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1.
Mircea Voiculescu 《Natural Hazards》2009,51(3):459-475
Snow avalanches represent an undeniable reality in the Southern Carpathians both as a geomorphic process and as a type of
hazard. Before the 1990s, few researchers focused on avalanches in Romania. However, after 1990, avalanches became an increasingly
important topic of Romanian research including research on their management implications. This study focuses on the Făgăraş
massif, a representative mountain unit in the Southern Carpathians that is dominant due to its glacial and periglacial relief,
high altitudes and high occurrence of avalanche hazards. Three main research issues are considered. First, types of avalanches
are delineated along with affected areas of the Balea glacial valley (on the northern slope) and the Capra glacial valley
(on the southern slope) using data from a research centre for snow and avalanche monitoring that was created in the Balea
glacial cirque in 2003. Second, the impact of avalanches on human activities is considered including transportation use of
the Transfăgărăşan Highway that traverses the highest elevations in Romania and winter recreation activities such as skiing,
snowboarding, climbing and hiking. The impacts on forests are also considered. Third, the needs and gaps of avalanche management
are considered, specifically in the Făgăraş massif and also more generally in the mountains of Romania. 相似文献
2.
Under the WCoE/IPL project, Landsat Enhanced Thematic Mapper plus (ETM+) and ASTER GDEM data were used to analyze factors associated with frequent debris flow and rock-debris avalanche on the Nigeria-Cameroon mountain range. Detailed processing of the ETM+ imageries of the vulnerable portions on the western part of Adamawa plateau was carried out to identify structural trends relatable to the slope failures. The processing identified the structural characteristics of the study area and clearly distinguished the lineaments associated with the debris flow and rock-debris avalanches. The strongly weathered and fragmented gneissic rocks, shallow groundwater table, as well as the distribution of faults and joint sets were significant factors predisposing the slopes to rapid movements. Recent landslides occurred at the locations with high lineament density and in areas close to major faults and long lineaments. The interaction among the moving mass, slope geometry, local geology, topography, and drainage then resulted in a long runout and a high degree of spreading. Analysis of the ASTER–GDEM delineated landforms, slope morphology, and drainage patterns, which was not possible with conventional mapping techniques. Integration of these results yielded reasonable interpretation of the predisposing factors for the long runout failures and provided logical basis for future landslide susceptibility analysis in the area. Accurate investigation of the predisposing factors and characteristics of landslides in environments that have experienced past failures is therefore important in understanding areas that may be susceptible to landsliding in future. 相似文献
3.
Snow avalanches are a major natural hazard for road users and infrastructure in northern Gaspésie. Over the past 11 years, the occurrence of nearly 500 snow avalanches on the two major roads servicing the area was reported. No management program is currently operational. In this study, we analyze the weather patterns promoting snow avalanche initiation and use logistic regression (LR) to calculate the probability of avalanche occurrence on a daily basis. We then test the best LR models over the 2012–2013 season in an operational forecasting perspective: Each day, the probability of occurrence (0–100%) determined by the model was classified into five classes avalanche danger scale. Our results show that avalanche occurrence along the coast is best predicted by 2 days of accrued snowfall [in water equivalent (WE)], daily rainfall, and wind speed. In the valley, the most significant predictive variables are 3 days of accrued snowfall (WE), daily rainfall, and the preceding 2 days of thermal amplitude. The large scree slopes located along the coast and exposed to strong winds tend to be more reactive to direct snow accumulation than the inner-valley slopes. Therefore, the probability of avalanche occurrence increases rapidly during a snowfall. The slopes located in the valley are less responsive to snow loading. The LR models developed prove to be an efficient tool to forecast days with high levels of snow avalanche activity. Finally, we discuss how road maintenance managers can use this forecasting tool to improve decision making and risk rendering on a daily basis. 相似文献
4.
