长白山火山次生泥石流灾害危险范围预测

长白山火山次生泥石流是由长白山火山喷发引起的火口湖中的水沿长白山北坡缺口,以类似水库溃坝的形式突然溢出而形成的短时间、大体积的水流,是携带着地表的松散堆积物,沿着沟谷和山坡向下快速流动的一种类似洪流的特殊泥石流.笔者在野外地质调查和室内模拟试验的基础之上,采用FLOW-3D数值模拟软件,对长白山火山喷发引起的次生泥石流灾害进行大范围的数值模拟,并着重研究其对二道白河镇地区的影响程度,旨在为政府决策和防灾提供依据.结果表明:泥石流总体积为30.27亿m³时,二道白河镇将完全被泥石流淹没;不论哪种泥石流体积假设情况,泥石流都将到达二道白河镇,并对其造成危害;一旦火山爆发,二道白河镇居民可逃生时间只有30~42 min.

Prediction on the Hazardous Extent of the Secondary Debris Flow Induced by Volcanic Disaster of Changbai Moutains

Using FLOW 3D software,basing on the field geological investigation and parameters obtained from indoor simulation,the authors simulated occurrence and development process of a special flood like debris flows which caused by Changbai Mountain volcanic eruption.The process of occurrence can be described as a sudden heavy overflow of a volcanic lake water carrying a large volume loose debris (volcanic lahars deposits ) through Tianchi gap quickly rushing down along the north slope.We simulated the influence of the debris flow to Erdaobaihe Town and drew the following conclusions:Under the condition of the debris flow volume of 3.027 billion m3 ,the town will be completely submerged by mudslides;no matter what kind of debris flow volume,Erdaobaihe Town will be eliminated by a debris flow once the volcano erupt,the escape time is only 30 to 42 minutes for the residents in the town.