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1.
喀斯特天坑略论   总被引：26，自引：11，他引：15  
上世纪80 年代, 人们知道我国四川省兴文县的石海洞乡(石林)风景区有个“ 小岩湾” 的大型喀斯特漏斗, 但多少年来并未引起喀斯特学术界的重视。近年来, 随着这类喀斯特形态在我国南方喀斯特区的一系列重要科学发现, 为我们对这一现象的一般性研究提供了机会。在初步研究的过程中我们认识到, 应该将这类形态从大型漏斗中分离出来, 并命名为“ 喀斯特天坑”(karst tiankeng)。本文是这一研究成果的初步小结, 内容包括:国内外天坑的现有发现;喀斯特漏斗与天坑、天坑定义;天坑的成因类型、形成条件与发育阶段;天坑在科学研究及旅游资源开发中的意义。   相似文献   

2.
The Taurus Mountain is one of the most important karstic region of the world and dolines are characteristics landforms of this area. However, the number and distribution of doline are unknown in the study area. The aims of this study are to explain the total number of dolines, distribution of doline density, effects of slope conditions and the change of doline orientation in the Taurus Mountains. According to the 1/25000 scale topographic maps utilized in this study, a total of 140,070 dolines were determined in a 13,189 km2 area on eleven high karstic plateaus bordered by steep slopes and deep gorges. These plateaus are substantially affected by highly-faulted and jointed systems and about 80% of each plateau is covered with neritic limestone. The dolines are located at an elevation between 10 and 2870 m. Average elevation of all dolines is 1842 m. 90% of dolines are located between 1300 and 2270 m and only 5% of dolines found under 1330 m. According to this results, the densest doline zone corresponds to the alpine and periglacial zone above the treeline. Doline density reaches?>?100 doline/km2 on Mt. Anamas and the Seyran, Geyik and Akda? ranges as well as the Ta?eli plateau. Maximum density (187 doline/km2) is found on the Akda? Mountains. However, 66% of the study area is characterized by low density, 29.9% with moderate density, 3.4% with high density and 0.7% with very high density. The highest doline densities are seen on gentle slopes (15°–25°/km2) and steep slopes (>?35°/km2) are limited doline distribution. According to the rose diagram formed by the azimuths of the long axis of the dolines at the Central Taurus, two direction are dominant in doline orientations (NW–SE and NE–SW). However, dominant directions are NE-SW at eastern, NE–SW and NW–SE at central and NW-SE at western part of the Central Taurus. According to this elongations, doline orientations are formed an arc which is formed by tectonic evolution of the Central Taurus.  相似文献   

3.
Debris flow is one of the most destructive mass movements. Sometimes regional debris flow susceptibility or hazard assessments can be more difficult than the other mass movements. Determination of debris accumulation zones and debris source areas, which is one of the most crucial stages in debris flow investigations, can be too difficult because of morphological restrictions. The main goal of the present study is to extract debris source areas by logistic regression analyses based on the data from the slopes of the Barla, Besparmak and Kapi Mountains in the SW part of the Taurids Mountain belt of Turkey, where formation of debris material are clearly evident and common. In this study, in order to achieve this goal, extensive field observations to identify the areal extent of debris source areas and debris material, air-photo studies to determine the debris source areas and also desk studies including Geographical Information System (GIS) applications and statistical assessments were performed. To justify the training data used in logistic regression analyses as representative, a random sampling procedure was applied. By using the results of the logistic regression analysis, the debris source area probability map of the region is produced. However, according to the field experiences of the authors, the produced map yielded over-predicted results. The main source of the over-prediction is structural relation between the bedding planes and slope aspects on the basis of the field observations, for the generation of debris, the dip of the bedding planes must be taken into consideration regarding the slope face. In order to eliminate this problem, in this study, an approach has been developed using probability distribution of the aspect values. With the application of structural adjustment, the final adjusted debris source area probability map is obtained for the study area. The field observations revealed that the actual debris source areas in the field coincide with the areas having high probability values on this final map.  相似文献   

