Terrain response to the 1819 Allah Bund earthquake in western Great Rann of Kachchh, Gujarat, India.

摘要

We report here the development of a drainage network following the 1819 Allah Bund earthquake in the western Great Rann of Kachchh. The juvenile nature of the drainage network, particularly along the scarp, indicates that earth surface processes have not yet attained equilibrium with the base level even after 200 years. Hence it serves as an ideal model of resurrection of topography dominantly controlled by the tectonics. Another important observation has been the identification of a submerged/subsided tax collection port around 60 km southwest of Sindri. Optical dating of pottery indicates that the subsidence is coeval with that of the Sindri fort. This would imply that during 1819 there were two subsiding areas separated by a marginally high land mass (Sunda high). In the absence of detailed structural data, a preliminary inference has been drawn based on field and satellite data. It suggests flexure folding of the footwall during the 1819 earthquake.