Older than nearby Mount Aso, it formed over the past 100 million years. Extensive volcanic activity took place 56 million years to 50 million years ago. The last eruption took place from 200,000 years to 150,000 years ago. In 1889 a 6.3 magnitude earthquake struck beneath the mountain. In 2016 the foreshock of the 2016 Kumamoto earthquakes also struck beneath Mount Kinbō.