THE RELATIONSHIP BETWEEN REGIONAL SEISMIC ENERGY RELEASE AND RELATIVE MOTION BETWEEN BLOCKS ON BOTH SIDES OF YISHU FAULT ZONE          下载免费PDF全文

ZHU Cheng-lin  GAN Wei-jun  JIA Yuan  LI Jie  YIN Hai-tao  KONG Xiang-yang 《地震地质》2018,40(2):299-309

Following the 11 March 2011 Japan M_W9.0 earthquake, frequent moderate and small events occurred on the Yishu fault zone and its either side. Using continuous GPS data and a sliding block model, this work studies the relationship between the energy release of these shocks and the block relative motion of either side of the Yishu fault zone. The results show that(1)the equivalent magnitude M from released energy and the two blocks' relative motion are well correlated when earthquakes are selected in a retrieval circle(whose center is the midpoint of the Yishu fault zone)with a radius of 250~500km and using a sliding time window of 3~10 months. The best correlation coefficient between M and the two blocks' relative motion is 0.74 and the T test shows a significant linear correlation between them.(2)Spatial distribution of the correlation coefficients shows that the relative motion of the blocks on both sides affects the energy release in the area from the north part of Yishu fault zone to the Jiaodong Peninsula area and southwest Shandong-Henan border area obviously.(3)Since June 2014, the relative motion of the two blocks on both sides of the Yishu fault zone presents a wave of change, which may be an expression of the accumulation of seismic strain energy in the Yishu fault zone and its two sides. The linear relationship between the equivalent magnitude M from released energy and two blocks' relative motion V can be fitted by linear equation M=0.51*V+3.9, showing that strain energy accumulation could be released by the moderate and small earthquakes in a timely manner, which may favorable to delay the seismic risk in the study area. It also shows, on the other hand, that earthquake energy was not released so completely in the study area since the end of 2015 to 2016, which is likely associated with the Changdao earthquake swarm in 2017.  相似文献   

再生空心砌块砌体填充墙-钢管再生混凝土框架骨架曲线模型研究          下载免费PDF全文

孟二从  余亚琳  苏益声  陈宗平 《世界地震工程》2018,34(1):131-137

为研究再生空心砌块砌体填充墙-钢管再生混凝土框架的骨架曲线模型,设计制作了2榀试件并对其进行低周反复加载试验,获取其滞回及骨架曲线。在此基础之上,对试件的骨架曲线模型进行相关的理论分析,建立了再生空心砌块砌体填充墙—钢管再生混凝土框架的四折线骨架曲线模型。研究表明:试件的滞回曲线呈现为饱满的梭形,表现出了良好的抗震耗能性能;通过相关理论分析建立的四折线骨架曲线模型与试验实测骨架曲线吻合良好,可为该类结构在地震作用下的弹塑性地震反应分析提供相关参考。  相似文献   

Semiactive control of rigid blocks under earthquake excitation          下载免费PDF全文

Marica L. Pecorelli  Rosario Ceravolo 《地震工程与结构动力学》2018,47(3):738-756

This paper investigates the usefulness of a semiactive control to reduce the overturning vulnerability of a rigid block on a rigid plane under earthquake excitation. The proposed feedback law is used to set the stiffness of restraints placed at the 2 lower corners of the block. The performance of the semiactive control is numerically validated by subjecting the block to 100 recorded accelerograms. Specific simulations are performed to study the effect of different anchorage design parameters on the utility of the control. Finally, the robustness of the proposed control is addressed with respect to typical issues of the real‐world implementation.  相似文献   

