Investigation of geomagnetic field variations in search of seismo-electromagnetic emissions associated with earthquakes in subduction zone of Andaman-Nicobar, India

Abstract

The study of seismo-electromagnetic (EM) emissions has the potential to provide new insights into the physics of seismic activity and improve our ability to monitor and predict earthquakes and other geophysical events. Continuous recording and monitoring of EM fields in seismically active areas are very complex, but it can open a new regime in the field of earthquake prediction. In this study, one year of ground based geomagnetic data during March 2019 to April 2020 in seismic active subduction zone of Andaman-Nicobar region in search of EM signatures related to lithospheric processes. An anomalous signature in the vertical component of geomagnetic field is preferred to study after removing the global and seasonal effect from the data. Apart from vertical component of geomagnetic field, polarization ratios which also include horizontal component, also studied from spectral density with the same purpose in ULF range. Over the duration of one year, we noted an 80% enhancement in polarisation ratios and 67% deviations in diurnal ratios average 18 days before of earthquake events. Apart from that, the significant enhancements in diurnal and polarization ratio were shown to be successfully correlated with 11 out of 14 earthquakes which is equivalent to approximately 78% success ratio.