4.
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.  相似文献   

5.
从“漏斗”到“天坑”看岩溶学术语的演变   总被引：1，自引：1，他引：0  
KRANJC Andrej 《中国岩溶》2009,28(2):169-174
岩溶学是一门发展变化的科学,岩溶学术语也与时俱进。以术语“漏斗（doline）”为例,它来源于斯洛文尼亚喀斯特地区的方言,在斯洛文尼亚语中,它（dolina,单数）的意思是谷地,主要指河谷。因此,在19世纪以前的斯洛文尼亚语的科学文献中,就是指谷地。随着19世纪上半叶岩溶学的发展,喀斯特高原的漏斗状地形逐渐引起研究者们的注意,德语系的奥地利地质学家们将这种地形定义为“漏斗（dolines,复数）”,相当于德语的Trichter（漏斗）,并声明是当地人的说法。因此,在19世纪下半叶奥地利地质学家的出版物中,普遍使用这一概念。如在Cvijic′的DasKarstp¨hanomen（岩溶现象）一书中,其漏斗（dolines）的概念可谓无所不包,除岩溶干谷和坡立谷以外,所有洼地都称为漏斗,不仅包括溶蚀漏斗和塌陷漏斗,也包括竖井、落水洞、天窗,甚至某些岩溶泉和洞穴洞口。同斯洛文尼亚语相似,在塞尔维亚语中,doline也是指一般谷地。因此,Cvijic′在塞尔维亚语文献中不再使用dolina表示漏斗状地形,而是用vrtaca,这是因为vrtaca和我们今天使用的doline的内涵非常相近,而且在法语、德语、意大利语、英语、克罗地亚语均有相似的词汇。在20世纪中期以前,斯洛文尼亚的地理学家们为了避免使用dolina引起歧义,对于漏斗状的地形均用vrtaca表达。在19世纪下半叶,漏斗（dolines）的成因有两派理论,一种持塌陷成因,一种持侵蚀成因,后者包括侵蚀和溶蚀两种作用。前者以Schmidl为代表,后者支持者是Cox,Diener和Mojsisovics。根据漏斗的形态,Cvijic将其分为三种,即碗状漏斗、漏斗状漏斗和井状漏斗。随着对漏斗状地形的深入研究,V.Panos＇s根据漏斗的不同发育阶段、漏斗的成因、漏斗的覆盖类型、漏斗形成的气候因素、漏斗的沉积类型以及漏斗的形态,将漏斗分为30种。根据最新的岩溶百科全书,按  相似文献   

6.
A logistic regression model is developed within the framework of a Geographic Information System (GIS) to map landslide hazards in a mountainous environment. A case study is conducted in the mountainous southern Mackenzie Valley, Northwest Territories, Canada. To determine the factors influencing landslides, data layers of geology, surface materials, land cover, and topography were analyzed by logistic regression analysis, and the results are used for landslide hazard mapping. In this study, bedrock, surface materials, slope, and difference between surface aspect and dip direction of the sedimentary rock were found to be the most important factors affecting landslide occurrence. The influence on landslides by interactions among geologic and geomorphic conditions is also analyzed, and used to develop a logistic regression model for landslide hazard mapping. The comparison of the results from the model including the interaction terms and the model not including the interaction terms indicate that interactions among the variables were found to be significant for predicting future landslide probability and locating high hazard areas. The results from this study demonstrate that the use of a logistic regression model within a GIS framework is useful and suitable for landslide hazard mapping in large mountainous geographic areas such as the southern Mackenzie Valley.  相似文献   