巴颜喀拉块体东北缘GPS应变率空间分布特征及其与2017年九寨沟M_S7.0地震的关系     

李承涛  苏小宁  孟国杰 《地震》2018,38(2):37-50

巴颜喀拉块体东北缘是构造变形和地震活动较强的区域, 2017年九寨沟M_S7.0地震就发生在该区域内。 利用多尺度球面小波方法解算GPS应变率场, 分析巴颜喀拉块体东北缘2009年至2017年的应变率场分布特征, 该方法的优点是可以将GPS应变率场按照不同的空间尺度进行小波分解, 给出不同空间尺度的应变率场。 结果表明在2017年九寨沟地震之前, 震中附近应变积累显著, 虎牙断裂北延断裂的左旋走滑速率为3.0 mm/a, 拉张速率为3.1 mm/a, 表明该条断裂以左旋走滑为主兼有拉张特征, 与九寨沟地震的震源机制解一致。 除九寨沟震中附近外, 在岷县与漳县交界处、 理县和汶川、 青川等地区主应变率、 面应变率、 最大剪应变率也较大, 这可能与2013岷县漳县(M_S6.6)、 2008年汶川(M_S8.0)、 2014年理县(M_S4.8)以及2014青川县(M_S4.8)地震有关。  相似文献   

川滇菱形块体东边界库仑应力演化及强震发生概率估算          下载免费PDF全文

徐晶  邵志刚  刘静  季灵运 《地球物理学报》2019,62(11):4189-4213

本研究基于分层黏弹介质模型,考虑强震或大地震同震位错、震后黏滞松弛及主断层段震间构造应力加载三方面效应,给出1480年以来,川滇菱形块体东边界鲜水河断裂带、安宁河断裂带、则木河断裂带和小江断裂带共20个断层段由三方面效应引起的累积库仑应力变化随时间的演化,分析强震间相互作用和强震发生的应力累积背景,定性分析各断层段的地震危险性.同时,分别采用现今台网地震目录和川滇菱形块体东边界各断层段强震复发间隔两种资料,定量计算2030年各断层段的强震发生概率;并基于摩擦本构理论,将周边强震引起的库仑应力变化量作为应力扰动,修正强震发生概率的计算结果.各断层段累积库仑应力演化的结果表明,鲜水河断裂带中部八美段、色拉哈段及南部磨西段、安宁河断裂带冕宁-西昌段、小江断裂带北部巧家-东川段和南部建水段的累积库仑应力显著增加.修正的强震发生概率计算结果显示,鲜水河断裂带中部八美-色拉哈-康定一带、安宁河断裂带冕宁-西昌段、小江断裂带南部华宁-建水一带强震发生概率较高,地震危险性值得关注.本研究基于库仑应力演化计算定性分析强震危险性的同时,基于摩擦本构律理论,结合地震引起的应力扰动和强震发生背景,定量计算修正的强震发生概率,为川滇菱形块体东边界强震危险地点及中长期发震紧迫程度判定提供方法和依据.  相似文献   

重力与地形数据揭示的巴颜喀拉块体东缘垂向构造应力场   总被引：3，自引：2，他引：1       下载免费PDF全文

佘雅文  付广裕  王灼华  高原 《地球物理学报》2017,60(6):2480-2492

利用基于消去-恢复原理的最小二乘配置方法,对2009-2013年相对重力/GPS联合观测数据与EGM2008模型数据进行融合,更新了巴颜喀拉块体东缘地区的自由空气与布格重力异常场.基于该布格重力异常数据,以CRUST1.0地壳密度模型为初始条件,使用二维多边形棱柱体正演与非线性最小二乘反演方法,获取了巴颜喀拉块体东缘地壳分层密度结构.基于地壳不可压缩和均衡调整原理提出了计算垂向构造应力新方法,并结合上述地壳分层密度结构和地形数据计算了巴颜喀拉块体东缘垂向构造应力分布.结果表明,龙门山断裂带中南段蓄积了较高的正向构造应力(约40 MPa),马尔康周边地区蓄积了较高的负向构造应力(约—30 MPa).对研究区域1970年以来5级(Ms)以上地震进行统计发现,地震多发生在垂向构造应力梯度带上,垂向构造应力为正的地区易触发浅源地震,为负的地区易触发深源地震.在地壳横向变形强烈的区域,垂向构造应力与地震深度的对应关系减弱.  相似文献   

