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本文采用有限差分和随机振动合成结合的复合方法,模拟了当礼县—罗家堡断裂发生矩震级Mw7.7级大地震时,在天水盆地产生的宽频带地震动场,分析了在设定地震条件下盆地内的地震动分布特征,为该区黄土地震滑坡分析提供了地震动参数结果。结果显示:(1)有限差分法和随机振动合成法可以很好地互补,得到盆地内地表宽频带地震动;(2)地震在盆地区域产生了强烈地震动,PGA(峰值加速度)介于150~900 gal,离断层较近的区域东南角的PGA最大,随着断层距的增加,PGA逐渐减小。河谷南侧的PGA值相比北侧较大,具备诱发滑坡的强大动力条件;(3)盆地区域PGV(峰值速度)最大为120 cm/s。受第四系覆盖层放大效应和地形放大效应共同影响,水平向地震动在盆地区域东侧和中部具有较大PGV,而西侧PGV相对较小。竖向地震动在盆地区域东侧较弱,而在中部和西侧较强,特别是最西侧陡峭的山坡上,PGV达到了最大值。此外,竖向地震动明显受到覆盖层厚度的影响,譬如在盆地区域南侧的中间部位,也具有较大的PGV。 相似文献
2.
四川汶川Ms 8 级地震触发的典型滑坡的风险指标反演 总被引：2，自引：0，他引：2
2008年汶川大地震触发了数以万计的崩塌和滑坡,特别是沿发震断裂分布一系列大型的高速远程滑坡。为了探索地震诱发大型高速远程滑坡运动速度的反演方法,以汶川大地震典型高速远程滑坡为例,在野外调查和室内分析的基础上,结合前人的研究成果,对沿映秀－北川断裂展布的5个典型滑坡的速度进行了反演和计算。结果表明,5个滑坡的最大速度均大于50m/s,其中大光包滑坡速度最大,其下部滑体的最大速度约为300m/s,上部滑体凌空飞行的初速度高达165.6 m/s。同时,对上述滑坡的视摩擦系数进行了计算,4个滑坡的视摩擦系数介于0.16~0.4之间。这一研究的目的在于为类似地区地震滑坡的速度、最大位移量的预测和风险评估提供基础数据,对于类似地区的防灾减灾具有一定的参考价值。 相似文献
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汶川八级地震滑坡特征分析 总被引：51，自引：8，他引：43
汶川地震诱发的15000多处滑坡明显受地震断裂控制,主要沿龙门山主中央断裂带和后山断裂带展布,沿龙门山主中央断裂带汶川映秀安县高川北川陈家坝平武南坝一线,滑坡面密度大于50%以上,最大可达70%。沿断裂带形成了大量的松动山体,在暴雨期间极易发生滑坡、泥石流灾害,对灾后重建构成严重威胁。据初步调查,汶川地震触发的体积最大的滑坡是位于主中央断裂带上的安县高川大光包滑坡,滑动距离长4500m,滑坡堆积体长2800m,宽1700~2200m,最大厚度达580m,若以平均厚度200m计,体积达11亿m3为我国已发生的单体滑坡之最。与常见滑坡明显不同的是,汶川地震极震区滑坡的滑床往往不具连续完整的滑面,剪出口滑坡特征不明显,呈现明显的尖点突起或边缘突出特征,反映出上部滑体被地震力振动解体,甚至抛掷后与下部滑床边缘发生撞击。以阶型滑坡、凸型滑坡、勺型崩滑、座落型（振胀型）滑坡和巨大滚石5种类型最为典型。根据强震地面运动纪录和大量实例调查表明,在汶川地震极震区,触发滑坡的地震竖向力作用是非常明显的,大量滑坡经历了初始斜坡（风化碎裂岩体）地震抛掷撞击崩裂高速滑流的作用过程。 相似文献
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本文以汶川地震强震区北川县典型研究区为例,利用高分辨率航片、SPOT5卫星图像对北川县典型研究区进行了512地震之后和924降雨之后诱发的滑坡解译,解译结果显示:512地震诱发滑坡1999个,924强降雨诱发滑坡828个,924强降雨导致原有地震滑坡面积扩大的滑坡150个。研究表明:地震和强降雨都是诱发滑坡的动力成因,924强降雨诱发的滑坡面积是512地震诱发滑坡面积的1/4倍,强降雨诱发滑坡的数量增加了41.4%; 强降雨不仅诱发新的滑坡,而且促使原来地震滑坡复活,并扩大其面积,强降雨导致地震诱发的滑坡面积扩大了原面积的68.7%。同时,在遥感解译数据基础之上,开展地震诱发滑坡与降雨诱发滑坡规模对比和控制因子耦合分析及地震与降雨耦合灾害链模式研究,为进一步分析研究地震灾区滑坡的产生、发展趋势、危险性和风险评价等预测预报提供科学依据,也为汶川震区恢复重建中的减灾防灾提供决策参考。 相似文献
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地震滑坡是在地震瞬间诱发的滑坡灾害。本文讨论了汶川地震灾区滑坡风险区划与常规滑坡风险区划的区别,认为地震滑坡风险区划应该在危险度区划中增加与地震相关的指标因子,如滑坡震中距和滑坡断层距。从而反映地震动能量对地震滑坡发育的贡献作用。而易损度区划中是难以体现地震因素作用的,这里采用滑坡密度、人口密度、道路密度、建筑物密度、耕地密度这5个指标进行易损度评价。最后采用权重叠加法进行了汶川地震极震区10个县市(面积26175.77km2)的滑坡风险区划,其中高、较高风险区分别占全区面积的9.03%和14.61%。说明震后灾区依然存在一定的滑坡风险。汶川地震极震区中,北川、青川、都江堰、彭州4地应该成为滑坡风险防御的主要地区。对滑坡风险区划结果进行了实地抽样检验,证明区划结果基本符合汶川极震灾区的情况。由此可见,本文介绍的地震滑坡风险区划方法是可靠的。 相似文献
7.
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。 相似文献
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老鹰岩滑坡成因机制与运动特征研究 总被引：1，自引：0，他引：1
老鹰岩滑坡是汶川地震触发的大型岩质滑坡,滑坡纵长450 m,最大展宽430 m,体积约1 500×104m3。滑坡掩埋了一座中型水电站,造成20余人死亡,巨大的滑体堆积厚达100余米的滑坡坝,形成了汶川震区库容量仅次于唐家山的第二大堰塞湖。强震触发形成老鹰岩滑坡分为三个阶段,即:①后缘震动拉裂阶段。老鹰岩滑坡后缘为一突兀山脊,地形对地震动力放大效应明显,震动拉裂沿长大结构面形成了一个陡峭、粗糙,与重力作用下呈光滑、有一定弧形的后缘拉裂面迥异的边界。②摩擦阻力降低、滑体溃滑阶段。地震动力的持续作用,地震波不断在滑面处发生反射和折射,使得滑面处摩擦阻力迅速降低,进而岩体内"锁固段"剪断,滑体顺层面高速下滑。③滑体高速流动堆积阶段。规模巨大的滑体,冲入姜巴沟,并对沟两侧的山体产生强烈的铲刮,高速碎屑流受到黄洞子沟左侧山体强力阻挡后折返,并震动堆积形成堰塞湖。 相似文献