An avalanche occurrence is a result of the structural collapse of the snow cover in the upper reaches of mountain slopes in the snowbound belt. They take a heavy toll, year after year and property worth millions is destroyed. Besides loss of lives, the avalanches also destroy forest and disrupt road communication, thereby hindering the hill area development and affecting the Defense of the nation.The paper brings out the cause of avalanche formation, magnitude of their destruction power and the techniques being followed in India by Snow and Avalanche Study Establishment (SASE), a DRDO Laboratory, for mitigating the avalanche disasters in Western Himalayan Region for the Defense forces. The authors suggest that for mitigating the avalanche disasters, an integrated plan at national level involving Defense forces and state governments should be drawn. 相似文献
5.
Flow-like mass movements in granular materials are among the most serious natural hazards, systematically producing huge amounts of damage and numerous victims, especially when involving volcanic soils. This is the case of the events in Southern Italy in May 1998, when rainfall triggered many destructive landslides along the slopes of a carbonate massif mantled by pyroclastic soils. Due to the complexity of the occurred phenomena, a shared interpretation of their triggering stage is still not available.
As a contribution to the topic, the paper initially discusses the geological and geomorphological features of the massif combining them in three hillslopes models. The models are then associated to the hydrogeological features and anthropogenic factors in order to define six typical landslides source areas that are not casually distributed on the massif. The study subsequently focuses on the most frequent type of source areas, associated to the largest unstable soil volumes and longest run-out distances. For these source areas, the triggering mechanism is discussed, with an example of geotechnical validation being proposed for a well monitored mountain basin. The geotechnical modelling at site scale confirms the geological analyses at massif scale and provides further insights into the events, thus highlighting the potential of a multidisciplinary approach for the interpretation of very complex slope instability phenomena. 相似文献
6.
Gravitational spreading of mountain ridges displays primary disequilibrium of flysch mountain areas of the Czech Carpathians.
The progression of various types of mass movements is a product of long-term ridge disintegration and is predisposed by the
geological structure of the area and the upper Tertiary-Quaternary morphogenesis of the mountain area. Deep-seated slope deformations
are spatially interconnected by the occurrence of some other types of slope deformations (e.g. debris flows, debris slides,
slumps, rock avalanches, etc.), which pose a considerable risk for the existence of human society. An important causative
factor in these dynamically developing hazardous processes is, among other factors, the way in which land has been used in
the last three centuries. Therefore, the occurrence of various types of slope deformations is studied in terms of their relation
to deep-seated gravitational deformations and in terms of other limiting factors (structural geological, morphological and
climatic factors, manmade impacts, etc.). The paper presents several case studies of slope deformations (Velká Čantoryje Mt,
Lysá hora Mt, Ropice Mt and Smrk Mt) in the area of the Outer Carpathians within the territory of the Czech Republic and also
adverts to some consequences in terms of the socioeconomic structure of the landscape. 相似文献
7.
Damage Potential and Losses Resulting from Snow Avalanches in Settlements of the Canton of Grisons,Switzerland 总被引：2，自引：1，他引：1
In the field of natural hazards, risk is usually expressed as a function of probability of occurrence and damage potential. A key factor in the development of avalanche risk is a change in damage potential. In this paper, the development of damage potential and losses is analysed for settlements in the canton of Grisons, Switzerland for the period between 1950 and 2000. The spatial development patterns of the residential population and the insured value of buildings on a municipal level are described. These patterns are overlain by an accentuated occurrence of avalanches that caused damage to buildings. Extensive results from areas threatened by avalanches in the municipality of Davos are presented. Although the natural avalanche activity remained constant during the last decades, the total amount of damage decreased due to mitigation measures. The example of the municipality of Davos shows that mitigation measures are able to compensate an increase of tangible assets which leads to a reduced avalanche risk compared to earlier decades. 相似文献
8.
地震诱发山体崩塌常形成巨大的灾害,特定地形地质条件下山体地震动力响应特性及破坏机制研究是工程地质的重要难题。本文以秦岭地区具代表性的翠华山甘湫池花岗岩崩塌为研究对象,制作有效反映花岗岩工程地质结构的试验模型,开展大型振动台试验,研究山体地震动力响应规律和崩塌变形破坏机制。试验发现,边坡内部加速度放大系数随激振强度的增加呈现出显著的三阶段变化趋势;水平加速度响应呈现出随高程的增加而单调增大的特征,而竖直加速度响应随着高程的增加出现先增加后减小再增加的波动变化特征;边坡的固有频率变化曲线可以分为3个阶段,整体呈现下降的趋势,表明边坡动力特性发生变化;破坏后的边坡可以分为2个区域:后缘启动区和崩塌堆积区。边坡在地震激振作用下的破坏过程为地震波激振输入→坡体后缘形成拉张裂缝→裂缝向下扩展贯通→不稳定坡体滑动→堆积坡脚。反演了山体破坏的4个阶段:振动致裂阶段、高速启动阶段、撞击减速阶段和堆积阶段,结果与现场工程地质调查分析十分一致。研究翠华山甘湫池花岗岩崩塌的发育特征、成因机理和演化过程,研究成果对揭示秦岭北缘乃至秦岭地区崩塌形成机制、发育规律和灾害有效防控、地质遗迹开发和保护具有重要意义。 相似文献
9.
W. A. Mitchell M. J. McSaveney A. Zondervan K. Kim S. A. Dunning P. J. Taylor 《Landslides》2007,4(3):245-254
This paper describes the geomorphology of rock avalanche deposits that resulted from a major mountain slope failure at Keylong
Serai on the north slope of the Indian High Himalaya, an area of high altitude desert. Cosmogenic 10Be exposure ages of the widespread deposits indicate their formation 7,510 ± 110 years BP. Proxy records for this region of
the Himalaya imply a similar dry climatic regime to the present day at this time, suggesting that precipitation was an unlikely
trigger for this rock avalanche. An alternative mechanism associated with rock-wall stress relaxation is also unlikely, given
the earlier timing of deglaciation in this area. Given the enormous volume of debris generated by this event, the most likely
trigger for this mountain collapse and resultant rock avalanche is high ground acceleration during a great earthquake (M > 8). It is proposed that rock avalanches can be used to extend the limited palaeoseismic record and improve information
on the recurrence interval of great earthquakes within the Himalaya arc. 相似文献
10.
梅里雪山雪崩多发,但缺乏系统监测和研究。1991年1月3日梅里雪山发生了造成中日联合登山队17名队员遇难的巨大雪崩事件。2019年安装在明永冰川末端附近的物候相机拍摄到临近梅里雪山明永冰川的一次雪崩事件。两次事件类型不同,这对我们进行雪崩预测预警有良好的指示作用。本研究以RAMMS(Rapid Mass Movement System)模型为手段,利用经验值和经验公式确定影响模拟结果的主要模型参数和积雪可能断裂深度,在优化分析的基础上,对两次雪崩事件进行重建,定量分析雪崩堆积量、堆积范围等。结果显示:1991年雪崩共持续了192s,雪崩体从海拔5730m处断裂,沿坡面崩塌而下最终堆积在海拔约5000m的冰川粒雪盆地区,形成面积为0.6km^(2),体积约67×10^(4)m^(3)的堆积体。2019年雪崩共持续了158s,雪崩流最大高度35.91m,最大速度79.34m·s,堆积量76.2×10^(4)m^(3),雪崩堆积范围与野外观测到的一致。两次雪崩事件发生地位于雪崩极高危险区和高危险区,在一定程度上验证了风险评估的准确性。研究结果可为梅里雪山地区未来潜在雪崩灾害的风险评估提供依据,为雪崩预测预警提供良好的参考。 相似文献
11.