青藏高原东缘地壳上地幔电性结构研究进展   总被引：6，自引：2，他引：4       下载免费PDF全文

王绪本  余年  高嵩  罗威  蔡学林 《地球物理学报》2017,60(6):2350-2370

经过数十年的努力,中国学者针对青藏高原东缘地壳上地幔探测,累积完成超过20000 km的大地电磁测深剖面,取得了一系列重要科学数据和认识,为青藏高原东缘构造格局、地壳上地幔电性结构、地震机制和动力学研究奠定了基础.根据青藏高原东缘的主要构造和断裂分布特征,本文重点对龙门山构造带、川滇构造带和三江构造带三个构造带分区进行研究,主要依据大地电磁探测工作成果和壳幔电性结构特征,系统地对青藏高原东缘地壳上地幔电性结构、与扬子西缘接触关系、汶川地震和芦山地震的电性孕震环境及弱物质流通道等几个方面进行了梳理和分析.一是青藏高原东缘地壳表层岩块和物质沿壳内高导层向龙门山造山带仰冲推覆,表现为逆冲推覆特征的薄皮构造;二是高原东部地壳中下部及上地幔顶部向龙门山造山带和上扬子地块西缘岩石圈深部俯冲,呈现刚性的上扬子地块西缘高阻楔形体向西插入柔性青藏块体的楔形构造;三是将汶川地震和芦山地震的震源投影到大地电磁剖面上,发现震源位于剖面下方的高阻块体与低阻体之间靠近高阻体的一侧,龙门山构造带岩石圈表现出高阻、高密度和高速的"三高"特征,这种非均匀电性结构可能构成地震孕育发生条件;四是川滇和三江地区的多条大地电磁剖面探测结果表明,在青藏高原东缘中下地壳存在下地壳流和局部管道流,大地电磁结果对其空间分布形态、位置及大小进行了较好的刻画.根据研究区壳幔电性结构特征的构造解析和综合实例分析,总结了青藏高原东缘六类壳幔电性结构模型,提出了下一步重点研究领域和目标.总之,青藏高原东缘壳幔电性结构的研究对揭示研究区岩石圈结构和构造格局提供了重要依据,对油气及矿产资源远景评价提供了背景资料,对"Y"型多地震区的构造关系和发震机理研究具有重要指导意义.  相似文献   

软流圈物质运动对鄂尔多斯块体周缘断陷盆地运动特征的影响          下载免费PDF全文

石云  廖欣  张达  刘春平  万飞 《地球物理学报》2017,60(7):2614-2627

研究软流圈物质运动及其对断陷盆地运动特征的影响,是揭示软流圈与岩石圈相互作用,认识华北克拉通破坏的深部动力学过程的基础.本文以鄂尔多斯块体周缘断陷盆地为研究对象,利用数值方法模拟了盆地底部软流圈物质的运动,进而分析了软流圈物质运动对周缘断陷盆地运动特征的影响.研究结果表明:(1)软流圈物质水平运动的区域流向为NWW-SEE向,流速基本一致,局部略有变化.随着深度增加,局部变化特征不再显著;(2)软流圈物质垂向运动存在区域性差异,其中鄂尔多斯体块体北部、西部以及北缘、西缘底部,物质以下沉流为主,尤其西缘下沉流更显著;块体中部、东部以及南缘、西南缘底部,以上升流为主;东缘底部,上升流与下沉流相间分布,以上升流为主.随着深度增加,上述区域性差异特征依然明显;(3)依据热物质的水平拖曳和垂向拉张作用对断陷盆地可能产生的影响,进一步推测,软流圈物质运动有利于北缘盆地的剪切走滑,东缘盆地的伸展拉张,南缘盆地的走滑兼拉张,西缘和西南缘盆地的走滑.  相似文献   

CHARACTERISTICS AND FORMATION MECHANISM OF LARGE ROCK AVALANCHES TRIGGERED BY THE LUDIAN M_S6.5 EARTHQUAKE AT HONGSHIYAN AND GANJIAZHAI          下载免费PDF全文

