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1.
More than 150 landslides originated in the eastern part of the Czech Republic (region of the Flysch Outer Western Carpathians—hereinafter, OWC) due to soil saturation caused by antecedent precipitation and long lasting and intensive rainfalls on 16–18 May 2010 (>300 mm as measured by some stations). As a consequence, a multitude of small failures originated 88% of which was smaller than 104 m2. Most landslides are characterised as shallow (<10 m) or middle–deep (10–30 m) incipient (rather short travel) landslides, debris slides and soil slips spatially clustered to a geological domain underlain by rather weak thin-bedded flysch and unconsolidated Quaternary deposits. An exception to this is represented by a kilometre-long rockslide (∼2–3 mil m3) affecting tectonically weakened and weathered claystone/mudstone-dominated flysch on the southern slope of Mt. Girová (the Beskydy Mountains). The rockslide is one of the largest long runout landslides in the territory of the Czech Republic activated over the past few decades as it reaches the dimensions of the largest documented Holocene long runout landslides in the Czech part of the OWC. A majority of the May 2010 landslide events developed inside older (Holocene or historic) landslide terrains, which points to their spatial persistency and recurrent nature. In spite of the fact that the May 2010 landslide event was not as destructive as some previous landslide activisation in the OWC region (e.g. July 1997 event), it left many slope failures at the initial stage of their potential future reactivation.  相似文献   

2.
Do Minh Duc 《Landslides》2013,10(2):219-230
Landslides are one of the most dangerous hazards in Vietnam. Most landslides occur at excavated slopes, and natural slope failures are rare in the country. However, the volume of natural slope failures can be very significant and can badly affect large areas. After a long period of heavy rainfall in the fourth quarter of 2005 in Van Canh district, a series of landslides with volumes of 20,000–195,000 m3 occurred on 15 December 2005. The travel distances for the landslides reached over 300–400 m, and the landslides caused some remarkable loud booming noises. The failures took place on natural slopes with unfavorable geological settings and slope angles of 28–31°. The rainfall in the fourth quarter of 2005 is estimated to have a return period of 100 years and was the main triggering factor. Because of the large affected area and low population density, resettling people from the dangerous landslide-prone residential areas to safer sites was the most appropriate solution. In order to do so, a map of landslide susceptibility was produced that took into account slope angle, distance to faults, and slope aspect. The map includes four levels from low to very high susceptibility to landslides.  相似文献   

3.
Landslide risk of the Campanian carbonate slopes covered by pyroclastic deposits is mainly connected with the occurrence of high-velocity debris avalanches and debris flows. Analyses show that flows initiate as small translational slides in the pyroclastics. The failure process is controlled by the interaction of both natural and human-induced factors. Geomorphological settings play a decisive role in locating the source failures. Therefore, the crucial aspects in landslide hazard and risk assessment are: (a) recognise the geomorphological control factors, (b) determine parameters defining landslide intensity (velocity, volume, depth of deposit) and (c) predict landslide runout distance. An approach combining geomorphology and numerical analysis has been adopted in the work reported here. Potential future landslide intensity scenarios are simulated predicting the runout behaviour of potential instabilities by using a dynamic model previously calibrated by back-analysing observed events of similar scale and type. The selected area is a sector of the Avella Mountains having the same geomorphological environment as the 1998 Sarno landslides (Campania, Southern Italy).  相似文献   

4.
Sadiq  Simon  Muhammad  Umar  Fuchs  Michael 《Natural Hazards》2022,110(3):2141-2162

Lineament extraction has long been performed through extensive field mapping. Recent advances in the field of remote sensing have made possible the availability of imageries from earth observation satellites with different Spatio-temporal resolutions, paving way for new automatic, semi-automatic, and manual techniques for the extraction of natural lineaments. The study focuses on the extraction of lineaments representing tectonic fault zones; the lineaments are extracted automatically and semi-automatically/manually. Results show that indirect information about the tectonic lineaments can be derived through automatic techniques whereas, the semi-automatic techniques are more effective to directly identify them. Detailed analyses of lineaments and landslides revealed that areas near lineaments, in general, experienced higher frequency of landslides. Moreover, it is also observed that lineaments are not the only factor that affects landslide density; other parameters like slope and lithology were also found to be the controlling factors in determining the spatial landslide distribution. Lastly, some recommendations have been made based on observations.

