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1.
山西壶关太行山大峡谷景区为中国最美十大峡谷之一,但景区落石灾害频发,严重威胁景区安全运营。本文基于高精度地形信息与岩土体强度特性,采用坡度角分布方法开展区域尺度潜在落石源区识别,并引入岩体破坏敏感性指标定量描述潜在落石源区失稳概率。然后,利用经验模型Flow-R模拟落石运动扩散过程,获取落石的传播概率与能量分布情况。最后,提出落石危险性双因子评价模型实现落石危险性定量评估。获得主要结论如下:(1)研究区内潜在落石源区面积为25.7 km2(35.7%),主要以条带状分布于峡谷两侧陡壁。其中岩体破坏高敏感性区为3.3 km2。(2)研究区落石高危险区面积达3.22 km2,主要威胁景区内游客集散地与交通线路,尤其在S327荫林线红豆峡入口处落石危险性最高。(3)野外调查验证结果表明了应用坡度角分布方法识别潜在落石源区的高效性与准确性,提出的双因子评价模型可为峡谷区落石危险性评估提供快速解决方案。本文提出的“区域落石源区识别-源区失稳概率分析-落石危险性评估”的一整套技术方案能够为类似的高山峡谷区落石灾害早期识别及风险防控提供技术参考。 相似文献
2.
Testing a new hybrid approach to seismic hazard assessment: an application to the Calabrian Arc (Southern Italy) 总被引：1，自引：1，他引：0
We tested a new hybrid method for the evaluation of seismic hazard. A recently proposed fault segmentation and earthquake recurrence model of peninsular Italy suggests that the interval for which the local historical catalogue is complete is shorter than the mean recurrence time of individual large faults (1000 years), or at the most comparable. These new findings violate the fundamental assumption of historical probabilistic seismic hazard methods that the historical record is representative of the activity of all the seismogenic sources. The hybrid method we propose uses time-dependent modelling of the major earthquakes and catalogue-based historical probabilistic estimates for all minor events. We assume that the largest earthquakes are characteristic for individual discrete fault segments, model their probability of occurrence by a renewal process and compute the shaking associated with each of them with a simplified procedure. Then we calculate the probability of exceeding a given threshold of peak ground acceleration for specific sites as the aggregate probability of occurrence of large characteristic earthquakes and minor shocks. We apply the method to the Calabrian Arc (Southern Italy) performing the calculations for five major towns. The exposure to seismic hazard of Reggio Calabria, Catanzaro and Vibo Valentia, which locate close to recently activated large faults, decreases with respect to traditional time-independent estimates. On the contrary, an increase of seismic hazard is obtained for Castrovillari, which locates in an area where large faults displaying Holocene activity have been recently recognized but no significant earthquake is reported in the historical catalogue. Cosenza has the highest probability to experience a significant peak ground acceleration with both the new hybrid and the traditional approaches. We wish to stress that the present results should be interpreted only in terms of the differences between the new hybrid and the traditional approaches, not for their absolute values, and that they are not intended to be used for updating or modifying the current national seismic zonation. 相似文献
3.
Megan van Veen D. Jean Hutchinson Ryan Kromer Matthew Lato Tom Edwards 《Landslides》2017,14(5):1579-1592
Using change detection and semi-automated identification methods, it is possible to extract detailed rockfall information from terrestrial laser scanning data to build a database of events, which can be used in the development of the frequency-magnitude relationship for a slope. In this study, we have applied these methods to the White Canyon, a hazardous slope that presents rockfall hazards to the CN Rail line in British Columbia, to build a database of rockfalls including their locations, volumes, and block shapes. We identified over 1900 rockfall events during a 15-month period, ranging in volume from 0.01 to 45 m3. The frequency of these events changed throughout the year, with the highest periods of activity occurring over the winter months. We investigated how the sampling interval, or duration between scans, can affect how the rockfalls are identified, and therefore the frequency-magnitude relationship for the slope using datasets with fewer scans. We show that as the duration between scans becomes larger, fewer rockfalls are detected, as multiple events that have occurred in the same location cluster together into a single event. The results of this study can be used to assist the railways in planning the appropriate number and duration between future scans, in order to capture frequency-magnitude data for the slope with a desired level of detail. 相似文献
4.
