Debris Flows, Floods and Beach Erosion and Their Mitigation

1.(1)默拉皮火山和unzen火山在喷出熔岩量达到10^7m^3时，均终止了一周期的穹丘生长活动。(2)默拉皮火山的地震、大地测量和地球化学观测揭示的火山喷发前的过程与樱岛和云仙山非常相似。(3)默拉皮火山和樱岛火山在山顶火山口下方几公里处都发现了地震活动间隙，这可能表明在火山大厦基底和火山产物层的交界处形成了岩浆穴。在爪哇岛默拉皮火山斜坡上的贝本河进行了泥石流观测和地形测量，这些工作表明，在最后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，而由于斜坡表层成分的快速变化，泥石流的频率正在减少。建立了预测泥石流产状、流量、含沙量和沉积面积的一维数值模型。数值结果表明，泥石流在坡度为2 ~ 4度的河段停止运动。建立了降雨径流模型，并将其应用于近十年来Wlingi大坝流域（2860km^2）的多次洪水。实现了在降雨特征已知的情况下，对洪水进行预测。Brantas河河床高程在1978 - 1989年间逐渐退化，但在1990年克鲁德火山喷发后开始退化，建立了一维数值模型来预测河床高程的变化。通过对沙努尔观测资料的分析，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差异。在旱季，沿巴厘岛南部东海岸出现高度70-100厘米、周期9-12秒（显著波月平均）的长浪和高浪。雨季浪高约50-70cm，周期7.5-8sec。利用这些波浪特征的结果，利用波浪对珊瑚礁的转化和岸线变化的数值模型，研究了滩礁中珊瑚-沙质海滩的侵蚀特性，明确了礁滩滩滩变化的机理，并提出了滩礁侵蚀控制的方法。灾后建造的临时房屋通常是用非常便宜的材料建造的。在印度尼西亚，临时住房经常被改造成永久性住房。在印尼建造临时房屋时，我们必须考虑当地的文化和自然特征。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