共查询到20条相似文献，搜索用时 31 毫秒
1.
On May 12, 2008, at 1428 hours (Beijing time), a catastrophic earthquake, with a magnitude of Ms 8.0, struck the Sichuan Province, China. About 200,000 landslides, as a secondary geological hazard associated with the earthquake, were triggered over a broad area. These landslides were of almost all types such as shallow, disrupted landslides, rock falls, deep-seated landslides, and rock avalanches. Some of these landslides damaged and destroyed large part of some towns, blocked roads, dammed rivers, and caused other serious damages. The purpose of this study is to detect correlations between landslide occurrence and the surface rupture plane, ground shaking conditions (measured by peak ground acceleration, PGA), lithology, slope gradient, slope aspect, topographic position, and distance from drainages by using two indices, landslide area percentage (LAP) and the landslide number density (LND), based on geographic information system (GIS) technology and statistical analysis method in a square region (study area) of Beichuan County, Sichuan Province, China. There were 5,096 landslides related with the earthquake which were delineated by visual interpretation and selected field checking throughout the study area. The total area (horizontal projection) of the 5,096 landslides is about 41.103 km2. The LAP, which is defined as the percentage of the plane area affected by landslides, was 10.276 %, and the LND, means the number of landslides per square kilometers, was 12.74 landslides/km2. Statistical analysis results show that both LAP and LND have a positive correlation with slope gradient and a negative correlation with distance from the surface rupture. However, the correlation between the occurrence of landslides with PGA, topographic position, and distance from drainages are uncertain, or has just a little positive correlation. The correlation between landslide and slope aspect also shows the effect of the directivity of the seismic wave. The Zbq formation had the most concentrated landslide activity with the LND value of 21.78 landslides/km , 2 and the ∈1 q Gr. geological units had the highest LAP value. Furthermore, weight index (W i) model is performed with a GIS platform to derive landslide hazard index map. The success rate of the model was 71.615 % and, thus, it was valid. In addition, comparison of five landslide controlling parameters’ influence on landslide occurrences was also carried out. 相似文献
2.
Landslides triggered by slipping-fault-generated earthquake on a plateau: an example of the 14 April 2010, Ms 7.1, Yushu, China earthquake 总被引：3，自引：1，他引：2
On 14 April 2010 at 07:49 (Beijing time), a catastrophic earthquake with Ms 7.1 struck Yushu County, Qinghai Province, China. A total of 2,036 landslides were interpreted from aerial photographs and satellite images, verified by selected field checking. These landslides cover about a total area of 1.194 km2. The characteristics and failure mechanisms of these landslides are presented in this paper. The spatial distribution of the landslides is evidently strongly controlled by the locations of the main co-seismic surface fault ruptures. The landslides commonly occurred close together. Most of the landslides are small; there were only 275 individual landslide (13.5 % of the total number) surface areas larger than 1,000 m2. The landslides are of various types. They are mainly shallow, disrupted landslides, but also include rock falls, deep-seated landslides, liquefaction-induced landslides, and compound landslides. Four types of factors are identified as contributing to failure along with the strong ground shaking: natural excavation of the toes of slopes, which mean erosion of the base of the slope, surface water infiltration into slopes, co-seismic fault slipping at landslide sites, and delayed occurrence of landslides due to snow melt or rainfall infiltration at sites where slopes were weakened by the co-seismic ground shaking. To analyze the spatial distribution of the landslides, the landslide area percentage (LAP) and landslide number density (LND) were compared with peak ground acceleration (PGA), distance from co-seismic main surface fault ruptures, elevation, slope gradient, slope aspect, and lithology. The results show landslide occurrence is strongly controlled by proximity to the main surface fault ruptures, with most landslides occurring within 2.5 km of such ruptures. There is no evident correlation between landslide occurrences and PGA. Both LAP and LND have strongly positive correlations with slope gradient, and additionally, sites at elevations between 3,800 and 4,000 m are relatively susceptible to landslide occurrence; as are slopes with northeast, east, and southeast slope aspects. Q4 al-pl, N, and T3 kn 1 have more concentrated landslide activity than others. This paper provides a detailed inventory map of landslides triggered by the 2010 Yushu earthquake for future seismic landslide hazard analysis and also provides a study case of characteristics, failure mechanisms, and spatial distribution of landslides triggered by slipping-fault generated earthquake on a plateau. 相似文献
3.
