The characteristics analysis of debris flow fan in Nujiang alpine canyon region

Debris flow fan is an important record of debris flow activities,and is an important part of the study of debris flow.In this paper,with remote sensing image recognition and field survey,it has been explicated for the Nujiang alpine gorge area debris flow fan space distribution characteristics and deployed analysis to debris flow fan morphological characteristics.The research finds that among the 200 debris flow gullies in the study area,there are 176 gullies that have developed obvious scale debris flow,with average area of debris flow fans 0.052km2.Besides,debris flow fans' average grade mostly fall in between 5°—10°,accounting for 59.7 percent,and the angle between the main river downstream is distributed between 90°—120°.In addition,the relationship of deposited fans to the main river is barrier type which is most widely distributed.Also,the relationship among debris flow basin area,the main groove slope and stacked fan area is not obvious.As accumulation fans are important living spaces to local residents for production,arable land distributed on accumulation fans,roads as well as bridges tend to be affected by the threat of severe mudslides.This research is hopefully to guide the mudslides disaster prevention work in Nujiang alpine gorge area.