7.
Karst in Gypsum and its environmental impact on the Middle Ebro Basin,Spain   总被引：1，自引：3，他引：1  
The Middle Ebro Basin in characterised by strong evaporitic profiles from the Miocene period, and in which gypsum formations are predominant. These groups of easy solubility produce in many areas typically karstic landforms, although there are certain features specific to them. The generated landforms appear on the surface as different morphological types of doline, which very often develop on the alluvium deposited by the River Ebro and its affluents. On the agricultural land of the Peñaflor-Villamayor area the functional character of karst causes collapse dolines to appear after heavy storms, and these are constantly filled in by farmers. Motorways and roads that cross these areas, as also the industrial estates existing on the outskirts of Zaragoza, are affected by dissolution processes that bring about continual collapses. The infiltration of water from unlined canals causes the generation of numerous dolines along canal banks.  相似文献   

8.
Landslides in the hilly terrain along the Kansas and Missouri rivers in northeastern Kansas have caused millions of dollars in property damage during the last decade. To address this problem, a statistical method called multiple logistic regression has been used to create a landslide-hazard map for Atchison, Kansas, and surrounding areas. Data included digitized geology, slopes, and landslides, manipulated using ArcView GIS. Logistic regression relates predictor variables to the occurrence or nonoccurrence of landslides within geographic cells and uses the relationship to produce a map showing the probability of future landslides, given local slopes and geologic units. Results indicated that slope is the most important variable for estimating landslide hazard in the study area. Geologic units consisting mostly of shale, siltstone, and sandstone were most susceptible to landslides. Soil type and aspect ratio were considered but excluded from the final analysis because these variables did not significantly add to the predictive power of the logistic regression. Soil types were highly correlated with the geologic units, and no significant relationships existed between landslides and slope aspect.  相似文献   

9.
The main purpose of this paper is to present the use of multi-resource remote sensing data, an incomplete landslide inventory, GIS technique and logistic regression model for landslide susceptibility mapping related to the May 12, 2008 Wenchuan earthquake of China. Landslide location polygons were delineated from visual interpretation of aerial photographs, satellite images in high resolutions, and verified by selecting field investigations. Eight factors, including slope angle, slope aspect, elevation, distance from drainages, distance from roads, distance from main faults, seismic intensity and lithology were selected as controlling factors for earthquake-triggered landslide susceptibility mapping. Qualitative susceptibility analyses were carried out using the map overlaying techniques in GIS platform. The validation result showed a success rate of 82.751 % between the susceptibility probability index map and the location of the initial landslide inventory. The predictive rate of 86.930 % was obtained by comparing the additional landslide polygons and the landslide susceptibility probability index map. Both the success rate and the predictive rate show sufficient agreement between the landslide susceptibility map and the existing landslide data, and good predictive power for spatial prediction of the earthquake-triggered landslides.  相似文献   

10.
The aim of this study is to evaluate the landslide hazards at Selangor area, Malaysia, using Geographic Information System (GIS) and Remote Sensing. Landslide locations of the study area were identified from aerial photograph interpretation and field survey. Topographical maps, geological data, and satellite images were collected, processed, and constructed into a spatial database in a GIS platform. The factors chosen that influence landslide occurrence were: slope, aspect, curvature, distance from drainage, lithology, distance from lineaments, land cover, vegetation index, and precipitation distribution. Landslide hazardous areas were analyzed and mapped using the landslide-occurrence factors by frequency ratio and logistic regression models. The results of the analysis were verified using the landslide location data and compared with probability model. The comparison results showed that the frequency ratio model (accuracy is 93.04%) is better in prediction than logistic regression (accuracy is 90.34%) model.  相似文献   

11.
滑坡灾害空间预测支持向量机模型及其应用   总被引：4，自引：1，他引：4  
戴福初  姚鑫  谭国焕 《地学前缘》2007,14(6):153-159
随着GIS技术在滑坡灾害空间预测研究中的广泛应用,滑坡灾害空间预测模型成为研究的热点问题。在总结滑坡灾害空间预测研究现状的基础上,简要介绍了两类和单类支持向量机的基本原理。以香港自然滑坡空间预测为例,采用两类和单类支持向量机进行滑坡灾害空间预测,并与Logistic回归模型进行了比较。结果表明,两类支持向量机模型优于Logistic回归模型,而Logistic回归模型优于单类支持向量机模型。  相似文献   

