Modeling landslide recurrence in Seattle, Washington, USA

To manage the hazard associated with shallow landslides, decision makers need an understanding of where and when landslides may occur. A variety of approaches have been used to estimate the hazard from shallow, rainfall-triggered landslides, such as empirical rainfall threshold methods or probabilistic methods based on historical records. The wide availability of Geographic Information Systems (GIS) and digital topographic data has led to the development of analytic methods for landslide hazard estimation that couple steady-state hydrological models with slope stability calculations. Because these methods typically neglect the transient effects of infiltration on slope stability, results cannot be linked with historical or forecasted rainfall sequences. Estimates of the frequency of conditions likely to cause landslides are critical for quantitative risk and hazard assessments. We present results to demonstrate how a transient infiltration model coupled with an infinite slope stability calculation may be used to assess shallow landslide frequency in the City of Seattle, Washington, USA. A module called CRF (Critical RainFall) for estimating deterministic rainfall thresholds has been integrated in the TRIGRS (Transient Rainfall Infiltration and Grid-based Slope-Stability) model that combines a transient, one-dimensional analytic solution for pore-pressure response to rainfall infiltration with an infinite slope stability calculation. Input data for the extended model include topographic slope, colluvial thickness, initial water-table depth, material properties, and rainfall durations. This approach is combined with a statistical treatment of rainfall using a GEV (General Extreme Value) probabilistic distribution to produce maps showing the shallow landslide recurrence induced, on a spatially distributed basis, as a function of rainfall duration and hillslope characteristics.     

县(市)级土地利用数据库系统的构建和实现

手工管理土地资料的方法, 数据更新周期慢, 综合利用率低, 查询统计复杂, 已经不能满足当前社会经济发展的需要.根据新一轮国土资源大调查中县(市) 级土地利用数据库标准和县(市) 级土地利用数据库建设技术规范2个标准的要求, 利用地理信息系统技术和空间数据库管理技术, 阐述了土地利用数据采集的技术路线, 空间数据的组织和分层管理模式, 空间数据库建立的工艺流程, 以及系统的运行环境要求和功能实现.      

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。     

甘肃岷县永光村滑坡特征及其成因研究

泥流型黄土滑坡发生的条件除一般滑坡具有的条件之外,还应包括特殊的状态因素、触发因素及相应的驱动剪应力条件。通过对甘肃岷县永光村滑坡的现场勘察和实地调查,分析其成因,结果表明：永光村滑坡平面形态虽与泥流类似,但其具有滑坡形成区以及滑坡发生所需要的特殊的地形地貌、岩土体性质以及水文地质条件。永光村滑坡发育于沟道上游的黄土塬地带,临空面较大,滑坡剪出口位置高,具有较高的势能,滑坡体的主要岩土体是马兰黄土,黄土具有大孔隙结构,垂直节理发育,有利于地表水的下渗。下部为新近系泥岩,渗透系数低,为一相对隔水层。长期灌溉导致地下水位较高,黄土层存在软弱夹层,地下水位上升,导致其软化饱和,强度迅速降低,形成潜在滑动面。永光村滑坡亦具有圆弧形的滑坡后壁,滑坡后缘顶部分布有多条拉张裂缝,在前期发生降雨的外部条件下,在岷县“7·22”地震诱发下,发生了低角度、快速和远程的泥流型黄土滑坡,滑体在冲出沟口后形成了扇形堆积区。永光村滑坡是一种特殊的地震引发的泥流型黄土滑坡。目前,泥流型黄土滑坡的研究还处在探索阶段,是作为黄土滑坡分类的一种补充,建议进一步加强对此类灾害发生机理及其稳定性计算方法的深入研究。     

Application of logistic regression model for slope instability prediction in Cuyahoga River Watershed,Ohio, USA

High incidences of slope movement are observed throughout Cuyahoga River watershed in northeast Ohio, USA. The major type of slope failure involves rotational movement in steep stream walls where erosion of the banks creates over-steepened slopes. The occurrence of landslides in the area depends on a complex interaction of natural as well as human induced factors, including: rock and soil strength, slope geometry, permeability, precipitation, presence of old landslides, proximity to streams and flood-prone areas, land use patterns, excavation of lower slopes and/or increasing the load on upper slopes, alteration of surface and subsurface drainage. These factors were used to evaluate the landslide-induced hazard in Cuyahoga River watershed using logistic regression analysis, and a landslide susceptibility map was produced in ArcGIS. The map classified land into four categories of landslide susceptibility: low, moderate, high, and very high. The susceptibility map was validated using known landslide locations within the watershed area. The landslide susceptibility map produced by the logistic regression model can be efficiently used to monitor potential landslide-related problems, and, in turn, can help to reduce hazards associated with landslides.     

