A channelised long run-out debris slide triggered by the Noto Hanto Earthquake in 2007, Japan
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- 作者：Yasuhiko Okada (1) okada10@ffpri.affrc.go.jp
Hirotaka Ochiai (1)
Ushio Kurokawa (1)
Yasuhiro Ogawa (1)
Shiho Asano (1) - 关键词：Debris slide ; Run ; out distance ; Topographic amplification ; Earthquake
- 刊名：Landslides
- 出版时间：May 2008
- 出版年：2008
- 期刊代码：76_1612-5118
- 类别：ear
- 卷：5
- 期：2
- 页码：235-239
- 数据来源：sp
摘要
A strong earthquake (M J 6.9, M W 6.6–6.7) at about 11 km depth hit the western shore of the Noto Peninsula on Honshu, Japan, at about 00:42 coordinated universal time (9:42 a.m. local time) on 25 March 2007 (the Noto Hanto Earthquake in 2007). The earthquake triggered only 61 landslides, with most traveling short distances. It caused one long run-out landslide in the Nakanoya district of Monzen town, Wajima city, Ishikawa Prefecture, when a portion of a deep-seated landslide transformed into a moderate debris slide down a channel. The rock slide occurred on a south-facing convex-shaped slope on a small spur where earthquake ground shaking likely was strongly amplified by topography. A portion of the rock slide reached a small channel floored by materials containing abundant groundwater. Constant-volume box-shear tests on normally consolidated saturated specimens revealed that the apparent angle of internal friction of the channel-floor material was 33–36掳 at 10-mm shear displacement and did not show much decrease in effective normal stress during shearing. In situ rock-sliding testing on the exposed channel materials showed a low kinetic-friction angle of about 21掳. We suggest that an unsaturated portion of the rock slide slid down the channel, with sliding between the rock-slide mass and the channel floor. Because the slope angle of the travel path nearly equaled the kinetic-friction angle, the unsaturated rock slide mass may have traveled at a moderately slow speed, or it might have decelerated and accelerated. Slow speed is supported by accounts from local residents that suggest movement of debris continued for 3 days after the main shock.