Seismic Image of the Volcanic Tremor Source at Izu-Oshima Volcano, Japan
The 1986 fissure eruption of Izu-Oshima volcano was followed by a strong activity of volcanic tremor. To investigate the characteristics of the activity and its relation to the magma system beneath the volcano, two seismological surveys were carried out; one was an array observation of volcanic tremor and the other was an investigation of the crustal structure using seismic signals generated by an air-gun. The first study revealed that two separated sources radiated high frequency tremor and that they were located beneath the northwestern and the southeastern parts of the caldera floor. The analysis of the air-gun data by the method of the semblance depicted the three-dimensional image of a magma-filled crack elongating in the NW-SE direction beneath the caldera. From these results, we deduced a kind of fluid-driven crack model of volcanic tremor in which the outflow of magma through the crack tips generates high frequency tremor and resonates the magma-filled crack.
KeywordsMagma Body Seismic Array Seismic Image Fissure Eruption Shot Point
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- Chouet B, Koyanagi RY, Aki K (1987) Origin of volcanic tremor in Hawaii. US Geol Surv Prof Pap 1350:1259–1280.Google Scholar
- Fukuyama E (1988) Saw-teeth-shaped tilt change associated with volcanic tremor at the Izu-Oshima volcano. J Volcanol Soc Jpn 33:S128–S135 (in Japanese).Google Scholar
- Furumoto M, Kunitomo T, Inoue H, Yamada I, Takagi Y (1988) Portable seismic array system: its versatile application. J Seismol Soc Jpn 41:419–429 (in Japanese).Google Scholar
- Furumoto M, Inoue H, Yamaoka K, Kunitomo T, Yamada I, Fukao Y, Suehiro K (1992) Holography of Izu-Oshiam volcano. (in prep).Google Scholar
- Ida Y and the group of the structure survey of Izu-Oshima (1987) Survey of the velocity structure of Izu-Oshima. Progr Abst Seismol Soc Jpn 1987,2:151 (in Japanese).Google Scholar
- Ikami A, Kunitomo T, Furumoto M, Inoue H, Suyehiro K (1989) Shalow seismic profile of Izu-Oshima Island as derived from air-gun blasts observation. J Seismol Soc Jpn (in Japanese) 42:219–226.Google Scholar
- Nakamura K (1961) Stratigraphic studies of the pyroclastics of Oshima Volcano Izu, deposited during the last fifteen centuries II. Sci Pap Coll Gen Educ Univ Tokyo 11:281–319.Google Scholar
- Nakamura K (1969) Arrangement of parasitic cones as a possible key to regional stress field. J Volcanol Soc Jpn 1:8–20.Google Scholar
- Watanabe H (1987) Eruption mechanism of Izu-Oshima volcano inferred from the observation of volcanic tremor. The Earth Monthly 9:475–481 (in Japanese).Google Scholar
- Watanabe H (1988) Seismic activity. In: Aramaki S (ed) The eruption of Izu-Oshima volcano. Earthq Res Inst Univ Tokyo 1986–1987.Google Scholar
- Sassa K (1935) Volcanic micro-tremors and eruption-earthquakes. Mem Fac Sci Kyoto Univ18:255–293.Google Scholar