12.
Landslides have had a huge effect on human life, the environment and local economic development, and therefore they need to be well understood. In this study, we presented an approach for the analysis and modeling of landslide data using rare events logistic regression and applied the approach to an area in Lianyungang, China. Digital orthophotomaps, digital elevation models of the region, geological maps and different GIS layers including settlement, road net and rivers were collected and applied in the analysis. Landslides were identified by monoscopic manual interpretation and validated during the field investigation. To validate the quality of mapping, the data from the study area were divided into a training set and validation set. The result map showed that 4.26% of the study area was identified as having very high susceptibility to landslides, whereas the others were classified as having very low susceptibility (47.2%), low susceptibility (22.21%), medium susceptibility (14.39%) and high susceptibility (11.93%). The quality of the landslide-susceptibility map produced in this paper was validated, and it can be used for planning protective and mitigation measures. The landslide-susceptibility map is a fundamental part of the Lianyungang city landslide risk assessment.  相似文献   

13.
This study describes the application of logistic regression to rock-fall susceptibility mapping along 11?km of a mountainous road on the Salavat Abad saddle, in southwest Kurdistan, Iran. To determine the factors influencing rock-falls, data layers of slope degree, slope aspect, slope curvature, elevation, distance to road, distance to fault, lithology, and land use were analyzed by logistic regression analysis. The results are shown as rock-fall susceptibility maps. A spatial database, which included 68 sites (34 rock-fall point cells with value of 1 and 34 no rock-fall point cells with value of 0) was developed and analyzed using a Geographic Information System, GIS. The results are shown as four classes of rock-fall susceptibility. In this study, distance to fault, lithology, slope curvature, slope degree, and distance to road were found to be the most important factors affecting rock-fall. It was concluded that about 76?% of the study area can be classified as having moderate and high susceptibility classes. Rock-fall point cells were used to verify results of the rock-fall susceptibility map using success curve rate and the area under the curve. The verification results showed that the area under the curve for rock-fall susceptibility map is 77.57?%. The results from this study demonstrated that the use of a logistic regression model within a GIS framework is useful and suitable for rock-fall susceptibility mapping. The rock-fall susceptibility map can be used to reduce susceptibility associated with rock-fall.  相似文献   

14.
基于逻辑回归模型和确定性系数的崩滑流危险性区划   总被引：1，自引：0，他引：1  
崩滑流是崩塌、滑坡和泥石流地质灾害的总称。本文根据逻辑回归模型和贵州省崩滑流地质灾害发生的确定性系数CF,统计贵州省内崩滑流发生概率与其影响因子之间的函数关系; 并利用GIS技术编制贵州省崩滑流地质灾害危险性区划图。首先根据影响因子子集中已发崩滑流灾害面积和影响因子子集面积来计算崩滑流地质灾害发生的确定性系数CF; 其次将灾害是否发生作为因变量,影响因子子集发生崩滑流地质灾害的确定性系数CF作为自变量,应用逻辑回归模型统计分析它们之间的函数关系; 然后利用GIS技术计算研究区内各独立属性单元发生崩滑流地质灾害的概率p,按p值10等分标准将研究区划分为10个危险性等级区,并绘制贵州省崩滑流地质灾害危险性区划图; 最后用已发崩滑流地质灾害的分布数据来检验危险性区划的效果。研究结果表明:本文根据逻辑回归模型和崩滑流地质灾害发生的确定性系数CF,将贵州省分为Ⅰ～Ⅹ的10个崩滑流地质灾害危险性等级区与实际情况基本符合,能够良好地反映贵州省境内发生崩滑流地质灾害的难易程度。  相似文献   