2010年青海玉树Ms 7.1级大地震引发了一系列次生地质灾害,其中地震落石是除地震滑坡外沿断裂带及其邻侧最常见的现象。对玉树震区落石的调查发现,该区多处存在非常典型的多期地震落石分布现象,指示该区地震落石的发育与其他古地震现象类似,具有多期性和一定的原地复发性。实地调查表明,该区地震落石分布的主要特征为:多集中发育在活动断裂带附近的陡峭基岩斜坡下方,分布零散,且滚动较远,并常与古地震滑坡相伴生。初步获得的8个地震落石钙膜U系测年结果分布在距今6030±300a BP、4720±210a BP、3530±490~3560±280a BP、2010±160a BP、1090±70a BP、760±20a BP和230±20a BP年龄段,与该区古地震探槽和滑坡反映的地震事件比较吻合,进一步揭示玉树断裂带附近在全新世中晚期发生过多期可导致地表产生地震落石的事件。同时也说明,地震落石及其钙膜测年是特别值得进一步探索的潜在古地震研究方法或途径。 相似文献
5.
Terrestrial laser scanning (TLS) monitoring has been used to estimate the location, volume, and kinematics of a variety of small magnitude rockfalls before failure (1–1000 m3 range), and in some cases, potential failure time has been assessed through the application of inverse velocity methods. However, our current understanding of rock slope pre-failure behavior for this magnitude range and prediction ability is based on observations of a small number of failure case histories. In this study, a pre-failure deformation database was constructed for rockfall volumes exceeding 0.1 m3, observed over a 1252-day study interval at the Goldpan rock slope, British Columbia, Canada, in order to better understand the pre-failure behavior of rock slopes and provide an empirical means of estimating temporal failure ranges. Repeated TLS datasets were acquired at an average scanning interval of 2–3 months. A total of 90 rockfall events were recorded at this site, during this time period, of which 64 (71%) exhibited measurable deformation prior to failure. Classification of rockfalls by volume suggests that a scale dependency may exist, as deformation was detected for a greater proportion of rockfalls >?5 m3 (92%) than for smaller rockfalls in the range of 0.1–0.5 m3 (61%). A lower rate of pre-failure deformation detection was also reported for planar sliding failures as compared with wedge or toppling failures, suggesting that deformation was less easily detected for these failure types. This study proposes and implements a framework for rockfall assessment and forecasting that does not require continuous monitoring of deformation. 相似文献
6.
受环太平洋地震带影响,华北平原地区地震频发,尤其是处于中国首都经济圈的京津冀地区的地震事件备受关注。通过对历史文献资料及地震台网记录中的地震事件统计、分析,重建该地区地震事件历史并获取其潜在的空间分布特征及时间规律,对未来地震事件的早期预警具有重要参考意义。分析结果表明,公元前231年至公元2018年期间京津冀地区发生的1044起地震事件中,以有感地震和中强地震为主,小地震、强烈地震以及大地震发生频次较低。地震记录完整性分析结果表明,除小地震外,其他等级地震记录自公元1400年以来基本完整。在空间分布上,京津冀地区历史地震呈“T”字形分布,沿1条北西—南东走向地震带和1条北东—南西走向地震带分布。在时间上,京津冀地区地震事件呈现出阶段性的变化,在公元1480—1680年间以及1950年以来2个时间段内较为活跃,发生频率较高,频谱分析结果进一步表明地震记录存在45年的复发周期。在月际尺度上,地震事件同样存在季节性差异且多发于夏秋季节,同时地震密集区域在年内呈现出自西向东迁移的现象。最后,根据历史地震事件发生的时间规律,在未来一段时间内京津冀地区仍将处于地震活跃期,存在发生强震的风险。 相似文献
7.
