ABSTRACT

Continuous He, ²²²Rn concentrations and gamma dose rate were simultaneously monitored for pre-seismic signatures at two thermal springs in India that are separated at a distance of approximately 1612 km. The recordings of six month monitoring period (September 15, 2007–March 15, 2008) are presented here. In this paper, we make a cross correlation study of the simultaneously recorded multi-component gas-geochemical data from the two thermal springs. In the monitoring period a number of prominent fluctuations beyond the regular diurnal variations in the gas composition were recorded. We attempt to find out the linkage between the recorded distinct variations with local and remote seismic activities. Anomalous fluctuations in the spring gases were observed during the period December 24–27, 2007 at both the thermal springs and these anomalies may be correlated to the distant (~1000 km) China earthquake of magnitude M = 6.3 that occurred on January 09, 2008. Based on the obtained sequence of data points a time series analysis to relate earthquake magnitude, epicentral distance and precursor time through statistical methods and empirical equations related to the zone of influence is made. Concurrent monitoring of multi-component gas-geochemical anomalies recorded at a number of distant sites appears to be a potential tool to deal with the commonly debated question of earthquake precursors.