史料からみた北海道駒ヶ岳1640年噴火

抄録

Historical materials have revealed that the Hokkaido-Komagatake Volcano erupted in 1640. In this study, we reviewed in detail the historical materials from a period closer to the eruption, which had yet to be investigated. We then evaluated the reliability of the historical materials and tried to interpret their descriptions from a volcanological point of view. As a result, we found descriptions that support the previous understanding of the number of deaths, tsunamis, and volcanic edifice collapses, or provide more detailed information. In contrast, we also found descriptions of the duration of the 1640 eruption, which lasted about one day and night, of the fallout tephra containing charred wood chips suggesting the occurrence of high-temperature phenomena and subsequent buoyant plumes, and of the volcanic activity that continued for a long time after the eruption. Examination of these historical materials revealed a picture of the eruption that could not be understood from the historical materials used in the past. This study demonstrates that investigating the characteristics of historical materials and the reliability of their descriptions and comparing the information obtained from them with volcanological knowledge can be useful in clarifying the phenomena and processes of past volcanic eruptions.