Summary ¶This paper compiles and analyzes the rockfall data in Hong Kong in the last fifty years. A simple rockfall hazard analysis is presented based on this rockfall inventory. A frequency-magnitude relation, which is analogous to the Gutenberg-Richter relation for earthquake occurrence, is proposed for rockfall, and direct correlation between rockfall frequency and the daily rainfall is observed. Data analysis shows that a threshold daily rainfall of about 150–200mm is expected in order to trigger rockfall events in Hong Kong. Among the 368 rockfall events in the 13 year period from 1984 to 1996 in Hong Kong, 35% of the incidents lead to blockage of or damage to roads, 22% lead to damages or evacuation of squatter huts, 21% lead to blockage of pedestrian pavement and footpath, and 15% affect buildings, such as housing apartments and schools. Only 15% of these rockfalls fell onto open space and caused negligible effects on human activities. Most of these rockfall events occurred during heavy rain and when landslide warning should has been issued by the Hong Kong Observatory, thus only 6% of these events led to injury or casualty, car damages, and damages to public utilities. Rockfall hazard zonation maps in terms of the spatial distribution of previous rockfalls are proposed for both Kowloon Peninsula and Hong Kong Island. 相似文献
8.
There exists a transition between rockfalls, large rock mass failures, and rock avalanches. The magnitude and frequency relations (M/F) of the slope failure are increasingly used to assess the hazard level. The management of the rockfall risk requires the knowledge of the frequency of the events but also defining the worst case scenario, which is the one associated to the maximum expected (credible) rockfall event. The analysis of the volume distribution of the historical rockfall events in the slopes of the Solà d’Andorra during the last 50 years shows that they can be fitted to a power law. We argue that the extrapolation of the F-M relations far beyond the historical data is not appropriate in this case. Neither geomorphological evidences of past events nor the size of the potentially unstable rock masses identified in the slope support the occurrence of the large rockfall/rock avalanche volumes predicted by the power law. We have observed that the stability of the slope at the Solà is controlled by the presence of two sets of unfavorably dipping joints (F3, F5) that act as basal sliding planes of the detachable rock masses. The area of the basal sliding planes outcropping at the rockfall scars was measured with a terrestrial laser scanner. The distribution of the areas of the basal planes may be also fitted to a power law that shows a truncation for values bigger than 50 m2 and a maximum exposed surface of 200 m2. The analysis of the geological structure of the rock mass at the Solà d’Andorra makes us conclude that the size of the failures is controlled by the fracture pattern and that the maximum size of the failure is constrained. Two sets of steeply dipping faults (F1 and F7) interrupt the other joint sets and prevent the formation of continuous failure surfaces (F3 and F5). We conclude that due to the structural control, large slope failures in Andorra are not randomly distributed thus confirming the findings in other mountain ranges. 相似文献
9.
Spatio-temporal analysis of rockfall pre-failure deformation using Terrestrial LiDAR 总被引：2，自引：2，他引：0
Manuel Jesús Royán Antonio Abellán Michel Jaboyedoff Joan Manuel Vilaplana Jaume Calvet 《Landslides》2014,11(4):697-709
We present a long-term spatio-temporal analysis of rock slope evolution using a Terrestrial LiDAR aiming to improve our understanding of the link between pre-failure deformation and the spatial prediction of rockfalls. We monitored the pilot study area located at the Puigcercós cliff (Catalonia, Spain) over a period of 1,705 days and detected the deformation of nine different cliff regions together with a high rockfall activity. An exact match was observed between the progressively deformed areas and the regions recently affected by three of the highest magnitude rockfall events, demonstrating a causal relationship between pre-failure deformation and rockfall occurrence. These findings allowed us to make a forward spatial prediction of future failures, hypothesizing a high probability of failure in the six remaining regions. We observed an exponential acceleration of the deformation close to failure, in accordance with tertiary creep theory. However, the temporal analysis of the deformed areas showed a complex and variable behavior, so no exact prediction of the date of failure can yet be made. Our findings have broadened our understanding of the pre-failure behavior of rockfalls and have clear implications for the future implementation of early warning systems. 相似文献
10.
The Kastamonu Castle located on a sandstone hill with Eocene age is one of the most historical and touristic places in Kastamonu city center. The settlement of the city expanded towards the hill of the Kastamonu Castle and adversely affected by rockfalls in the past. The rockfall problems around the castle could be related to jointing, weathering, freezing-thawing and earthquake effects or a combination. In this study, the rockfall hazard at the castle is evaluated by two-dimensional rockfall analyses along 17 profiles selected in different orientations. Different size of rock blocks and various types of movements are taken into consideration in the analyses. Fall-out distance, bounce height, kinetic energy and velocity of the sandstone blocks are separately evaluated. The obtained data are used to define the possible rockfall hazard zones. Finally, the areas having potential rockfall risks are distinguished. Based on the evaluation of the data, rock bolting after removing of unstable blocks and supporting the area with the protective fences are suggested. 相似文献
11.
《Quaternary International》2006,142(1):110-121
The frequency of debris flows and rockfalls was estimated by temporal distribution of these events during the last 50 years. This parameter was expressed by annual probability of occurrence and mean interval of recurrence of historical events. More recurrent events in this sector of the Central Andes are associated with the Guido locality and tunnels situated along International road No. 7. Furthermore, these events are more frequent in Cordillera Frontal where the mean recurrence interval was lower than in Precordillera. The maximum interval of recurrence is rarely greater than 20 years, showing the activity of these events on human lives and infrastructure in this region. The accuracy of the determined recurrence frequency is discussed. A future scenario indicates that landslides will be probably more frequent under global climate change. As a consequence, those most vulnerable elements in the region, the international access routes, may be severely damaged in the future, implying an adverse impact in our regional economy. 相似文献
12.
我国多山,崩塌灾害频繁发生,相应的风险评价也得到了越来越多的关注。由于崩塌发生和运移过程的高度不确定性以及历史数据的不完备,往往很难进行相应的定量风险评价。四川罗家青杠岭的崩塌现场非常典型,而且现场资料较全、历史数据较多并且明确,是开展崩塌风险定量研究的很好实例。通过现场工程地质调查、测绘和统计分析,确定了历史崩塌的物源区、堆积区、最大运移距离、年发生概率以及坡体上的4块典型危岩体A-D。基于历史崩塌堆积区的块石统计特征以及物源区危岩体失稳启动位置的不确定性,利用二维Rockfall模拟软件对所在坡面的恢复系数及摩擦系数进行了反演。在此基础上,对危岩体A-D失稳后的运动特征进行了随机性数值模拟和统计分析,从而确定了崩塌的到达概率。基于崩塌发生概率、到达概率、承灾体时空分布概率和易损性的乘积,作者对罗家青杠岭崩塌进行了定量风险评价。评价结果表明,危岩体A和D的风险值处于不可接受的风险区间,块石B和C的风险值处于警告的风险区间,严重威胁着坡脚附近居民的生命财产安全,有必要采取相应的防灾减灾措施。 相似文献
13.
14.
Understanding rainfall-landslide relationships in man-modified environments: a case-history from Caramanico Terme, Italy 总被引：2，自引：0，他引：2
J. Wasowski 《Environmental Geology》1998,35(2-3):197-209
The expansion of Caramanico Terme in this century has led to the urbanization of marginally stable valley slopes, and this
has coincided with the apparent acceleration of landslide processes. Recent landslides on man-modified slopes were caused,
but not necessarily triggered, by heavy precipitation (antecedent moisture was a more critical factor than the amount of storm
rainfall). Because no important landslides on natural slopes in the same period were reported in the Caramanico area, a clear
distinction must be made between natural settings and those modified by man when determining rainfall thresholds for predictive
purposes. In recently urbanized mountainous environments, the thresholds used to assess landslide hazards should not be weighted
too heavily on old historical records of precipitation and associated mass movements. Instead, more weight ought to be given
to the period following the occurrence of any major anthropogenic and natural (e.g. high-magnitude earthquake) modification
of slope setting.
