Abraded sand volcanoes as a tool for recognizing paleo-earthquakes, with examples from the Cisuralian Talchir Formation near Angul (Orissa, eastern India)

One of the bedding planes of a sandstone unit belonging to the Cisuralian Talchir Formation is well exposed along the Nandir Jhor river in eastern India. It shows a few dozens of circular structures, commonly with diameters of a few decimetres: a concentration is found in an area of some 50 m(2), where 12 well-developed specimens occur. The structures are interpreted as abraded sand volcanoes, which interpretation is supported by the occurrence on the same bedding plane of a sand volcano with a diameter of over a meter. The concentrated structures thus represent a sand-volcano field, a phenomenon that has not been recognized earlier in the pre-Holocene geological record, but that in recent times seems always to be related to an earthquake. The structures described here might therefore help to recognize earthquakes that occurred in the geological past. (C) 2011 Elsevier B.V. All rights reserved.