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5.
西藏墨脱公路工程地质灾害遥感勘察与解译方法   总被引：5，自引：1，他引：5  
在地处南迦巴瓦峰地区的西藏墨脱公路工程地质遥感勘察中，以Landsat-7 ETM＋卫星影像为信息源，运用彩色合成、数据融合、主成分分析等数字图像处理方法，结合基于地学知识的图像识别及解译技术，对墨脱公路沿线的泥石流、滑坡、活动断裂等地质灾害进行全面解译分析及专题制图，查明了公路方案线区域内活动断裂发育特征。其中，帕隆藏布断裂带、岗日嘎布断裂带等对错拉隧道将产生较大影响。大型滑坡主要有5个，沿南迦巴瓦峰南坡的雅鲁藏布江河谷两岸发育，分布在仓孔、墨脱及洒拉库等地。泥石流、崩塌广泛发育，主要分布在雅鲁藏布江河谷、帕隆藏布河谷沿线的派、拉格-汗密、岗乡-波密一带。勘察及解译结果为墨脱公路工程线路方案选择、工程地质条件评价提供了充分的科学依据。  相似文献   

6.
Heavy rainfall on February 20, 2010, triggered numerous shallow rapid landslides across Madeira Island, a Portuguese archipelago in the North Atlantic. Two days after the extreme rainfall event, a field campaign was started which involved describing and mapping a variety of landslide types and the related losses at 120 different locations throughout the Island. Most of the failures started as debris slides or avalanches at high elevations and transformed into debris flows which rushed downslope into populated coastal areas. Over half of the mapped landslides were located in the central and southern area of the island. A further 1,257 landslide locations were revealed in these areas using remote sensing data which were then assembled in a spatial database. Due to anthropogenic influences caused by urban development and population expansion, the event demonstrated the increased vulnerability of the island??s infrastructure. In order to mitigate future losses, it is important to quantify the typical preparatory factors which contribute to rainfall-induced landslides. This increases our understanding of the hazards and associated risks. The analysis shows that based on their spatial frequency, distribution and in the context of the drainage system, three main factors contribute to the triggering of the landslides due to the heavy rainfall event in February 2010: the characteristic soil type, the land cover and the slope gradient. It can now be recognized that the distribution of landslides is highly dependent on the temporal and spatial distribution of these factors. Furthermore, the anthropogenic impact on the extent of the hazard becomes obvious due to poor settlement planning and drainage system modification.  相似文献   

7.
2022年9月5日四川泸定县发生MS 6.8级地震, 地震诱发大量同震崩滑体, 并导致湾东河断流。基于现场调查、影像解译和区域地质资料分析, 采用空间统计和水文计算的方法, 对湾东河流域同震崩滑体分布特征和潜在泥石流危险性进行了研究。结果表明: 湾东河流域内同震崩滑体主要分布在地震烈度Ⅸ度区, 规模以中小型为主, 主要沿沟道两侧展布, 尤其是单薄山脊两侧临空面发育密度较大, 距断层距离和坡度对其分布具有明显的控灾效应; 未来湾东河流域暴发溃决型泥石流的冲出量可能为同等触发条件下震前泥石流的约两倍。依此提出了加强流域内溃决型泥石流风险防范, 尽快通过综合监测预警获取泥石流发生的临界雨量值, 在泥石流防治工程设计中应充分考虑泥石流规模放大系数等防灾减灾建议, 为泸定地震后泥石流灾害防灾减灾提供科学参考。   相似文献   

