霍西煤矿区地表滑坡灾害敏感性数值建模与等级划分

本文以山西省霍西煤矿区为研究区,利用遥感和GIS方法对滑坡灾害的敏感性进行了数值建模与定量评价。利用交叉检验方法构建了径向基核函数支持向量机滑坡敏感性评价模型,并基于拟合精度对模型进行了定量评价;对各评价因子在模型中的重要性进行对比分析;基于空间分辨率为30m的评价因子,通过径向基核函数支持向量机模型获得了霍西煤矿区滑坡敏感性指数值,并利用分位数法将霍西煤矿区的滑坡敏感性分为极高、高、中和低4个等级。结果表明：拟合精度建模阶段和验证阶段分别为87.22%和70.12%;与滑坡敏感性关系最密切的5个评价因子依次是岩性、距道路距离、坡向、高程和土地利用类型;极高和高敏感区域分布了93.49%的滑坡点,面积占总面积的50.99%,是比较合理的分级方案。本研究不仅可以为研究区人工边坡调查和煤矿资源合理开采提供借鉴,对相似矿区的相关工作也具有参考价值。     

四川省滑坡灾害气象预警模型建立与验证

四川省滑坡灾害严重,特别是2008年之后,灾情显著加剧,如何预防滑坡灾害是保护人民生命财产安全的有效途径。滑坡灾害的预警模型研究是滑坡灾害预防领域的核心课题。本文对四川省滑坡灾害危险性进行了评价,并开展了滑坡灾害气象风险预警模型研究。①以确定性系数的方法量化坡度、地形起伏度、水文地质岩性、植被覆盖度、地震烈度和年均降雨量因子,建立逻辑回归模型,定量地进行四川省滑坡灾害危险性区划,并对结果进行验证。结果表明,四川省滑坡灾害高危险性区域成“Y”字型分布,此外川中、川东北地区滑坡灾害危险性也非常高,这与四川省滑坡灾害的空间分布情况相符。②在前期滑坡灾害与降雨量统计分析、滑坡灾害危险性评价的基础上,以滑坡灾害危险性评价为静态因子,日降雨量数据为动态因子,通过逻辑回归模型的结果,确定以当日降雨量概率化值、滑坡灾害危险性值、前一日降雨概率化值、前两日降雨概率化值、前三日降雨概率化值为临灾模型影响因子,各因子对预警结果影响程度按上述顺序递减,建立了地质-气象耦合的临灾气象预警模型。通过检验区数据对模型的检验表明,该预警模型能成功预警80%以上的滑坡灾害;通过滑坡灾害群发个例检验发现,该预警模型与四川省现用模型相比,预警区域明显减小,空报率和漏报率显著降低。     

泸石高速公路沿线历史地震诱发滑坡遥感调查及发育分布规律

泸(定)石(棉)高速公路沿线断裂构造发育,地震频发,造成区域内历史地震诱发的滑坡数量多且规模大,然而这些地震滑坡体表面生长大量植被,传统调查难以高效查明地震滑坡分布位置及发育规律。为了减少地震滑坡对公路建设带来的安全隐患,首先以高精度机载LiDAR数据对地震滑坡进行了识别,并通过野外复核验证识别的准确性;其次利用高精度机载LiDAR影像对地震滑坡的变形特征进行了分析;最后,综合考虑地形、地质、地震三大因素(6个因子),对地震滑坡的空间分布特征进行了分析。结果表明：利用机载LiDAR技术能够有效地发现植被层下的地震滑坡,在泸石高速公路沿线共识别出地震滑坡23处,野外复核验证精度达100%;通过对控制地震滑坡空间分布的6个因子的分析,得出与断裂构造和地震相关性最高。研究结果为植被茂密山区高速公路的滑坡识别调查提供了一定的参考并为泸石高速公路滑坡灾害防治与风险评价提供了数据支撑。     

