Abstract: The refined risk assessment of geological disasters is a crucial method for improving the efficiency of geological disaster prevention and control at the town-scale and reducing disaster risks. Meanwhile,the research on the town-scale risk assessment technology based on refined survey data has become the research focus in this field. The geological disasters in the research area,Quanwang Town of Quzhou City are characterized by diverse types,being influenced by topography and human activities in terms of distribution,having obvious seasonal characteristics and posing great potential hazards. However,at present, due to factors such as insufficiently refined assessment methods,inaccurate and incomplete data,and limitations of technical means,the disaster assessment work carried out can hardly accurately quantify the risks of geological disasters. Based on the Geographic Information System (GIS) spatial analysis technology and the comprehensive index method,this paper takes into account the geological environmental background and human engineering activities in Quanwang Town and constructs a refined evaluation index system for the vulnerability and hazard of geological disasters at the town-scale. By integrating multi-source refined geological disaster data,the susceptibility of slope units to geological disasters in Quanwang Town is evaluated in a refined manner. Moreover,by adding four different rainfall condition indicators for heavy rain,rainstorm,torrential rain and extraordinary rainstorm,and taking the rainfall within 24 hours as the triggering factor,the instability probability and spatial intensity of disasters occurring in slope units under different conditions are analyzed,and the hazard levels of geological disasters in Quanwang Town under four different rainfall conditions are evaluated in a refined manner. Finally,the refined risk assessment results of Quanwang Town are obtained,and the grades of geological disaster risk areas are demarcated. The obtained results are consistent with the current situation of landslide geological disasters in Quanwang Town and have certain reference value for the refined geological disaster risk investigation and assessment at the town-scale. 

Key words: geological hazard,geographic information system,township scale,vulnerability,hazard,risk assessment