基于证据权与Logistic回归模型耦合的滑坡易发性评价

滑坡灾害易发性研究对地质灾害风险管理及减灾防灾有着重要的现实意义。目前,多模型耦合的评价方法在国内外应用较为广泛,但将证据权与其他方法相结合用于滑坡易发性评价的研究却较少。鉴于此,本文以浙江省永嘉县为例进行滑坡易发性评价,选取高程等9个因素作为滑坡易发性的评价因子。利用证据权模型计算得到的证据权对比度与分级栅格比、滑坡栅格比进行比较,实现各评价因子状态分级处理;再运用Logistic回归模型算得各评价因子的权重。综合两种模型确定的状态分级权重和评价因子权重,基于GIS的栅格运算功能得到各评价单元的滑坡发生概率,实现研究区滑坡易发性分级区划。研究结果表明,证据权与Logistic回归耦合模型的评价结果的合理性与精确度均优于两种单一模型;且极高易发区和高易发区主要分布在水系延展区、断层密集区、岩组软弱区。研究结果对滑坡灾害风险管理及城市防灾规划具有一定的参考价值。     

三峡库区滑坡灾害与地质环境关系分析

采用敏感性系数方法分析三峡工程库区滑坡灾害与地质环境各因子不同区段（类型）的关系，以敏感性系数的灾点分析法进行统计分析，得出各因子的不同区段（类型）对滑坡灾害发育的敏感性大小和三峡工程库区斜坡地段滑坡灾害发生的优势地质环境因子组合。     

降雨诱发区域性滑坡预报预警方法研究

论文以四川省雅安市雨城区为研究区，将逻辑回归模型引入区域降雨型滑坡预警预报，建立了同时考虑降雨强度和降雨过程的降雨临界值表达式。在滑坡危险性区划的基础上，研究提出了区域降雨型滑坡预警预报指标，包括临界值降雨指数R和滑坡发生指数L，并利用20台自动遥测雨量计和地质灾害群测群防网络，采用历史记录雨量和预报雨量，建立了区域降雨型滑坡预报预警体系。     

基于分形理论的南江县滑坡敏感性分析与易发性评价

定量分析滑坡发生的敏感性,能为易发性区划、危险性评价、风险性评估等提供定量依据,对研究滑坡的成灾背景、发育规律具有重要意义。文章基于ArcGIS技术应用“累计和分形理论”对滑坡的敏感性进行了分析,得到各致灾因子的累计和分维值及滑坡发生对各致灾因子的敏感性;基于滑坡对致灾因子的敏感性绘制南江县易发性区划图,将南江县滑坡易发性等级分为极高易发区、高易发区、中易发区、较低易发区、极低易发区五个等级。     

基于有效降雨阈值的澧源镇滑坡灾害危险性分析

以湖南省澧源镇为例,利用证据权模型和灰色关联度模型分别计算了坡度、地层岩性、斜坡形态、土地利用类型、人类工程活动5个因子二级状态证据权值和一级因子权重;综合2种模型确定全区滑坡易发性指数后,完成基于斜坡单元的全区滑坡易发性区划;根据研究区岩土体类型(碎屑岩类、碳酸盐岩夹碎屑岩类、碳酸盐岩类和松散岩土体类)分组研究不同滑坡发生概率下的有效降雨阈值曲线(I-D曲线)。研究降雨时间为3日、有效强度为22.4 mm/d的降雨工况下各岩土体类型滑坡发生的时间概率。综合时间概率和易发性结果得到澧源镇基于有效降雨阈值的滑坡灾害危险性区划图。研究结果表明:澧源镇滑坡灾害高和极高易发区占研究区总面积的25%,主要沿澧河分布;极高危险区和高危险区占研究区总面积的14%,主要分布在澧河北侧。     