走滑断裂型地震诱发的滑坡在断裂两盘的空间分布差异 总被引：2，自引：0，他引：2
以玉树地震滑坡为实例,选择高程、坡度、坡向、坡位、水系、地层岩性、同震地表破裂、地震动峰值加速度(PGA)8个因子,以地震滑坡面积百分比(LAP)与滑坡点密度(LND)为指标,研究走滑断裂型地震诱发滑坡在断裂两盘的空间分布差异。在分析这些影响因子的断裂两盘的差异的基础上,基于LAP与LND两个指标详细分析断裂两盘每个因子内部级别滑坡发育的情况。结果表明,总体上北盘的滑坡较南盘发育,除了个别因子级别内南北盘滑坡差别较大外,大部分表现为南北盘滑坡分布情况类似。总之,玉树地震滑坡在断裂两盘的空间分布基本类似,只是在某些因子分级内存在一定的差异。 相似文献
4.
2008年汶川地震滑坡详细编目及其空间分布规律分析 总被引：3，自引：0，他引：3
最新研究成果表明, 2008年5月12日汶川MS 8.0级地震触发了超过197000处滑坡。首先,基于GIS与遥感技术构建了汶川地震滑坡的3类编目图,分别为单体滑坡面分布数据、滑坡中心点位置和滑坡后壁点位置。构建方法为基于地震前后高分辨率遥感影像的目视解译方法,区分单体滑坡并圈定其边界,对滑坡后壁进行识别与定点,并开展了部分滑坡的野外验证工作。这些滑坡分布在一个面积大约为110000km2的区域内,滑坡总面积约为1160km2。选择一个面积约为44031km2的区域作为研究区,区内滑坡数量为196007个,滑坡面积为1150.622km2,这是最详细完整的汶川地震滑坡编录成果,也是单次地震事件触发滑坡最多的记录。其次,开展研究区内的地震滑坡空间分布规律的研究。基于滑坡面与滑坡中心点分别构建滑坡空间分布面积密度图与点密度图,结果表明:滑坡多沿着映秀北川断裂分布,多发生在断裂的上盘。滑坡的高密度区位于映秀北川同震地表破裂的南西段(映秀镇与北川县之间)的上盘区域,这一区域恰对应着逆冲分量为主的断裂上盘,表明逆冲断裂对上盘区域发生滑坡的极强烈的控制作用,而该区域正是形变最大的区域,因此说明是地震滑坡发生的强烈控制作用。基于滑坡面密度(LAP)、滑坡中心点密度(LCND)与滑坡后壁点密度(LTND)这3个衡量指标,使用统计分析方法,评价了汶川地震滑坡与地震参数、地质参数、地形参数的关系。结果表明:LAP、LCND与LTND这3个衡量指标与坡度、地震烈度与PGA存在明显的正相关关系; 与距离震中、距离映秀北川同震地表破裂存在负相关关系; 斜坡曲率越接近0,滑坡越不易发生; LAP、LCND与LTND的高值高程区间为1200～3000m; 滑坡发生的优势坡向为E、SE、S方向; 滑坡发育的易发岩性为砂岩与粉砂岩(Z)、花岗岩; 滑坡与坡位的相关关系不太明显。统计结果还表明LCND与LTND两个衡量指标的差异对地震与地质因子不敏感,而对地形因子较敏感。最后将本文的统计结果与以往的汶川地震滑坡空间分布规律统计成果进行了一些对比,对比结果表明,对于某些因子,如高程、岩性、距离震中、距离映秀北川断裂的统计分析结果,采用不完整的滑坡分布数据或点数据,与采用较完整的滑坡分布面数据会有一定的差异,这种差异并未出现在针对坡度与坡向等因子的统计对比结果中。总之,作者认为一个完备、详细的地震滑坡分布面要素编目图是地震滑坡空间分布规律定量分析、危险性定量分析与滑坡控制的地震区地貌演化研究的重要基础,否则,与实际情况相比,得到统计结果会有一定的偏差,本文的研究成果与以往成果的对比结果证明了这一点。 相似文献
5.
