| Project/Area Number |
07300017
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| Research Category |
Grant-in-Aid for Co-operative Research (A).
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| Allocation Type | Single-year Grants |
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
KOBAYASHI Yoshimasa Kyoto Univ.Fac.Science Professor, 理学部, 教授 (80027284)
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| Co-Investigator(Kenkyū-buntansha) |
EHARA Sachio Kyushu Univ.Fac.Eng.Professor, 工学部, 教授 (10002346)
WATANABE Kazunori Kumamoto Univ.Fac.Edu.Professor, 教育学部, 教授 (10040049)
SHIMIZU Hiroshi Kyushu Univ.Fac.Science Assoc.Prof., 理学部, 助教授 (50178985)
HIRABAYASHI Junich Tokyo Inst.Tech.KVL.Assoc.Prof., 草津白根火山観測所, 助教授 (30114888)
SUDO Yasuaki Kyoto Univ.Fac.Science Assoc.Prof., 理学部, 助教授 (40025466)
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| Project Period (FY) |
1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Keywords | Kuju volcano / phreatic explosion / volcanic activity / mechanism of eruption / ground deformation / seismic activity / geomagnetic variation / magma / 噴火材構 |
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| Research Abstract |
Soon after the phreatic explosion in October 1995 many observational points were installed for earthquakes, geomagnetism, geodetic-and temperature variations, etc.around the Iwoyama area to seize the situation and to elucidate the mechanism of the eruption. On earthquakes around the Kuju volcano area : 1) most events did not occur beneath the newlycreated crater array but were concentrated in shallow subsurface beneath the fumarolic area that had existed for ling ; 2) few events occurred on the southern side of the crater array ; 3) the sources of events during the periods of ash eruptions exhibited vertical alignment on the northern side of the crater array ; and 4) sources in the western area were deeper than those in the Iwoyama area and tended to be shallower toward Iwoyama. All the geodetic measuring points except those for GPS were located on the northern side of the new crater array and exhibited contraction of the area with time at a rate 3-4.5 cm/month. The totalintensity of geomagnetism converted its sense from magnetization to de-magnetization around Dec.20,1995. The top of the magma was presumed to exist at 2-5km blow the ground surface from analyzes of volcanic ashes. From volcanic gas analyzes high-temperature gas components seemed to increase.
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