Received: 19 October 1996 · Accepted: 25 June 1997 相似文献
15.
Michael Hilbe Flavio S. Anselmetti Raymond S. Eilertsen Louise Hansen Walter Wildi 《Swiss Journal of Geoscience》2011,104(3):425-443
Bathymetric data available for Swiss lakes have typically only low to moderate resolution and variable quality, making them
insufficient for detailed underwater geomorphological studies. This article presents results of a new bathymetric survey in
perialpine Lake Lucerne using modern hydrographic equipment. A digital terrain model (DTM) of the lake floor (raster dataset
with 1 m cell size) covering the Chrüztrichter and Vitznau basins documents signatures of major Holocene mass movements and
relics from the glacial history of the lake. Combining the bathymetry data with reflection seismic profiles and an existing
event chronology allows investigating the morphology in its geological context. Subaqueous sediment slide scars with sharp
headwalls cover large areas on moderately inclined slopes. The particularly large Weggis slide complex, correlated with an
historical earthquake (ad 1601), features a ~9 km long and 4–7 m high headwall and covers an area of several square kilometers. Large debris cones
of prehistoric rockfalls and the deposits of recent rockfall events imaged on the almost flat basin plain document mass-movement
activity on steep slopes above the lake. Six transverse moraines, visible as subaqueous ridges, as lake-floor lineaments,
or only imaged on reflection seismic profiles, indicate a complex glacial-inherited morphology. As many of the documented
features result from potentially catastrophic events, high-resolution bathymetry can significantly improve natural hazard
assessment for lakeshore communities by extending classical hazard maps to the subaqueous domain. 相似文献
16.
Rockfall susceptibility zoning at a large scale: From geomorphological inventory to preliminary land use planning 总被引：3，自引：0，他引：3
Rockfall, up to several hundreds of cubic meters, is a frequent and rapid landslide which menaces extensive areas in mountainous territories. Rockfall susceptibility zoning map at a large scale (1:5000–1:25 000) can be the first tool for land use planning in order to manage rockfall risk. A methodology allowing to analyze susceptibility in extensive areas with optimum cost/benefit relationship is needed. This work analyzes rockfall susceptibility in an extensive rocky mountain of the Principality of Andorra (Pyrenees Mountains), first on the rock slope and then on the exposed area located below. The rockfall record, obtained by means of geomorphological analysis, supplies the main data to analyze the susceptibility on the rock slope. An additional historical inventory verifies the accuracy of rockfall sizes recorded by means of the geomorphological analysis. According to the classification recommended by the Guidelines of Joint Technical Committee, the density of rockfall features on the rock slope assesses susceptibility in four levels. Subsequently, susceptibility on exposed areas has been analyzed by means of reach probability of rock blocks analysis using empirical models. Data acquired from thirteen recent events, from 1999 to 2004, have been used to verify the accuracy of the two empirical models mainly used (reach angle and shadow angle). Five reach probability limits (1, 0.5, 0.25, 0.01, and 0) establish boundaries between susceptibility levels. The resulting rockfall susceptibility zoning map allows: (a) to identify land areas and human elements exposed to rockfalls and, (b) to establish several exposition levels. This map can be a useful and cost-effective tool for administrations responsible to manage natural risk in order to guide urban grow in extensive areas or decide upon work programs based on in-depth analysis (hazard and risk). 相似文献
17.
A Review of Studies Dealing with Tree Rings and Rockfall Activity: The Role of Dendrogeomorphology in Natural Hazard Research 总被引：1，自引：0，他引：1
M. Stoffel 《Natural Hazards》2006,39(1):51-70
Over the last few years, rockfall research has increasingly focused on hazard assessment and risk analysis. Input data on
past rockfall activity were gathered from historical archives and lichenometric studies or were obtained through frequency–volume
statistics. However, historical records are generally scarce, and lichenometry may only yield data with relatively low resolutions.
