地震效应下的土壤侵蚀空间分布特征及分析——以九寨沟地震为例  

Spatial distribution characteristics and analysis of soil erosion under earthquake effect:A case study of Jiuzhaigou earthquake

作　　者：夏冰 范宣梅[1] 郭晓军[2] 杨帆[1] 邹城彬 熊坤勇 XIA Bing;FAN Xuanmei;GUO Xiaojun;YANG Fan;ZOU Chengbin;XIONG Kunyong(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,610059,Chengdu,China;Chengdu Institute of Mountain Hazards and Environment,Chinese Academy of Sciences Ministry of Water Resources,610041,Chengdu,China)

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610059 [2]中国科学院水利部成都山地灾害与环境研究所,成都610041

出　　处：《中国水土保持科学》2020年第1期79-89,共11页Science of Soil and Water Conservation

基　　金：国家自然科学基金优秀青年基金“西南山区强震诱发滑坡坝堰塞湖形成条件与环境效应研究”(41622206);国家自然科学基金国际(地区)合作与交流项目“汶川地震诱发地质灾害时空演化规律及风险评价研究”(41661134010);四川省国土资源厅科研项目“8.8九寨沟地震灾区生态化地质灾害防治重大科技支撑研究课题”(KJ-2018-22)。

摘　　要：在空间信息技术(GIS)支持下应用USLE模型定量计算出九寨沟地震前后受灾区的土壤侵蚀强度,并对地震前后土壤侵蚀参数做了简要的对比分析,划分出受地震影响较大的区域,探讨该区域土壤侵蚀的空间分布规律与距发震断层距离、坡度、高程和坡向4个方面之间的关系,为震后灾区水土保持工作提供科学依据。结果表明:相比2015年该区域的侵蚀参数,地震后侵蚀面积增加55 km2,侵蚀总量提高57%,平均侵蚀强度增加45%;在侵蚀强度类别中轻微度、轻度和中度的面积占比在震后全部下降,强度侵蚀及以上侵蚀的面积占比都有所上升,在地震影响下研究区的土壤侵蚀强度等级有向强度侵蚀等级及以上侵蚀等级转移的趋势;地震造成土壤侵蚀严重加剧的区域主要集中在距发震断层2 km范围内、坡度≥30°~60°、高程≥2000~4000 m、坡向为北坡、东北坡和东南坡的地带。[Background]The natural factors affecting soil erosion are soil,rainfall and vegetation.The structure and particle composition of the soil affect the soil′s ability to resist erosion and erosion.When the soil is loose,the adhesion between particles is weak,and the structure is loose,it is susceptible to water erosion.The earthquake in Jiuzhaigou caused the mountain body to be broken,soil loose and vegetation destruction in Jiuzhaigou county,which greatly increased the probability of soil erosion in Jiuzhaigou County.[Methods]Based on GIS and USLE models,the soil erosion intensity in the disaster area before and after the earthquake was quantitatively calculated,and the soil erosion parameters before and after the earthquake were briefly compared and analyzed,and the areas affected by the earthquake were divided.Combined the regional statistical analysis(Zonal)with ArcGIS,the relationship between the spatial distribution of soil erosion in this area and the distance from the fault,slope,elevation and aspect were explored.[Results]1)Compared with that before the earthquake,the erosion area after the earthquake increased by 8.1%,the total erosion increased by 28%,and the erosion intensity increased by 18.39%.In the erosion intensity category,the area proportion of slight,light and moderate erosion all decreased after the earthquake,while the area proportion of moderate and serious and above erosion increased.2)The closer the distance from the fault was,the larger the area of the earthquake prone was.As the distance from the fault increasing,the area of the easily-affected area decreased.In the easily-affected area,the increment of erosion intensity decreases sharply with the distance from the fault increasing.3)The areas susceptible to earthquake in the study area mainly occured at elevations of 2000-4000 m,accounting for 99%of the total area.In the slope range of 30°-60°,the erosion area accounted for 89.25%of the total area of the susceptible area,respectively.The areas affected by earthquake were distributed

关 键 词：土壤侵蚀 九寨沟地震 地理信息系统(GIS) 通用土壤流失方程(USLE) 

分 类 号：S157.1[农业科学—土壤学]