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APPLICATION OF TWO SIMPLIFIED NEWMARK MODELS TO THE ASSESSMENT OF LANDSLIDES TRIGGERED BY THE 2008 WENCHUAN EARTHQUAKE
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At present, with the wide application of the Newmark method, various Newmark empirical formulas with different ground motion parameters have been fitted by many researchers based on global strong-motion records. However, the existing study about the Wenchuan earthquake does not quantitatively evaluate the applicability of different Newmark models based on the actual landslides distribution. The aim of this paper is to present a comparison between observed landslides from the 2008 Wenchuan earthquake and predicted landslides using Newmark displacement method based on different ground motion parameters. The factor-of-safety map and critical acceleration(ac)map in the study area are obtained by using the terrain data and geological data. The distribution of Arias intensity(Ia)and PGA in the study area is obtained by using the attenuation formulas of Arias intensity(Ia)and PGA, which is regressed by Wenchuan ground motion records. Based on the distribution of Arias intensity(Ia)and PGA parameters, we obtained the predicted locations of landslide using Newmark regression equations which are generated using global strong-motion records. The results shows that the assessment results can better reflect the macroscopic distribution characteristics of co-seismic landslides, most predicted landslide cells are distributed on the two sides of the Beichuan-Yingxiu Fault, especially the Pengguan complex rock mass in the hanging wall. The abilities to predict landslide occurrence of the two Newmark simplified models are different. On the whole, the evaluated result of simplified model based on parameter Ia is better than that based on PGA parameter. The GFC values obtained by the Newmark model of Ia and PGA parameters are 65.7% and 34.9%respectively. The evaluated result based on Ia can better reflect the macro distribution of coseismic landslides. The Ls_Pred value based on the Newmark model of parameter Ia is 26.5%, and the Ls_Pred value based on the Newmark model of PGA parameter is 10.3%. However the total area of predicted landslides accounts for 2.4% of the study area, which indicates that the predicted landslide cells are greater than the observed landslide cells. This reminds us that depending on the current input of shear strength and ground-motion parameters, we can only conduct landslide hazard assessment in macro areas, the ability to predict landslide can be improved using more accurate topographic data and input parameters. 相似文献
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以芦山、汶川地震震中为中心,选择了8个井点,对2个地震引起的井水位同震变化进行了比较,重点分析了3口同震变化反向的井点,即重庆的荣昌华江井、北碚柳荫井和四川的泸沽湖井。为使对比研究结果可靠,进一步收集了2011年3月11日日本9.0级地震、2012年4月11日苏门答腊北部海域8.6级地震引起的井水位同震变化资料。对汶川、芦山地震引起的同震体应变的计算结果显示:汶川地震时,荣昌华江井、北碚柳荫井和泸沽湖井水位同震变化与井点位置处的同震体应变一致,即位于同震体应变压缩区的井水位上升,位于体应变膨胀区的井水位下降;芦山地震时,3口井的水位同震变化与同震体应变不一致,表现出与日本、苏门答腊地震时相似的同震变化特征。 相似文献
