The eruptive cycle of Nazko Cone 7200 years ago started with the eruption of two different progressions of fluid lava flows, an older grey basalt overlain by a younger, darker black basalt. The passive eruptions were followed by a period of explosive eruptions. This explosive activity built three overlapping cinder cones near the end of the explosive phase of activity. The last phase of explosive activity spread tephra to the north and east of the cones. The deepest deposits near the cones are over 3 m deep and thin to less than a few centimetres only a few kilometres away, which suggests that the explosive eruptions at Nazko Cone were fairly small. However, the last eruption from Nazko Cone could have started forest fires, since there is charcoal inside the tephra layer.