# Research on Risk Assessment Method for Land Subsidence in Tangshan Based on Vulnerability Zoning
###### Abstract
[PERSON] et al. studied the vulnerability of karst collapse hazards based on ArcGIS and the analytic hierarchy process [21]. [PERSON] et al. conducted a risk assessment of the study area based on the analytic hierarchy process [22]. [PERSON] et al. determined each of the unit risk grades via the method of fuzzy synthetic evaluation on the basis of the index attributes and corresponding weights, and the results were distributed in space using ArcGIS to obtain the groundwater risk-grade map of various aquifers in different groundwater function zones of Tianjin City [23]. [PERSON] et al. divided the risk grade according to the standards of sixteen grades based on those of five initial grades [24]. [PERSON] analyzed the indicators for the assessment of the karst collapse risk and established a risk assessment model for karst collapse [25]. [PERSON] et al. used the Disaster Risk Index method and analytic hierarchy process (AHP) along with Geographic Information System (GIS) tools to assess the risk of land subsidence in Kathmandu Valley, Nepal [26]. [PERSON] et al. assessed the vulnerability of karst collapse in Wuhan using the comprehensive index method and the analytic hierarchy process [27]. [PERSON] assessed the risk in coal-mining areas based on the analytic hierarchy process-information value method and ArcGIS technology [28]. [PERSON] et al. used GRA-FAHP to select 14 influencing factors as major subsidence indicators and qualitatively and quantitatively evaluated the risk of karst collapse [29]. [PERSON] et al. investigated road cavity collapse accidents nationwide and developed a risk assessment method for urban road cavity hazards [30]. [PERSON] et al. conducted a vulnerability assessment for karst collapse using the analytic hierarchy process in the Huaihua region and obtained a hazard zoning map of the area [31]. [PERSON] et al. identified risk factors and developed a risk assessment framework for urban road collapse and established a road collapse risk assessment model [32]. [PERSON] et al. used the InSAR technique and analyzed Sentinel-1 data acquired from 2014 to 2020, identified some localized subsidence zones in the region, and performed a risk assessment by considering the hazards and using the vulnerability approach [33]. [PERSON] et al. employed a GIS-based DRASTIC model to assess the groundwater vulnerability in Tangshan City, a coastal area in China, and obtained the early warning standard of the groundwater decline rate [34]. [PERSON] et al. employed a combined methodology of full-consistency decision making (FUCOM) and the geographical information system (GIS) to assess the vulnerability of Iran to subsidence and obtained the land subsidence risk zoning map of the study area [35]. Existing studies have predominantly focused on either vulnerability zoning or risk assessment methods in isolation, with a limited number of studies integrating both aspects. Furthermore, while influencing factors, characteristics, causal mechanisms, and engineering prevention measures have been extensively discussed in these studies, theoretical research has been relatively limited. To address this gap, we aimed to carry out vulnerability zoning research based on ArcGIS and the risk assessment method based on the AHP-IV model. In this study, an initial single-factor analysis was conducted, based on ArcGIS, followed by a weighted overlay analysis using the raster calculator. Values were assigned and classified for each factor to generate a vulnerability zoning map of the ground subsidence in Tangshan City, thereby defining the study area. Moreover, the analytic hierarchy process-information value (AHP-IV) model was employed as a theoretical basis in this study. This model was utilized to evaluate the ground subsidence risk; to establish an evaluation index system; to construct an evaluation judgment matrix; and to calculate the weight of each risk assessment indicator, the information value of each individual indicator, and the total information value of the study area.