The basin\'s geology is shaped by complex active faulting, stemming from the collisions of the continental plates containing India and Asia during the mid-Oligocene (23–34 Ma BP), and subsequent formation of the Bengal Basin (Allison, 1998b). The Comilla Terrace is an uplifting region, underlain by buried folds, whilst the Madhupur Tract was uplifted in the Palomid 529 which tilts towards the east and is potentially faulted towards the west (Steckler et al. 2008a) (Fig. 3). Sediment is thickening towards the east and Indo-Burma belt, due to subduction (Uddin and Lundberg, 2004). Almost all of the foredeep is filled with fluvio-deltaic sediment and alluvium from the Ganges–Brahmaputra river system deposited in the last 66 million years and is up to 16 km thick (Allison, 1998a). The Holocene deposits (from 11,700 years BP) are estimated to be 30 m to 70 m thick in the deltaic plains and include stiff clays, mud, silt, sand and peats (Khan and Islam, 2008).