Investigating Narcondam offshore using high-resolution seismic reflection data

Abstract

Abstract The Andaman Sea is a back-arc basin that hosts the active Barren and the dormant Narcondam volcanoes. Despite its geological and geophysical significance, there are limited studies conducted over offshore Andaman. Here, a geophysical study of Narcondam offshore is presented to investigate basinal deposits and associated fluids and their migration paths using a 30 km long high-resolution 2D seismic reflection. The migrated section reveals a subsurface image highlighting evidence of a bright seafloor- parallel reflector with negative polarity at a two-way time (TWT) of 2.78-2.82 s (~2.2-2.3 km) with an interval velocity of 1.56 km/s. Amplitude Versus Angle (AVA) analysis using Aki Richard's two-term equation is further conducted to characterize the reserved fluid. The AVA analysis yields an increase in amplitude with angle, providing compelling evidence of fluid presence. Additionally, the depth converted migrated seismic section exhibits indications of columnar faults of Neogene period influencing the migration of fluids within the basin.