On the origin of the artesian groundwater and escaping gas at Narveri after the 2001 Bhuj earthquake

Abstract

At Narveri, north of Khavada in the Great Rann of Kachchh, an outflow of groundwater continued even more than four months after the Bhuj earthquake of 26 January 2001, although at a considerably reduced rate compared to that immediately following the earthquake. Air or gas bubbling through the freshly oozing water has also been observed. We had collected a large number of samples from different parts of Gujarat, where post-earthquake groundwater outpourings were reported. Narveri, however, was the only site where the samples showed dissolved helium concentrations, significantly above the air equilibration value. Based on measurements of helium, radon, chloride, sulphate and sodium concentrations and temperature, we suggest that the flowing water and escaping gases at Narveri have a deep confined source with a reservoir age in excess of ~ 10⁴ years.