著者

小室 裕明 志知 龍一 和田 浩之 糸井 理樹

出版者

特定非営利活動法人 日本火山学会

雑誌

火山 (ISSN:04534360)

巻号頁・発行日

vol.41, no.1, pp.1-10, 1996-03-05 (Released:2017-03-20)

参考文献数

31

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Sanbe Volcano is a large lava dome, 2 km in diameter, emplaced at the center of an elliptical caldera with a long axis of 7 km and a short axis of 5 km. One crater is exposed in the center of this dome, and four peaks surround this crater. However, the basement depth of the caldera has not been determined. We have made gravity measurements around Mt. Sanbe in order to investigate the caldera morphology. The residual gravity anomaly (which is obtained after the regional gravity trend is taken away from the Bouguer anomaly, assumed to be 2.67 g/cm3 in density) is low at the center of Sanbe Caldera. Mass deficiency, estimated by Gauss's theorem, indicates that Sanbe Caldera is one of the low anomaly type calderas, as large as the Mashu caldera. Basement depression under Sanbe Caldera has been determined by three dimensional analysis, when the density contrast between the basement rocks and Sanbe volcanic rocks is 0.43 g/cm3. The depression is square shaped, with a steep rim and a flat floor. The square outline suggests that the depression part may be subsided along normal faults ; accordingly this caldera may have originated in a cauldron. The western and eastern rims of the depression correspond to the somma, but the northern and southern rims are discordant. The poor topographic expression in these areas may be due to collapse of the caldera walls. The deepest part of the basement is centered on the east side of the present crater. This deep center may be the only vent of Sanbe Volcano, because other depressions are not observed beneath the lava dome.

著者

上明戸 昇 野上 英和 山下 恭弘 財満 健史 大脇 雅直 杉山 武 和田 浩之

出版者

日本建築学会

雑誌

日本建築学会計画系論文集 (ISSN:13404210)

巻号頁・発行日

vol.67, no.553, pp.17-22, 2002

被引用文献数

2 1

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We developed a system that is a combination of sound information and picture. We studied the estimation of the direction of incidental plane waves with a small sized electric generator outdoor experimentally. As average numbers of the cross spectrum increase, sound source points are concentrated in a place, in the case that the sound source is random noise. We studied the visualization of sound insulation by this svstem in the anechoic room and outdoors. We confirmed the result and we were able to visualize the diffraction by setting the wall.