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平溪村滑坡是汶川地震触发的高速岩质滑坡,面积为3.7×104m2,体积约65×104m3。滑坡距离映秀—北川发震断裂带中的石坎断层不足500m,在强大地震力作用下,滑坡滑动面陡峭、粗糙,与重力作用下呈圆弧、平滑的滑面迥异。地震触发的滑坡可分为三个阶段:①震动拉裂阶段;②摩擦阻力降低、"锁固段"剪断阶段;③滑体溃滑,高速流动堆积阶段。然后结合结构面的力学分析,通过数值模拟对地震作用下的应力变化和震裂机制进行了初步分析。 相似文献
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以穿越汶川震区的成兰铁路龙门山关键段为例, 探索提出了强震扰动背景下重大工程场区多尺度滑坡危险性评估方法。利用信息量模型反演评估了汶川地震诱发的同震滑坡空间分布特征, 以此为前提开展了区域和局地两种空间尺度的滑坡危险性预测评估。在区域廊带尺度上, 分别利用可能最大降雨量预测方法和信息量模型, 进行了日超越概率10%的最大降雨量时空分布预测及其诱发滑坡的危险性评估; 同时, 结合地震危险性区划成果, 开展了50年超越概率10%的基本地震动诱发滑坡的危险性评估。在局地场站尺度上, 利用基于崩塌运动过程模拟的Rockfall Analyst软件, 开展了柿子园大桥周边崩塌运动学特征(Runout)模拟和危险性评估。滑坡和崩塌危险性评估的结果分别为铁路规划选线和场站防护设计提供了不同尺度的地质安全依据。 相似文献
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利用模糊数学方法建立汶川地震滑坡灾害评判标准 总被引：1，自引：0，他引：1
利用汶川地震主震在龙门山震区的强震资料,建立了利用地震动参数估计斜坡位移的Newmark累积位移模型。借助于模糊数学中的隶属函数方法,实现了对模型估计累积位移的隶属度定量计算,进而用以判定滑坡危险性分级。为使计算结果定量化,进一步利用模糊转换方法,将定性的滑坡危险性判定结果转换为定量的概率表达,使滑坡判定结果可以继续应用于其他环节的计算分析。以汶川地震在龙门山震区的滑坡分布为例,对模型的计算结果及其定量转换结果与实际情况进行了分析,表明模型结果与实际情况非常吻合。分析认为,以概率方式可以使滑坡灾害的空间分布描述更为准确,文中的方法使之得以实现。 相似文献
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Cheaib Aya Lacroix Pascal Zerathe Swann Jongmans Denis Ajorlou Najmeh Doin Marie-Pierre Hollingsworth James Abdallah Chadi 《Landslides》2022,19(3):603-619
Landslides are the main secondary effects of earthquakes in mountainous areas. The spatial distribution of these landslides is controlled by the local seismic ground motion and the local slope stability. While gravitational instabilities in arid and semi-arid environments are understudied, we document the landslides triggered by the Sarpol Zahab earthquake (November 12, 2017, Mw7.3, Iran/Iraq border), the largest event ever recorded in the semi-arid Zagros Mountains. An original earthquake-induced landslide inventory was derived, encompassing landslides of various sizes and velocities (from rapid disrupted rockfalls to slow-moving coherent landslides). This inventory confirms the low level of triggered landslides in semi-arid environments. It also displays clear differences in the spatial and volumetric distributions of earthquake-induced landslides, having 386 rockfalls of limited size triggered around the epicenter, and 9 giant (areas of ca. 106 m2) active and ancient deep-seated landslides coseismically accelerated at locations up to 180 km from the epicenter. This unusual distant triggering is discussed and interpreted as an interaction between the earthquake source properties and the local geological conditions, emphasizing the key role of seismic ground motion variability at short spatial scales in triggering landslides. Finally, the study documents the kinematics of slow-moving ancient landslides accelerated by earthquakes, and opens up new perspectives for studying landslide triggering over short (~?1–10 years) and long-time (~?1000–10,000 years) periods.