15.
Erosion and sediment redistribution are important processes in landscape changes in the short and long term. In this study, the RMMF model of soil erosion and the SEDD model of sediment delivery were used to estimate annual soil loss and sediment yield in an ungauged catchment of the Spanish Pre-Pyrenees and results were interpreted in the context of the geomorphic features. The Estaña Catchment is divided into 15 endorheic sub-catchments and there are 17 dolines. Gullies and slopes were the main erosive geomorphic elements, whereas the colluvial, alluvial, valley floor, and doline deposits were depositional elements. Spatially distributed maps of gross soil erosion, sediment delivery ratio (SDR), and sediment yield (SY) were generated in a GIS. Severe erosion rates (>100 Mg ha?1 year?1) were found in gullies, whereas mean and maximum erosion rates were very high on slopes developed on Keüper Facies and high in soils on Muschelkalk Facies. Where crops are grown, the depositional-type geoforms were predicted by the models to have an erosive dynamic. Those results were consistent with the rates of erosion quantified by 137Cs which reflects the significant role of human activities in triggering soil erosion. Catchment area was positively correlated with erosion rate, but negatively correlated with SDR and SY. The latter were negatively correlated with the proportion of the surface catchment covered with forests and scrublands. The topography of the area influenced the high SDR and SY in the dolines and valley floors near the sinks. Intra-basin stored sediment was 59.2% of the total annual eroded soil in the catchment. The combination of the RMMF and SEDD models was an appropriate means of assessing the effects of land uses on soil erosion and obtaining a better understanding of the processes that underlie the geomorphic changes occurring in mountainous environments of the Mediterranean region.  相似文献   

16.
The aim of the present study is to analyze relationships between epithermal Au‐Ag deposits of the hydrothermal type and related geological factors and integrate the relationships using probabilistic and statistical models in a geographic information system (GIS) environment. A variety of spatial geological data were compiled, evaluated and integrated to produce a map of potential Au and Ag deposits in the Gangreung area, Korea. This empirical approach assumes that all deposits shared a common genesis. The method consists of three main steps: (i) identification of spatial relationships; (ii) quantification of such relationships and (iii) integration of multiple quantified relationships. A spatial database containing Au and Ag deposits, topographic, geologic, geophysical and geochemical data was constructed using a GIS. The factors relating to 103 Au and Ag mineral deposits are the geological data such as lithology and fault structure, geochemical data including the abundance of Al, As, Ba, Ca, Cd, Co, conductivity, Cr, Cu, Eh, Fe, HCO3–, K, Li, Mg, Mn, Mo, Na, Ni, Pb, pH, Si, Sr, V, W, Zn, Cl?, F?, PO43?, NO2?, NO3? and SO42?, and geophysical data including Bouguer and magnetic anomalies. Using the constructed spatial database, the relationships between mineral deposit areas and 36 related factors are identified and quantified by probabilistic and statistical modeling; that is, likelihood ratio, weights of evidence and logistic regression. All the factors were combined to produce a map of the regional mineral potential using the overlay method in a GIS environment. The mineral potential map was then verified by comparison with known mineral deposits. The verification results give respective accuracies of 82.52%, 72.45% and 81.60% for the likelihood ratio, weights of evidence and logistic regression models, respectively. The mineral potential map can be used as a source of basic information for mineral resource development.  相似文献   

17.
Statistical analysis of landslide susceptibility at Yongin, Korea   总被引：35，自引：1，他引：35  
The aim of this study is to evaluate the susceptibility of landslides at Yongin, Korea, using a geographic information system (GIS). Landslide locations were identified in the Yongin area from interpretation of aerial photographs, field surveys, and maps of the topography, soil type, timber cover, and geology. These data were collected and constructed into a spatial database using GIS. The factors that influence landslide occurrence, such as slope, aspect, and curvature of topography, were calculated from the topographic database. Texture, material, drainage, and effective soil thickness were extracted from the soil database, and type, age, diameter, and density of timber were extracted from the forest database. Lithology was extracted from the geological database, and land use was classified from the Landsat TM satellite image. Landslide susceptibility was analyzed using the landslide occurrence factors by probability and logistic regression methods. The results of the analysis were verified using the landslide location data. The validation results showed satisfactory agreement between the susceptibility map and the existing data on landslide location. The GIS was used to analyze the vast amount of data efficiently, and statistical programs were used to maintain specificity and accuracy. The results can be used to reduce associated hazards, and to plan land use and construction.  相似文献   

