Powerful jets of incandescent lava rise above the crater of a cinder cone along Kamchatka's Tolbachik south-flank rift zone in late-July 1975. This cinder cone, the first of three large cones formed along the northern part of the rift zone during the early stage of the eruption, began to grow on July 6. At times, powerful lava fountains rose 1-2.5 km above the vent and ash columns reached 10-18 km heights. After July 27, eruptions from the first cone became dominantly effusive. Activity at the first cone ceased on August 9.
On August 16, 1975, a new fissure opened along the south rift zone of Tolbachik volcano during the Great Tolbachik Fissure Eruption of 1975-76. The following day formation of the third of a group of new cinder cones at the northern end of the rift zone began. Formation of the first cone began on July 6 and ended on August 9, the day that the second cone began erupting. The eruption occurred along a fissure system that extends 70 km SSW of Plosky Tolbachik volcano