Ground penetrating radar characterization of fault-generated Quaternary colluvio-fluvial deposits along the seismically active Kachchh Mainland Fault, Western India

Quaternary colluvio-fluvial deposits in the seismically active Kachchh Mainland Fault (KMF) zone have been studied using ground penetrating radar (GPR). The deposits form a north-sloping similar to 2-3 km wide, deeply dissected surface to the north of the KMF scarps developed in Mesozoic rocks forming the northern limb of the Habo dome. The northward slope of the surface and decreasing trend of incision towards the north are attributed to neotectonic activity along KMF. Exposed river sections and trench sections correlate well with the GPR data. The various sedimentary facies identified vary from bouldery gravel to finer gravel and gravelly sand. Discontinuous wavy radar reflections relate to bouldery gravel deposits, whereas the parallel discontinuous reflections indicate finer gravels or gravelly sands. In contrast, the parallel and continuous radar reflections characterize the well-stratified gravels. The study demonstrates the utility of GPR in colluvial and reworked colluvial deposits in active fault zones.