Susceptibility assessments of the Wenchuan earthquake-triggered landslides in Longnan using logistic regression

In this study a Wenchuan earthquake-induced landslide susceptibility assessment was carried out in the Longnan area in northwestern China using a GIS-based logistic regression model. This region has frequently been affected by landslides in the past, and was intensively affected by the 5.12 Wenchuan earthquake which received considerable international attention. The data used for this study consist of the landslides triggered by the Wenchuan earthquake and a landslide pre-disposing factor database. Information regarding the landslide causative factors came from additional data sources, such as a digital elevation model (DEM) with a 30 × 30 m² resolution, orthophotos, geological and land-use maps, precipitation records, and information on peak ground acceleration data from the 2008 earthquake. The statistical analysis of the relationship between the Wenchuan earthquake-triggered landslides and pre-disposing factors showed the great influence of lithological and topographical conditions on slope failures. The quality of susceptibility mapping was validated by splitting the study area into training and validation sections. The prediction capability analysis demonstrated that the landslide susceptibility map could be used for land planning as well as emergency planning by local authorities.     

Application of an incomplete landslide inventory, logistic regression model and its validation for landslide susceptibility mapping related to the May 12, 2008 Wenchuan earthquake of China

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.     

实际滑坡是滑坡危险性评价结果合理性检验最好的标准

王涛等基于简化Newmark位移模型的区域地震滑坡危险性快速评估以汶川MS8.0级地震为例一文的地震滑坡危险性快速评价结果与2008年汶川地震触发实际滑坡空间分布的相关性较低。本文试图通过对该文中基础数据、分析处理过程、研究结果的分析与讨论,找出这种相关性较低的原因。结果表明值得针对王涛等文章中的Arias烈度分布数据的准确性、工程地质岩组的划分情况、汶川地震滑坡危险性评价结果的客观性共三个方面开展更深入的分析与研究。本文对探索与发掘更客观的地震滑坡危险性评价模型起到了积极的作用。     

同震滑坡发生概率研究——新一代地震滑坡危险性模型

地震滑坡发生真实概率研究基本空白。本研究创新性的利用贝叶斯概率方法与机器模型开展了中国地震滑坡危险性真实概率研究,制作了第一代中国地震滑坡危险性概率图。基于9个地震案例开展研究,包括1999年台湾集集、2005年克什米尔、2008年汶川、2010年玉树、2013年芦山、2013岷县、2014鲁甸、2015尼泊尔、2017九寨沟地震,这9次地震中7次发生在中国,2005年克什米尔与2015尼泊尔地震均发生在中国邻区,可以更好的控制模型预测精度。这些地震事件均有详细完整的,利用面要素标识的地震滑坡数据,包括306 435处真实的地震滑坡记录。考虑到真实的地震滑坡发生区域,滑坡面积规模的差别,滑坡与不滑样本的比例等因素,共选取了5 117 000个模型训练样本。选择绝对高程、相对高差、坡度、坡向、斜坡曲率、坡位、地形湿度指数、土地覆盖类型、植被覆盖度、与断层距离、地层、年均降水量、地震动峰值加速度共13个地震滑坡影响因子。采用贝叶斯概率方法与机器学习模型相结合,建立地震滑坡发生的多因素影响模型,得到各个连续因子的权重与分类因子的各个分类的权重。再将模型应用到整个中国研究区,地震动峰值加速度因子为触发因子。分别考虑研究区在经历不同地震动峰值加速度（0.1~1 g,每0.1 g一个结果,共10个结果）下的地震滑坡发生真实概率。此外,还结合中国地震动峰值加速度分布图,得到了中国地震动峰值加速度背景下的地震滑坡发生真实概率分布。     

Interpretation of earthquake-induced landslides triggered by the 12 May 2008, M7.9 Wenchuan earthquake in the Beichuan area, Sichuan Province, China using satellite imagery and Google Earth