Geometric parameters are useful for characterizing earthquake-triggered landslides. This paper presents a detailed statistical analysis on this issue using the landslide inventory of the 2013, Minxian, China Mw 5.9 earthquake. Based on GIS software and a 5-m resolution DEM, geometric parameters of 635 coseismic landslides (with areas larger than 500 m2) were obtained, including height, length, width, reach angle (arc tangent of the height-length ratio), and aspect ratio (length-width ratio). The fitting relationship of height and length from these data is H = 0.6164L + 0.4589, with an average reach angle of 31.65°. The landslide aspect ratios concentrate in the range of 1.4～2.6, with an average of 2.11. According to the plane geometric shapes and aspect ratios, the landslides are classified into four categories: transverse landslide (LA1, L/W ≤ 0.8), isometric landslide (LA2, 0.8 < L/W ≤ 1.2), longitudinal landslide (LA3, 1.2 < L/W ≤ 3), and elongated landslide (LA4, L/W > 3). Statistics of these four types of landslides versus ten classified control factors (elevation, slope angle, slope aspect, curvature, slope position, distance to drainages, lithology, seismic intensity, peak ground acceleration, and distance to seismogenic fault) are used to examine their possible correlations and the landslide-prone areas, which would be helpful to the landslide disaster mitigation in the affected area. 相似文献
6.
Javed Iqbal Tanoli Chen Ningsheng Amar Deep Regmi Li Jun 《Arabian Journal of Geosciences》2017,10(13):277
The 2015 Mw7.8 Gorkha earthquake triggered thousands of landslides of various types scattered over a large area. In the current study, we utilized pre- and post-earthquake high-resolution satellite imagery to compile two landslide inventories before and after earthquake and prepared three landslide susceptibility maps within 404 km2 area using frequency ratio (FR) model. From the study, we could map about 519 landslides including 178 pre-earthquake slides and 341 coseismic slides were identified. This study investigated the relationship between landslide occurrence and landslide causative factors, i.e., slope, aspect, altitude, plan curvature, lithology, land use, distance from streams, distance from road, distance from faults, and peak ground acceleration. The analysis showed that the majority of landslides both pre-earthquake and coseismic occurred at slope >30°, preferably in S, SE, and SW directions and within altitude ranging from 1000 to 1500 m and 1500 to 3500 m. Scatter plots between number of landslides per km?2 (LN) and percentage of landslide area (LA) and causative factors indicate that slope is the most influencing factor followed by lithology and PGA for the landslide formation. Higher landslide susceptibility before earthquake is observed along the road and rivers, whereas landslides after earthquake are triggered at steeper slopes and at higher altitudes. Combined susceptibility map indicates the effect of topography, geology, and land cover in the triggering of landslides in the entire basin. The resultant landslide susceptibility maps are verified through AUC showing success rates of 78, 81, and 77%, respectively. These susceptibility maps are helpful for engineers and planners for future development work in the landslide prone area. 相似文献
7.
2010年1月12日海地MW 7.0级地震触发了大量的滑坡。我们基于GIS与遥感技术构建了3类详细完备的海地地震滑坡编录图,分别为单体滑坡面分布数据,滑坡中心点位置数据与滑坡后壁点位置数据。结果表明海地地震触发了30828处滑坡,这些滑坡大致分布在一个面积为3192.85km2的区域内,滑坡覆盖面积为15.736km2。基于滑坡中心点密度(LCND)、滑坡后壁点密度(LTND)、滑坡面积百分比(LAP)与滑坡剥蚀厚度(LET)这4个衡量指标,使用统计分析方法,分析了海地地震滑坡及其剥蚀厚度与地震参数、地形参数、公路参数的关系。分析结果表明滑坡与坡度、地震动峰值加速度(PGA)存在大致的正相关关系; 与距离恩里基约芭蕉园断裂、距离水系存在大致的负相关关系; 滑坡沿着恩里基约芭蕉园断裂距离的统计结果表明,震中以西距离震中22~26km与8~12km的区域,与震中以东距离震中6~18km的区域是地震滑坡易发区域; 斜坡曲率值越接近0,也就是坡面较平的斜坡越不容易在地震条件下发生滑动; LCND、LTND、LAP与LET高值对应的高程区间为200~1200m; 滑坡发生的优势坡向为E方向; 滑坡的发生与距离震中、距离公路没有太明确的关系。 相似文献
8.