Assessment of landslide susceptibility on the natural terrain of Lantau Island, Hong Kong

 Steep terrain and the high frequency of tropical rainstorms make landslide occurrence on natural terrain a common phenomenon in Hong Kong. For example, more than 800 slope failures were triggered by a rainstorm in November 1993 on Lantau Island, Hong Kong. Maps of recent landslides interpreted from aerial photographs, in combination with a geographical information system, were used to evaluate the frequency and distribution of landslides, with particular reference to such physical parameters as lithology, slope gradient, slope aspect, elevation, vegetation cover, and proximity to drainage line, all of which are considered to be influential in the occurrence of landslides. A stepwise logistic regression model was obtained between landslide susceptibility and the above mentioned physical parameters. The study area has been classified into five classes of relative landslide susceptibility, namely, very low, low, moderate, high, and very high, based on this methodology. Received: 17 December 1999 · Accepted: 21 March 2000     

基于Mamdani FIS模型的滑坡易发性评价研究

滑坡的形成是众多非线性关系的影响因子相互作用的结果,传统滑坡预测方法需要大量实地勘查数据。利用Mamdani FIS(模糊推理系统)模型对三峡库区巴东-秭归段进行滑坡易发性预测,并对结果进行评价。通过地理信息系统(geographic information system,GIS)、遥感(remote sensing,RS)技术和区域地质背景资料获取地形类、生态环境类和地质背景类共3类7种滑坡影响因子,建立了192条相关的推理规则,在Matlab平台下基于Mamdani FIS模型得到研究区滑坡易发性预测指数,并生成滑坡易发性区划图。预测结果的受试者工作特征曲线下的面积值为82.8%,显示滑坡评估效果良好。结果证明,与其他模型相比,基于空间信息技术的Mamdani FIS模型,利用其非线性分析能力和基于专家意见的推理规则,评估滑坡易发性时不需要先验知识支撑,简化了模型使用时对数据的要求。另外,该模型只需通过专家意见改变推理规则就可以应用于不同的地质地理环境区域,显示其较强的适应性。     

广西宁明县海渊镇土地质量地球化学评价

为了查清广西宁明县海渊镇土地质量地球化学基本状况并提出优质土地资源开发利用建议,本文以第二次全国土地调查成果中的土地利用图斑为评价单元,系统采集了该区土壤及农作物样品,并分析了土壤的养分指标（氮、磷、钾、硒）、环境指标（pH、镉、汞、砷、铜、铅、锌、铬、镍）,农作物样品的评价指标（硒和镉、汞、砷、铜、铅、锌、铬、镍）,在此基础上参照《土地质量地球化学评价规范》进行了土地质量评价,划分了无污染风险富硒土地。结果表明：该区土壤养分质量较差,综合等级以较缺乏和缺乏为主;土壤环境质量优质,无风险等级土壤占比95.57%;土壤质量一般,评价等级以中等为主,面积124.01 km2,占全区总面积的56.28%,主要由土壤养分缺乏导致;水稻样品富硒比例高达66.67%,水稻重金属超标率仅为1.67%,圈定无污染风险富硒土地35.69 km2。上述评价结果可为当地富硒等优质土地开发与农产品安全利用提供重要的地球化学依据。     

Data driven bivariate landslide susceptibility assessment using geographical information systems: a method and application to Asarsuyu catchment, Turkey

In the last decades, landslide hazard assessment has attracted many researchers' attention. A number of parameters are suggested to be responsible to quantitatively explain the mechanism of landslides; many of these parameters are very important and factual. However, some data types and models are site-specific and could not be applied to different locations. Furthermore, the data stored in continuous parameter maps are divided into a number of classes arbitrarily, depending on the vision of the expert. Basically, this division controls the result of bivariate analysis. Besides, the responsible portion of the parameter map controlling the mechanism is also weighted arbitrarily. Based on these two facts, the class boundaries put a prejudice on the produced susceptibility/hazard maps, which result in dependence on the knowledge of the user rather than being dependent on the data and the fact itself. The aim of this study is to refine the previously defined methods in a more data-dependent trend. To achieve this goal, two new concepts: seed cells and percentile maps are introduced. Seed cells are the zones that are considered to represent the best undisturbed morphological decision rules (conditions before landslide occurs) and would be achieved by adding a buffer zone to the crown and flank areas of the landslide. To quantitatively classify the input parameter maps, the data distributions of seed cells in the parameter maps are divided into a number of classes on the basis of their distribution's percentile break-points upon which the parameter maps are directly dependent on the seed cell distributions, hence to the data itself.     