The 12 May 2008 M7.9 Wenchuan earthquake in the People’s Republic of China represented a unique opportunity for the international community to use commonly available GIS (Geographic Information System) tools, like Google Earth (GE), to rapidly evaluate and assess landslide hazards triggered by the destructive earthquake and its aftershocks. In order to map earthquake-triggered landslides, we provide details on the applicability and limitations of publicly available 3-day-post- and pre-earthquake imagery provided by GE from the FORMOSAT-2 (formerly ROCSAT-2; Republic of China Satellite 2). We interpreted landslides on the 8-m-resolution FORMOSAT-2 image by GE; as a result, 257 large landslides were mapped with the highest concentration along the Beichuan fault. An estimated density of 0.3 landslides/km² represents a minimum bound on density given the resolution of available imagery; higher resolution data would have identified more landslides. This is a preliminary study, and further study is needed to understand the landslide characteristics in detail. Although it is best to obtain landslide locations and measurements from satellite imagery having high resolution, it was found that GE is an effective and rapid reconnaissance tool.     

2008年汶川地震滑坡详细编目及其空间分布规律分析

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。     

Characteristics and remediation of a landslide complex triggered by the 2008 Wenchuan, China earthquake-case from Yingxiu near the earthquake epicenter

During the 2008 Wenchuan earthquake, the river valley from Yingxiu to Wenchuan experienced numerous landslides and became a prominent area of landslide complexes. The present large landslide complex near the earthquake epicenter consisted of Laohuzui slide 1, Laohuzui slide 2 and Douyaping slide. The scale, geology, morphology, sliding process, and failure mechanism of the landslide complex are analyzed by means of field investigation, aerial photograph and stereographic projection technique. Characteristics of these three slides including seismic response of slope, landslide debris, damage and potential failure are discussed: the convex slope and the upslope of fractured granitic rock at high altitude are highly prone to landsliding under earthquake; the high source altitude and long travel path determine grain sizes and the deposit angle of the slide debris; the landslide complex completely buries the G213 roadway and dams up the Minjiang River in these sections; after the earthquake, rainfall, aftershocks and river erosion may retrigger new failures, such as retrogressive slide of weathered fractured rock, colluvial landslide, debris flow, embankment failure and rockfall. The following are presented as suggested remedial measures to protect the roadway and stabilize the slope: the removing and trenching, protective concrete/rock blocks against erosion, retaining structure, rockfall stopping wall, rockfall restraining net, rock bolt, and the planting of vegetation.     

基于GIS与ANN模型的地震滑坡易发性区划

基于遥感数据、地理信息系统(GIS)技术和人工神经网络(ANN)模型,开展地震滑坡易发性区划研究.2010年4月14日玉树地震后,基于航片与卫星影像目视解译,并辅以野外调查的方法,在地震区圈定了2036处地震诱发滑坡.选择高程、坡度、坡向、斜坡曲率、坡位、与水系距离、地层岩性、与断裂距离、与公路距离、归一化植被指数(NDVI)、与同震地表破裂距离、地震动峰值加速度(PGA)共12个因子作为地震滑坡易发性评价因子.这些因子均是应用GIS技术与遥感影像处理技术,基于地形数据、地质数据、遥感数据得到.训练样本中的滑动样本有两组,一组是滑坡区整个单滑坡体的质心位置,另一组是滑坡滑源区滑前的坡体高程最高的位置.应用这12个影响因子,分别采用这两组评价样本,基于ANN模型建立地震滑坡易发性索引图,基于GIS工具建立地震滑坡易发性分级图.分别应用训练样本中滑坡分布的点数据去检验各自的结果正确率,正确率分别为81.53％与81.29％,表明ANN模型是一种高效科学的地震滑坡易发性区划模型.     