The Ms 8.0 Wenchuan earthquake of May 12, 2008 is one of the most disastrous earthquakes in China. The earthquake triggered tens of thousands of landslides over a broad area, including shallow, disrupted landslides, rock falls, deep-seated landslides, and rock avalanches, some of which buried large sections of some towns and dammed the rivers. The purpose of this study is to investigate correlations between the occurrence of landslides with geologic and geomorphologic conditions, and seismic parameters. Over 56,000 earthquake-triggered landslides, with a total area of 811 km2, are interpreted using aerial photographs and remote sensing images taken following the earthquake. The spatial distribution of these landslides is analyzed statistically using both landslide-point density (LPD), defined as the number of landslides per square kilometer, and landslide-area density (LAD), the percentage of the area affected by landslides, to determine how the occurrence of landslides correlates with distance from the epicenter, distance from the major surface rupture, seismic intensity and peak ground acceleration (PGA), slope angle, slope aspect, elevation, and lithology. It is found that both LAD and LPD have strong positive correlations with slope steepness, distance from the major surface rupture and seismic intensity, and that Pre-Sinian schist, and Cambrian sandstone and siltstone intercalated with slate have the most concentrated landslide activities, followed by the Permian limestone intercalated with shale, and Devonian limestone. Statistical analyses also indicate that the major surface rupture has influence on the spatial distribution of landslides, because LAD and LPD are relatively higher on the hanging wall than on the footwall. However, the correlation between the occurrence of landslides with distance from the epicenter of the earthquake is complicated, rather than a relatively simple negative correlation as found from other reported cases of earthquakes. This is possibly due to complicated rupture processes of the earthquake. 相似文献
9.
Landslide susceptibility evaluation is one of the most important issues in watershed management. After an earthquake, the landslide susceptibility decreases functionally with increases in the distance from the epicenter. Under the same rainfall intensity, landslides are more likely to occur in an area where earthquakes occur more frequently. However, the questions of how much an earthquake should be weighted and how to evaluate the effects of an earthquake still need to be studied. To understand how earthquakes affect rainfall-triggered landslides, the horizontal peak ground acceleration (PGA) data from the Central Weather Bureau Seismic Network is used as the earthquake factor and combined with other factors to determine the weight of earthquakes in landslide susceptibility using logistic regression. The results indicate that the ability of landslide prediction is better when considering the earthquake factor. This study also proved that although there are no co-seismic landslides (after earthquakes) in the study area, the earthquake factor is still required to increase the model accuracy. PGA has been described as a usable factor. In areas with frequent earthquakes and high geological activity, when using historical data to evaluate landslide susceptibility, the earthquake factor should be taken into consideration to prevent errors. 相似文献
10.
Tapas R. Martha Priyom Roy Ritwik Mazumdar K. Babu Govindharaj K. Vinod Kumar 《Landslides》2017,14(2):697-704
High magnitude earthquakes trigger numerous landslides and their occurrences are mainly controlled by terrain parameters. We created an inventory of 15,551 landslides with a total area of 90.2 km2 triggered by the 2015 Mw 7.8 (Gorkha) and Mw 7.3 (Dolakha) earthquakes in Nepal, through interpretation of very high resolution satellite images (e.g. WorldView, Pleiades, Cartosat-1 and 2, Resourcesat-2). Our spatial analysis of landslide occurrences with ground acceleration, slope, lithology and surface defomation indicated ubiquitous control of steep slope on landslides with ground acceleration as the trigger. Spatial distribution of landslides shows increasing frequency away from the Gorkha earthquake epicentre up to 130 km towards east, dropping sharply thereafter, which is an abnormal phenomenon of coseismic landslides. Landslides are laterally concentrated in three zones which matches well with the seismic rupture evolution of Gorkha earthquake, as reported through teleseismic measurements. 相似文献
11.