8.
The Faroe Islands in the North Atlantic Ocean are susceptible to flow-type landslides in coarse-grained highly organic colluvium. Following several hazardous debris avalanche events, research work has been initiated to quantify landslide risk. A central task in this work is to predict landslide runout behavior. From numerical simulation of four debris avalanches, this study provides a first screening of which rheology and appertaining input parameters best predict runout behavior of debris avalanches in the Faroe Islands. Three rheologies (frictional, Voellmy, and Bingham) are selected and used for individual back analysis of the events in the numerical models BING and DAN3D. A best fit rheology is selected from comparing predicted and observed landslide runout behavior. General back analysis to identify the optimal input parameters for the chosen rheology is performed by cross validation, where each debris avalanche is modeled with input parameters from the three other events. Optimal input parameters are found from the model run producing the most accurate runout length and velocity. The Bingham is selected as the best fit rheology, a result differing from similar studies of coarse-grained landslides. A reason for why particularly the frictional rheology proves unsuitable is its tendency to produce too long runout lengths of the low-weight runout material, a result showing important limitations for using the frictional rheology in DAN3D. Optimal Bingham input parameters are τ y ?=?980 Pa and μ b ?=?117 Pa/s. However, future studies performed in 2D models are needed for precise parameterization before results can be used for landslide risk assessment.  相似文献   

9.
The mobility of long-runout landslides   总被引：17，自引：0，他引：17  
Fran  ois Legros 《Engineering Geology》2002,63(3-4):301-331
Several issues relevant to the mobility of long-runout landslides are examined. A central idea developed in this paper is that the apparent coefficient of friction (ratio of the fall height to the runout distance) commonly used to describe landslide mobility is physically meaningless. It is proposed that the runout distance depends primarily on the volume and not on the fall height, which just adds scatter to the correlation. The negative correlation observed between the apparent coefficient of friction and the volume is just due to the fact that, on the gentle slopes on which landslides travel and come to rest, a large increase in runout distance due to a large volume corresponds to a small increase in the total fall height, hence to a decrease in the apparent coefficient of friction.

It is shown that the spreading of a fluid-absent, granular flow is not able to explain the large runout distances of landslides, and in particular does not allow the centre of mass to travel further than expected for a sliding block. This contrasts with the behaviour of natural landslides, for which the centre of mass is shown to travel much further than expected from a simple Coulomb model. The presence of an interstitial fluid which can partly or entirely support the load of particles allows the effective coefficient of solid friction to be reduced or even suppressed. Air is not efficient for fluidising large landslides and a loose debris cannot slide over a basal layer of entrapped and compressed air, as air would rapidly pass through the debris in the form of bubbles during batch sedimentation. Water is much more efficient as a fluidising medium due to its higher density and viscosity, and its incompressibility. As water is known to enhance the mobility of the saturated debris flows, it is proposed that water is also responsible for the long runout of landslides. This is consistent with the fact that the increase in runout with volume is similar for debris flows and landslides. Field evidence suggests that most landslides are unsaturated with water but not dry, even on Mars.

Comparison of the velocity of well-documented landslides with that predicted by fluid-absent, granular models shows that these models predict landslides that are much faster and less responsive to topography than natural ones. The relatively low velocities of landslides suggest that energy dissipation is dominated by a velocity-dependent stress and that the coefficient of solid friction is very low. This is consistent with the physics of fluidised or partly fluidised debris and suggests that landslide velocity may be controlled by local slope and flow thickness rather than by the initial fall height. In the absence of a supply of fluid at the base, fluidisation requires a net downward flux of sediment, implying some deposition at the base of landslides, which may thus progressively run out of material. In such a model, the spreading of the portion of a landslide beyond a certain distance would primarily depend on the volume passing this distance and not on the total volume of the landslide. Landslide deposits may therefore have self-similar shapes, in which the area covered beyond a certain distance is a constant function of the volume beyond that distance. It is shown that the shape of some well-documented landslide deposits is in reasonable agreement with this prediction. One consequence is that, as recently proposed for debris flows, assessment of hazards related to landslides should be based on the correlation between the volume and the area covered by the deposit, rather than on the apparent coefficient of friction.  相似文献   


