The methods taken to evaluate extensively the vulnerabilities of mountain slope to earthquake-triggered landslide were examined. The landslides that occurred in associations with the Mid Niigata Earthquake in 2004 were chosen for the study as a good example of the incidents that occur in the Tertiary sedimentary rock region where a number of multiple landslides are identified. Topographical and geological data that are extensively obtainable in combination with result of seismic analysis response data derived from finite element method were scrutinized for distinctive features of the subjected area. Further considerations were given in addition, as to what extent organizing these available data of conditions that would predispose each recognized location to seismic slope disaster may facilitate prognostication of the size and magnitude of the danger. From this study, a considerable additions were gained to the knowledge that would lead to the extensive prediction of seismically induced multiple slope disaster.

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A series of flume experiments for basic research has been performed to make clear the mechanism of earthquake-induced rock avalanches, which were commonly triggered at Wenchuan Earthquake in Sichuan province, China, on May 2008. Based on the results, it is found that the deposit could be divided into two parts and its reason is suggested in this paper; the prediction method for the longest travelling distance and its distribution is proposed; and a new relationship between moving velocity and travelling distance is derived. However, the causes of so long travelling distance as the case in Xiejiadian has not been found yet, and further work needs to be carried out in the future to confirm this observation.

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This paper presents analysed results of landslides distribution and scale with distance from epicenter and source fault of recent 4reverse-fault earthquakes, Chuetsu earthquake in 2004, Noto Peninsula earthquake in 2007, Chuetsu-offshore earthquake in 2007 and Iwate-Miyagi Inland earthquake in 2008. The results show that more in number and larger in scale of landslides occur on hanging-wall of the source fault compared to that on foot wall. The scale of landslide tends to decrease with increasing the distance from source fault. The results suggest that landslide distribution is strongly influenced by the distance from source fault compared to that from epicenter, slope gradient and geological component.

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Many landslides and slope failures triggered by heavy rainfall associated with Typhoon 0514 occurred in Miyazaki, Japan. Tsukinokawachi-landslide is one of the huge landslides distributed in Wanitsuka Mountains formed landslide dam due to 2005heavy rainfall. The slide block of Tsukinokawachi-landslide is overlain by several marker tephra layers such as AT (29cal ka) , K-Ah (7. 3cal ka) and Kr-M (4. 6cal ka) , but not by A-Fm (31cal ka) , A-Iw (45-50ka) and A-Fk (90ka) . These occurrences of tephra layers suggest that former movement of Tsukinokawachi-landslide occurred between 31 and 29 cal ka.

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The present paper focuses on areal expansion and equivalent coefficient of friction (H/L) of old landslides in two mountainous areas: Tanzawa and Hakone areas in the southern Kanto Region, Japan. These indices were estimated from morphometric measurements of old landslides on published landslide maps. Plots of slope of source area against H/L showed a distinct positive correlation for the both areas, while plots of landslide magnitude (size of source area) against H/L were scattered. Lower prediction limit of H/L for a given slope of source area was well agreed with actual H/L of a new landslide `Sounzan Landslide' in Hakone area. This result indicates that the analysis is useful for prediction of travel distance of future landslides. The areal expansion ratio, which is defined as the ratio of total landslide area including slid mass to source area of the landslide, ranged from 1. 0 to 2. 0, excepting that three landslides in Hakone area exceeded 2. 0. In average, landslides in Hakone area have smaller H/L and higher areal expansion ratios than those in Tanzawa area, indicating that the Hakone area has a higher potential of landslide disaster.

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