Debris Flows, Floods and Beach Erosion and Their Mitigation

1.（1）默拉皮火山和云仙火山在喷出熔岩量达到10^7 m^3时，都终止了一个穹丘生长周期的活动。（2）地震、大地测量和地球化学观测所揭示的默拉皮火山喷发前的火山作用与樱岛和云仙山的火山作用十分相似。（3）在默拉皮火山和樱岛火山口下数公里处发现了地震活动空区，这可能表明在火山建筑物基底与火山产物层之间的边界处形成了岩浆囊。这些工作表明，在最近一次火山碎屑流大事件发生近10年后，斜坡上的物质浪费仍然非常活跃，而泥石流的频率由于斜坡表层成分的快速变化而正在减少。本文建立了一个一维数值模型， ...更多信息 预测泥石流的发生、流量、含沙量和淤积面积。数值结果表明，泥石流在坡度为2-4 °的河段基本停止运动。3.建立了降雨径流模型，并将其应用于Willingi坝流域（2860km^2）近10年来的几次洪水。认识到只要知道降雨特征，就可以预报洪水。1978 ~ 1989年Brantas河河床高程逐渐下降，1990年Kelude火山爆发后河床高程开始下降，本文建立了一维数学模型，预测了河床的变化。4.通过对沙努尔实测资料的分析，明确了巴厘岛南部海岸入射波的特征。波浪特征的显著特征是干湿季节性差异。长而高的波浪，高度范围为70- 100厘米，周期为9- 12秒（月平均有效波），在旱季附着在巴厘岛南部的东海岸。在雨季，波高约为50- 70厘米，周期为7.5- 8秒。利用这些波浪特性的研究成果，通过波浪在珊瑚礁上的转化和海岸线变化的数值模型，研究了海滩礁中珊瑚砂海滩的侵蚀特性，以明确礁滩中海滩变化的机理，并提出了控制海滩侵蚀的方法。在印度尼西亚，临时住房往往被改建为永久性住房。在印尼建造临时房屋时，我们必须考虑到文化和自然特征。少

1.(1)Both Merapi and Mt.Unzen terminated one-cycle activity of dome growth when the amount of extruded lava reached 10^7m^3. (2)Volcanic process prior to eruption revealed by seismic, geodetic and geochemical observations at Merapi is quite similar to those at Sakurajima and Mt.Unzen.(3)Seismicity gap a few kilometers beneath the summit crater are found out at both Merapi and Sakurajima, which may suggest the formation of a magma pocket at the boundary between the basement of volcanic edifice and the layer of volcanic products.2.An observation of debris flow and a topographic survey have been executed at the Bebeng river on the slope of Merapi volcano in Jawa island, and these works clarified that nearly 10 years after the last big event of pyroclastic flows, mass wasting on the slopes is still very active, while the frequency of debris flow is decreasing due to a rapid change in the composition of the surface layer of the slope. One dimensional numerical model has been developed for p … More redicting the occurrence, flow discharge, sediment concentration and deposition area of debris flow. The numerical results show that debris flows cease their movements in the river reaches with the slope of 2-4 degrees.3.Rainfall run off model has been developed and applied to several floods these ten years at the drainage area of Wlingi Dam(2860km^2). It is realized the flood can be predicted if the rainfall characteristics are known. The bed elevation of Brantas river degraded gradually from 1978 to 1989, but began to agrade due to the 1990 eruption of Mt.Kelude, One dimensional numerical model has been developed to predict such bed variations.4.Characteristics of the incident waves in the coasts in south Bali were made clear by analysis of observed data in Sanur. Remarkable feature of wave characteristics is the seasonal differences between in wet and dry. Long and high waves of which height ranges 70-100cm and period 9-12sec (monthly mean of significant wave) attach east coast along south Bali in dry season. In wet season wave height is around 50-70cm and the period 7.5-8sec. Using these results of wave characteristics, erosive properties of coral-sandy beaches in beach reefs have been investigated with numerical models for wave transformation on the coral reef and shoreline changes to make clear the mechanism of beach changes in reef flat and the method of beach erosion control was proposed.5.The temporary houses built after disaster were usually constructed by very cheap level. In Indonesia, the temporary houses were often converted to permananent houses. When we construct the temporary houses in Indonesia, we must take the culture and natural features into consideration. Less