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STUDY ON THE DISTRIBUTION PATTERN OF EARTHQUAKE- TRIGGERED LANDSLIDES BASED ON SEISMIC LANDSLIDE SUSCEPTIBILITY ANALYSIS: A CASE STUDY OF LANDSLIDES TRIGGERED BY THE MS6.5 LUDIAN EARTHQUAKE IN 2014
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On August 3, 2014, an MW6.5 earthquake occurred in Ludian County, Yunnan Province, which triggered significant landslides and caused serious ground damages and casualties. Compared with the existing events of earthquake-triggered landslides, the spatial distribution of co-seismic landslides during the Ludian earthquake showed a special pattern. The relationship between the co-seismic landslides and the epicenter or the known faults is not obvious, and the maximum landslide density doesn't appear in the area near the epicenter. Peak ground acceleration (PGA), which usually is used to judge the limit boundary of co-seismic landslide distribution, cannot explain this distribution pattern. Instead of correlating geological and topographic factors with the co-seismic landslide distribution pattern, this study focuses on analyzing the influence of seismic landslide susceptibility on the co-seismic distribution. Seismic landslide susceptibility comes from a calculation of critical acceleration values using a simplified Newmark block model analysis and represents slope stability under seismic loading. Both DEM (SRTM 90m)and geological map (1 ︰ 200 ̄ ̄000)are used as inputs to calculate critical acceleration values. Results show that the most susceptible slopes with the smallest critical accelerations are generally concentrated along the banks of rivers. The stable slopes, which have the larger critical accelerations and are comparably stable, are in the places adjacent to the epicenter. Comparison of the distribution of slope stability and the real landslides triggered by the 2014 MW6.1 Ludian earthquake shows a good spatial correlation, meaning seismic landslide susceptibility controls the co-seismic landslide distributions to a certain degree. Moreover, our study provides a plausible explanation on the special distribution pattern of Ludian earthquake triggered landslides. Also the paper discusses the advantages of using the seismic landslide susceptibility as a basic map, which will offer an additional tool that can be used to assist in post-disaster response activities as well as seismic landslides hazards zonation. 相似文献
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我们收集了紫坪铺水库区域台网记录到的2004年8月16日至2008年5月12日汶川地震前发生在震中区及附近区域的486个小震震源机制资料,运用碎裂分析法对这些震源机制数据进行分析,获得了汶川地震前3年多时间内震源区应力水平随时间的演化过程.结果显示,强震发生前震源及附近区域约在2007年6月发生了应力突变,出现了2个应力异常高值区,其形成过程同时伴随着龙门山中央断裂的应力水平降低,最终强震发生在高应力区和低应力区之间的应力梯度带上.汶川地震前应力状态的演化过程,类似于实验研究中出现的非均匀断层失稳前的地震成核现象,符合地震成核的宏观表现.巴颜喀拉块体的南边界-鲜水河断裂的短基线测量也显示出,在同一时间段鲜水河断裂南段由左旋滑动转为异常的右旋错动,反映了汶川强震前整个巴颜喀拉块体有向东加速运动的异常过程. 相似文献
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汶川M_S 8.0特大地震破坏特征初步研究 总被引:9,自引:0,他引:9
2008年5月12日的汶川8.0级特大地震造成了巨大的人员伤亡和经济损失。地震现场考察认为:极震区烈度为Ⅺ度,表现为强烈的带状分布,且破坏很重,地震破坏在垂直于断裂的方向上衰减非常快;Ⅹ度区和Ⅸ度区垂直于断裂的方向上极窄,Ⅹ度区和Ⅸ度区偏小;烈度在断层两侧迅速衰减,但Ⅵ度、Ⅶ度区的影响范围非常大,Ⅵ度区的影响范围约24万km2。垂直于断裂的方向上南部破坏范围在Ⅵ度区远大于北部地区。在不同烈度区均出现了大量的烈度异常点。对各类建(构)筑物、地貌、地形的破坏类型、破坏方式均有了新的认识 相似文献
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A PANORAMA OF LANDSLIDES TRIGGERED BY THE 8 AUGUST 2017 JIUZHAIGOU,SICHUAN MS7.0 EARTHQUAKE