青藏高原东缘是全球重要的活动构造区,高原峡谷区斜坡陡峻,高位崩滑灾害多发。采用遥感解译、地面调查、钻孔勘探及测年分析等方法,研究了西藏洛隆察达沟和易贡扎木弄沟两处高位崩滑堆积体的多动力多期次演化特征。研究结果表明：(1)沿陡峻沟道发生的高位崩滑灾害多为复合成因,兼具内动力和外动力作用交替促发特征;(2)洛隆察达沟晚更新世以来的堆积物形成序列可分为4期,分别经历了以冰川作用为主的冰碛物堆积、古地震引发的高位崩滑-碎屑流堆积、气候变暖背景下的冰-岩崩滑堆积及近代重力崩滑堆积;(3)易贡扎木弄沟在过去5500年中,先后发生了8次以上较大规模崩滑堆积,测年结果显示了巨型崩滑事件存在百年数量级的复发周期,由于不同期次巨型崩滑体的成因不同,复发周期可能存在长、中、短的差异;(4)近年来受全球气候变化影响,冰-岩崩滑灾害频现,可能成为高原峡谷区高位远程地质灾害研究的焦点。本文关于高位崩滑灾害多期次演化过程的认识对于高原峡谷区重大地质灾害防灾减灾具有一定启示意义。 相似文献
12.
Avalanche hazard and risk mapping is of utmost importance in mountain areas in Europe and elsewhere. Advanced methods have been developed to describe several aspects of avalanche hazard assessment, such as the dynamics of snow avalanches or the intensity of snowfall to assume as a reference meteorological forcing. However, relatively little research has been conducted on the identification of potential avalanche release areas. In this paper, we present a probabilistic assessment of potential avalanche release areas in the Italian Autonomous Province of Bolzano, eastern Alps, using the Weights of Evidence and Logistic Regression methods with commonly available GIS datasets. We show that a data-driven statistical model performs better than simple, although widely adopted, screening criteria that were proposed in the past, although the complexity of observed release areas is only partly captured by the model. In the best case, the model enables predicting about 70 % of avalanches in the 20 % of area classified at highest hazard. Based on our results, we suggest that probabilistic identification of potential release areas could provide a useful aid in the screening of sites for subsequent, more detailed hazard assessment. 相似文献
13.
沟道型滑坡-碎屑流具有隐蔽性强、危险性高、力学机理复杂的特点,研究其运动距离预测模型具有重要的理论意义和实践意义。本文基于遥感GIS技术,结合野外调查,获取了汶川地震触发的38个沟道型滑坡-碎屑流的基础数据。通过相关性分析确定沟道型滑坡-碎屑流最大水平运动距离L的影响因素从大到小依次是滑坡体积V、最大垂直运动距离H、滑源区高差Hs、沟道段坡度β。采用逐步回归方法建立了滑坡-碎屑流最大水平运动距离L的最优多元回归模型,检验结果表明模型具有较高精度。将最优多元回归模型与国际上应用较多的滑坡运动距离和泥石流运动距离预测模型进行对比,表明考虑滑坡体积、地形落差和沟道段坡度的运动距离预测指标体系,具有最高的拟合优度和较好的物理含义,可为沟谷山区滑坡-碎屑流危险性评价提供参考依据。 相似文献
14.
