Subsurface geology of the Bombay Harbour

Abstract

As part of engineering pre-design investigations, high resolution geophysical surveys were carried out in and around Bombay harbour, India. The depth in the area varies from dries over the mudflats to about 14m towards the offshore end. The seabed topography is smooth over the clay covered areas and is uneven where either the bedrock outcrops or the sea floor is formed of stiff clay. Recent sediments, comprising mostly of unconsolidated clay (max. 16m) overlie generally on a fractured, weathered/eroded bedrock which is the continuation of the onshore Deccan flood basalts. Buried channels, interbedded sand bodies, small scale ripples, scouring of the seabed and gas charged sediments were identified. The subsurface geology of the area, relevant to offshore engineering projects is discussed.