HR: 0800h
AN: G51A-0064    [Abstracts]
TI: Time Dependent Model of Magma Intrusion in and around Miyake and Kozu Islands, Central Japan in June-August, 2000
AU: * MURASE, M
EM: murase@eps.nagoya-u.ac.jp
AF: Research Center for Seismology, Volcanology and Disaster Mitigation, Graduate School of Environmental Studies, Nagoya University, Furo Chikusa, Nagoya, Aichi, 464-8602 Japan
AU: Irwan, M
EM: irwan@eps.nagoya-u.ac.jp
AF: Research Center for Seismology, Volcanology and Disaster Mitigation, Graduate School of Environmental Studies, Nagoya University, Furo Chikusa, Nagoya, Aichi, 464-8602 Japan
AU: Kariya, S
EM: kariya@eps.nagoya-u.ac.jp
AF: Research Center for Seismology, Volcanology and Disaster Mitigation, Graduate School of Environmental Studies, Nagoya University, Furo Chikusa, Nagoya, Aichi, 464-8602 Japan
AU: Tabei, T
EM: tabei@cc.kochi-u.ac.jp
AF: Faculty of Science, Kochi University, Akebono, Kochi, 780-8072 Japan
AU: Okuda, T
EM: okuda@seis.nagoya-u.ac.jp
AF: Research Center for Seismology, Volcanology and Disaster Mitigation, Graduate School of Environmental Studies, Nagoya University, Furo Chikusa, Nagoya, Aichi, 464-8602 Japan
AU: Miyajima, R
EM: miyajima@seis.nagoya-u.ac.jp
AF: Research Center for Seismology, Volcanology and Disaster Mitigation, Graduate School of Environmental Studies, Nagoya University, Furo Chikusa, Nagoya, Aichi, 464-8602 Japan
AU: Kimata, F
EM: kimata@seis.nagoya-u.ac.jp
AF: Research Center for Seismology, Volcanology and Disaster Mitigation, Graduate School of Environmental Studies, Nagoya University, Furo Chikusa, Nagoya, Aichi, 464-8602 Japan
AU: Fujii, N
EM: fujii@seis.nagoya-u.ac.jp
AF: Research Center for Seismology, Volcanology and Disaster Mitigation, Graduate School of Environmental Studies, Nagoya University, Furo Chikusa, Nagoya, Aichi, 464-8602 Japan
AB: We discuss a time dependent model of magma intrusion in and around Miyake and Kozu Islands, Central Japan from GPS measurements at 28 sites in Miyake Island, Kozu Island and their surrounding islands in the period from June 27 to August 27, 2000. A dike complex model of three sheets is assumed between Miyake and Kozu Islands, suggested from the precise hypocenter distribution map (Sakai et al., 2003). Other dike intrusion models, a dike with an aseismic creep model (Nishimura et al.,2001; Furuya et al.,2003) and a dike with a deep deflation source model (Yamaoka et al., submitted) , are also discussed. Akaike's Information Criteria (AIC) value of optimal parameters of a dike complex model indicates lower than that of other two models. After fixing the geometry of three dikes using a genetic algorithm (GA), the amounts of dike openings of top, inside, and bottom of each dike are estimated by GA for seven time periods. In the period from June 27 to July 8, dike opening is concentrated in the dike near Miyake Island, and a large deflation is also estimated at a depth of 5 km of Miyake Volcano. It suggests that magma is supplied from the depths of Miyake Island. In next period until August 10, a huge dike intrusion is characterized in the dike near Kozu Island and the lower parts of dike in central and near Miyake Island. This suggests that magma is supplied from depth between Miyake and Kozu Islands. In the period of August 10 to 27, a huge deflation is estimated at a depth of 10 km under Miyake Volcano, and dike opening is limited
DE: 8400 VOLCANOLOGY
DE: 8419 Eruption monitoring (7280)
DE: 8434 Magma migration
DE: 9320 Asia
DE: 1200 GEODESY AND GRAVITY
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting