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91.
Recent advances in image-matching techniques and VHR satellite imaging at submeter resolution theoretically offer the possibility to measure Earth surface displacements with decimetric precision. However, this possibility has yet not been explored and requirements of ground control and external topographic datasets are considered as important bottlenecks that hinder a more common application of optical image correlation for displacement measurements. This article describes an approach combining spaceborne stereo-photogrammetry, orthorectification and sub-pixel image correlation to measure the horizontal surface displacement of landslides from Pléiades satellite images. The influence of the number of ground-control points on the accuracy of the image orientation, the extracted surface models and the estimated displacement rates is quantified through comparisons with airborne laser scan and in situ global navigation satellite measurements at permanent stations. The comparison shows a maximum error of 0.13 m which is one order of magnitude more accurate than what has been previously reported with spaceborne optical images from other sensors. The obtained results indicate that the approach can be applied without significant loss in accuracy when no ground control points are available. It could, therefore, greatly facilitate displacement measurements for a broad range of applications.  相似文献   
92.
玉树地震滑坡分布调查及其特征与形成机制   总被引:2,自引:2,他引:0  
On April 14, 2010 at 07:49 (Beijing time), a catastrophic earthquake with MS7.1 occurred at the central Qinghai-Tibetan Plateau. The epicenter was located at Yushu county, Qinghai Province, China. A total of 2036 landslides were determined from visual interpretation of aerial photographs and high resolution remote sensing images, and verified by selected field investigations. These landslides covered a total area of about 1.194km2. Characteristics and failure mechanisms of these landslides are listed in this paper, including the fact that the spatial distribution of these landslides is controlled by co-seismic main surface fault ruptures. Most of the landslides were small scale, causing rather less hazards, and often occurring close to each other. The landslides were of various types, including mainly disrupted landslides and rock falls in shallows and also deep-seated landslides, liquefaction induced landslides, and compound landslides. In addition to strong ground shaking, which is the direct landslide triggering factor, geological, topographical, and human activity also have impact on the occurrence of earthquake triggered landslides. In this paper, five types of failure mechanisms related to the landslides are presented, namely, the excavated toes of slopes accompanied by strong ground shaking; surface water infiltration accompanied by strong ground shaking; co-seismic fault slipping accompanied by strong ground shaking; only strong ground shaking; and delayed occurrence of landslides due to snow melt or rainfall infiltration at sites where slopes were weakened by co-seismic ground shaking. Besides the main co-seismic surface ruptures, slope fissures were also delineated from visual interpretation of aerial photographs in high resolution. A total of 4814 slope fissures, with a total length up to 77.1km, were finally mapped. These slope fissures are mainly distributed on the slopes located at the southeastern end of the main co-seismic surface rupture zone, an area subject to strong compression during the earthquake.  相似文献   
93.
There is much interest on the occurrence of water and ice in the past history of Mars. Because landslides on Mars are much better conserved than their terrestrial counterparts, a physical examination and morphological analysis can reveal significant details on the depositional environment at the instant of failure. A study of the landslides in Valles Marineris based on their physical aspect is presented and the velocity of the landslides is calculated with a stretching block model. The results show that the landslides were subject to strong basal lubrication that made them travel at high speed and to long distances. We use physical analysis to explore the four alternative possibilities that the natural lubricant of the landslides in Valles Marineris was either ice, deep water, a shallow carpet of water, or evaporites. Examination of the furrows present on the surface of the landslide deposits shows that either sub-surface ice or evaporites were likely present on the floor of Valles Marineris during the mass failures.  相似文献   
94.
汶川地震滑坡与地震参数及地质地貌因素之间的相关关系   总被引:4,自引:0,他引:4  
在对汶川地震诱发的典型滑坡进行野外调查和相关资料收集、分析和整理的基础上,对汶川地震滑坡与地震参数及坡度、岩土体特性等地质地貌因素之间的相关关系进行了统计分析。结果表明: (1)汶川地震滑坡主要发生在Ⅶ~Ⅺ烈度区, Ⅵ度及以下烈度区中发生的滑坡较少; (2)汶川地震滑坡主要发生在距震中300km的范围内,且距震中200km的范围内滑坡分布最为集中; (3)汶川地震滑坡的易发斜坡坡度为30~50,其中30~40是汶川地震滑坡发育最为敏感的坡度; (4)汶川地震滑坡主要发生在600~1500m的高程范围内,在600~1000m高程范围内的中低山和丘陵区滑坡分布最为集中; (5)砂泥岩、板岩、片岩、千枚岩等软岩类和土质类岩性是汶川地震滑坡的易发岩性,其次是软硬岩组合类,在统计的47个典型滑坡中,花岗岩、碳酸盐岩等硬岩类中发生的滑坡最少,而且由汶川地震直接导致复活的老滑坡也比较少。  相似文献   
95.
地震滑坡资料是深入研究地震滑坡问题的宝贵基础资料,但是目前对这些资料缺乏有效的管理和利用。本文介绍的地震滑坡数据库管理系统可以科学合理地对这些资料进行高效管理,节省科研前期的投入,提高工作效率。本系统界面友好、操作方便,具有良好的可维护性、可扩充性和升级换代能力,可以加速地震滑坡问题的研究步伐,是地震滑坡问题研究的一个有力工具。  相似文献   
96.