10.
在系统总结活动断裂遥感影像解译标志的基础上,利用Landsat ETM、Google Earth及ASTER GDEM等影像资料,结合前人研究成果,重点分析了龙门山构造带南段主要活动断裂的空间展布及几何学与运动学特征。研究结果表明,龙门山构造带在向南延伸过程中发生了明显的断裂分散现象,整个断裂带逐渐展宽,主要包括5条断裂带且其中包含多条次级断裂,至最南端被北西向鲜水河左旋走滑断裂带阻挡。其中活动性较为明显的断裂自西向东主要有4条:泸定断裂、天全断裂、芦山断裂和大邑-名山断裂,前两者是北川-映秀断裂的南延分支,而后两者是安县-灌县断裂的南延部分。由于龙门山构造带南段的构造变形被分解至多条次级断裂上,导致单条断裂错断地表的活动迹象明显变弱,因此单条断裂的潜在发震频率和强度也将相应变小,但潜在震源区会更为分散。结合已有的地震地质资料认为,未来应注意泸定和雅安2个地区的地壳稳定性及未来强震危险性问题。   相似文献   

11.
近年来,在汶川地震等强震区常发生一种特大的高位滑坡地质灾害,它从高陡斜坡上部位置剪出并形成凌空加速坠落,具有撞击粉碎效应和动力侵蚀效应,导致滑体解体碎化,从而转化为高速远程碎屑流滑动或泥石流流动,并铲刮下部岩土体,使体积明显增加。新磨滑坡就是这种典型,它发生于2017年6月24日,滑坡后缘高程约3450m,前缘高程约2250 m,高差1200 m,水平距离2800 m,堆积体体积达1637×10~4m~3,摧毁了新磨村村庄,导致83人死亡。新磨滑坡地处叠溪较场弧形构造带前弧西翼,母岩为中三叠统中厚层变砂岩夹板岩,是1933年叠溪Ms7.5级震中区(烈度X度)和汶川Ms8.0级强震区(烈度IX度),形成震裂山体。滑源区分布多组不连续结构面,将厚层块状岩体分割成碎裂块体,在高程3150~3450 m区间形成明显的压裂鼓胀区,特别是存在2组反倾节理带,具有典型的"锁固段"失稳机理。滑坡体高位剪出滑动,连续加载并堆积于斜坡体上部,体积达390×10~4m~3,导致残坡积岩土层失稳并转化为管道型碎屑流;碎屑流高速流滑至斜坡下部老滑坡堆积体后,因前方地形开阔、坡度变缓,转化为扩散型碎屑流散落堆积,具有"高速远程"成灾模式。据此,可建立强震山区高位滑坡的早期识别方法,当陡倾山脊存在大型岩质高位滑坡时,应当考虑冲击作用带来的动力侵蚀效应和堆积加载效应,特别是沿沟谷赋存丰富的地下水时,发生高速远程滑坡的可能性将明显增加。因此,在地质灾害调查排查中,在高位岩质滑坡剪出口下方的斜坡堆积体上的聚居区等应划定为地质灾害危险区。在强震山区地质灾害研究中,不仅应采用静力学理论分析滑坡的失稳机理,而且应采用动力学方法加强运动过程的成灾模式研究。  相似文献   

12.
This study uses results from a series of analogue models, and field observations, scanned data and sections of natural landslides to investigate the kinematics and internal deformation during the failure of an unstable slope. The models simulate collapse of granular slopes and focus on the spatial and temporal distribution of their internal structures. Using a series of systematically designed models, we have studied the effect of friction and deformability of the runout base on internal deformation within a granular slope. The results of these different models show that the collapse of granular slopes resulted in different-generation extensional faults at the back of the slope, and contractional structures (overturned folds, sheath folds and thrusts) at the toe of the slope. The failure surfaces and the volume of the failure mass changed both spatially and temporally. Younger failure surfaces formed in the back of the older ones by incorporating additional new material from the head of the slope. Our model results also show that the nature of the runout base has a significant influence on the runout distance, topography and internal deformation of a granular slope. Model results are compared with natural landslides where local profiles were dug in order to decipher the internal structures of the failure mass. The natural cases show similar structural distribution at the head and toe of the failure mass. As in model results, our field observations indicate the presence of at least two generations of failure surfaces where the older ones are steeper.  相似文献   

