A possible explanation of conductivity anomalies near Ujjain and Jaipur

Abstract

Short-period events such as bays and SSCs have been analysed to investigate the nature of conductivity anomalies at two Indian magnetic observatories: Ujjain (UJJ) and Jaipur (JAI). The induction vectors calculated for these events indicate a high electrical conductivity contrast to the north-west of these stations. To determine an exact cause of anomaly, the direction of induced electric currents is estimated from horizontal disturbance vector$(\vartriangle \vec B_A )$ taking Alibag (ABG) as a normal station. These induced currents are found to flow south-west near JAI and westward near UJJ. It is suggested that possible cause of anomaly at JAI is a sub-surface conductivity contrast (possibly asthenospheric upwelling) along the Aravalli belt where high heat flow measurements have been reported. At UJJ, an approximately east-west conductor north of it seems to be responsible for conductivity anomalies.