Research On Debris Flow In South Of Liaoning In Background Of Quaternary Period

In mountain area of South of Liaoning debris flow occurred frequently in history. At first the paper investigates structure,form,climate,river,soil and vegetation in this area. Then find out the environmental factors which influence debris flow to break out. The paper makes a study of the development history of debris flow and environment changes in Quaternary Period. Profiles of debris flow in South of Liaoning were found and examined which formed in different stages of Quaternary Period. It appears that debrisflow in South of Liaoning mainly broke out at 0.7Ma. B.P.,0.15～0.07Ma. B.P.,0.035～0.029Ma. B.P.,0.01～0.008Ma. B.P. and 0.003～0Ma. B.P. It can be seen that the debris flow activities in this area have concentrated on since Middle Pleistocene. It is researched that South of Liaoning had risen frequently and intensely before Middle Pleistocene. This Geological condition let debris flow easy to break out. Earthquake is the most obviously reflection of modern activity. Intense earthquake can destroy stability of hill directly, reduce the intensity of rock and increase origin of solid matter. It is material foundation ang power condition of debris flow formation of mountain area. South of Liaoning is in the lattice of intense earthquake activity. The formation of debris flow is also related intimately to precipitation. Atmosphere precipitation is the necessary impetus condition for debris flow to break out. In Middle Pleistocene, with the accelerative uplift of the Tibetan Plateau, the southeast monsoon strengthened. Sequentially the southeast monsoon let rainfall in South of Liaoning abundant, precipitation concentrated and cloudburst increased. According to analyzes, the formation of debris flow goes in step with the global climate fluctuation. In warm period cloudburst activities became frequent and debris flow activities also increased. In cold period cloudburst activities became weak and debris flow activities also decreased. So we can accord to predict climate change of the future to calculate when debris flow to break out and put the countermeasures of the disaster reduction in advance. On the basis of prediction the intensity of precipitation tends to strengthen obviously. Besides what the frequency of instable weather increases can makes debris flow in South of Liaoning break out frequently.