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 2 000-4 000 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 in the north slope, the northeast slope and the southeast slope, the erosion area accounted for 61.07% of the total area.

Conclusion The spatial distribution characteristics of soil erosion are closely related to the distance, elevation, slope and aspect of the fault. This result may provide a theoretical basis for soil and water conservation after the earthquake.