芦山县滑坡灾害影响因素的空间分异性

近年来受多次地震影响,芦山县的地质环境和生态结构较为脆弱,滑坡灾害高发,制约了县内基础建设和经济发展,威胁着人民生命财产安全,研究静态地质环境下芦山县滑坡影响因素的空间分异性,可为区内国土空间规划提供基础资料,为滑坡灾害预测与防治提供数据支持。本文使用信息量模型和地理探测器分析了高程、坡度等12个影响因素与滑坡发育的关系,总结了滑坡发育规律,分析了影响因素的空间分异特征,并使用GIS加权叠加生成了滑坡易发性评价图。研究结果表明: ①滑坡主要集中于高程较低([571,1 300) m)、距道路距离较近([0,300) m)、距水系距离较近([0,300) m)、地形起伏度较小([0,30) m)、坡度较缓([0°,30°))、距断层距离较近([0,600) m)的地区,岩土类型以粉砂质泥岩、泥质粉砂岩、泥岩等软弱沉积岩和砂卵砾石土层的第四系堆积物为主,土地利用类型以建设用地、农业用地等为主; ②滑坡发育主要受高程、距道路距离、工程地质岩组等因素控制,此外土地利用类型、距水系距离、地形起伏度、坡度、距断层距离等因素也有较高的贡献率; ③两种不同影响因素对滑坡发育的作用较单一因素而言均呈现双因子或非线性增强,以高程和距道路距离与其他因素的交互作用最为强烈; ④滑坡高易发区和极高易发区主要分布于东南部中低山峡谷区、丘陵区以及河流沟谷地貌。     

威海市批后监管系统设计与实现

威海市国土资源局利用地理信息技术创新国土资源监管的手段,加强建设用地批后监管工作,有力保障用地行为依法进行,有效推进土地节约集约利用。该文介绍了批后监管系统的建设目标和建设原则,并详细论述了批后监管的总体框架和功能设计,说明了该系统的主要特点;并结合建设用地批后监管工作中的应用,总结了建设用地批后监管的应用经验。     

Field-based monitoring of sediment runoff from natural gas well sites in Denton County,Texas, USA

This study evaluates sediment runoff from gas well development sites in Denton County, Texas. The magnitude of sediment runoff was investigated by intercepting sediment in traps and weirs at the periphery of each gas well site and by measuring the growth of debris lobes that formed down slope from two sites. Four debris lobes formed at one gas well site and one formed at a second site. Debris lobes ranged in size from 30 to 306 square meters. Sediment from one site entered local creek channels, either as a component of storm water runoff or, in one case, as a debris lobe that flowed into a channel. The study findings suggest that sediment movement is significantly diminished once areas disturbed by gas well construction become naturally re-vegetated. Based on estimates of debris lobe volumes, sediment loading rates of about 54 metric tonnes per hectare per year were calculated for one site. It is concluded that gas well development sites in areas similar to those studied, especially where vegetation has been removed and terrain has relatively steep slopes (greater than 6%), generate sediment runoff comparable to small construction sites and should therefore be considered for regulations requiring erosion and sediment control measures.     

陕西宝鸡地区千阳县地质灾害易发性评价

在对千阳县地质灾害详细调查的基础上,采用定性分析与定量评价相结合的方法,对千阳县地质灾害易发程度进行了评价分区。首先初步定性分析了地质灾害的分布特征和影响因素;其次利用地理信息系统技术,选取斜坡几何形态、工程地质岩组、黄土覆盖层厚度、地质构造和水文地质条件5个方面共28个指标作为评价因子,利用信息量模型对千阳县的地质灾害进行易发性评价分区。评价分区结果表明：高易发区占全区面积的4.89%,主要分布于千河北岸黄土塬区一级支流沟谷两侧的塬边斜坡地区;中易发区占全区面积的24.18%,主要位于千河北岸台塬区一级支流沟谷的两侧,北部山区二、三级支流冲蚀的基岩（白垩系—侏罗系砂泥岩）与黄土的接触区,南部山区局部黄土覆盖的高陡区域;低易发区占全区总面积的41.29%,主要位于千阳北部山区的二、三级河流河道冲蚀区,千河北岸黄土塬区和千河南部的基岩山区。     

