Fig. 8
From: In-situ monitoring of 3He/4He in summit gases of Kilauea Volcano (Hawaii) prior to the 2020 eruption
Correlation plot of 4He concentration (in ppm) reported by the Barry stable isotope lab, Woods Hole Oceanographic Institution (WHOI) (Table 2) versus the corresponding 4He instrument response as partial pressure (PP) in Torr (Table 1). Solid black line is least-squares regression fit to the WHOI fumarole and near-ground gas data. Dashed line is suggested correlation fit if there is a downward calibration offset to the WHOI 4He data, which is strongly suggested by the lower-than-air 4He values for the three near-ground gas samples (see text for explanation). Orange rectangle shows the 4He (ppm) range of Peek et al. (2020)