13.
汶川地震发生后,灾区暴雨泥石流活动进入一个新的活跃期。根据对北川震区2008年9月24日暴雨泥石流调查,泥石流流域中地震诱发大量滑坡导致松散物源巨大,泥石流过程的洪峰流量比通常的要大数倍,应用以往泥石流危险范围预测模型进行计算的结果与实际的误差较大。因此,需要建立适用于强震区的泥石流危险范围预测方法。本文以9.24北川暴雨泥石流为典型实例,结合野外调查,利用震后高分辨航空图像和9.24暴雨后SPOT5图像分别提取泥石流发生前流域中滑坡物源储量及发生后形成的堆积扇特征数据,应用多元回归方法建立了汶川震区泥石流危险范围预测模型,该方法可用于估算泥石流最大堆积距离和堆积宽度。验证和应用结果表明:该模型适用于强震区泥石流危险范围的预测,模型方法可为震区重建中安全地段选择和未来地震区风险管理提供重要依据。  相似文献   

14.
This paper is focussed on the hazard impact of landslides in the Three Gorges, and represents the progression of our ongoing study on regional land instability assessment in the Three Gorges area using imagery data from the Advanced Spaceborne Thermal Emission Radiometer (ASTER). The key development here is the establishment of a model that integrates land instability with several factors that can relate hazard to human life, such as slope failures occurring in proximity to built-up areas and roads, and areas of high landslide risk along the bank of Yangtze and its major tributaries. The method correctly identifies some of the known destructive landslides in the region, like Qianjiangping and Huangtupo, as belonging to areas of potentially high landslide impact. Our results suggest that several population centres, including the towns of Wushan and Badong, are rated at high landslide hazard levels. This study highlights the importance of differentiating between landslide types within susceptibility assessment, and identifies those locations in the Three Gorges where the probability of landslide occurrence with negative impact to life and property is greatest.  相似文献   

15.
帕米尔东北缘-西昆仑的构造地貌及其构造意义   总被引：5，自引：2，他引：3  
帕米尔东北缘-西昆仑位于青藏高原西北部,受三条大型断裂:康西瓦断裂、主帕米尔-铁克里克断裂和公格尔断裂的制约.通过野外考察、卫星遥感图像解译、ASTER GDEM高程数据的分析,对上述三条断裂及整个区域进行构造地貌研究,并探讨其构造意义.结果表明:康西瓦断裂为左行走滑断裂;主帕米尔-铁克里克断裂为逆冲断裂;公格尔断裂和塔什库尔干断裂分别为右行、左行走滑正断层,连接两者的是塔合曼正断裂.通过ASTER GDEM高程数据的高程分布、局部高程差和坡度分析,表明帕米尔东北缘-西昆仑至塔里木盆地存在三级特征地貌(塔里木盆地、塔里木盆地南缘山前褶皱逆冲带和帕米尔东北缘-西昆仑);西昆仑地区受印度/亚洲板块碰撞而产生垂向物质运动,由于三条大型断裂控制在西侧断裂附近存在水平方向的物质运动,垂直和水平两种运动的存在促使靠近康西瓦和公格尔断裂形成高山地貌.  相似文献   

16.
Landslide hazard is one of the crucial environmental constraints for the development of Ethiopia, representing a limiting factor for urbanization and infrastructures. The high relief and the rugged topography induced by a strong Plio-Quaternary uplift, the occurrence of clayey horizons within the sedimentary sequences, the dense network of tectonic fractures and faults, the thick eluvial mantles on volcanic outcrops, and the thick colluvial–alluvial deposits at the foot of steep slopes are the predisposing factors for a large variety of mass movements. Heavy summer rainfall is the main triggering factor of most landslides, some of which undergo a step-like evolution with long-lasting quiescence intervals. First generation movements are commonly restricted to shallow phenomena, such as soil slips or mud flows in eluvial–colluvial material. Fast moving slope failures, such as rock slides, topplings and falls, are also triggered by earthquakes. To mitigate the landslide risk, any first priority measure should include adequate drainage of slopes in order to reduce water infiltration. On the other hand, appropriate site selection for buildings, transferring risky settlements, accurate geological control of works, and education campaigns are all strongly recommended.  相似文献   

