Fundamental Study on Partitior of Energy Release Associated with Volcanic Eruptions
| Project/Area Number |
59460038
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体地球物理学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KAMO Koushuke Disaster Prevention Research Institute Kyoto University, Professor, 防災研究所, 教授 (70025328)
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| Co-Investigator(Kenkyū-buntansha) |
IGUCHI M Disaster Prevention Research Institute Kyoto University, Research Associate, 防災研究所 (60144391)
ISHIHARA K Disaster Prevention Research Institute Kyoto University, Research Associate, 防災研究所 (30027297)
NISHI K Disaster Prevention Research Institute Kyoto University, Research Associate, 防災研究所 (70027241)
ETO T Disaster Prevention Research Institute Kyoto University, Research Associate, 防災研究所, 助手 (00027236)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1986: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1985: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1984: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | volcanic eruption / magma / thermal energy / kinetic energy / volcanic earthquake / air shock / potential energy / strain energy / ブルカ / 式噴火 / ストレイン・ステップ / マグマ溜り / 火道 / 前兆現象 |
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| Research Abstract |
In the process of a volcanic explosion at the summit crater of Sakurajima Volcano, an exlposion earthquake occurs at a depth of 1-3 km beneath the crater, and then shock waves are generated and volcanic bombs and ashes are ejected at the crater abou13EA\ : t 1 second later. This fact suggests that the explosion earthquake takes a role of trigger of the explosion at the crater. Prior to explosive eruptions, upper part of the volcanic conduit is closed by lava domes in the crater. Shock-waves and strain13EA\ : -steps are abserved associated with explosive eruptions. It is inferred that chambers of volcanic gas dissolved from magma are formed at the upper part of the conduit. Energy released by air-shocks are estimated to be 1-2 orders greater than that by13EA\ : explosion earthquakes. Kinetic energy by the ejection of volcanic materials are furthermore 1-2 orders greater than that by air-shocks. The main source of energy of vulcanian explosions is attributed to the gas chambers formed beneath the crater. A13EA\ : mplitudes of explosion earthquakes and air-shocks associated with Strombolian explosions at Suwanosejima Volcano are smaller than those of Vulcanian explosions at Sakurajima. The rations of air-shock energy to seismic one are different depending on the mode of eruptions. Explosive eruptions at Mt.Tokachi Volcano in 1988-1989 are more intense than those at Suwanosejima but less intense than those at Sakurajima. Energy released by an explosion at Mt.Tokachi is as large as a standard explosion a13EA\ : t Sakurajima. Observation of infrasonic waves are useful to monitor the process and mode of eruptions at distant volcanoes and to estimate the energy and intensity of them.
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Report
(2 results)
Research Products
(6 results)