基于GIS的滑坡灾害危险性区划研究——以重庆市万州区为例

为了弥补滑坡灾害危险性区划研究中影响因子和等级划分的不确定性,结合前人研究成果,依据斜坡几何形态、岩性、地质构造、河流侵蚀、土地利用类型、人类工程活动、降水条件等影响因子与研究区实际已发生的滑坡灾害数之间的关系,编制重庆市万州区滑坡灾害危险性评价标准,并基于GIS技术和信息量模型法,计算滑坡评价因子的信息量,就万州区滑坡危险性进行区划,最后基于乡镇行政区对该区滑坡危险性区划进行细化。结果表明:建设用地、坡高为90～200 m的地形、1 024～1 060 mm的年降雨量以及侏罗系中统上沙溪庙组岩层等因素对万州区滑坡发生影响较大;根据滑坡灾害危险性评价标准,万州区滑坡灾害被划分为高、中、低、极低等4个危险区;应用信息量模型法得到的万州区滑坡危险性区划与实际情况比较吻合;高危险区和中危险区面积分别为564.4 km2和848.6 km2,分别占万州区总面积的16.3%和24.5%,主要分布于长江干流及支流两岸的居民相对集中区以及公路干线地段;高危险和中危险乡镇主要分布在万州区经济较为发达的长江干流两岸,尤其是左岸的黄柏乡、太龙镇、天城镇、李河镇等以及万州主城区。     

构造动力对滑坡灾害发育的影响———以喜马拉雅东构造结地区为例北大核心CSCD

基于有限元数值模拟技术,利用GPS数据获取喜马拉雅东构造结区域的断裂运动状态和构造应力场,并结合区域滑坡隐患探讨构造活动对滑坡灾害发育的影响。结果显示,差异化的断裂运动会造成显著相异的构造应力分布,而区域滑坡灾害更集中分布在断层锁固引起的构造应力异常区域;对应力异常区的斜坡进行稳定性研究发现,受应力长期累积影响,斜坡表层应力场持续扰动,造成潜在危险滑移面安全系数降低,促进滑坡失稳。研究表明,断裂构造运动模式可对区域滑坡灾害的发育和分布造成不可忽视的影响,且长期持续的构造应力荷载将促进滑坡灾害的发育。     

基于ETM+遥感数据的闽南地区断裂活动性评价探讨

以闽南地区为研究区域,以ETM+遥感影像数据为基础,通过广泛收集、分析研究区地质背景资料,分析区域内断层活动情况,进而提取研究区线性构造信息,结合地震地质资料对闽南地区主要断裂的分布情况及活动性做系统的分析研究。同时对闽南地区的新构造活动及构造应力场,线性构造和水系的分形分维,地震活动及其危险性和地热异常等主要影响因子做初步探讨。在确定影响断裂活动性的主要因素后,对研究区进行初步分区和定量化评价。最终判定研究区可圈定为:相对较不活动区、相对较活动区、相对活动区3个活动性级别。其中相对活动区面积占整个研究区3/5以上;相对较不活动区面积较小,造成相对活动的关键性因素是地震、活动断裂。     

三峡库首区河长坡降指标及其地质构造意义

利用数字高程数据和空间分析方法,提取三峡库首区长江支流的河长坡降指标（SL）以及标准化坡降指标（SL/K）,对该区构造活动进行分析。结果显示,研究区水系发育主要受断裂构造、地层岩性和新构造运动的影响,在空间上存在一定差异性,说明研究区构造活动存在区域性差异。在不同岩性地区,特别是三叠系地层区,水系响应较为明显,这与地层的抗水流侵蚀强度有关。该区水系发育受断裂构造控制作用较小,但受新构造抬升影响较大。     

基于层次分析法的地质灾害易发性评价应用——以日照市为例

以基础地质数据为数据源,充分研究日照市地质灾害孕灾环境,采用层次分析法,分析选取地貌、构造、地层、岩浆岩、降水量和人类工程活动强度6种评价因子,建立层次结构模型,计算各个影响因子的权重,对各个因子进行分析并进行归一化处理,将各个评价因子与其权重进行加权叠加计算,最终得出日照市地质灾害易发性分区结果,划分出低、中和高易发区3类分区并完成精度检验。日照市地质灾害重点分布于沂沭断裂带的昌邑-大店断裂、安丘-莒县断裂通过的区域和低山、丘陵地貌区以及矿产资源开采引发的采空塌陷等地,此类区域需重点防治。采用层次分析法将地质灾害危险性评价过程层次化、定量化,从一个新的角度对日照市地质灾害危险性进行定量化评价和分区,分区结果较客观地反映实际情况。     

