Correlation of Satpura electrical conductivity anomaly with the Jabalpur earthquake of May 22, 1997

Abstract

Data from a linear profile magnetometer array along Bakshaho-Mandla-Bhandara transect have revealed an elongated Satpura electrical conductivity anomaly in the region of Son-Narmada-Tapti lineament and Satpura Range of Central India. Reversal in the sign of vertical (Z) component of the geomagnetic field at Jabalpur and Paraswada defines the anomalous higher electrical conductivity zone due to the concentration of induced currents between Jabalpur and Paraswada. Also, the observed vertical (Z) component of nearly zero at Kalpi indicates the centre of conductivity anomaly, The higher electrical conductivity in the Jabalpur-Paraswada region has been interpreted as due to saline water/aqueous fluids trapped in the deep crust along reactivated deep-seated faults. The center of the Satpura conductivity anomaly located beneath Kalpi is just 15 km southeast of Kosarnghat, the epicentre of the Jabalpur (M 6.0) earthquake of May 22, 1997. The hypocentre section of the main shock and aftershocks of the Jabalpur earthquake of May 22, 1997 and the depths of equivalent line currents causing the Satpura conductivity anomaly are well correlated with each other. The epicentral region of this earthquake is therefore, the seat of an anomalous electrical conductivity structure.