Figure 8: Ionospheric anomalies recorded during the period from September 1 to November 30, 2010, and related to the October 26 eruption of Merapi volcano. (a) Available nighttime DEMETER orbits and distance between the satellite footprint and the volcano; no data available are drawn with downwards black triangles. (b) Distance between the satellite and the volcano. (c) Recognised ionospheric anomalies. (d) Daily displacement rate on the southern flank of the volcano and SO2 flux discharge (following Surono et al., 2012). (e) Daily Kp index and synthetic activity. Light grey rectangle corresponds to the end of the mechanical fatigue period, medium grey rectangle fits to the dynamical processes period, and dark grey rectangle matches with the beginning of the surface activity.