Hazard forecasting method by development of standard model of volcanic eruption

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H02404
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 25030:Disaster prevention engineering-related
• Research Institution: Kyoto University
• Principal Investigator: IGUCHI MASATO 京都大学, 防災研究所, 教授 (60144391)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 火山噴火 / 火山性地震 / 地盤変動 / テフラ / 火砕流 / 溶岩流

Outline of Final Research Achievements

A standard model of volcanic eruptions is developed by examining the volcanic earthquakes and ground motions that precede active volcanic eruptions in Indonesia and the area of tephra, pyroclastic flows, and lava flows associated with the eruptions. 1) Ground deformation precede eruptions, followed by volcano-tectonic and low-frequency earthquakes. This means the process of elastic deformation due to magma intrusion, initiation of rupture due to increased stress, and initiation of magma foaming. 2) The volume of ejecta is correlated with the volumetric change of pressure source due to volcanic seismic energy and ground deformation, and an upper limit to the volume of ejecta is recognized. 3) The distribution ratio of magma volume to tephra, pyroclastic flow, and lava flow depends on the amount of volatile components immediately before the eruption, and the higher the magma intrusion rate, the more explosive the eruption with predominant tephra.

Free Research Field

火山防災

Academic Significance and Societal Importance of the Research Achievements

火山性地震、火山体の膨張などの異常現象の発現から噴火の発生を想定することができるが、噴火ハザードエリアの決定は、それぞれの火山における過去の異常現象の発現と噴出物の飛散・到達範囲との対応関係に基づいて、火山毎に個別に決定されている。個別の火山における対応関係よりも、どの火山にも適用可能な異常現象－噴出物到達範囲の対応関係の標準モデルを用いることにより、テフラ、火砕流、溶岩流の個別のハザード要因への噴出物量が推定でき、噴火に先行する地震活動、地盤変動から噴火発生前のハザード予測ができる可能性がある。