基于GIS和RS的库区滑坡风险分析——以北京密云库区为例

基于遥感(RS)和地理信息系统(GIS)技术,采用多层次分析(AHP)法,以北京密云水库上游部分库区为研究对象,根据库区实际情况,选取植被覆盖率、土壤类型、坡度、高程、降雨量、土地利用六种影响滑坡灾害发生的因素作为评价因子,对区域滑坡风险进行分析。同时,在ArcGIS的空间分析环境中运行权重叠加,将研究区域划分成无危险区、低危险区、中危险区、高危险区和极危险区。结果表明,研究区域内大部分地区比较稳定,最易发生滑坡的区域主要集中在密云水库东北部的河谷、山谷地带,呈零星状分布。     

黄土区滑坡研究中地形因子的选取与适宜性分析

黄土高原是中国生态较为脆弱的地区,也是滑坡发育的地层之一。黄土滑坡发育是孕灾环境、致灾因子和承灾体等多种因素联合作用的结果,其中作为重要孕灾环境因素的地形因子的选取是黄土滑坡风险研究的基础。本文选取黄土滑坡灾害多发的甘谷县作为研究区,综合利用敏感性指数、确定性系数和相关系数方法进行地形因子在滑坡灾害研究中的适宜性分析,得出以下结论：基于确定性系数法、敏感性分析模型和相关系数法,最终筛选出适宜于本区域滑坡灾害评价的地形因子为：坡度、坡度变率、坡形和地表粗糙度;确定性系数法、敏感性分析模型都基于分析单一因子与滑坡之间的关系进行致灾因子选取,忽视地形因子之间的相关性。实验结果表明,研究区稳定性较差的区域与已发生滑坡灾害分布数量具有较好的对应关系,并深入分析了滑坡与地形因子分级范围的关系,发现地形因子分级范围对地质灾害风险研究具有重要的影响,是导致部分区域的差异性主要原因之一。实地调查发现,河网切割密度及人类工程活动也对研究区危险性具有重要的控制作用,是重要的地形因素。     

Dynamic assessment of rainfall-induced shallow landslide hazard

The assessment of rainfall-induced shallow landslide hazards is a significant issue in the Three Gorges Reservoir area in China due to the rapid development of land in the past two decades. In this study, a probabilistic analysis method that combines TRIGRS and the point-estimate method for evaluating the hazards of shallow landslides have been proposed under the condition of rainfall over a large area. TRIGRS provides the transient infiltration model to analyze the pore water pressure during a rainfall. The point-estimate method is used to analyze the uncertainty of the soil parameters, which is performed in the geographic information system (GIS). In this paper, we use this method to evaluate the hazards of shallow landslides in Badong County, Three Gorges Reservoir, under two different types of rainfall intensity, and the results are compared with the field investigation. The results showed that the distribution of the hazard map is consistent with the observed landslides. To some extent, the distribution of the hazard map reflects the spatial and temporal distribution of the shallow landslide caused by rainfall.     

Influencing factors of sediment deposition and their spatial variability in riparian zone of the Three Gorges Reservoir,China

Many factors can affect the sediment deposition and soil erosion process in riparian zone, including terrain, sediment transport and water level fluctuations. Clarifying the factors influencing sediment deposition process in the riparian zone of the Three Gorges Reservoirs is an important problem to determine the key area of sediment deposition and its trend of development in the study area. In order to reveal the influence of these environmental factors on the sediment deposition in riparian zone of the Three Gorges Reservoir, this study investigated 1) the amount of deposited sediment in different environmental conditions, 2) the potential factors affecting sediment deposition in riparian zone of the Three Gorges Reservoir, 3) the relationship between the deposited sediment amount and these factors previously mentioned using correlation analysis, and 4) the influence of human activities considered as an additional factor. This study found that 1) slope gradient, elevation, inundating duration and human activities were the main factors influencing sedimentation in riparian zone of the Three Gorges Reservoir, and 2) the impact of each factor varied with spaces. Specifically, in the upper reach from Jiangjin to Fuling, human activities such as gravel dredging, bank revetment and ports and wharfs constructing disturbed considerable amounts of deposited sediment, as a result, there was no natural law to dictate the distribution. In the middle reach from Fuling to Fengjie, slope gradient and inundating duration were the controlling factors, and the sediment deposition amount was greater in the areas with a gentler slope or lower elevation. Water flow on gentler slopes generally had lower velocity, resulting in more sediment to deposit. Sites with lower elevations would be drowned by sediment-laden flow with a longer duration resulting from hydrologic regime controlled by the operating strategy of the Three Gorges Reservoir, leading to a larger amount of sediment deposition. In the lower reach from Fengjie to Zigui, slope gradient was similar to the middle reach, performing a primary factor, while other factors showed little relationship with sediment amount.     

