Hydrogeological pattern of groundwater flow of landslides in Cretaceous claystones based on long-term groundwater monitoring and hydrologging measurement   总被引：1，自引：0，他引：1  

Jan Novotný  Miroslav Kobr 《Environmental Geology》2009,58(1):25-32

Long-term groundwater monitoring has been carried in the model locality of the landslide area at Třebenice, situated in the northern part of the Czech Republic in Cretaceous claystones to marlstones. Primarily, long-term fluctuation of the groundwater and piezometric levels has been monitored. Monitoring of groundwater flow was carried out in selected wells also by the photometry logging method using a dilution technique of a marked liquid. On the basis of these results, the pattern of the groundwater flow through the landslide area was determined in lithologically homogeneous Cretaceous claystones to marlstones. Interpretation of monitoring results indicated that water flows preferentially through the zone of near-surface loosening of the claystone rock massif, in general parallel to the slope inclination between 8 and 10-m depth below ground level. This zone exhibits a higher permeability given by 1–2 orders of hydraulic conductivity compared with overlying strata and underlying rock in which this zone is closed. This verified pattern of groundwater flow has a significant effect on the stability of the sliding slope and it is one of the main factors affecting the evolution of landslides on the slopes formed by these rocks.  相似文献   

History of landslide susceptibility and a chorology of landslide-prone areas in the Western Ghats of Kerala,India   总被引：3，自引：0，他引：3  

Sekhar L. Kuriakose  G. Sankar  C. Muraleedharan 《Environmental Geology》2009,57(7):1553-1568

Kerala is the third most densely populated state in India. It is a narrow strip of land, of which 47% is occupied by the most prominent orographic feature of peninsular India, The Western Ghats mountain chain. The highlands of Kerala experience several types of landslides, of which debris flows are the most common. They are called “Urul Pottal” in the local vernacular. The west-facing Western Ghats scarps that runs the entire extent of the mountain system is the most prone physiographic unit for landslides. The highlands of the region experience an annual average rainfall as high as 500 cm through the South-West, North-East and Pre-Monsoon showers. A survey of ancient documents and early news papers indicates a reduced rate of slope instability in the past. The processes leading to landslides were accelerated by anthropogenic disturbances such as deforestation since the early 18th century, terracing and obstruction of ephemeral streams and cultivation of crops lacking capability to add root cohesion in steep slopes. The events have become more destructive given the increasing vulnerability of population and property. Majority of mass movements have occurred in hill slopes >20° along the Western Ghats scarps, the only exception being the coastal cliffs. Studies conducted in the state indicates that prolonged and intense rainfall or more particularly a combination of the two and the resultant pore pressure variations are the most important trigger of landslides. The initiation zone of most of the landslides was typical hollows generally having degraded natural vegetation. A survey of post-landslide investigation and news paper reports enabled the identification of 29 major landslide events in the state. All except one of the 14 districts in the state are prone to landslides. Wayanad and Kozhikode districts are prone to deep seated landslides, while Idukki and Kottayam are prone to shallow landslides.  相似文献   

暴雨诱发滑坡致灾机理与减灾方法研究进展   总被引：6，自引：1，他引：5  

周创兵  李典庆 《地球科学进展》2009,24(5):477-487

暴雨滑坡是多发性的地质灾害.阐述了暴雨诱发滑坡致灾机理、风险评估与减灾方法研究的重要意义.分别从暴雨诱发滑坡的地质力学机制、暴雨诱发滑坡的机理、暴雨诱发滑坡演化过程的数值模拟方法、暴雨滑坡动态风险评估方法以及暴雨诱发滑坡灾害的减灾方法5个方面,详细综述了国内外研究的主要成果和进展.在此基础上,指出了目前暴雨诱发滑坡灾害研究中存在的主要问题.最后,提出了在暴雨诱发滑坡灾害的研究中应以暴雨作用下的斜坡演化动力学过程为主线,以暴雨诱发滑坡的地质力学机制研究为基础,以暴雨诱发滑坡机理研究为核心,以暴雨诱发滑坡灾害的风险评估为手段,以最大可能地防灾减灾为目标.  相似文献   