CHANG Zu-feng  CHANG Hao  YANG Sheng-yong  CHEN Gang  LI Jian-lin 《地震地质》2017,39(5):1030-1047

The 3 August 2014 Ludian, Yunnan M_S6.5 earthquake has spawned more than 1, 000 landslides which are from several tens to several millions and over ten millions of cubic meters in volumes. Among them, the Hongshiya and Ganjiazai landslides are the biggest two with volumes over 1 000×10⁴m³. The Hongshiya and Ganjiazai landslides are two typical landslides, the former belongs to tremendous rock avalanche, and the latter belongs to unconsolidated werthering deposit landslide developed in concave mountain slope. Based on field investigations, causes and formation mechanism of the two landslides are discussed in this study. The neotectonic movement in the area maintains sustainable uplifting violently all the time since Cenozoic. The landform process accompanied with the regional tectonic uplifting is the violent downward erosion along the Jinshajiang River and its tributary, forming landforms of high mountains and canyons, deeply cut valleys, with great height difference. The regional seismo-tectonics situation suggests that:Ludian earthquake region is situated on the southern frontier boundary of Daliangshan secondary active block, and is seismically the strongest active area with one earthquake of magnitude greater than M5.0 occurring every 6 years. Frequent and strong seismicity produces accumulated effects on the ground rock to gradually lower the mechanical strength of slopes and their stability, which is the basis condition to generate large-scale collapse and landslide at Hongshiyan and Ganjiazhai. The occurring of Hongshiyan special large rock avalanche is associated with the large terrain height difference, steep slope, soft interlayer structure and unloading fissures and high-angle joints. The formation mechanism of Hongshiyan rock avalanche may have three stages as follows:Stage 1, when P wave arriving, under the situation of free surface, rocks shake violently, the pre-existent joints(in red)parallel to and normal to the river and unloading cracks are opened and connected. Stage 2, on the basis of the first stage, when S wave arriving, the ground movement aggravates. Joints(in green)along beds develop further, resulting in rock masses intersecting each other. Stage 3, rock masses lose stability, sliding downward, collapsing, and moving over a short distance along the sliding surface to the inside of the valley, blocking the river to form the dammed lake. The special large landslide at Ganjiazhai is a weathering layer landslide occurring in the middle-lower of a large concave slope. Its formation process may have two stages as follows:Firstly, under strong ground shaking and gravity, the ground rock-soil body around moves and assembles to the lower of the central axis of the large concave slope, which suffers the largest earthquake inertia force and firstly yields plastic damage to generate compression-expansion deformation, because of the largest water content and volume-weight within the loose soil of it. Secondly, in view of the steep slope, along with the compression, the plastic deformation area enlarges further in the lower of slope, giving rise to a tensional stress area along the middle of the slope. As soon as the tensional stress exceeds the tensile strength of the weathering layer, a tensional fracture will occur and the landslide rolls away immediately making use of momentum. This two large landslides are the basic typical ones triggered by the M_S6.5 Ludian earthquake, and their causes and mechanism have a certain popular implication for the landslides occurring in this earthquake region.  相似文献   

九寨沟M_S7.0地震对巴颜喀拉块体东北缘活动断裂影响的有限元模拟     

石富强  朱琳  王莹  丁晓光  邱玉荣  石军 《中国地震》2017,33(4):463-470

在详细调研地震地质资料的基础上,构建了巴颜喀拉地块东北缘三维有限元模型。以九寨沟M_S7.0地震同震位错为荷载,模拟计算了九寨沟地震的发生对巴颜喀拉块体东北缘主要活动断裂加卸载效应的影响。模拟结果显示,九寨沟地震的发生对龙日坝断裂、虎牙断裂、青川-平武断裂西段、迭部-白龙江断裂西段和东段、临潭-宕昌断裂东段,以及处于甘青川交界危险区内的东昆仑断裂东段、塔藏断裂西段,处于六盘山南-西秦岭东危险区的西秦岭北缘断裂东段表现为库仑应力加载;对岷江断裂、塔藏断裂东段库仑应力卸载效应显著。  相似文献