Seismogenic fault and topography control on the spatial patterns of landslides triggered by the 2017 Jiuzhaigou earthquake

Jiuzhaigou National Park, located in northwest plateau of Sichuan Province, is a UNESCO World Heritage Site, and one of the most popular scenic areas in China. On August 8, 2017, a Mw 6.5 earthquake occurred 5 km to the west of a major scenic area, causing 25 deaths and injuring 525, and the Park was seriously affected. The objective of this study was to explore the controls of seismogenic fault and topographic factors on the spatial patterns of these landslides. Immediately after the main shock, field survey, remote-sensing investigations, and statistical and spatial analysis were undertaken. At least 2212 earthquake-triggered landslides were identified, covering a total area of 11.8 km~2. Thesewere mainly shallow landslides and rock falls. Results demonstrated that landslides exhibited a close spatial correlation with seismogenic faults. More than 85% of the landslides occurred at 2200 to 3700 m elevations. The largest quantity of landslides was recorded in places with local topographic reliefs ranging from 200 to 500 m. Slopes in the range of ~20°-50° are the most susceptible to failure. Landslides occurred mostly on slopes facing east-northeast(ENE), east(E), east-southeast(ESE), and southeast(SE), which were nearly vertical to the orientation of the seismogenic fault slip. The back-slope direction and thin ridge amplification effects were documented. These results provide insights on the control of the spatial pattern of earthquake-triggered landslides modified by the synergetic effect of seismogenic faults and topography.     

气候变化情景下广东省降雨诱发型滑坡灾害潜在分布及预测

降雨诱发型滑坡灾害导致了人居环境的破坏并带来巨大的经济损失,尤其是在经济高度发达的粤港澳大湾区城市群。因此,急需有关降雨诱发型滑坡灾害分布的影响因素以及未来气候变化情景下潜在分布的研究。本文从气候变化角度出发,基于最大熵（MaxEnt）模型,结合气候、地形、地表覆盖等数据,揭示不同影响因素对当前气候环境下广东省滑坡空间分布的作用,进而阐述了未来气候情景下滑坡的潜在分布。结果表明：① 影响滑坡灾害空间分布的主要因子为最湿季度降雨量、7月降雨量、海拔和4月降雨量;② 当最湿季度降雨量处于593~742 mm、7月降雨量处于139~223 mm、海拔处于81~397 m和4月降雨量处于154~186 mm之间时,滑坡灾害较易发生;③ 受到气候变化的影响,当前密集分布于粤东地区的滑坡灾害高风险区的潜在分布范围和危害性总体呈现扩大趋势。本研究的结果可以为国土空间规划及城市群灾害预防提供科学依据。     

三峡库区大型-特大型层状岩质滑坡成因模式及地质特征分析

三峡库区大型-特大型滑坡发育，尤以层状岩质滑坡的危害性大。因库区各段地质条件差异使得滑坡成因模式各不相同，这影响了滑坡的运动形式和岩土体解体程度。在收集三峡库区51处典型的大型-特大型层状岩质滑坡调查资料基础上，根据堆积岩体结构和区段地质条件反推该段滑坡破坏成因模式，而不同成因模式下的滑坡坡体渗透性不同，分析已有滑坡对库水位变动存在的复活响应差异，据此得出以下结论:①在成因模式上，除顺层滑移型滑坡在库区中均有分布外，从库首至库尾随着岩层倾角的逐渐减缓，滑坡成因模式从崩塌型、反倾弯曲型逐渐过渡到平推式；②在坡体渗透性上，成因模式造成的岩体结构变化与坡体中的泥质含量共同作用，导致顺层滑移型滑坡前后缘渗透性存在较大差异；反倾型滑坡渗透性则整体变化较小；③在库水位变动影响下，不同坡体渗透性与滑面形态共同决定了滑坡的复活变形差异。      