18.
In volcanic terrains, dormant stratovolcanoes are very common and can trigger landslides and debris flows continually along stream systems, thereby affecting human settlements and economic activities. It is important to assess their potential impact and damage through the use of landslide inventory maps and landslide models. In Mexico, numerous geographic information systems (GIS)-based applications have been used to represent and assess slope stability. However, there is no practical and standardized landslide mapping methodology under a GIS. This work provides an overview of the ongoing research project from the Institute of Geography at the National Autonomous University of Mexico that seeks to conduct a multi-temporal landslide inventory and produce a landslide susceptibility map by using GIS. The Río El Estado watershed on the southwestern flank of Pico de Orizaba volcano, the highest mountain in Mexico, is selected as a study area. The geologic and geomorphologic factors in combination with high seasonal precipitation, high degree of weathering, and steep slopes predispose the study area to landslides. The method encompasses two main levels of analysis to assess landslide susceptibility. First, the project aims to derive a landslide inventory map from a representative sample of landslides using aerial orthophotographs and field work. Next, the landslide susceptibility is modelled by using multiple logistic regression implemented in a GIS platform. The technique and its implementation of each level in a GISs-based technology is presented and discussed.  相似文献   

19.
This case study presented herein compares the GIS-based landslide susceptibility mapping methods such as conditional probability (CP), logistic regression (LR), artificial neural networks (ANNs) and support vector machine (SVM) applied in Koyulhisar (Sivas, Turkey). Digital elevation model was first constructed using GIS software. Landslide-related factors such as geology, faults, drainage system, topographical elevation, slope angle, slope aspect, topographic wetness index, stream power index, normalized difference vegetation index, distance from settlements and roads were used in the landslide susceptibility analyses. In the last stage of the analyses, landslide susceptibility maps were produced from ANN, CP, LR, SVM models, and they were then compared by means of their validations. However, area under curve values obtained from all four methodologies showed that the map obtained from ANN model looks like more accurate than the other models, accuracies of all models can be evaluated relatively similar. The results also showed that the CP is a simple method in landslide susceptibility mapping and highly compatible with GIS operating features. Susceptibility maps can be easily produced using CP, because input process, calculation and output processes are very simple in CP model when compared with the other methods considered in this study.  相似文献   

20.
Flooding can have catastrophic effects on human lives and livelihoods and thus comprehensive flood management is needed. Such management requires information on the hydrologic, geotechnical, environmental, social, and economic aspects of flooding. The number of flood events that took place in Busan, South Korea, in 2009 exceeded the normal situation for that city. Mapping the susceptible areas helps us to understand flood trends and can aid in appropriate planning and flood prevention. In this study, a combination of bivariate probability analysis and multivariate logistic regression was used to produce flood susceptibility maps of Busan City. The main aim of this research was to overcome the weakness of logistic regression regarding bivariate probability capabilities. A flood inventory map with a total of 160 flood locations was extracted from various sources. Then, the flood inventory was randomly split into a testing dataset 70 % for training the models and the remaining 30 %, which was used for validation. Independent variables datasets included the rainfall, digital elevation model, slope, curvature, geology, green farmland, rivers, slope, soil drainage, soil effect, soil texture, stream power index, timber age, timber density, timber diameter, and timber type. The impact of each independent variable on flooding was evaluated by analyzing each independent variable with the dependent flood layer. The validation dataset, which was not used for model generation, was used to evaluate the flood susceptibility map using the prediction rate method. The results of the accuracy assessment showed a success rate of 92.7 % and a prediction rate of 82.3 %.  相似文献   

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