相似文献13.
Preliminary investigation of some large landslides triggered by the 2008 Wenchuan earthquake, Sichuan Province, China 总被引：14，自引：5，他引：9
Fawu Wang Qiangong Cheng Lynn Highland Masakatsu Miyajima Huabin Wang Changgen Yan 《Landslides》2009,6(1):47-54
The M
s 8.0 Wenchuan earthquake or “Great Sichuan Earthquake” occurred at 14:28 p.m. local time on 12 May 2008 in Sichuan Province, China. Damage by earthquake-induced landslides was an important part of the
total earthquake damage. This report presents preliminary observations on the Hongyan Resort slide located southwest of the
main epicenter, shallow mountain surface failures in Xuankou village of Yingxiu Town, the Jiufengchun slide near Longmenshan
Town, the Hongsong Hydro-power Station slide near Hongbai Town, the Xiaojiaqiao slide in Chaping Town, two landslides in Beichuan
County-town which destroyed a large part of the town, and the Donghekou and Shibangou slides in Qingchuan County which formed
the second biggest landslide lake formed in this earthquake. The influences of seismic, topographic, geologic, and hydro-geologic
conditions are discussed. 相似文献
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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
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基于地震滑坡危险性评估的Newmark累积位移模型,利用震前获取的震区地形数据、区域地质资料,结合地震动近实时获取技术,开展了四川九寨沟M_s7.0级地震诱发滑坡的应急快速评估。地震滑坡位移分析结果表明,同震滑坡活动的中—高强度区分布在断层两侧宽约4 km的带状区域内,整体沿北西方向延伸。其中,极震区的丰雪塘、日则和干海子等城镇驻地及附近道路的滑坡强度相对较高;震前、震后影像对比表明九寨沟地震诱发的滑坡类型以浅表型碎屑流及小规模崩塌为主,且同震碎屑流多是在震前已有碎屑流的基础上进一步活动扩展而来,震后汛期泥石流隐患也不容忽视;通过典型地区滑坡位移分析结果与震前、震后影像对比,表明滑坡位移分析结果能够较好的反映同震滑坡的宏观分布特征,但在场地尺度上吻合程度欠佳,后续将通过提升岩性和地形等数据质量进行改进。研究结果可为灾情研判提供宝贵信息,对提高灾害应急救援效率具有重要意义。 相似文献
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Statistical approach to earthquake-induced landslide susceptibility 总被引：13，自引：0，他引：13
Chyi-Tyi Lee Chien-Cheng Huang Jiin-Fa Lee Kuo-Liang Pan Ming-Lang Lin Jia-Jyun Dong 《Engineering Geology》2008,100(1-2):43-58
Susceptibility analysis for predicting earthquake-induced landslides has most frequently been done using deterministic methods; multivariate statistical methods have not previously been applied. In this study, however, we introduce a statistical methodology that uses the intensity of earthquake shaking as a landslide triggering factor. This methodology is applied in a study of shallow earthquake-induced landslides in central western Taiwan. The results show that we can accurately interpret landslide distribution in the study area and predict the occurrence of landslides in neighboring regions. This susceptibility model is capable of predicting shallow landslides induced during an earthquake scenario with similar range of ground shaking, without requiring the use of geotechnical, groundwater or failure depth data. 相似文献