Estimating potential landslide sites of an upland sub-watershed in Western Ghat’s of Kerala (India) through frequency ratio and GIS

The purpose of this study is to assess the susceptibility of landslides in parts of Western Ghats, Kerala, India, using a geographical information system (GIS). Landslide inventory of the area was made by detailed field surveys and the analysis of the topographical maps. The landslide triggering factors are considered to be slope angle, slope aspect, slope curvature, slope length, distance from drainage, distance from lineaments, lithology, land use and geomorphology. ArcGIS version 8.3 was used to manipulate and analyse all the collected data. Probabilistic-likelihood ratio was used to create a landslide susceptibility map for the study area. The result was validated using the Area under Curve (AUC) method and temporal data of landslide occurrences. The validation results showed satisfactory agreement between the susceptibility map and the existing data on landslide locations. As the result, the success rate of the model was (84.46%) and the prediction rate of the model was (82.38%) shows high prediction accuracy. In the reclassified final landslide susceptibility zone map, 5.68% of the total area is classified as critical in nature. The landslide susceptibility map thus produced can be used to reduce hazards associated with landslides and to land cover planning.     

Landslides triggered by the 1949 Khait earthquake, Tajikistan, and associated loss of life

Earthquake-triggered landslides are a major geological hazard in Central Asia. In July 1949, the M7.4 Khait earthquake triggered many hundreds of landslides in a mountainous region near the southern limit of the Tien Shan Mountains, central Tajikistan. These landslides involved widespread rock-slope failure as well as large numbers of flowslides in loess that mantles the steep slopes of the region. In the Yasman valley hundreds of loess landslides coalesced to form a massive loess flow (est. vol. 245 Mm³) that travelled up to 20 km on a slope of only 2°. In an adjacent valley, the Khait landslide involved transformation of an earthquake-triggered rockslide into a very rapid flow by the entrainment of saturated loess into its movement. It travelled 7.41 km over a vertical distance of 1421 m with an estimated average velocity of ~30 m/s. We estimate its volume as 75 Mm³, an order of magnitude less that previously published estimates. The Khait landslide was simulated using DAN. The number of casualties due to earthquake-triggered landslides in the epicentral region was considerable. Approximately 4000 people were killed in the Yasman valley loess flow as 20 villages (kishlaks) were overwhelmed. In the Khait landslide alone we estimate ca. 800 people lost their lives when the villages of Khait and Khisorak were overrun by rapidly moving debris. Our data indicates that a total of approximately 7200 people were killed by earthquake-triggered landslides in the epicentral region of the Khait earthquake and that, in terms of loss of life, the 1949 Yasman valley loess flow was one of the most destructive landslides in recent history.     

Vertical acceleration effect on landsides triggered by the Wenchuan earthquake,China

The 2008 Wenchuan earthquake with Ms8.0 triggered extensive throwing-pattern landslides in the area within or near the seismic faults. The resultant landslides from this earthquake brought to the fore the effect of vertical earthquake acceleration on landslide occurrence. The pseudostatic analysis and the dynamic response on landslide stability due to the Wenchuan earthquake are studied with the Chengxi (West Town) catastrophic landslide used as a case study. The results show that the epicenter distance is an important factor which affects the vertical acceleration and thus the stability of landslide. Also, the vertical acceleration was found to have a significant impact on the FOS of landslide if the earthquake magnitude is quite large. Within the seismic fault, the amplitude effect of vertical acceleration is very dominant with the FOS of landslide, for vertical acceleration ranging from positive to negative, having a variation of 25 %. The variation of FOS of landslide for vertical acceleration ranging from positive to negative are 15 and 5 % for landslides near seismic fault and outside seismic fault, respectively. For landslide with a slope angle <45°, the FOS of landslide with both horizontal and vertical accelerations is significantly greater than the one without vertical acceleration. Further, the results computed from both the pseudostatic method and dynamic analysis reveal that the FOS during the earthquake varied significantly whether vertical acceleration is considered or not. The results from this study explain why lots of throwing-pattern catastrophic landslides occurred within 10 km of the seismic fault in the Wenchuan earthquake.     

