Chemical and Noble Gas Isotope Compositions of Formation Gases from a 3 km Deep Scientific Borehole in the Koyna Seismogenic Zone, Western India

Figure 7

Plots showing downhole electrical resistivity (purple line) and calliper (blue line) logs along with helium concentration from QMS measurements (red diamonds) in the granitic basement section 1500-3000 m in the borehole KFD1. High resolution electrical (FMI) and acoustic (UBI) images of two typical depth sections 2141-2151 m (a) and 2619-2629 m (c) showing highly fractured basement rocks corresponding to zones of helium enhancements are also shown.