An analysis of the relation between precipitation and earthquake in the Indian region

Abstract

The paper aims to examine the relation between rainfall anomalies and occurrence of earthquakes (magnitude > 6.5) in the Indian region. For this purpose, earthquakes of Sikkim (18 September 2011), Gujarat (26 January 2001), Uttarkashi (20 October 1991) and Assam (15 August 1950) are considered. Anomaly in rainfall magnitude is calculated from the synoptic seasonal fluctuation of rainfall as the seasonal ambient level, considering gridded rainfall data from India Meteorological Department (IMD) (1°×1°), NECP/NCAR reanalysis (2.5°×2.5°), and monthly accumulated rainfall data from the Indian Institute of Tropical Meteorology (IITM). Monthly spatial rainfall distribution obtained from Tropical Rainfall Measuring Mission (TRMM) is also plotted over the epicenter zone of the earthquakes under consideration. In Sikkim, Gujarat and Assam earthquake cases, high positive anomaly (beyond ambient level) in rainfall is observed in the earthquake months, whereas no such association is detected for Uttarkashi event. Further, the rainfall anomalies are associated with earthquake induced heat flux and the results obtained are discussed in terms of the seasonal atmospheric variabilities and geographical features of the region near to earthquake epicenter.