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土工结构地震滑动位移统计分析 总被引：1，自引：0，他引：1
土工结构在地震荷载下的滑动位移是评估结构安全性能的重要参数。采用一种新型的地震波选择方法,在强震数据库中选择修改地震波,以有效地在结构动力分析中引入不同特征地震波的影响。通过一个简单的土工结构地震滑移模型,系统地分析了结构基本周期和滑动面屈服系数对地震滑移概率及相应滑移距离的影响,并提出了滑动体在不同地震场景和基本周期条件下的滑移概率和累积滑动位移的统计模型,对基于性能的土工结构抗震设计具有重要的参考意义。 相似文献
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Landslide hazards triggered by the 2008 Wenchuan earthquake, Sichuan, China 总被引：35，自引：16，他引：19
The 2008 Wenchuan earthquake (M
s = 8.0; epicenter located at 31.0° N, 103.4° E), with a focal depth of 19.0 km was triggered by the reactivation of the Longmenshan
fault in Wenchuan County, Sichuan Province, China on 12 May 2008. This earthquake directly caused more than 15,000 geohazards
in the form of landslides, rockfalls, and debris flows which resulted in about 20,000 deaths. It also caused more than 10,000
potential geohazard sites, especially for rockfalls, reflecting the susceptibility of high and steep slopes in mountainous
areas affected by the earthquake. Landslide occurrence on mountain ridges and peaks indicated that seismic shaking was amplified
by mountainous topography. Thirty-three of the high-risk landslide lakes with landslide dam heights greater than 10 m were
classified into four levels: extremely high risk, high risk, medium risk, and low risk. The levels were created by comprehensively
analyzing the capacity of landslide lakes, the height of landslide dams, and the composition and structure of materials that
blocked rivers. In the epicenter area which was 300 km long and 10 km wide along the main seismic fault, there were lots of
landslides triggered by the earthquake, and these landslides have a common characteristic of a discontinuous but flat sliding
surface. The failure surfaces can be classified into the following three types based on their overall shape: concave, convex,
and terraced. Field evidences illustrated that the vertical component of ground shaking had a significant effect on both building
collapse and landslide generation. The ground motion records show that the vertical acceleration is greater than the horizontal,
and the acceleration must be larger than 1.0 g in some parts along the main seismic fault. Two landslides are discussed as
high speed and long runout cases. One is the Chengxi landslide in Beichuan County, and the other is the Donghekou landslide
in Qingchuan County. In each case, the runout process and its impact on people and property were analyzed. The Chengxi landslide
killed 1,600 people and destroyed numerous houses. The Donghekou landslide is a complex landslide–debris flow with a long
runout. The debris flow scoured the bank of the Qingjiang River for a length of 2,400 m and subsequently formed a landslide
dam. This landslide buried seven villages and killed more than 400 people. 相似文献