Spatial distribution of large-scale landslides induced by the 5.12 Wenchuan Earthquake

The 5.12 Wenchuan Earthquake in 2008 induced hundreds of large-scale landslides. This paper systematically analyzes 112 large-scale landslides (surface area > 50000 m2), which were identified by interpretation of remote sensing imagery and field investigations. The analysis suggests that the distribution of large-scale landslides is affected by the following four factors: (a) distance effect: 80% of studied large-scale landslides are located within a distance of 5 km from the seismic faults. The farther the distance to the faults, the lower the number of large-scale landslides; (b) locked segment effect: the large-scale landslides are mainly located in five concentration zones closely related with the crossing, staggering and transfer sections between one seismic fault section and the next one, as well as the end of the NE fault section. The zone with the highest concentration was the Hongbai-Chaping segment, where a great number of large-scale landslides including the two largest landslides were located. The second highest concentration of large-scale landslides was observed in the Nanba-Donghekou segment at the end of NE fault, where the Donghekou landslide and the Woqian landslide occurred; (c) Hanging wall effect: about 70% of the large-scale landslides occurred on the hanging wall of the seismic faults; and (d) direction effect: in valleys perpendicular to the seismic faults, the density of large-scale landslides on the slopes facing the seismic wave is obviously higher than that on the slopes dipping in the same direction as the direction of propagation of the seismic wave. Meanwhile, it is found that the sliding and moving directions of large-scale landslides are related to the staggering direction of the faults in each section. In Qingchuan County where the main fault activity was horizontal twisting and staggering, a considerable number of landslides showed the feature of sliding and moving in NE direction which coincides with the staggering direction of the seismic faults.     

长江三峡工程库首区诱发地震危险性研究

对国内外及三峡工程邻区的水库震例研究表明，诱发地震的形成及其诱震地点、强度是受水库区地质环境影响和制约的，因而水库地震危险性预测主要是依据库区的诱发地震环境条件。在研究长江三峡水库诱发地震地质环境条件的基础上，采用地质环境和概率分析两种方法对库首区蓄水后的诱发地震危险性进行了评估，认为本区发生中、强地震的可能地点是九湾溪断裂和仙女山断裂北端，诱发地震的震级上限为5．5级。     

顾及降雨及库水位因素的滑坡时滞分析与预测——以三峡库区新铺滑坡为例

降雨及库水位涨落是引起库岸滑坡形变失稳的主要诱发因素,但滑坡位移速率对此类诱发因素的响应具有一定的滞后性,影响人类对滑坡所处运动状态的判断与预测.针对常规预测模型中未考虑时滞效应的问题,利用三峡库区新铺滑坡的GNSS位移监测数据、奉节气象站降雨数据以及三峡库区库水位涨落数据,通过对监测区内9个GNSS监测点的位移速率序...     

Construction of lake bathymetry from MODIS satellite data and GIS from 2003 to 2011

In recent years, sedimentation conditions in Dongting Lake have varied greatly because of significant changes in runoff and sediment load in the Changjiang （Yangtze） River following the construction of Three Gorges Dam. The topography of the lake bottom has changed rapidly because of the intense exchange of water and sediment between the lake and the Changjiang River. However, time series information on lake-bottom topographic change is lacking. In this study, we introduced a method that combines remote sensing data and in situ water level data to extract a record of Dongting Lake bottom topography from 2003 to 2011. Multi-temporal lake land/water boundaries were extracted from MODIS images using the linear spectral mixture model method. The elevation of water/land boundary points were calculated using water level data and spatial interpolation techniques. Digital elevation models of Dongting Lake bottom topography in different periods were then constructed with the multiple heighted waterlines. The mean root-mean-square error of the linear spectral mixture model was 0.036, and the mean predicted error for elevation interpolation was -0.19 m. Compared with field measurement data and sediment load data, the method has proven to be most applicable. The results show that the topography of the bottom of Dongting Lake has exhibited uneven erosion and deposition in terms of time and space over the last nine years. Moreover, lake-bottom topography has undergone a slight erosion trend within this period, with 58.2% and 41.8% of the lake-bottom area being eroded and deposited, respectively.