Interpretation of earthquake-induced landslides triggered by the 12 May 2008, M7.9 Wenchuan earthquake in the Beichuan area, Sichuan Province, China using satellite imagery and Google Earth   总被引：5，自引：2，他引：3  

H. P. Sato  E. L. Harp 《Landslides》2009,6(2):153-159

The 12 May 2008 M7.9 Wenchuan earthquake in the People’s Republic of China represented a unique opportunity for the international community to use commonly available GIS (Geographic Information System) tools, like Google Earth (GE), to rapidly evaluate and assess landslide hazards triggered by the destructive earthquake and its aftershocks. In order to map earthquake-triggered landslides, we provide details on the applicability and limitations of publicly available 3-day-post- and pre-earthquake imagery provided by GE from the FORMOSAT-2 (formerly ROCSAT-2; Republic of China Satellite 2). We interpreted landslides on the 8-m-resolution FORMOSAT-2 image by GE; as a result, 257 large landslides were mapped with the highest concentration along the Beichuan fault. An estimated density of 0.3 landslides/km² represents a minimum bound on density given the resolution of available imagery; higher resolution data would have identified more landslides. This is a preliminary study, and further study is needed to understand the landslide characteristics in detail. Although it is best to obtain landslide locations and measurements from satellite imagery having high resolution, it was found that GE is an effective and rapid reconnaissance tool.  相似文献   

Multifractal and entropic properties of landslides in Japan   总被引：4，自引：0，他引：4  

C. Goltz 《International Journal of Earth Sciences》1996,85(1):71-84

Landslide distributions in two major areas of northern Japan, Tohoku and Hokkaido, are analysed for multifractal properties. For the latter data set, also the multifractal spectrum for the spatial landslide size distribution is determined and compared to the probability distribution. It is concluded that the fields possess definite multifractal character. This finding is supported by the known multifractality of the main triggering processes, rain and earthquakes. Further support comes from a configuration entropy analysis which is found to be a useful complimentary tool to multifractal analysis. Models leading to multifractality are briefly reviewed. Careful attention is paid to the algorithms used and to the verification of the numerical results. Some general suggestions concerning numerical methods are made.  相似文献   

A hydroclimatic threshold for landslide initiation on the North Shore Mountains of Vancouver, British Columbia   总被引：5，自引：0，他引：5  

Matthias Jakob  Hamish Weatherly   《Geomorphology》2003,54(3-4):137-156

Landslides triggered by rainfall are the cause of thousands of deaths worldwide every year. One possible approach to limit the socioeconomic consequences of such events is the development of climatic thresholds for landslide initiation. In this paper, we propose a method that incorporates antecedent rainfall and streamflow data to develop a landslide initiation threshold for the North Shore Mountains of Vancouver, British Columbia. Hydroclimatic data were gathered for 18 storms that triggered landslides and 18 storms that did not. Discriminant function analysis separated the landslide-triggering storms from those storms that did not trigger landslides and selected the most meaningful variables that allow this separation. Discriminant functions were also developed for the landslide-triggering and nonlandslide-triggering storms. The difference of the discriminant scores, ΔCS, for both groups is a measure of landslide susceptibility during a storm. The variables identified that optimize the separation of the two storm groups are 4-week rainfall prior to a significant storm, 6-h rainfall during a storm, and the number of hours 1 m³/s discharge was exceeded at Mackay Creek during a storm. Three thresholds were identified. The Landslide Warning Threshold (LWT) is reached when ΔCS is −1. The Conditional Landslide Initiation Threshold (CTL_I) is reached when ΔCS is zero, and it implies that landslides are likely if 4 mm/h rainfall intensity is exceeded at which point the Imminent Landslide Initiation Threshold (ITL_I) is reached. The LWT allows time for the issuance of a landslide advisory and to move personnel out of hazardous areas. The methodology proposed in this paper can be transferred to other regions worldwide where type and quality of data are appropriate for this type of analysis.  相似文献   

