长白山天池火山溃湖洪水最大流量的初步估算及影响分析

EFFECT ANALYSIS AND PRELIMINARY ESTIMATION OF VOLCANO LAKE OUTBURST FLOOD MAXIMUM FLOW OF CHANGBAISHAN TIANCHI VOLCANO

长白山天池火山是目前最具潜在喷发危险的活火山。依据长白山天池火山的最新监测研究成果,结合地形地貌、水文流域特点及天池火山历史喷发类型,重点分析了长白山天池火山未来喷发时发生溃湖洪水的危险性。利用相关的水动力学公式,建立了溃口规模和洪水湿周、流量和流速的内在关系。详细分析溃湖洪峰在下游二道白河镇、白山水电站、红石水电站等关键位置的最大流量及流速。结果表明,若天池火山湖水溃泄一半即10亿m3时,距火山口50km处的二道白河镇瞬时洪水流速达84904m3/s,该镇将全部被淹没。下游的白山水库、丰满水库将分别受到流量23560m3/s和1505m3/s洪水的冲击,水库安全受到严重威胁。

The active volcano-Changbaishan Tianchi Volcano in China, has an urgent eruption danger at present. There have been several eruptions in the past. In recent years, ground deformation and earthquake monitoring stations were established in the Changbaishan Volcano area, and the monitoring data show that the magma underground has triggered earthquake swarm activities and led to ground deformation. A lot of research results show that Changbaishan Tianchi Volcano is in an early unrest stage at present, the future eruption risk is increasing. The volcano disaster is very complicated. The determinants include volcano eruption pattern, crater position and magma ingredients. To the Changbaishan Tianchi Volcano ,once it erupts in the future,in addition to generating volcano mud flow, debris flow and ash cloud, the flooding dam overflow caused will be the most influential and worst secondary disaster. Changbaishan Tianchi Volcano Lake is one of the highest volcano lakes in the world,with a lake area 10kmz, depth 371m,water volume 2 billion m3, once it bursts, it will cause huge economic loss and people death to the downstream region. This article elaborates the topography and hydrology and watershed characteristics of Changbaishan Tianchi volcano. Using the hydraulic formula,we estimate the volcano lake dam-break model and analyze maximum volcano lake outburst flood flow and the flood evolution process to downstream area under the different conditions. The conclusion shows that, if the volcano lake dam collapses by half,the Er-Dao town will be flooded,and the downstream Baishan reservoir will suffer a serious threat from the floodwaters.