17.
Causes of large-scale landslides in the Lesser Himalaya of central Nepal   总被引：1，自引：0，他引：1  
Geologically and tectonically active Himalayan Range is characterized by highly elevated mountains and deep river valleys. Because of steep mountain slopes, and dynamic geological conditions, large-scale landslides are very common in Lesser and Higher Himalayan zones of Nepal Himalaya. Slopes along the major highways of central Nepal namely Prithvi Highway, Narayangadh-Mugling Road and Tribhuvan Highway are considered in this study of large-scale landslides. Geologically, the highways in consideration pass through crushed and jointed Kathmandu Nappe affected by numerous faults and folds. The relict large-scale landslides have been contributing to debris flows and slides along the highways. Most of the slope failures are mainly bechanced in geological formations consisting phyllite, schist and gneiss. Laboratory test on the soil samples collected from the failure zones and field investigation suggested significant hydrothermal alteration in the area. The substantial hydrothermal alteration in the Lesser Himalaya during advancement of the Main Central Thrust (MCT) and thereby clay mineralization in sliding zones of large-scale landslide are the main causes of large-scale landslides in the highways of central Nepal. This research also suggests that large-scale landslides are the major cause of slope failure during monsoon in the Lesser Himalaya of Nepal. Similarly, hydrothermal alteration is also significant in failure zone of the large-scale landslides. For the sustainable road maintenance in Nepal, it is of utmost importance to study the nature of sliding zones of large-scale landslides along the highways and their role to cause debris flows and slides during monsoon period.  相似文献   

18.
Predicting where and when landslides are likely to occur in a specific region of interest remains a key challenge in natural hazards research and mitigation. While the basic mechanics of slope‐failure initiation and runout can be cast into physical and numerical models, a scarcity of sufficiently detailed and real‐time measurements of soil, rock‐mass and groundwater conditions prohibits accurate landslide forecasting. Researchers are therefore increasingly exploring multivariate data analysis techniques from the fields of data mining or machine learning in order to approximate future occurrences of landslides from past distribution patterns. This work has elucidated patterns of spatial susceptibility, but temporal forecasts have remained largely empirical. Most machine learning techniques achieve overall success rates of 75–95 percent. Whilst this may seem very promising, issues remain with data input quality, potential overfitting and commensurate inadequate choice of prediction models, inadvertent inclusion of redundant or noise variables, and technical limits to predicting only certain types and sizes of landslides. Simpler models provide only slightly inferior predictions to more complex models, and should guide the way for a more widespread application of data mining in regional landslide prediction. This approach should especially be communicated to planners and decision makers. Future research may want to develop: (1) further best‐practice guidelines for model selection; (2) predictions of occurrence and runout of large slope failures at the regional scale; and (3) temporal forecasts of landslides.  相似文献   

19.
陈剑  陈瑞琛  崔之久 《地学前缘》2021,28(4):349-360
本文总结了当前有关高速远程滑坡远程机制的研究现状,探讨了滑坡地貌学和沉积学对于揭示高速远程滑坡运动学机理的重要意义。通过梳理前人关于高速远程滑坡堆积形态的分类,分析了高速远程滑坡主要的形态学特征、蕴含的运动学信息以及高速远程滑坡的脱落块体、丘体、脊结构、断层等的地貌结构特征,并进一步指出这些地貌结构的形成主要是滑坡体物质不均匀运动的结果,其受地形和内聚力的影响。高速远程滑坡的沉积学特征明显受到岩性、地形和基底等因素的影响,本文对高速远程滑坡的沉积相模式及其运动学意义进行了分析,并对地层不变性与反序结构两个重要堆积特征进行了讨论。最后,指出高速远程滑坡地貌学与沉积学研究当前主要存在的一些问题,建议将大型物理模拟与数值模拟方法相结合,加强对高速远程滑坡地貌微形态和堆积结构的形成机制研究。  相似文献   

20.
高速远程崩滑所造成的地质灾害极为严重,波及范围大,早已引起国内外工程技术人员的关注.2008年5·12汶川8级地震所诱发的崩塌和滑坡数以万计,其中高速远程崩滑数量虽不多,但是灾害严重.与一般崩塌和滑坡相比,高速远程崩滑的形成条件究竟有何差异？为了预测高速远程崩滑灾害的严重性和波及范围,以便为国土规划和防治对策设计提供依...  相似文献   

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