Rockfalls that trigger scree‐laden snow avalanches are common in mountain ranges, but the resulting avalanche development and its role in understanding the sedimentology of scree slopes are rarely described in detail. On Riepenwand (2774 m above sea‐level, Kalkkögel range, Alps), on 6 May 2011 a 5800 m3 rockfall of dolostone detached from the flank of a gorge in the upper part of the mountain. After first collapsing into the gorge, the fragmented rock mass fell down freely for 150 m onto a talus covered by coarse‐granular snow. Rockfall impact triggered a medium‐scale avalanche that developed: (i) a lower layer A of entrained, pure snow; and (ii) an upper layer B of clay‐sized to boulder‐sized fragments mixed with snow. This ‘two‐layer scree/snow avalanche’ halted in the distal slope segment of the talus. Boulders within layer B mainly came to rest in the distal part of the avalanche deposit. Fragments smaller than cobble‐size grade did not show obvious downslope segregation. With snowmelt, the rockfall fragments dispersed in layer B were concentrated to a clast‐supported veneer that was draped over the older talus surface upon slower melting of avalanche layer A. In the grain‐size fraction ≤16 mm, a mean of 5 wt% matrix (silt‐sized to clay‐sized grains) of the rockfall‐derived scree of layer B is similar to a mean matrix content of 7 wt% within stratified talus slopes of the Kalkkögel range. This similarity suggests that a major share of matrix – widespread in stratified talus – stems from rockfalls. The characteristics of the scree veneer as melt‐lag of a scree‐laden snow avalanche will be blurred with time. Fossil talus successions may contain a substantial proportion of scree carried down by snow avalanches. The formation of a distinct sedimentary facies of snow avalanche‐deposited scree is impeded by processes of redeposition and deposit modification on talus. 相似文献
15.
雪崩是冰冻圈内主要的自然灾害之一,严重威胁高寒山区内的交通廊道、能源输送和通信干线、矿区、牧区、旅游区等安全并造成基础设施毁坏和人畜死伤,阻碍山区社会经济的可持续发展。随着气候变化和人类活动不断向高寒山区扩展,暴露在雪崩危险之下的人口及基础设施日趋增多,雪崩的风险显著增强。为保障山区的社会经济可持续发展,对雪崩灾害防治管理需求不断增加。在梳理我国1960年以来主要雪崩研究进展基础上,结合世界各地雪崩研究成果,总结了雪崩的影响因素和区域规律、雪崩的形成与运动机理、雪崩监测预警、雪崩风险评估和雪崩工程防治等方面的进展和亟须研究的前沿问题以及科学难点。同时本文论述了气候变化对雪崩活动的影响,以及人类活动与雪崩活动之间的相互影响,展望了未来雪崩防灾减灾的需求并提出对策,推动雪崩防灾减灾研究。 相似文献
16.
Snow avalanches are a major natural hazard in the cryosphere. It seriously threatens transportation corridors, energy transmission and communication lines, mining and touristic areas in the cold mountainous regions and often causes the destruction of infrastructure and human casualties, hindering the sustainable development of society and economy in mountainous areas. Under climate change and the expansion of human activities to alpine mountains, more population and infrastructure will expose to the risk of avalanches. In order to ensure the sustainable development in mountainous areas, the demand for the prevention and management of avalanche disasters is increasing. Based on the review of the main avalanche research progress in China since 1960 and the avalanche research results all over the world, this paper summarized the progress on the influencing factors and regional distribution of avalanche activities, avalanche formation and movement mechanism, avalanche monitoring and early warning, avalanche risk assessment and engineering prevention, as well as the frontier problems and scientific difficulties that need to be studied. In addition, the impact of climate change on avalanche activities and the interaction between human activities and avalanche activities are discussed. By looking forward to the future needs of avalanche disaster prevention and reduction, including the countermeasures, the research on avalanche in China is promoted. © 2022 by the Author(s). 相似文献
17.
Marcia Phillips 《Natural Hazards》2006,39(3):353-379
Snow-supporting avalanche defence structures are increasingly being built at high altitudes in potential permafrost areas.
Special construction methods and guidelines have been developed to ensure a minimal stability of the structures, which have
a vital role in the protection of underlying settlements and transport infrastructure against snow avalanches. If the avalanche
slopes are located on ice-rich permafrost terrain, as is the case in a steep avalanche gully above Pontresina (Eastern Swiss
Alps), other means of protection must be used – such as deflection or retention dams – as construction on ice-rich sediments
can be very problematic. Experimental snow-supporting structures were built in 1997 in order to test different types of structures
and their foundations, to develop specially adapted construction methods and to monitor the long-term behaviour of the structures
in moderately creeping frozen ground with volumetric ice contents under 20%. Snow-nets were found to be the most suitable
type of protection against avalanches in this type of permafrost terrain due to their deformability and because they are well
adapted to rock fall. The structures do not improve slope stability but contribute towards maintaining permafrost as they
delay snow melt by modifying the spatial and temporal distribution of the snow cover. The results of the project described
have led to a better understanding of permafrost-related avalanche defence problems. 相似文献
18.