Xuanmei Fan Gianvito Scaringi Qiang Xu Weiwei Zhan Lanxin Dai Yusheng Li Xiangjun Pei Qin Yang Runqiu Huang 《Landslides》2018,15(5):967-983
On 8th August 2017, a magnitude Ms 7.0 earthquake struck the County of Jiuzhaigou, in Sichuan Province, China. It was the third Ms ≥?7.0 earthquake in the Longmenshan area in the last decade, after the 2008 Ms 8.0 Wenchuan earthquake and the 2013 Ms 7.0 Lushan earthquake. The event did not produce any evident surface rupture but triggered significant mass wasting. Based on a large set of pre- and post-earthquake high-resolution satellite images (SPOT-5, Gaofen-1 and Gaofen-2) as well as on 0.2-m-resolution UAV photographs, a polygon-based interpretation of the coseismic landslides was carried out. In total, 1883 landslides were identified, covering an area of 8.11 km2, with an estimated total volume in the order of 25–30?×?106 m3. The total landslide area was lower than that produced by other earthquakes of similar magnitude with strike-slip motion, possibly because of the limited surface rupture. The spatial distribution of the landslides was correlated statistically to a number of seismic, terrain and geological factors, to evaluate the landslide susceptibility at regional scale and to identify the most typical characteristics of the coseismic failures. The landslides, mainly small-scale rockfalls and rock/debris slides, occurred mostly along two NE-SW-oriented valleys near the epicentre. Comparatively, high landslide density was found at locations where the landform evolves from upper, broad valleys to lower, deep-cut gorges. The spatial distribution of the coseismic landslides did not seem correlated to the location of any known active faults. On the contrary, it revealed that a previously-unknown blind fault segment—which is possibly the north-western extension of the Huya fault—is the plausible seismogenic fault. This finding is consistent with what hypothesised on the basis of field observations and ground displacements. 相似文献
12.
Chong Xu Xiwei Xu Fuchu Dai Zhide Wu Honglin He Feng Shi Xiyan Wu Suning Xu 《Natural Hazards》2013,68(2):883-900
The main purpose of this paper is to present the use of multi-resource remote sensing data, an incomplete landslide inventory, GIS technique and logistic regression model for landslide susceptibility mapping related to the May 12, 2008 Wenchuan earthquake of China. Landslide location polygons were delineated from visual interpretation of aerial photographs, satellite images in high resolutions, and verified by selecting field investigations. Eight factors, including slope angle, slope aspect, elevation, distance from drainages, distance from roads, distance from main faults, seismic intensity and lithology were selected as controlling factors for earthquake-triggered landslide susceptibility mapping. Qualitative susceptibility analyses were carried out using the map overlaying techniques in GIS platform. The validation result showed a success rate of 82.751 % between the susceptibility probability index map and the location of the initial landslide inventory. The predictive rate of 86.930 % was obtained by comparing the additional landslide polygons and the landslide susceptibility probability index map. Both the success rate and the predictive rate show sufficient agreement between the landslide susceptibility map and the existing landslide data, and good predictive power for spatial prediction of the earthquake-triggered landslides. 相似文献
13.
The aim of this study is to establish a detailed and complete inventory of the landslides triggered by the Mj 7.3 (Mw 7.0) Kumamoto, Japan, earthquake sequence of 15 April 2016 (16 April in JST). Based on high-resolution (0.5–2 m) optical satellite images, we delineated 3,467 individual landslides triggered by the earthquake, occupying an area of about 6.9 km2. Then they were validated by aerial photographs with very high-resolution (better than 0.5 m) and oblique field photos. Of them, 3,460 landslides are distributed in an elliptical area about 6000 km2, with a NE-SW directed 120-km-long long axis and a 60-km-long NW-SE trending short axis. Most of the landslides are shallow, disrupted falls and slides, with a few flow-type slides and rock and soil avalanches. The analysis of correlation between the landslides and several control factors shows the areas of elevation 1000–1200 m, stratum of Q3-Hvf, seismic intensity VIII and VIII+, and peak ground acceleration (PGA) 0.4–0.6 g register the highest landslide abundance. This study also discussed the relationship between the spatial pattern of the landslides and the seismotectonic structure featured by a strike-slip fault with a normal component and the volcanism in the study area. 相似文献
14.
