- 著者
- IRIKURA Kojiro FUKUSHIMA Yoshimitsu
- 出版者
- Japanese Group for the Study of Natural Disaster Science
- 雑誌
- Journal of natural disaster science (ISSN:03884090)
- 巻号頁・発行日
- vol.16, no.3, pp.39-46, 1995-06-01
- 参考文献数
- 10
- 被引用文献数
- 2
The peak horizontal acceleration and velocity of observed records from the 1995 Hyogoken-nambu earthquake are compared with those predicted from empirical attenuation relations that were found applicable to the near-distance area. The observed peak values match well the existing empirical attenuation relations, although unpredictable severe damages occured due to strong ground motions in Kobe and adjacent cities close to the faulting zones. The observed peak vertical accelerations are about half the peak horizontal ones at less than 100 cm/s/s, as in the empirical relations, but they tend to be more than half at more than 100 cm/s/s. This suggests that the horizontal motions were more markedly affected by the horizontal non-linear behavior of the soils in the surface layers during strong horizontal motion than during vertical motions.
- 著者
- CHIGIRA,Masahiro
- 出版者
- Japanese Group for the Study of Natural Disaster Science
- 雑誌
- Natural disaster science
- 巻号頁・発行日
- vol.4, no.2, 1982
A peculiar "collapsing" landslide occurred at Nanamawari, Mitaka-iriya, on the Izu Peninsula during the 1978 Izu-Oshima-Kinkai earthquake. Field invstigations showed the causes and phenomena connected with this slide. The landslide began on a slope of 25゜with the sliding of scoria, soil and part of paleosol. The sliding surface was formed within the upper part of the paleosol, probably in a weathered ash bed, several meters below the original surface of the slope. During of transportation, the sliding materials disintergrated into dry debris and flowed onto the flat surface across the river, dashed against the opposite slope then rebounded and settled in a lobe-shaped deposit with lateral ridges and a distal mound. The landslide continued less than 30 seconds, but its maximum velocity was more than 11.7 m/s. The basic causes of the landslide were insufficient lateral support by strata on the lower and weak halloysite-rich paleosol in which the sliding surface formed. The landslide at Nanamawari is considered a special type of slide found in Japan.