汶川、芦山和鲁甸地震滑坡分布规律对比研究

汶川M_S8.0级地震、芦山M_S7.0级地震和鲁甸M_S6.5级地震均引发了大量的滑坡灾害。由于震级差异和地质地形条件的不同,地震滑坡分布情况有较大区别。本文综合已有的研究成果,从地震、地质和地貌3个方面,对比分析了地震滑坡的分布规律。结果表明:（1）3次地震滑坡数量和密度随着PGA和震级的增加而增加。汶川和鲁甸地震随烈度的增加,滑坡数量呈现递增的趋势。但芦山地震在较低烈度区也发育着大量滑坡。（2）断层影响滑坡分布的最大距离随着震级的增加而增加。在最大影响距离0.2倍的范围内,汶川地震分布有80%的滑坡,而其他两次地震仅30%。此外,汶川地震滑坡数量随断层距离呈指数衰减关系。（3）地震滑坡的分布受到地形的强烈影响。Ⅶ度及以上烈度区地形切割深度越大,地震触发的滑坡集中分布区域相对高差越大。同时,滑坡集中发育的坡度会随之增加。切割深度越大,地震滑坡更易发生在地势较陡的山脊或者上坡处,这可能与地形放大效应有关。     

1920年海原8.5级地震高烈度区滑坡编录与分布规律

发生在黄土高原的1920年12月16日的海原M_S8.5级大地震触发了大量的滑坡,这些滑坡直接造成了大量的人员伤亡。近年来,出现了一些关于本次地震触发滑坡的专题研究,然而,这些研究多是基于局部震区或者个别单体滑坡进行,极少有关于该地震触发滑坡详细全面的成果出现。这种情况已经成为了深入理解海原地震触发滑坡的规模与程度、发育规律等的障碍。本研究拟基于谷歌地球平台,采用人工目视解译方法,以海原地震高烈度区（Ⅸ~Ⅺ）为研究区,开展地震滑坡解译工作,并分析这些滑坡的分布规律与影响因子之间的关系。结果表明本次地震在Ⅸ~Ⅺ度区内触发了至少5384处滑坡,滑坡总面积为218.78 km2。滑坡密度最高的区域为Ⅸ烈度圈的北西部分。通过分析这些滑坡与地形、地震、地质等因子的关系发现,高程1700~2000 m为滑坡的高发与高易发区间;大多数滑坡集中发育在坡度15°~25°范围内,滑坡密度随着坡度的增加而显著增加;坡位越低,也就是距离河流越近,滑坡密度越大;新生代地层、尤其是第四系黄土覆盖地区是海原地震滑坡发生的主要区域,也是高易发区域。本文为探索黄土地区地震滑坡发育规律、减轻黄土地震滑坡灾害等提供了科学参考。     

An open dataset for landslides triggered by the 2016 Mw 7.8 Kaikōura earthquake,New Zealand

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).

     

Spatial distribution of landslides triggered by the 2008 Ms 8.0 Wenchuan earthquake,China

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.     

汶川大型地震滑坡的类型及启程剧动机理研究

2008年汶川大地震诱发大型地震滑坡300余处,造成了巨大的生命财产损失,研究其发生机理有重要的理论意义和防灾减灾的实用价值.经收集分析已有地震滑坡的研究成果及多次深入现场调查,本文发现众多大型地震滑坡发生时都伴随有区别于汶川主震的地面震动,并将其称为滑坡地面震动,简称滑坡震动.本文在论述滑坡震动依据、成因及特征的基础上,根据滑坡震动力与主震力的组合情况及其对大型地震滑坡的影响不同,将汶川地震滑坡划分为3种类型:主震型地震滑坡,迟震型地震滑坡和同震型地震滑坡.认为主震型地震滑坡在主震结束前滑动,其主导失稳力学因素为主震力和重力,无滑坡震动或可忽略; 同震型地震滑坡亦在主震结束前滑动,但其主导失稳力学因素除主震力和重力外,滑坡震动力起重要作用; 迟震型地震滑坡在主震结束后滑动,主导失稳力学因素为滑坡震动力和重力.认为大型地震滑坡地面震动的发生与活断层导致地震类似,据此提出了滑坡震动加速度的估算方法,并以此为基础分析研究了各类型地震滑坡的启程剧动机理.     