基于有效降雨强度的滑坡灾害危险性预警

选取湖北省恩施地区1 000 km2区域作为典型研究区, 在全面分析该区域历史滑坡资料的基础上, 根据该区滑坡生成与地层岩性之间的关系, 将研究区地层划分为高、中、低3类易发性岩组.分岩组统计降雨监测数据与历史滑坡信息, 得出有效降雨强度与关键降雨持续时间的散点图, 由此确定不同滑坡发生概率的有效降雨强度阈值, 提出该区的滑坡灾害危险性预警判别模型.基于样本区统计数据建立滑坡预测指标体系, 运用GIS得出研究区域的滑坡空间易发性区划结果, 并根据不同易发岩组-有效降雨强度模型, 叠加滑坡灾害易发性分区结果与降雨危险性预警等级分级结果, 对研究区的滑坡灾害危险性进行了预测预警.结果表明: 不同易发岩组-有效降雨强度模型所得预警结果与实际情况吻合, 预警模型具有考虑全面和预警精度高的特点, 在实际预警中切实可用.      

基于信息量法的湖北省秭归县滑坡易发性评价

本文以湖北省秭归县为研究区,选取高程、水系距离、道路距离、岩土体类型、坡向、坡度、土地覆盖类型、年降雨量等8个评价因子开展滑坡易发性评价工作,依据ArcGIS软件数据分析工具完成各评价因子相关性分析。对评价因子相关性值|r|>0.1的高程、坡向因子剔除,计算各因子信息量值。利用信息量模型进行滑坡易发性评价,将研究区划分为四个区域：(1)极高易发区,面积140.0864 km²,占研究区总面积6.18%,主要分布在长江及支流沿岸;(2)高易发区,面积1002.445 km²,占研究区总面积44.23%,主要呈带状分布在极高易发区两侧,部分位于两河口镇、磨坪乡周边区域;(3)中易发区,面积833.8711 km²,占研究区总面积36.79%,呈带状分布在极高易发区两侧,零散分布;(4)低易发区,面积290.2564 km²,占研究区总面积12.80%,多分布在高山人稀区域。本文研究结果能够较好地反映研究区滑坡灾害分布规律,可为秭归县防灾减灾工作提供依据。     

基于环境因子AI-GIS方法的天然滑坡危险性预测--以香港大屿山岛为例

利用人工神经元网络(AI)及地理信息系统(GIS)技术,将多元空间信息分析与非线性理论相结合,建立了基于环境因子的区域滑坡非线性预测模型.选择天然滑坡比较发育的香港大屿山岛中部作为试验研究区,定量分析了滑坡与各种环境因子的空间关系,进行了因子筛选,据此对区域天然滑坡进行了危险性分区.结果表明,该方法可获取较高的预测精度,是完全可行的.该方法的应用将为区域滑坡危险性区划及滑坡灾害的防治提供重要依据.     

基于位移比模型的三峡库区云阳县域内蠕变型滑坡降雨预警

建立高效合理的区域滑坡灾害降雨预警模型对滑坡防治具有重要意义.然而以往的研究多侧重于临滑预警,对蠕变型滑坡在强降雨工况下的短暂加速变形的预警研究还有待深入.以三峡库区云阳县域内滑坡为例,首先根据滑坡地表位移监测数据的特点对统计样本进行合理筛选.再通过降雨因子与滑坡发生的相关性分析以及对滑坡在降雨条件下位移变化情况的数值模拟,确定了适用于不同时间阶段的降雨统计变量.然后将考虑了滑坡规模特征的滑坡位移比（累计位移与滑坡纵长之比）作为变形指标,分时段统计滑坡地表位移监测数据与历史降雨信息,建立了日降雨数据与月位移数据的对应关系,得到了可用于确定降雨量阈值的位移比模型,并获得了云阳县蠕变型滑坡的五级预警分区.最后分别选用研究区滑坡险情实例、长年位移监测数据及极端降雨事件对模型预警效果进行检验.结果显示基于专业监测数据的位移比模型的滑坡降雨预警结果与实际情况相符,可为蠕变型滑坡的预警预报提供依据.      