奎屯河新龙口右岸山体崩塌原因及再次失稳可能性分析 总被引：1，自引：0，他引：1
奎屯河新龙口段山体历史上多次发生山体塌滑破坏,最近一次山体崩塌较为反常地发生在1月寒冷季节,而不是通 常的7、8月雨季,针对该段山体频繁发生破坏而且还出现反季节崩塌这种特殊情况,从区域地质背景、地震作用、地形地貌、气 候及降水等几个方面分别详细论述了产生崩塌的原因,同时指出这次反季节崩塌产生的触发原因在于气候反常造成雪水入 渗、短时间内发生多次冻融,裂隙中液态水结冰产生膨胀力诱发了此次山体崩塌。采用赤平投影分析论证了潜在崩塌的可能 性问题,指出发生此次崩塌后的右岸山体仍然未达到稳定状态,还可能再次发生破坏,同时应用实体比例投影法圈定了最有 可能破坏的山体位置并对崩塌方量进行了计算,从而对山体潜在崩塌可能性及规模有了一定把握,对该段山体崩塌的防治具 有实际的工程意义。 相似文献
19.
东兴区地质灾害数量众多,分布广泛,危害严重,以小型崩塌(危岩)为主。主要分布在区域东北部、西北部窄谷深丘地貌区及中南部人口相对密集地区。即地质灾害中易发区;其发生时间多集中在每年7~9月。地质灾害发育分布受多种因素控制及影响。即地形地貌控制着地质灾害的规模及空间分布;软硬相间的岩性组合易产生差异性风化,引起斜坡失稳;近水平的地质构造可产生大量的斜坡失稳;斜坡结构形式控制着崩塌(危岩)发生的可能性;降雨使岩体受到冲刷及软化并且在岩体内部产生水压力,促进斜坡失稳;人类工程活动导致斜坡原始状态破坏,诱发斜坡失稳。根据地质灾害的发育分布特征及控制和影响因素,建议采取治理与避险搬迁、加强监测以及保护斜坡地质环境等措施减少地质灾害的发生。 相似文献
20.
Nesibe Köse Abdurrahim Aydın Ünal Akkemik Hüseyin Yurtseven Tuncay Güner 《Natural Hazards》2010,54(2):435-449
Many parts of our planet are exposed to natural disasters such as snow avalanches, floods and earthquakes. Detailed knowledge
on these natural disasters is crucial for human safety. On December 25–26, 1992, two avalanches occurred at Kayaarkası-Kastamonu
in northern Turkey. The first avalanche took place at night of 25–26 December and caused no damage. The second avalanche took
place at morning of 26 December, killed four people and did damage to properties. The purpose of the present study is to determine
the effects of the snow avalanches on tree rings and to investigate the boundaries and velocities of the avalanches using
a numerical simulation model and the tree-ring data. Increment cores from 71 trees in the avalanche-impacted area and the
control site were sampled to obtain individual standard chronologies. In the analyses, trees were grouped as (1) heavily damaged
by the avalanche, showing a decrease in tree-ring widths since the event, (2) trees heavily damaged by the avalanche, showing
an increase in tree-ring widths a couple of years later the event and (3) trees that were not damaged by the avalanche. In
this study, one of the most important results is the precise determination of the temporal and spatial patterns of the undocumented
avalanche (the first avalanche) event. Avalanches were numerically simulated using dynamical avalanche simulation software
ELBA+. Comparison of the simulation model with tree-ring analysis revealed valuable results about the boundaries of the zone
of influence of the avalanches. 相似文献