2020 Volume 129 Issue 5 Pages 611-634
Natural phenomena such as volcanic eruptions, earthquakes, and tsunami, have long been regarded by many people around the world as indicating the wills of deities. Such superstitions have been replaced gradually by modern scientific thinking. The Ainu people believed that evil deities caused volcanic eruptions, so they prayed to benevolent deities in order to avert them. As such, the Ainu people had superstitious beliefs on the causes of volcanic eruptions and how they could be prevented. In spite of their superstitious beliefs, the Ainu people actually had scientifically accurate ideas on the process of a volcanic eruption, the origins of material ejected from a crater, and the process of lava dome formation. This was long before scientific conception of volcanology and the geomorphology of volcanoes emerged in Japan. Modern science was introduced to Japanese volcanology and the geomorphology of volcanoes in the 1890s. Around the 1791, the Ainu people, who were neither scientists nor specialists, surmised that a volcanic eruption was actually caused by burning material under ground rising up from a crater through a fire well to the surface. The Ainu people's deductions on the process of a volcanic eruption were similar to the latest theories on magma eruptions in volcanology. The Ainu people's course of action of seeking refuge when Mt. Usu erupted was not based on superstition but on their memories of past eruptions. These memories informed them that a series of earthquakes heralded an eruption, as well as the facts that damage to areas by eruptions and their personal sufferings were actually due to pyroclastic flows and surges from past eruptions of Mt. Usu.