国道212线甘肃段地貌特征与滑坡泥石流关系研究   总被引:6,自引:3,他引:3  
国道212线甘肃段是甘肃省南北向的主要通道,在甘肃境内全长707km,公路沿线是我国滑坡、泥石流的主要发育区,特别是陇南市的宕昌武都段是我国最主要的滑坡、泥石流灾害区之一。线路通过地区的自然地理条件迥异,造成滑坡、泥石流类型和性质有很大差别。本文分析了该区地形地貌时、时空规律性及其与滑坡、泥石流的关系,为未来的高速公路建设提供理论依据。  相似文献   
97.
There are both internal and external controlling factors leading to slope instability and susceptibility to mass movement processes. This paper explores which external climatic variables of different temporal scales influence the occurrence of high-magnitude landslide events. The investigations were focused on the Wellenkalk-cuesta scarp in the Thuringia Basin (Thüringer Becken) in central Germany. The cuesta scarp is composed of a densely jointed limestone caprock (Wellenkalk), and impermeable mudstones and marls of the Upper Bunter Sandstone (Röt) in the lower part of the slope. Mass movements are a typical feature of the Wellenkalk-scarp. The entire scarp slope length (1000 km) has been systematically mapped and investigated in a comprehensive research project in order to provide reliable information on the spatial distribution and control of the mass movements. More than 20% of the scarp slope has been influenced by various types of Holocene mass movements with strong differences in spatial frequencies. Sixteen high-magnitude landslides (Sturzfließungen) were identified by field inspection and mapping of slope geomorphology. Information on locations, morphometric characteristics, stratigraphic positions and rainfall-related attributes of the scarp slopes affected by the large landslides is presented.Mean annual rainfall amounts decrease from more than 800 mm in the western part of the basin to less than 550 mm in the east. Meteorological statistics on the spatial distribution of heavy rainfall intensities of different durations and return periods show that greatest precipitation intensities in short events (1 h) are reached at the western margin. Differences in rainfall intensities between the western and eastern parts decrease with increasing duration of the events. Where available, event-related meteorological information was collected. The spatial distribution of the landslides is most closely mirrored in the pattern of mean annual precipitation, though this variable is generally not thought to be a satisfactory or reliable climatic controlling factor. No landslides occur below a threshold value of 700 mm. The empirical data show that some general level of average perennial water input into the slope system seems to be of decisive importance for the occurrence of high-magnitude mass movements. Only when the precondition of a more general hydrological disposition is fulfilled, a direct triggering of high-magnitude mass movements by a short-time intensive rainfall period or event can become effective.  相似文献   
98.
Slope instability studies appear to recognize a number of potential superficial slide-producing agents, which may be directly detected and monitored with Earth Observation (EO) data. The main objective of this work is to use conventional EO data and automatic techniques for providing land-use change maps useful in landslide prevention. The idea is to use the detection of changes in areas already involved in landslide events as a precursory sign of variations in the equilibrium status of the slope, independently from other natural triggering events, such as rain and seismic events. Attention is focused on man-induced surface changes, such as deforestation, urban expansion and construction of artificial structures. A historical set of 20 multi-temporal Landsat TM images, covering the period 1987–2000, was analyzed using a supervised change detection technique on a test site affected by slope instability phenomena located in the Abruzzo region in Southern Italy. A change image is obtained by comparing year-specific thematic map pairs. It contains useful information not only on the place where a transition occurred, but also on the specific classes involved in the transitions between two different years. The full set of change images is used to extract class-conditional transition probabilities, to evaluate variations in specific class distribution and the total number of changed pixels in time. Four classes and their transitions were considered in the analysis: (1) arboreous land, (2) agricultural land, (3) barren land, and (4) artificial structures. The quantitative analysis of the class-joint transition probability values of some specific class-transitions that may worsen slope stability showed that in an area prone to landslides the probability of landslide re-activation or first activation is higher where changes have occurred. Although based on a limited number of known events, such a result encourages extensive experimentation of the proposed technique on better documented landslide test sites.  相似文献   
99.
A National Research Council, Research Institute for Hydrogeological Protection (IRPI) study on Italian monuments included in the UNESCO World Heritage List has revealed that many are affected by geological, geomorphological, and engineering geological problems. These monuments are static entities set in an environment that often manifests highly dynamic processes. As part of the efforts to protect sites of cultural and natural heritage, this study has applied a preliminary and empirical Geographical Information System-based method developed to characterize the environmental hazards at the sites where the monuments are located. Because the study of hydrogeological degradation falls within the province of IRPI, this hazard zoning focuses on river and mountain slope dynamics specifically concerning landslides and floods.  相似文献   
100.
Global landslide and avalanche hotspots   总被引:6,自引:7,他引:6  
Allocating resources for natural hazard risk management has high priority in development banks and international agencies working in developing countries. Global hazard and risk maps for landslides and avalanches were developed to identify the most exposed countries. Based on the global datasets of climate, lithology, earthquake activity, and topography, areas with the highest hazard, or “hotspots”, were identified. The applied model was based on classed values of all input data. The model output is a landslide and avalanche hazard index, which is globally scaled into nine levels. The model results were calibrated and validated in selected areas where good data on slide events exist. The results from the landslide and avalanche hazard model together with global population data were then used as input for the risk assessment. Regions with the highest risk can be found in Colombia, Tajikistan, India, and Nepal where the estimated number of people killed per year per 100 km2 was found to be greater than one. The model made a reasonable prediction of the landslide hazard in 240 of 249 countries. More and better input data could improve the model further. Future work will focus on selected areas to study the applicability of the model on national and regional scales.  相似文献   
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