GIS支持下基于CF方法的2013年芦山地震滑坡因子敏感性分析

本文依据研究区现有地形因子(高程、坡度、坡向、斜坡曲率)、地质因子(岩性、距深大活动断裂距离)和地震因子(PGA、距震中距离)等相关影响因子资料并结合地震区基本情况,以GIS技术作为操作平台,采用确定性系数法,开展较为详细的芦山地震区地震滑坡影响因子敏感性分析工作。首先,以GIS技术作为操作平台将地震滑坡的8个影响因子据研究区特征进行分级,构建不同影响因子分级的栅格图层进行地震滑坡分布相关参数统计; 其次,采用确定性系数法计算8个地震滑坡影响因子分级区间对应的CF值,分别提取出地震滑坡最为敏感分级区间以进行地震滑坡影响因子敏感性分析,从而衡量不同影响因子分级区间对地震滑坡易发性敏感程度。地震滑坡影响因子敏感性分析结果表明,除斜坡曲率因子与距震中距离因子对地震滑坡易发性不敏感外,其他6个影响因子对地震滑坡易发性均很敏感,分别是影响滑坡发生的主要地形、地质和地震因子。针对斜坡曲率因子和距震中距离因子对滑坡的易发性不是很敏感是否受内部其他影响因子限制所进行的分析与讨论结果表明,SW向很可能限制了斜坡曲率对地震滑坡易发性的敏感程度,地层岩性对距震中距离因子限制作用更为明显,除奥陶系、志留系外的地层岩性对距震中距离因子敏感性程度都有限制。文章所得成果具有一定的方法理论意义,对于防震减灾工作也具有一定参考意义。     

Predicting natural arsenic contamination of bedrock groundwater for a local region in Korea and its application

A logistic regression model for the probability of arsenic exceeding the drinking water guidelines (10 μg/L) in bedrock groundwater was developed for a selected county in Korea, where arsenic occurrence and release reactions have been investigated. Arsenic was enriched naturally by the oxidation of sulfide minerals in metasedimentary rocks and mineralized zones, and due to high mobility in alkaline pH conditions, concentrations were high in groundwater of the county. When considering these reactions of arsenic release and water quality characteristics, several geological and geochemical factors were selected as influencing variables in the model. In the final logistic regression model, geological units of limestone and metasedimentary rocks, the concentrations of nitrate and sulfate, and distances to closed mines and adjacent granite were retained as statistically significant variables. Predicted areas of high probability agreed well with known spatial contamination patterns in the county. The model was also applied to an adjacent county, where the groundwater has not previously been tested for the presence of arsenic, and a probability map for arsenic contamination was then produced. Through the analysis of arsenic concentrations at the wells of high probability, it was determined that the applied model accurately indicated the arsenic contamination of groundwater. The logistic regression approach of this study can be applied to predict arsenic contamination in areas of similar geological and geochemical conditions to the county used in this model.     

单沟泥石流灾害风险简易评价模型

按照灾害风险评价的一般框架,定性定量相结合,运用沟谷、降水、成灾因子、遭遇特征与易损程度等五项指标,尝试提出单沟泥石流灾害风险简易评价模型,并结合防治规划,提出了单沟泥石流灾害风险管理对策建议。采用云南新平县泥石流灾害调查数据,开展了实例校验,结果表明,该模型基本反映了沟谷泥石流灾害的相对风险水平,可为现阶段管理提供更加明确的分级依据。     

单体滑坡灾害风险简易评价研究

按照灾害风险评价的一般框架,定性定量相结合,运用破坏概率、滑坡强度、承灾因子、遭遇特征与易损程度等5项指标,尝试提出单体滑坡灾害风险简易评价模型,并结合防治规划,提出了滑坡灾害风险管理对策建议。采用云南新平县滑坡灾害调查数据,开展了实例校验,结果表明,该模型基本反映了滑坡灾害的相对风险水平,可为现阶段管理提供更加明确的分级依据。同时,以期抛砖引玉,讨论险情调查与风险调查之间的关系。     

