Evidences of Neotectonic Activities as Reflected by Drainage Characteristics of the Mahananda River Floodplain and Its Adjoining Areas, Bangladesh

The drainage pattern in the Bengal Basin as a whole has been greatly controlled by the tectonic features of the basin. Considerable evidence of significant tectonic movements has been recorded within and along the boundary of the basin in Late Tertiary and the Quaternary times. This paper tried to unveiling the signatures of neotectonic activities in the Mahananda River floodplain and its surrounding areas with the help of drainage characteristics. To carry out this interpretation historical maps, satellite imagery and earthquake records were used. The interpretation implies that the area is being structurally controlled. Changing of river courses, shifting of rivers, restriction of the Punarbhaba, Tangon and Kulic River valleys against the comparatively narrow Mahananda River, abrupt change in the sinuosity of the Mahananda River at a particular area and presence of large number of depressions/sag ponds are clear indication of the structural control of the area. In the recent past few earthquakes occurred in this region which also supports the same view about neotectonics. All these features and evidences strongly support the structural control of the area.