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Title of paper | Recognition of pre- and co-seismic electromagnetic signals in magnetotelluric measurements: a case study in the northern region of Algeria |
List of authors | Kasdi, A.S., Hamoudi, M., Bouzid, A., Kerbadj, N. |
Affiliation(s) |
Center of Research in Astronomy, Astrophysics and Geophysics, Subsurface Geophysics Division, 16340, BP 63 route de l'Observatoire Bouzarèah, Algiers, Algeria., University of Science and Technology Houari Boumediene, Department of Geophysics - FSTGAT, BP 32 El Alia Bab-Ezzouar, 16111, Algiers, Algeria. |
Summary | Seismo-electromagnetic signals are anomalous electromagnetic (EM) signals related to seismic activity. In recent years, the northern part of Algeria has experienced numerous moderate earthquakes. This seismic activity provided a rare opportunity to study earthquake-related temporal patterns of EM signals using magnetotelluric (MT) measurements. In this paper, we present an analysis of the MT time series using wavelet transform for several cases where co-seismic EM signals were observed. We present the precursor signatures of two main earthquakes using the spectral polarization technique. The results of the wavelet analysis revealed the time-frequency characteristics of the co-seismic EM signal with a high spectral amplitude at different frequency ranges. The spectral polarization technique revealed the existence of anomalies related to the earthquake several hours before its occurrence. This anomaly is correlated with the Dst index. We inferred that the unusual pre-earthquake behavior is related to the precursor signature but not to the solar-terrestrial effect. |
Session Keyword | 3.0 Exploration, Monitoring and Hazards |
File upload |
3.0_recognition_of_pre-_and_c_kasdi.pdf
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