Debris avalanche deposits from Kyogatake Volcano and the recent faulting events in Fukui Prefecture, central Japan.

Kyogadake碎屑雪崩沉积形成于中更新世Kyogadake火山的西侧和西南侧，分布在山的西至西南脚下。近50 ka来发生了5次大的边坡破坏。最古老的破坏发生在山体西侧37 ~ 46 ka左右，泥石流主要分布在西坡。第二次发生在西侧31 ka，泥石流从西侧向西南坡移动。接下来的3次断裂分别发生在山体西南侧25.30ka、2.1ka和5.6 ~ 6.0 ka。到25.30ka的断裂时，岩屑雪崩向西南直下超过10km，形成了名为冢原野高地的岩屑高原。后两次断裂产生的碎屑雪崩也向西南方向下移，在冢原野丘陵地区缓坡东北侧形成了细长的高地。西侧4 ~ 5ka发生了小的塌陷。右走滑断层位于这些断层东南约2-4公里处。在Tsukaharano高地南侧向N-S方向延伸的Kiotoshi断裂，其中一条断裂史与最后一次边坡破坏的时间一致。这表明，坡体破坏可能是由经过京宅山东南侧的断层破裂引起的。

Kyogadake debris avalanche deposits were derived form the west and southwest side of the middle Pleistocene Kyogadake Volcano, and spread over the west to southwest foot of the mountain. The large slope failures have occurred 5 times in recent 50 ka. The oldest failure was generated about 37-46 ka on the west side of the mountain and the debris avalanche spread mainly over the west slope. The next one was 31 ka on the west side and the debris avalanche went down the west to southwest slope. The next three failures occurred on the southwest side of the mountain at 25.30ka, 2.1ka and 5.6-6.0 ka. By the 25.30ka failure, the debris avalanche went down to southwest straight over 10km, and formed the debris plateau called Tsukaharano upland area. The debris avalanches generated by the next two failures also went down to southwest and formed the elongated lob on gentle slope northeast side of Tsukaharano upland area. Small collapse occurred on the western side at 4-5ka.The dextral strike-slip faults are situated of about 2-4 km southeast of these failures. One of the rupture histories of Kiotoshi fault, which extends N-S at the south side of Tsukaharano upland area, shows the same time as that of the last slope failure. This indicates that the slope failure may have triggered by the rupture of the fault passing southeast side of Mt. Kyogadake.