基于GIS与信息量法的北流市地质灾害易发性评价

广西北流市地质灾害多发频发,急需开展地质灾害易发性评价工作。基于Arc GIS分析筛选后选取了坡度、坡向、岩性、地貌、水系、道路、构造、工程切坡强度、最大24 h降雨均值为评价因子。运用信息量模型进行了易发性区划,将北流市划分为极高、高、中、低、极低易发区,分别占研究区面积的27. 75%、21. 83%、29. 38%、14. 44%、6. 58%。从评价成果知,地质灾害主要集中发生在坡度为0～23°;坡向为西北、北、西南和南;地层岩性为岩浆岩类;地貌类型为低山丘陵和丘陵盆地;工程切坡强烈且未加以防护区域;水系、道路和地质构造发育等特征区域。通过受试者工作特征曲线的线下面积进行检验,结果为73. 6%,说明分区结果合理,能够为北流市地质灾害的防灾减灾工作提供一定的科学依据。

Evaluation of the Geological Hazard Vulnerability in the Beiliu City Based on GIS and Information Value Model

Geological disasters occurred frequently in the Beiliu city, Guangxi province, so it is urgent to evaluate the vulnerability of geological disasters. After been analyzed and screened by ArcGIS, slope, aspect, lithology, landform, water system, road, geological structure, engineering slope cutting intensity and maximum 24 h rainfall average were selected as evaluation indexes. An information value model was used to divide the city into extremely high, high, medium, low and extremely low prone areas, which accounted for 27.75%, 21.83%, 29.38%, 14.44% and 6.58% of the research area respectively. According to the evaluation results, geological disasters mainly occurred in areas characterized by slope ranging from 0° to 23°, northwest, north, southwest and south magmatic strata lithology, low hills and hilly basins, strong slope cuts with no protective measures, water system, road and geological structure developed areas. The examination result of the area below the receiver operating characteristic curve was 73.6%, indicating that the zoning results are reasonable and can provide a certain scientific basis for the prevention and reduction of geological disasters in the Beiliu city.