全国地质灾害趋势预测及预测图编制

NATION-WIDE MAIN GEOLOGIC HAZARD FORECAST AND MAPPING

区域地质灾害预测是地质灾害研究的难题。本文运用基于地理信息系统的风险评价方法对这一问题进行了探讨。将全国剖分为２７００个单元，对地质灾害进行现状评价，并与已数字化的地质灾害图件进行单要素叠加，编制了全国地质现状等值线图，在现状评价基础上，对地质灾害进行趋势预测，将降雨条件、区域地震活动、区域地壳稳定程度、区域岩组条件和人类工程活动等作为区域地质灾害演变的因素，运用模糊综合评判模型进行综合评判，编制了１：６００万中国地质灾害趋势预测图。

The GIS-based nation-wide main geologic hazard forecast and mapping is discussed with risk theory and methodology, in which the country is divided into more than 2700 elements (60km×60km) and individual geologic hazard information is digitized. The hazard information is symbolized by 'A'. 'B'. 'C' and ' D'respectively. A means high vulnerability and the value is assigned 4; B, moderate vulnerability and the value 3; C, low vulnerability and the value 2; D, sleight vulnerability and the value 1. The forecast is conducted on the base of situation evaluation that combines rainfall intensity, seismic activity, regional structure, regional rockinass formation and human engineering activity with fuzzy multijudgement method. The result on the fuzzy multi-judgement presents the triggered-geological hazard potential, and is divided into strong-triggereld (Ⅰ), moderate-triggered (Ⅱ) and weak-triggered (Ⅲ). The risk degree is overlaid between geologic hazard current situation and triggered-geological hazard potential element by element, and the nation-wide geologic hazard is classified into 'high risk zone','moderate risk zone', 'low risk zone'. The nation-wide comprehensive map 'MAP of MAIN GEOLOGIC HAZARD FORECAST of CHINA' (1: 6000 000) is completed which presents the three layers: 1) a situation of geologic hazard; 2) an evaluation on the situation; 3) a forecast on tendency of geologic hazard.The GIS-based support system of nation-wide geologic hazard evaluation and forecast has been primarily established, which provides a powerful tool of regional geologic hazard analysis' The system includes the follows: (1) Information and its storage All of the important information, including landslide, rockfall, mudflow, and also, geography, climatology, geomorphology, will be input the GIS system'(2) Information analysis and evaluation model On the base of spatial data base management system, the individual factor is calculated and overlaid to reveal the geologic hazard pattern, distribution, occurrance, scale and loss degree. The model of expert judgement, fuzzy comprehensive assessment and risk index are developed to evaluate the potentiality of geologic hazard. (3) Forecast of geologic hazard On the geologic qualitative analysis, the GIS--base math models are applied to indicate the geologic hazard--proned zone, primary triggered factors and hazard pattern, to estimate the occurring period and risk index, and to forecast the geologic hazard and establish the pattern of geologic hazard evolution combined with economic development and environment change. (4) Mapping the nation-wide and provincal geologic hazard, including in risk degree map, current situation map, etc. The forecast and zoning are conducted of the nation--wide geologic hazard and the seven key regions are determined on the 'MAP of MAIN GEOLOGIC HAZARD FORECAST of CHINA' (1: 6000 000) combined with national social and economic development programme, including: 1) high risk zone of the landslide, rockfall, debris hazard along the Baoji--Chengdu railway; 2) high risk zone of the landslide, rockfall, debris hazard along the Chengdu-Kunming railway; 3) high risk zone of the landslide, rockfall, debris hazard along the Baoji--Lanzhou railway; 4) high risk zone of the landslide, rockfall, debris hazard in the Three Gorges Reservoir of the Yangtze River; 5) high risk zone of the landslide and ground fracture in the Ordos; 6) high risk zone of karst collapse in Ginzhou and'Guangh; 7) moderate risk zone of debris hazard in northern Hebei and southern Liaoning.