<災害調査報告>桜島爆発による特別警報発表に関する考察

Abstract

After the vulcanian eruption on July 24, 2022 at Sakurajima volcano, a special warning (Level 5) was issued with an alert zone of 3 km from the Minamidake summit crater, and residents were evacuated from the southern villages of Sakurajima. Problems of issuing information, warning, and evacuation orders regarding this eruption are summarized. The flight distance of volcanic bombs estimated by JMA remains questionable. It is essential to have an accurate state of volcanic activity. It took 45 minutes from the onset of the eruption to issue the special warning, and 90 minutes to issue an evacuation order. It takes too much time to respond to the eruption. Rapid evacuation decision-making is necessary. The volcanic alert level is an index that indicates the extent of the area requiring alert. Level 5 means that the warning is required even in residential areas, but the keyword “Level 5” alone no longer indicates the extent of the alert zone. It is necessary to issue warning that pushes the range of the alert zone to the forefront.