2, laboratory experiments reveal that AE of maximal intensity are recorded directly before and during the fragmentation of the specimen, while strong avalanche-like EME precedes this phase (Baddari et al, 2011;Morgounov, 2001).…”

“…However, recent accumulated laboratory evidence indicates that the recorded AE and EME, in general, are not two sides of the same coin. There are two categories of AE signals -namely AE signals that are associated with EME signals, and AE signals that are not associated with EME signals (e.g., Yamada et al, 1989;Rabinovitch et al, 1995;Morgounov, 2001;Mori et al, 1994Mori et al, , 2004aMori et al, , b, 2006Mori et al, , 2009Mori and Obata, 2008;Lacidogna et al, 2010;Baddari and Frolov, 2010;Baddari et al, 2011;Carpinteri, 2012). Importantly, laboratory experiments performed recently reveal that the final stage of the failure process coincided in time with the maximum of AE and quiescence in EME, while strong avalanche-like EME precedes this phase (Morgounov, 2001;Baddari et al, 2011).…”

“…More specifically, electromagnetic emissions (EME) and acoustic emissions (AE) in a wide frequency spectrum ranging from the kHz to the MHz bands are produced by opening cracks, which can be considered as the so-called precursors of general fracture. Recently, improvements in the MHz-kHz EME technique have permitted a real-time monitoring of the fracture process (Fukui et al, 2005;Kumar and Misra, 2007;Chauhan and Ashok Misra, 2008;Baddari et al, 1999Baddari et al, , 2011Baddari and Frolov, 2010;Lacidogna et al, 2010;Schiavi et al, 2011;Carpinteri et al, 2012). However, the MHz-kHz electromagnetic (EM) precursors are detectable not only at the laboratory but also at the geological scale; a stressed rock behaves like a stress-EM transducer (Sadovski, 1982;Hayakawa and Fujinawa, 1994;Gokhberg et al, 1995;Hayakawa, 1999Hayakawa, , 2009Hayakawa and Molchanov, 2002;Eftaxias et al, 2007Eftaxias et al, , 2011Eftaxias, 2012;Molchanov and Hayakawa, 2008).…”

Temporal correlation patterns in pre-seismic electromagnetic emissions reveal distinct complexity profiles prior to major earthquakes

“…In the direction of understanding the underlying complex nonlinear processes involved in the preparation of an EQ, two research fields have attracted the particular interest of scientists. One of them, to which huge efforts have been devoted, is the study of fracture phenomena at the laboratory scale (e.g., Lockner et al, 1991;Lockner, 1996;Chauhan and Misra, 2008;Johnson et al, 2008;Baddari and Frolov, 2010;Ben-David et al, 2010;Zapperi, 2010;Baddari et al, 2011;Lacidogna et al, 2011;Hadjicontis et al, 2011;Schiavi et al, 2011;Carpinteri et al, 2012;Chang et al, 2012), while the other is the study of different phenomena which are observed in the field prior to the occurrence of significant EQs.…”

Acoustic Emission Monitoring and Failure Precursors of Sandstone Samples under Various Loading and Unloading Paths

“…Based on the biaxial compression tests, Baddari et al [13] adopted electromagnetic radiation and acoustic emission to study the failure process of large rock samples, and the results can provide an analysis platform for forecasting the dynamic disaster. Three triaxial compression tests on granite samples were carried out by Thompson et al [14], and new observations of fracture nucleation were proposed according to AE monitoring.…”