Rock hardness and landform development in the Gunong Mulu National Park,Sarawak, E. Malaysia     

Michael J. Day 《地球表面变化过程与地形》1981,6(2):165-172

Rock hardness, measured by the Schmidt Test Hammer, is an important factor in explaining some of the sharp contrasts in relief and wide variety of landforms in The Gunong Mulu National Park. It is also useful in consideration of contemporary geomorphological processes, such as landsliding.  相似文献   

Scaling properties of landslides in the Rif mountains of Morocco   总被引：2，自引：0，他引：2  

M. Rouai  E. B. Jaaidi   《Engineering Geology》2003,68(3-4):353-359

Landslides in the central Rif mountains (Morocco) were analyzed by multifractal analysis. Our results suggest that spatial distribution of landslides in the region is not a homogeneous fractal structure but a heterogeneous one with generalized dimensions D(1)=1.713>D(2)>…>D(12)=1.325. The value of D(12)=D(∞) is the fractal dimension of the most intensive clustering in the heterogeneous fractal set. It is worthwhile to note that we found D(0)<D(1). The analysis of areas affected by sliding from the geological map of Beni Ahmed at a scale 1:50 000 shows the power law size distribution: N(A>a)∝a^−1.57. This confirms the scale invariance of sliding and suggests that real landslides may exhibit a Self-Organized Criticality (SOC) behaviour.  相似文献   

Climatic effect of ENSO associated with landslide occurrence in the Central Andes, Mendoza Province, Argentina   总被引：1，自引：2，他引：1  

Stella M. Moreiras 《Landslides》2005,2(1):53-59

Temporal distribution of landslides can be verified by means of climatic anomalies linked to the ENSO phenomenon. An increasing number of landslides triggered by rainfall have been recorded during warm episodes (El Niño) in the Cordillera Frontal, and a decreasing number during cold episodes (La Niña), concluding that this geological province is mainly influenced by the Pacific Anticyclone. However, slope instability in the Precordillera, located east of the Cordillera Frontal, seems to be mainly influenced by the Atlantic Anticyclone. Analysis of variance shows that there is no significant difference between landslide records and cold-warm episodes, and a higher number of landslides were recorded in years linked to wet periods than during dry periods. Furthermore, the precipitation threshold value associated with landslide occurrence and antecedent precipitation are analysed.  相似文献   

Radon variations in an active landslide zone along the Pindar River, in Chamoli District, Garhwal Lesser Himalaya, India     

V.M. Choubey  S.K. Bartarya  R.C. Ramola 《Environmental Geology》2005,47(6):745-750

Radon measurements were made in the soil and spring/seepage water in and around an active landslide located along the Pindar river in the Chamoli District of Uttaranchal in Garhwal Lesser Himalaya, to understand the application of radon in geological disasters. The landslide is a compound slide i.e. a slump in the crown portion, and debris slide and fall in the lower part. The bedrock consists of gneisses and schists of the Saryu Formation of the Almora Group of Precambrian age. The presence of several small slump scars and debris slide/fall scars along the length of the slide indicates continuous downward movement. The radon concentrations in the present study are much lower in comparison to values reported from other regions. However, the present radon data show relative variation in the slide zone. The concentration of radon measured in landslide zones varies from 3.1 Bq/l to 18.4 Bq/l in spring water and from 2.3 kBq/m³ to 12.2 kBq/m³ in the soil gas of the debris. Along the section of the slide, the radon values in water and soil are slightly higher in the upper slopes i.e. toward the crown portion of the landslide as compared to the distal portion. The relatively low concentration of radon both in soil gas and water in the toe portion of the landslide may be due to the high porosity of the debris, which does not allow radon to accumulate in the soil and water, whereas, towards the crown portion, the high frequency of fractures increases the surface area due to particle size reduction, and the near absence of debris enhances the radon emanation in soil.  相似文献