著者

Paul K. B. ALANIS Yusuke YAMAYA Akihiro TAKEUCHI Yoichi SASAI Yoshihiro OKADA Toshiyasu NAGAO

出版者

The Japan Academy

雑誌

Proceedings of the Japan Academy, Series B (ISSN:03862208)

巻号頁・発行日

vol.89, no.8, pp.383-389, 2013-10-11 (Released:2013-10-11)

参考文献数

20

被引用文献数

8 9

---

Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a large high resistivity anomaly (∼100 Ω·m) with a volume of at least 3 km × 3 km × 3 km, which is capped by a conductive layer (∼10 Ω·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a large hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a large hydrothermal reservoir and the stagnant magma below may have influences on the volcano’s activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions.(Communicated by Seiya Uyeda, M.J.A.)