桂东大瑶山成矿带新坪矿区花岗斑岩与金多金属成矿作用关系

新坪花岗斑岩位于桂东大瑶山成矿带中部新坪金矿区内。在野外地质观察的基础上,报道了在该新坪斑岩体接触带附近发现金矿体并首次在岩体内部发现石英脉型辉钼矿(化)体,认为新坪花岗斑岩体与金多金属矿化关系密切。新坪花岗斑岩LA-ICP-MS锆石U-Pb同位素定年结果表明,该斑岩体形成于早古生代奥陶纪(462.9±6.4) Ma,属加里东期花岗岩类,因此与岩体有关的金矿化、铜钼矿化时间不会早于奥陶纪。岩体稀土元素分析结果显示,新坪花岗斑岩与邻近的古袍、圆珠顶、大黎矿区花岗斑岩体具有相似的稀土元素分布特征,可能为同源岩浆不同阶段的演化产物,说明新坪花岗斑岩体具有一定的金、钼等多金属成矿潜力。通过以上综合研究分析,初步认为新坪矿区具有寻找斑岩型金矿以及钼矿床的找矿前景。     

基于不同耦合模型的县域滑坡易发性评价对比分析

为有效预测县域滑坡发生的空间概率,探索不同统计学耦合模型滑坡易发性定量评价结果的合理性和精度,以四川省普格县为研究对象。选取坡度、坡向、高程、工程地质岩组、断层和斜坡结构等6项孕灾因子作为评价指标体系,基于信息量模型（I）、确定性系数模型（CF）、证据权模型（WF）、频率比模型（FR）分别与逻辑回归模型（LR）耦合开展滑坡易发性评价。结果表明:各耦合模型评价结果和易发程度区划均是合理的,极高易发区主要分布于则木河、黑水河河谷两侧斜坡带,面积介于129.04～183.43 km2（占比6.77%～9.62%）,各模型评价精度依次为WF-LR模型（AUC=0.869）>I-LR模型（AUC=0.868）>CF-LR模型（AUC=0.866）>NFR-LR模型（AUC=0.858）。研究成果可为川西南山区县域滑坡易发性定量评估提供重要参考。     

Assessment of water inrush risk using the principal component logistic regression model in the Pandao coal mine,China

In order to improve the accuracy of floor water inrush assessment, the risk prediction model of floor water inrush was established by combining the principal component logistic regression analysis (PCLRA) and GIS spatial geographic analysis. In this paper, the geological data of Pandao coal mine was taken as the engineering background. First of all, main controlling factors of floor water inrush were determined and quantified. Next, PCLRA was used to determine the weight of each factor and establish the mathematical model for predicting the floor water inrush. And then, GIS’s spatial analysis and data processing function was used to draw related single factor thematic maps. Related thematic maps were weighted superposed to draw a floor water inrush zoning map based on PCLRA mathematical model. The study areas were divided into five levels by Jenks optimization method and vulnerability index initial model. And the corresponding threshold range was determined. The results show that (1) the high sensitivity factors in floor failure depth were added to evaluate the water inrush, and the fault fractal dimension was used to replace the fault structure related factors, and the main controlling factors of floor water inrush are more comprehensive; (2) the fitting degree of PCLRA model is high and the test accuracy is 83.3%; (3) the prediction results were well fitted to the actual position of water inrush (three water inrush points are located in the dangerous area, and two water inrush points are located in the relatively dangerous area).     

