玉龙雪山冰川崩塌成因分析

The Analysis of Icefall at Mt. Yulong

玉龙雪山是亚欧大陆距赤道最近的海洋型冰川分布区。2004-03-12上午,玉龙雪山东坡干河坝山谷上方漾弓江5号冰川区发生一次剧烈的的崩塌,2005年又有小规模的崩塌发生。通过实地考察认为,这是冰岩体崩塌事件。通过对气象资料的分析发现,区域气候变暖对冰川和永冻带稳定性的干扰是崩塌发生的主要原因,特别因为2003年和2005年为两个极端干热的年份。通过与本区其他冰川的变化对比,说明这次冰川崩塌可能是本区一些小冰川对区域变暖响应的另一种方式。同时发现,这次崩塌在现场留下的堆积物,在合适的天气条件下极易形成泥石流。

On 12 Mar. 2004, a violent natural landslip happened at the east slope of Mt. Yulong Lijiang region, Yunnan province. And at 2005 the similar landslip happened again. In order to realize what caused this landslip, we got to the locale of landslip on 21 Apr. and 7 May 2006 for two times, and found it was a ice-rock avalanche event. Based on meteorological observations from Lijiang, it can be easily found that the mean annual temperature in Lijiang region was rose gradually. In this case, the stability of glacier and rock wall is likely destroyed, especially at 2003 and 2005, the average temperature is 0.8℃ and 1.04℃ higher than the average temperature from 1951 to 2005 respectively, but at the same time, the precipitation at 2003 and 2005 is 66.7 mm and 133.3 mm less than the mean yearly precipitation from 1951 to 2005. That is to say, 2003 and 2005 are two extremely hot-dry years in Lijiang region. At last, this event remained about 2.13 × 10^6 -3.55 × 10^6 m^3 solid mass, if there is a suitable weather condition, the solid mass will run off as debris flow.