Fig. 9
Comparison between the dLOS time series and other observations (thermal, volcanic gas, and GNSS observation). a Co-plot of the dLOS time series, He/CH4 ratio of fumarole gases, apparent equilibrium temperature (AET) of fumarole gases, and GAA. The striped rectangle indicates the time period when relatively larger values of He/CH4 ratio (> 1.0) were observed by Tokai Univ. et al. (2018). The black rectangles indicate time periods at which relatively larger AET values (> 400 °C) were observed by Tokai Univ. et al. (2018). The pink-shaded zones indicate time periods at which GAA increases were observed by Tajima et al. (2020). The red and blue circles indicate dLOS time series of path 131 and 23 at peak B (same as in Fig. 8). b Plot of cumulative volume change of the magma chamber at 7-km depth after November 2013, derived from GNSS baseline observation (JMA 2019). The red arrow indicates the timing of the Shinmoe-dake eruption with co-eruptive deflation of the magma chamber