基于GIS的哀牢山戛洒镇小流域滑坡易发性评价

根据研究区的基本情况,选择坡度、坡向、地层岩性、距断层距离、降雨、土地利用等6个评价因子,采用滑坡灾害易发性评价的GIS与AHP耦合模型进行戛洒镇滑坡灾害易发性评价,并将滑坡灾害分为极高、高、中、低和极低易发区5个区域进行了滑坡灾害易发性评价结果分析,以期为后期的小流域滑坡风险评估研究服务。     

金乡县节约集约用地调查分析及对策

近年来,随着经济社会的迅速发展和工业化、城镇化的顺利推进,金乡县土地供应“瓶颈”制约矛盾日益突出。该文对全县节约集约利用土地的现状、存在的问题及制约因素进行调查分析,提出推进节约集约用地的对策与措施,必将更好地推动全县经济与社会的科学发展。     

Assessing landslide volume using two generic models: application to landslides in Whatcom County,Washington, USA

Landslides - Geomorphological analysis of landslide processes in mountainous terrains with difficult access has benefited from virtual representation of topography through the use of...     

Probabilistic landslide hazards and risk mapping on Penang Island, Malaysia

This paper deals with landslide hazards and risk analysis of Penang Island, Malaysia using Geographic Information System (GIS) and remote sensing data. Landslide locations in the study area were identified from interpretations of aerial photographs and field surveys. Topographical/geological data and satellite images were collected and processed using GIS and image processing tools. There are ten landslide inducing parameters which are considered for landslide hazard analysis. These parameters are topographic slope, aspect, curvature and distance from drainage, all derived from the topographic database; geology and distance from lineament, derived from the geologic database; landuse from Landsat satellite images; soil from the soil database; precipitation amount, derived from the rainfall database; and the vegetation index value from SPOT satellite images. Landslide susceptibility was analyzed using landslide-occurrence factors employing the probability-frequency ratio model. The results of the analysis were verified using the landslide location data and compared with the probabilistic model. The accuracy observed was 80.03%. The qualitative landslide hazard analysis was carried out using the frequency ratio model through the map overlay analysis in GIS environment. The accuracy of hazard map was 86.41%. Further, risk analysis was done by studying the landslide hazard map and damageable objects at risk. This information could be used to estimate the risk to population, property and existing infrastructure like transportation network.     

地理探测器在判别滑坡稳定性影响因素中的应用

高山峡谷区是滑坡灾害频发地区,随着气候变化和人类活动加剧,滑坡呈多发、频发态势。本文选择坐落于横断山高山峡谷区的西藏江达县作为研究区,利用野外调查获取的85个滑坡数据,选取坡度、河流密度、地貌类型、降水量、距断层距离、道路密度、地震动峰值加速度、岩性等8个稳定性影响因素,运用地理探测器对滑坡稳定性的影响因素进行了探测。结果表明：（1）按滑坡体体积划分等级,江达县滑坡主要以中、小型滑坡为主;按其稳定性划分,50%以上的滑坡处于稳定状态;按危险等级划分,以Ⅲ级、Ⅳ级为主;江达县滑坡主要沿河流与道路分布,全县地面调查发现85处滑坡全部分布于河流附近,其中71.76%的滑坡分布于道路两侧。（2）江达县滑坡稳定性的主要影响因子为地貌类型、河流密度、道路密度和距断层距离,其贡献率分别为0.501,0.477,0.465,0.332;当影响因子两两相互作用时,因子解释力总是大于单个因子对滑坡稳定性的解释力,即当两种影响因子相互作用时,对于滑坡的失稳具有促进作用。     

新疆吉木萨尔县贾家湾村滑坡防治工程

吉木萨尔县贾家湾村滑坡长期威胁着当地人民生命财产的安全,对其进行有效防治,已迫在眉睫。根据该滑坡灾害防治工程勘察、设计、施工全过程的资料成果,对其进行了进一步整理,在此基础上对滑坡产生的原因、稳定性、主要影响因素做系统分析,提出合理、可行的桩板墙防治工程措施。并对治理工程施工注意的问题和治理效果做了分析评价,为新疆后期的类似土质滑坡防治工程提供一些借鉴。