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XU Chong WANG Shi-yuan XU Xi-wei ZHANG He TIAN Ying-ying MA Si-yuan FANG Li-hua LU Ren-qi CHEN Li-chun TAN Xi-bin 《地震地质》2018,40(1):232-260
The MS7.0 Jiuzhaigou earthquake in Sichuan Province of 8 August 2017 triggered a large number of landslides. A comprehensive and objective panorama of these landslides is of great significance for understanding the mechanism, intensity, spatial pattern and law of these coseismic landslides, recovery and reconstruction of earthquake affected area, as well as prevention and mitigation of landslide hazard. In this paper, we use the trinity method of space, sky and earth to create a panorama of the landslides triggered by this event. There are 4 roads in the distribution area of the coseismic landslides. The Jinglinghai-Xiamo and Jiudaoguai-Jiuzhaitiantang road sections register the most serious coseismic landslides. The landslides are mainly of moderate-and small-scales, and also with a few large landslides and avalanches. A detailed visual interpretation of the coseismic landslides is performed in two areas of Wuhuahai(11.84km2) and Zharusi-Shangsizhai village(47.07km2), respectively. The results show the overall intensity of landsliding(1088 landslides, a total area 1.514km2) in the Wuhuahai area is much higher than those in the Zharusi-Shangsizhai village area(528 landslides, a total area 0.415km2). On the basis of a scene of post-earthquake Geoeye -1 satellite images, we delineate more than 4 800 coseismic landslides with a total occupation area 9.6km2. The spatial pattern of these landslides is well related with the locations of the inferred seismogenic fault and aftershocks. Widely distributed earthquake-affected weakened slopes, residual loose materials staying at high-position slopes and in valleys have greater possibilities to fail again and generate new landslides or debris flows under the conditions of strong aftershocks or heavy rainfalls in the future. Geological hazard from these events will become one of the most serious problems in the recovery and reconstruction of the earthquake-affected area which should receive much attention. 相似文献
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宁夏数字强震动台网记录的汶川8.O级地震加速度资料分析 总被引:1,自引:1,他引:0
通过收集整理宁夏强震动监测台网记录的汶川8.0级地震资料,统计分析了各个强震台的地震动峰值加速度记录结果,进一步探讨了宁夏境内地震动加速度衰减规律,并确定了衰减关系,为宁夏的工程抗震设防工作提供可靠依据. 相似文献
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2010年4月14日青海省玉树县发生了MS7.1地震.文中基于现场考察与遥感影像目视解译的方法,对玉树地震滑坡进行分析,并制作了玉树地震滑坡空间分布图.结果表明,该地震触发了约2 036处滑坡灾害,总面积约1.194km2;地震滑坡分布受主地表破裂控制作用强烈;滑坡类型多样,但以崩塌型滑坡为主;滑坡有5种成因机制:人工开挖坡脚型、地表水入渗致坡体震动滑动型、断裂错断震动型、震动型、后期冰雪融化或降雨入渗型;除地震主地表破裂外,还有许多坡体裂缝,主要分布在主地表破裂带SE端的SW盘,该部位在地震中受到了强烈的挤压作用. 相似文献
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XU Chong TIAN Ying-ying SHEN Ling-ling MA Si-yuan XU Xi-wei ZHOU Ben-gang HUANG Xue-qiang MA Jun-xue CHEN Xi 《地震地质》2018,40(5):1115-1128
