Interpretation of ship-track magnetic data near Narcondam and Barren Island volcanoes revisited

Abstract

We interpret the legacy ship-track magnetic and bathymetric profile data to investigate the role of the lithospheric scale West Andaman Fault (WAF) in the dormant Narcondam and active Barren Island volcanoes. We use data-based automated interpretation of total magnetic intensity (TMI) profiles using a contact model in order to delineate geometrical and physical parameters of several faults including the WAF and then investigate its implications in recent volcanism at the Barren Island. Our data-based interpretation of TMI data requires transformation of it into the first order analytical signal and tilt angle, which in turn, requires estimation of the first order horizontal and vertical derivatives of TMI data. We ensure robust estimation of the first order horizontal and vertical derivatives using Savitzky–Golay derivative filter and Hilbert–Noda transformation, respectively. We have identified several anomaly segments of the TMI anomaly profiles and used data-based quantitative interpretation in each segments with a contact model. We then make a comprehensive interpretation using bathymetry, geological setup and the results from quantitative data-based interpretation of magnetic data, and ascertain possible role of the WAF in Barren Island volcanism.