An empirical model for landslide travel distance prediction in Wenchuan earthquake area

Sliding mass of landslides highly endangered the area along travel path, especially landslides with long travel distance. It is necessary to develop an effective prediction model for preliminarily evaluating landslide travel distance so as to improve disaster prevention and relocation. This paper collected 54 landslides with 347–4,170 m travel distance triggered by the 2008 Wenchuan earthquake to discuss the effectiveness of various influential factors on landslide travel distance and obtained an empirical model for its prediction. The results revealed that rock type, sliding source volume, and slope transition angle were the predominant factors on landslide travel distance. The validity of proposed model was verified by the satisfactory agreement between observations and predictions. Therefore, this model might be practically applicable in Wenchuan earthquake area and other similar geomorphological and geological regions.     

国内外地震滑坡研究：现状、问题与展望

地震滑坡一直是地学界关注的研究热点之一,特别是2005年10月8日克什米尔M_s 7.8地震、2008年5月12日汶川M_s 8.0地震、2010年玉树M_s 7.1地震、2014年云南鲁甸M_s 6.5地震、2015年4月25日尼泊尔M_s 8.1地震以及2017年8月8日九寨沟M_s 7.0地震等一系列强震活动,都不同程度地触发了大量地震滑坡,并伴生了许多次生灾害,从而促进地震滑坡研究进入了新的阶段。本文通过总结国内外地震滑坡研究现状,归纳了地震滑坡的特征和分布规律、地震动参数与地震滑坡关系、边坡地质条件与地震滑坡关系、地震滑坡的动力响应特征、地震滑坡预测以及地震滑坡危险性与风险区划等6方面的研究现状,在此基础上进一步提出了未来地震滑坡应关注的主要研究方向和重点。     

Landslide susceptibility analysis using probabilistic likelihood ratio model—a geospatial-based study

The crucial and difficult task in landslide susceptibility analysis is estimating the probability of occurrence of future landslides in a study area under a specific set of geomorphic and topographic conditions. This task is addressed with a data-driven probabilistic model using likelihood ratio or frequency ratio and is applied to assess the occurrence of landslides in the Tevankarai Ar sub-watershed, Kodaikkanal, South India. The landslides in the study area are triggered by heavy rainfall. Landslide-related factors—relief, slope, aspect, plan curvature, profile curvature, land use, soil, and topographic wetness index proximity to roads and proximity to lineaments—are considered for the study. A geospatial database of the related landslide factors is constructed using Arcmap in GIS environment. Landslide inventory of the area is produced by detailed field investigation and analysis of the topographical maps. The results are validated using temporal data of known landslide locations. The area under the curve shows that the accuracy of the model is 85.83%. In the reclassified final landslide susceptibility map, 14.48% of the area is critical in nature, falling under the very high hazard zone, and 67.86% of the total validation dataset landslides fall in this zone. This landslide susceptibility map is a vital tool for town planning, land use, and land cover planning and to reduce risks caused by landslides.     

基于简化 Newmark位移模型的区域地震滑坡危险性快速评估以汶川MS 8.0级地震为例

以汶川MS8.0级地震重灾区的11县市为例,初步提出了基于简化Newmark位移模型的地震滑坡危险性应急快速评估方法。利用汶川地震即时地震动参数、工程地质岩性经验分组及地形坡度数据,借助ArcGIS空间数据建模工具编制了地震滑坡危险性快速评估流程模块。计算了区域浅表层饱和岩土体斜坡的静态安全系数Fs、临界加速度ac,并借此分析了地震滑坡易发性。利用经验式获得了汶川地震Arias强度和区域滑坡位移DN分布,实现了汶川地震重灾区地震滑坡危险性的快速评估,为应急救灾决策提供了参考。通过对比评估结果和震后滑坡调查成果,可知数十处灾难性滑坡绝大部分位于-高危险区的龙门山主中央断裂带两侧约20km地带中,显示了评估方法的可靠性; 同时,分析指出了空间数据精度及更新不足导致局部评估结果欠佳的局限性,并提出了改进建议。