广西平南新坪金矿成矿流体特征及矿床成因初探

广西新坪金矿地处大瑶山多金属成矿带六岑矿田,矿体主要受新坪复式背斜和近东西向的断裂破碎带控制,赋存于寒武系黄洞口组砂岩、砂泥岩中。石英流体包裹体数据显示,成矿流体为中温低盐度低密度含CO₂的流体;流体中阳离子以Na⁺、Ca²⁺、Mg²⁺、K⁺为主,阴离子以Cl^-为主。氢氧同位素分析表明,成矿流体中水可能主要来源于岩浆,并叠加有变质水,且不排除有少量大气水加入的特征;矿石硫化物的硫同位素组成范围较窄,多为距离零轴很近的负值,推断可能是深源硫与地层硫的混合。根据本次分析及结合前人研究表明,Au来源具有多源性,主要来源于寒武系地层,但区内深源岩浆岩也有提供Au的可能性。据以上分析,结合前人对该地区矿床成因的研究,初步认为新坪金矿属于变质-岩浆热液叠加成矿。     

Landslide susceptibility mapping in the Damrei Romel area, Cambodia using frequency ratio and logistic regression models

This study applied, tested and compared a probability model, a frequency ratio and statistical model, a logistic regression to Damre Romel area, Cambodia, using a geographic information system. For landslide susceptibility mapping, landslide locations were identified in the study area from interpretation of aerial photographs and field surveys, and a spatial database was constructed from topographic maps, geology and land cover. The factors that influence landslide occurrence, such as slope, aspect, curvature and distance from drainage were calculated from the topographic database. Lithology and distance from lineament were extracted and calculated from the geology database. Land cover was classified from Landsat TM satellite imagery. The relationship between the factors and the landslides was calculated using frequency ratio and logistic regression models. The relationships, frequency ratio and logistic regression coefficient were overlaid to make landslide susceptibility map. Then the landslide susceptibility map was compared with known landslide locations and tested. As the result, the frequency ratio model (86.97%) and the logistic regression (86.37%) had high and similar prediction accuracy. The landslide susceptibility map can be used to reduce hazards associated with landslides and to land cover planning.     

Assessment of ground subsidence hazard near an abandoned underground coal mine using GIS

This study constructs a hazard map for ground subsidence around abandoned underground coal mines (AUCMs) at Samcheok City in Korea using a probability (frequency ratio) model, a statistical (logistic regression) model, and a Geographic Information System (GIS). To evaluate the factors related to ground subsidence, an image database was constructed from a topographical map, geological map, mining tunnel map, Global Positioning System (GPS) data, land use map, lineaments, digital elevation model (DEM) data, and borehole data. An attribute database was also constructed from field investigations and reports on the existing ground subsidence areas at the study site. Nine major factors causing ground subsidence were extracted from the probability analysis of the existing ground subsidence area: (1) depth of drift; (2) DEM and slope gradient; (3) groundwater level, permeability, and rock mass rating (RMR); (4) lineaments and geology; and (5) land use. The frequency ratio and logistic regression models were applied to determine each factor’s rating, and the ratings were overlain for ground subsidence hazard mapping. The ground subsidence hazard map was then verified and compared with existing subsidence areas. The verification results showed that the logistic regression model (accuracy of 95.01%) is better in prediction than the frequency ratio model (accuracy of 93.29%). The verification results showed sufficient agreement between the hazard map and the existing data on ground subsidence area. Analysis of ground subsidence with the frequency ratio and logistic regression models suggests that quantitative analysis of ground subsidence near AUCMs is possible.     

云南省新平县地质灾害与线性构造的相关性研究

新平县因其特殊的地理和地质环境,地质灾害高发。采用ETM753与全色波段融合的空间分辨率为15m的遥感图像作为解译的底图,提取四级线性构造信息,应用地理信息系统构建标准格网对线性构造的频率和密度进行分析,配以方位频率、方位密度和平均方位密度统计,采用盒计维数法获取线性构造分维特征,将地质灾害与线性构造分析统计结果作叠加分析,研究表明：区内的线性构造主要分布在中部和东部频率值为3条,4km^2～8条/4km^2和密度值为3～4km／4km^2的区域,NE-SW和NNW-SSE向的线性构造主要控制不稳定斜坡和滑坡发育,NW-SE向线性构造主要控制泥石流发育,全县的线性构造分维值在中国西南地区偏高为1．760。验证了线性构造与地质灾害的正相关性。