Analysis of a spatial distribution of landslides triggered by the 2004 Chuetsu earthquakes of Niigata Prefecture, Japan 总被引：15，自引：1，他引：15
On October 23, 2004, a series of powerful earthquakes with a maximum M
w = 6.6 located near the western coast of northern Honshu struck parts of northern Japan, particularly Niigata Prefecture;
these earthquakes were known as the Chuetsu event. Thousands of landslides, as a secondary geotechnical hazard associated
with these earthquakes, were triggered over a broad area; these landslides were of almost all types. The purpose of this study
was to detect correlations between landslide occurrence with geologic and geomorphologic conditions, slope geometry, and earthquake
parameters using two indexes based on Geographic Information Systems (GIS). In the study area, the landslide–area ratio (LAR),
which is defined as the percentage of the area affected by landslides, was 2.9%, and the landslide concentration (LC), the
number of landslides per square kilometer, was 4.4 landslides/km2, which is much more than other reported cases of seismic activity with the same magnitude. This was possibly due to heavy
rainfall just before the Chuetsu earthquakes. Statistical analyses show that LAR has a positive correlation with slope steepness
and distance from the epicenter, while LC is inversely correlated with distance from the epicenter. The Wanazu Formation had
the most concentrated landslide activity, followed by the Kawaguchi, Ushigakubi, Shiroiwa and Oyama Formations, although the
Wanazu Formation occupied only 4.5% of the total area of geological units. With 8.2% of the area affected by seismic landslides,
the Kawaguchi Formation had the highest LAR. It was followed by the Shiroiwa, Ushigakubi and Wanazu Formations with LAR ranging
from 4.6% to 6.0%. For lots of geological subunits, landslides are more frequent in a range of slope angles between 15° and
40°. The susceptibility to landsliding of each geologic unit was thus evaluated to correlate with slope steepness. It was
also noted that the effects of the earthquakes were made far worse by antecedent rainfall conditions induced by a␣typhoon,
and further research emphasizing the role of antecedent rainfall was discussed. 相似文献
15.
2010年4月14日07时49分(北京时间),青海省玉树县发生了Ms7.1级大地震。作者基于高分辨率遥感影像解译与现场调查验证的方法,圈定了2036处本次地震诱发滑坡。这些滑坡受地震地表破裂控制强烈,规模相对较小,常常密集成片分布。滑坡类型多样,以崩塌型滑坡为主,还包括滑动型、流滑型、碎屑流型、复合型等类型的滑坡。本文基于地理信息系统(GIS)与遥感(RS)技术,应用逻辑回归模型开展玉树地震滑坡危险性评价,并对结果合理性进行检验。应用GIS技术建立玉树地震滑坡灾害及相关滑坡影响因子空间数据库,选择高程、斜坡坡度、斜坡坡向、斜坡曲率、与水系距离、坡位、断裂、地层岩性、归一化植被指数(NDVI)、公路、同震地表破裂、地震动峰值加速度(PGA)共12个因子作为玉树地震滑坡影响因子,在GIS平台下将这些因子专题图层栅格化。应用逻辑回归模型得到每个因子分级的回归系数,然后建立滑坡危险性指数分布图。利用玉树地震滑坡空间分布图对滑坡危险性指数图进行检验,正确率达到83.21%。滑坡危险性分级结果表明,在占研究区总面积4.97%的"很高危险度"的较小范围内,实际发育滑坡数量为766个,占总滑坡面积的比例高达37.62%,表明地震滑坡危险性评价结果良好。不同危险性级别的滑坡点密度统计结果表明,滑坡点密度随着危险性级别的升高而非常迅速的升高。 相似文献
16.
