A catastrophe of debris flow happened in the evening of July 11, 1994, in Xiyu Gully,Xiaoqinling gold mining region (34°24’-34°30’N, 110°21’-110°34’E).51 persons were killed, several hundreds of persons were missing and economic loss is serious. The catastrophe was caused by unreasonable human activity under the heavy rain induced. Due to a large scale of gold mining privately,several million cubic metres of waste stones.are free stored on the steep slope and in the gullies of upstream of the catchments. The gullies were blocked by waste stones,strong flood washed away the waste stones, and then caused a large scale debris flow 3h of heavy rain later. It was the largest catastrophe of man-caused debris flow in China. Until now several million cubic metres of waste stones are still stored in the gullies, the gold mining is exploited inordinately, an insidious danger is still existing, and the probability is that the catastrophe of debris flow will be induced by heavy rain again. 更多