In this study, a detailed database of landslides triggered by the 25 April 2015 Gorkha (Nepal)MW7.8 earthquake is constructed based on visual interpretation of pre- and post-earthquake high-resolution satellite images and field reconnaissance. Results show the earthquake triggered at least 47 200 landslides, which have a NWW direction spatial distribution, similar with the location and strike of the seismogenic fault. The landslides are of a total area about 110km2 and an oval distribution area about 35 700km2. On the basis of a scale relationship between landslide area (A)and volume (V), V=1.314 7×A1.208 5, the total volume of the coseismic landslides is estimated to be about 9.64×108m3. In the oval landslide distribution area, the landslide number density, area density, and volume density were calculated and the results are 1.32km-2, 0.31%, and 0.027m, respectively. This study provides a detailed and objective inventory of landslides triggered by the Gorkha earthquake, which provides very important and essential basic data for study of mechanics of coseismic landslides, spatial pattern, distribution law, and hazard assessment. In addition, the landslide database related to an individual earthquake also provides an important earthquake case in a subduction zone for studying landslides related to multiple earthquakes from a global perspective. 相似文献
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2014年鲁甸M_S6.5地震震前与同震滑坡空间分布规律对比分析 总被引:3,自引:3,他引:0
2014年8月3日,云南省昭通市鲁甸县发生了MS6.5地震,地震诱发了大量滑坡。文中以牛栏江沿线鲁甸县、巧家县和会泽县交界处面积为44.13km2的区域为研究区,开展地震震前与同震滑坡的空间分布规律对比分析。根据震前Google Earth高分辨率影像与震后0.2m分辨率的超高分辨率航片数据,分别建立了震前滑坡与同震滑坡数据库。结果表明,研究区内震前有284处滑坡,本次地震触发1 053处滑坡。借助10m×10m分辨率的数字高程模型(DEM)数据,基于GIS平台提取研究区的高程、坡度、坡向、曲率、岩性、烈度、河流共7个主要因子,并利用滑坡的面积百分比(Landslide Areas Percentage,LAP)和点密度(Landslide Number Density,LND)对比分析震前与同震滑坡的空间分布规律。结果表明,震前与同震滑坡的易发高程区间分别为1 200m与1 200~1 300m。坡度越大越容易发生滑坡,其中坡度10°的区域由于距离河流很近,也为滑坡易发区。震前与同震滑坡发育的优势坡向都是近S向。当斜坡为凹坡时(曲率值为负值),滑坡易发性较高。地震烈度越大,越易发生同震滑坡。灰岩夹白云质灰岩分布区很容易发生滑坡,玄武岩和火山角砾岩分布区在地震力的作用下边坡的稳定性也大大降低。震前、同震滑坡的发生与到河流的距离大致呈现正相关性。震前滑坡LAP的峰值大多数都与震前已经存在的大型滑坡有密切的对应关系。 相似文献
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2013年芦山地震滑坡空间分布分析——以太平镇东北方向的一个典型矩形区为例 总被引:3,自引:2,他引:1
选择2013年芦山地震中受到强烈地震动的太平镇东北方向一个20kmxl0km的矩形区作为研究区,开展芦山地震滑坡空间分析工作.基于震后野外调查与高分辨率航片人工目视解译法,建立了研究区内地震滑坡空间分布图.结果表明,在研究区内芦山地震至少触发了688处滑坡,区域内滑坡点密度为3.44个/km2.统计了地震滑坡密度与地形因子、地层岩性、地震因子的关系.滑坡最易发高程为1 600~1 800m;滑坡密度大体随着坡度的增加而增加;E与SE方向是地震滑坡的易发坡向与高发坡向;凸坡的地震滑坡易发性最高.二叠系阳新组(Py)的灰岩与白云岩、元古界花岗岩(Pt)是地震滑坡的易发岩性.地震因子与滑坡密度的统计结果表明,大体上PGA值越大,地震烈度越高,地震滑坡越易发生;地震滑坡与距离双石-大川断裂的统计结果表明在双石-大川断裂的出露处地震滑坡密度未发生突变.因子的交互统计结果表明了坡度与PGA这2个因子作用于地震滑坡的独立性. 相似文献
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2013年四川省芦山“4.20”7.0级强烈地震触发滑坡 总被引:5,自引:2,他引:3
2013年4月20日,四川省芦山县发生了MS7.0地震.文中简要介绍了芦山地震的基本情况与芦山地震区历史地震及其相关地震滑坡情况.依据2008年汶川地震滑坡与地震动峰值加速度(PGA)的空间关系,对芦山地震滑坡大体分布范围进行了推测.根据地震滑坡分类学,将芦山地震滑坡分为破坏型滑坡、连贯型滑坡、流滑型滑坡3大类.其中,破坏型滑坡包括岩质崩塌、岩质滑动、岩质崩滑、土质崩塌、土质滑动等5类;连贯型滑坡包括土质坍塌与慢土流2类;流滑型滑坡为快速流滑.破坏型滑坡如岩质崩塌、岩石滑动、土质崩塌这3类是芦山地震滑坡中最常见的类型.基于震后可利用的高分辨率航片,初步解译得到3 883处滑坡位置点数据.最后,从余震对滑坡的影响,芦山地震滑坡与邻区地震滑坡对比分析,对后续基于高分辨率遥感影像的滑坡精细解译的启示等3个方面开展了分析与讨论. 相似文献
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汶川8.0级地震陡坎(北川以北段)探槽的记录特征 总被引:18,自引:4,他引:14
汶川8.0级地震在龙门山中央断裂(北川-映秀断裂)上形成了长度约240km的地震地表破裂带,同时在前山断裂(灌县-江油断裂)上形成了长约72km的地震地表破裂带。我们在中央断裂北段(北川以北)的地震陡坎上开挖探槽,揭露了本次地震的构造变形特征,同时通过对探槽内所揭露地层的相互关系的讨论,以及邻近区域内地貌面的对比,认为该段断裂在本次汶川8.0级地震之前可能还存在一次震级相当的地震事件,其发生时间至少早于该区域内T1阶地形成的最新年龄3000 a 相似文献