Figure 1: Generalised final areal distribution of the 2012–13 Tolbachik lava flow field.

Eruption occurred on the southern flank of Tolbachik volcano (lavas shown in translucent pink are superimposed over a NASA EO-1 ALI satellite image taken on 5 April 2013; multiple kipukas are not shown). White eruptive cloud rising above the active scoria cone (the Naboko vent) is drifting towards the northwest. The relative ages of the lava flows can be distinguished by the shades of grey: light-grey—the older flows partly covered by snow; and dark grey—the youngest flows. The merged edifices of Ostry and Plosky Tolbachik volcanoes are in the upper right corner of the image. The summit caldera of Plosky Tolbachik subsided substantially during the 1975–76 fissure eruption. The major branches of the 2012–13 lava flows are identified by numbers: 1—Vodopadnoye field; 2—Leningradskoye field; and 3—Toludskoye field. The Toludskoye lava field was actively growing through the snowpack during the course of this study (observation locations are indicated by circles). The scale bar (lower left) is 4 km in length. The inset shows the location of Tolbachik volcano on the Kamchatka Peninsula. EO-1 image is courtesy of NASA’s Earth Observing One (EO-1) satellite managed by the Goddard Space Flight Center (http://eo1.gsfc.nasa.gov).