On forested slopes, in contrast, tree-ring analyses may help, generally providing annual data on past rockfall activity over
long periods. It is the purpose of the present literature review to survey the current state of investigations dealing with
tree-ring sequences and rockfall activity, with emphasis on the extent to which dendrogeomorphology may contribute to rockfall
research. Firstly, a brief introduction describes how dendrogeomorphological methods can contribute to natural hazard research.
Secondly, an account is provided of the output of dendrogeomorphological studies investigating frequencies, volumes or spatial
distributions of past rockfall activity. The current and potential strengths of dendrogeomorphology are then presented before,
finally, the weaknesses of tree rings as natural archives of past rockfall activity are discussed and promising directions
for further studies outlined. 相似文献
18.
《Russian Geology and Geophysics》2014,55(9):1065-1073
We present the first results of application of long-term tree-ring chronologies for dating seismically triggered rockfalls and determining the upper age of Holocene rockfalls in southeastern Altai. Based on the results of seismic dendrochronological analysis, dating of penetrating wood injuries is proposed and tested, and the criterion for the distinguishing of seismically triggered rockfalls among slope processes of climatic nature is formulated. An earlier unknown strong earthquake of 1532 has been recognized; its traces are dated by the radiocarbon method. Based on the new data and calibration of earlier radiocarbon dates, the recurrence period of strong earthquakes in the southeastern Altai is refined. 相似文献
19.
在高陡边坡危岩体的调查中,复杂的地形条件经常限制工作的正常开展,如何快速准确地获取地质灾害信息一直是地质灾害调查研究中的难点之一。以往的研究中对无人机遥感技术在黄土、高原等地区应用有所报道,但对西南地区高陡边坡危岩体灾害调查的研究尚无报道。文章以锦屏二级水电站出线场边坡落石灾害所在区域为例,将无人机摄影测量技术应用于高陡边坡危岩体调查中,通过无人机倾斜摄影获取高分辨率遥感影像,开展遥感影像三维建模,进行地质灾害遥感解译,总结了无人机遥感系统在高陡边坡危岩体调查的技术流程。通过三维实景模型,精确地分析了落石灾害的空间分布、失稳模式及演化过程,查明了区域内危岩隐患点的分布特征;基于三维点云模型,提取出地质灾害体的属性信息,测得落石方量为11.7 m3,采用最小二乘法进行平面拟合,得到落石两组主控结构面产状为275.4°∠31.2°、103.5°∠63.3°。实践表明,无人机遥感技术在高陡边坡地区落石灾害调查中具有明显的可行性和优越性,可以较好地应用于高陡边坡危岩体调查中。 相似文献
20.
Although earthquakes are thought to be one of the factors responsible for the occurrence of landslides in Hokkaido, there
exist no enough records which can allow correlating many of the old slope failures in the island with earthquakes. In the
absence of these records, an attempt was done in this study to use the abundance, frequency, magnitude, depth, and distribution
of historical earthquakes to deduce that many of the slope failures in the region were triggered by strong and continuous
seismicity. The determination of the zones of influences of selected earthquakes using an existing empirical function has
also supported this conclusion. Moreover, the use of a 10% probability of exceedance of earthquake intensity in 50 years,
and the geological and slope maps has allowed preparing a landslide hazard map which explains the role of future earthquakes
in the formation of slope failures. The result indicates a high probability of occurrences of landslides in the hilly regions
of the southeastern part of Hokkaido due to expected strong seismicity and earthquake intensities in these areas. On the other
hand, the low level of intensity in the north has given rise to low probability of landslide hazard. There are also places
in the center of the island and high intensity regions in the east where the probability of landslide hazard was influenced
by the contribution of the geological and slope maps. 相似文献