On July 22, 2013, an earthquake of Ms. 6.6 occurred at the junction area of Minxian and Zhangxian counties, Gansu Province, China. This earthquake triggered many landslides of various types, dominated by small-scale soil falls, slides, and topples on loess scarps. There were also a few deep-seated landslides, large-scale soil avalanches, and fissure-developing slopes. In this paper, an inventory of landslides triggered by this event is prepared based on field investigations and visual interpretation of high-resolution satellite images. The spatial distribution of the landslides is then analyzed. The inventory indicates that at least 2330 landslides were triggered by the earthquake. A correlation statistics of the landslides with topographic, geologic, and earthquake factors is performed based on the GIS platform. The results show that the largest number of landslides and the highest landslide density are at 2400 m–2600 m of absolute elevation, and 200 m–300 m of relative elevation, respectively. The landslide density does not always increase with slope gradient as previously suggested. The slopes most prone to landslides are in S, SW, W, and NW directions. Concave slopes register higher landslide density and larger number of landslides than convex slopes. The largest number of landslides occurs on topographic position with middle slopes, whereas the highest landslide density corresponds to valleys and lower slopes. The underlying bedrocks consisting of conglomerate and sandstone of Lower Paleogene (Eb) register both the largest number and area of landslides and the highest landslide number and area density values. Correlations of landslide number and landslide density with perpendicular- and along-strike distance from the epicenter show an obvious spatial intensifying character of the co-seismic landslides. The spatial pattern of the co-seismic landslides is strongly controlled by a branch of the Lintan-Dangchang fault, which indicates the effect of seismogenic fault on co-seismic landslides. In addition, the area affected by landslides related to the earthquake is compared to the relationship of “area affected by landslides vs. earthquake magnitude” constructed based on earthquakes worldwide, and it is shown that the area affected by landslides triggered by the Minxian–Zhangxian earthquake is larger than that of almost all other events with similar magnitudes. 相似文献
17.
The M w 7.8 2015 Gorkha earthquake and its aftershocks significantly impacted the lives and economy of Nepal. The consequences of landslides included fatalities, property losses, blockades of river flow, and damage to infrastructural systems. Co-seismic landslides triggered by this earthquake were significantly widespread and pose a major geodisaster. There were tens of thousands of landslides triggered by the earthquake, majority of which were distributed in between the epicenter of the main shock and the M w 7.3 aftershock. Although 14,670 landslides triggered by this earthquake were identified, only approximately 23% of them were of moderate to large scale with areas greater than 100 m2. Of the moderate- to large-scale landslides identified, just over 90% were triggered by the main shock and smaller aftershocks prior to the major (M w 7.3) aftershock, while nearly 10% were triggered by the ground shaking induced by the major aftershock. Moreover, the number of landslides triggered by the 2015 Gorkha earthquake, specifically by the main shock, was slightly more than the expected number of landslides for the recorded maximum peak ground acceleration (PGA) in comparison to the co-seismic landslides triggered by 26 earthquakes. Over 90% of those moderate- to large-scale landslides were concentrated within the estimated fault rupture surface. Majority of these moderate- to large-scale landslides were disrupted failures with over 96% of which were classified as earth falls. However, the majority of small-scale landslides were rock or boulder falls. The most number of moderate- to large-scale landslides were triggered in the slate, shale, siltstone, phyllite, and schist of the Lesser Himalayan formation followed by an equally significant number in both schist, gneiss, etc. of the Higher Himalayan formation and the phyllite, metasandstone, schist, etc. of the Lesser Himalayan formation. The sizes (i.e., areas) of the landslides were lognormally distributed, with a mode area of 322.0 m2. Slope inclinations of the moderate- to large-scale landslides followed a normal distribution with a mean slope inclination of 32.6° and standard deviation of 13.5°. There exists a strong correlation between the number of landslides and the peak ground acceleration within the study area, specific for different geological formations. 相似文献
18.
Tanyaş Hakan Görüm Tolga Fadel Islam Yıldırım Cengiz Lombardo Luigi 《Landslides》2022,19(6):1405-1420
On November 14, 2016, the northeastern South Island of New Zealand was hit by the magnitude Mw 7.8 Kaikōura earthquake, which is characterized by the most complex rupturing mechanism ever recorded. The widespread landslides triggered by the earthquake make this event a great case study to revisit our current knowledge of earthquake-triggered landslides in terms of factors controlling the spatial distribution of landslides and the rapid assessment of geographic areas affected by widespread landsliding. Although the spatial and size distributions of landslides have already been investigated in the literature, a polygon-based co-seismic landslide inventory with landslide size information is still not available as of June 2021. To address this issue and leverage this large landslide event, we mapped 14,233 landslides over a total area of approximately 14,000 km2. We also identified 101 landslide dams and shared them all via an open-access repository. We examined the spatial distribution of co-seismic landslides in relation to lithologic units and seismic and morphometric characteristics. We analyzed the size statistics of these landslides in a comparative manner, by using the five largest co-seismic landslide inventories ever mapped (i.e., Chi-Chi, Denali, Wenchuan, Haiti, and Gorkha). We compared our inventory with respect to these five ones to answer the question of whether the landslides triggered by the 2016 Kaikōura earthquake are less numerous and/or share size characteristics similar to those of other strong co-seismic landslide events. Our findings show that the spatial distribution of the Kaikōura landslide event is not significantly different from those belonging to other extreme landslide events, but the average landslide size generated by the Kaikōura earthquake is relatively larger compared to some other large earthquakes (i.e., Wenchuan and Gorkha).
