Journal : Acta Geophysica Polonica
Article : A review and analysis of electromagnetic precursory phenomena

Authors :
Varotsos, P.
Solid Earth Physics Institute, University of Athens Panepistimiopolis, Athens, Greece,,
Abstract : The recent experimental results on the electromagnetic (EM) precursory signals detected in Japan, Greece, USA, etc. are summarized. Concerning the ground-based ULF magnetic field measurements, a careful inspection of the data shows that the main characteristics (e.g., amplitude, frequency range, lead time) of the precursory changes reported to date for the large EQs (i.e., Spitak in 1988, Loma Prieta in 1989, Guam in 1993, Biak in 1996) are similar to those reported long ago by VAN for the magnetic field variations (a few to several tenths of nT) associated with SES preceding EQs with M>= 6.5. The complex field measurements carried out in Japan of the ULF magnetic field variations along with acoustic emissions (AE) are also shortly presented; this is accompanied by a suggestion for the tentative explanation of the detection of the latter (AE). Furthermore, the most recent theoretical models forwarded for the explanation of the EM precursory effects are shortly reviewed.

Keywords : electromagnetic precursory phenomena, acoustic emission, subionospheric VLF propagation,
Publishing house : Instytut Geofizyki PAN
Publication date : 2001
Number : Vol. 49, nr 1
Page : 1 – 42

Qute : Varotsos, P. ,Varotsos, P. , A review and analysis of electromagnetic precursory phenomena. Acta Geophysica Polonica Vol. 49, nr 1/2001