相似文献19.
Characteristics of landslides in western Colorado,USA 总被引：1，自引：1，他引：0
Mass movement can be activated by earthquakes, rapid snowmelt, or intense rainstorms in conjunction with gravity. Whereas mass movement plays a major role in the evolution of a hillslope by modifying slope morphology and transporting material from the slope to the valley, it is also a potential natural hazard. Determining the relationships of frequency and magnitude of landslides are fundamental to understanding the role of landslides in the study of landscape evolution, hazard assessment, and determination of the rate of hillslope denudation. We mapped 735 shallow and active landslides in the Paonia to McClure Pass area of western Colorado from aerial photographs and field surveys. The study area covers ～815 km2. The frequency–magnitude relationships of the landslides illustrate the flux of debris by mass movement in the area. The comparison of the probability density of the landslides with the double Pareto curve, defined by power scaling for negative slope (α), power scaling for positive slope (β), and location of rollover (t), shows that α?=?1.1, β?=?1.9, and t?=?1,600 m2 for areas of landslides and α?=?1.15, β?=?1.8, and t?=?1,900 m3 for volumes of landslides. The total area of landslides is 4.8?×?106 m2 and the total volume of the landslides is 1.4?×?107 m3. The areas (A) and the volumes (V) of landslides are related by V?=?0.0254?×?A 1.45. The frequency–magnitude analysis shows that landslides with areas ranging in size from 1,600 to 20,000 m2 are the most hazardous landslides in the study area. These landslides are the most frequent and also do a significant amount of geomorphic work. We also developed a conceptual model of hillslope development to upland plateau driven by river incision, shallow landsliding, and deep-seated large landsliding. The gentle slope to flat upland plateau that dominated the Quaternary landscape of the study area was modified to the present steep and rugged topography by the combined action of fluvial incision and glacial processes in response to rock uplift, very-frequent shallow landsliding, and less-frequent deep-seated landsliding. 相似文献
20.
Ching-Ying Tsou Masahiro Chigira Daisuke Higaki Go Sato Hiroshi Yagi Hiroshi P. Sato Akihiko Wakai Vishnu Dangol Shanmukhesh C. Amatya Akiyo Yatagai 《Landslides》2018,15(5):953-965
The devastating Gorkha earthquake (M w 7.8) on April 25, 2015 and its aftershocks triggered numerous landslides across the Lesser and Higher Himalayas of central Nepal. This study aims to characterize these landslides, based on the local topography and geology, and to develop data for landslide hazard zoning. This study focused on a mountainous catchment of the Trishuli River, where a digital elevation model was used to examine hilllslope and river profiles, aerial photos were used to identify 155 coherent landslides, and satellite images were used to map 912 earthquake-induced landslides. The topography of this area is mainly characterized by incised V-shaped inner gorges and steep (> 35°) SW-facing scarp slopes. Although most of the coherent landslides were not reactivated by the earthquakes, the Gogane landslide was affected by the earthquake and partly failed. A majority of the earthquake-induced landslides (91%) were new landslides, while the others were enlarged old landslides. The earthquake-induced landslides occurred mainly on the steep slopes of V-shaped inner gorges and scarp slopes, in gneiss and quartzite strata of the Lesser Himalayas, and they were primarily associated with fractured rock masses. This analysis provides a framework for zoning areas vulnerable to earthquake-induced landslides. 相似文献