2011年日本M_W9.0地震震后形变机制与震源区总体构造特征          下载免费PDF全文

刘泰  付广裕  周新  苏小宁 《地球物理学报》2017,60(9):3406-3417

本文利用较为完备的球体位错理论,结合4.5年的震后位移数据,优化了2011年日本M_W9.0地震震源区岩石圈弹性层厚度与地幔黏滞性因子,更新了该强震断层余滑时空演化过程.首先,基于日本列岛215个均匀分布的GPS连续观测站震前2年与震后4.5年的观测数据,提取了2011年日本M_W9.0地震引起的震后位移时空变化;接着,依据断层余滑衰减相对较快的特点,利用黏弹性球体位错理论对震后3~4.5年的GPS观测数据进行反复拟合,确定2011年日本M_W9.0地震震源区地幔黏滞性系数和岩石圈弹性层厚度的最优解分别为6×10¹⁸ Pa·s和30 km;然后,从震后3年内GPS观测数据中剔除地幔黏滞性松弛效应,获取了断层余滑对应的震后位移场;最后,利用基于球体位错理论的反演算法,反演了2011年日本M_W9.0地震断层余滑的时空演化过程.结果表明,2011年日本M_W9.0地震引起的断层余滑在震后半年内变化显著,震后2年主震区域余滑基本停止,断层的两端存在一定的余滑效应,断层余滑的累计矩震级达到8.59;地震后4年,地幔黏滞性松弛效应对震后位移场的贡献在总体上超过断层余滑的贡献.  相似文献   

STUDY ON DISPLACEMENT OF THE PEAKS OF THE HIMALAYA GENERATED BY THE 2015 NEPAL EARTHQUAKE SEQUENCE          下载免费PDF全文

WAN Yong-ge  JIN Zhi-tong  CUI Hua-wei  HUANG Ji-chao  LI Yao  LI Xiang 《地震地质》2017,39(4):699-711

Based on the rupture models of the 2015 Nepal earthquake sequence and half space homogeneous elastic model, the displacement field near the epicenters is estimated. The horizontal components converge to the epicenters from north and south with maximum value of 871~962mm. The farther the epicenter distance is, the smaller of the horizontal displacement occurred. The displacement on the south side of the epicenters decreases more rapidly than that on the north side as the distance from the epicenter increased. Significant settlement occurred on the north side of the epicenters with maximum of 376~474mm, while large uplift occurred on the epicenters and its south side with maximum value of 626~677mm. Then, the displacement of the peaks of the Himalaya near the epicenters is estimated. The largest displacement occurred at the peak of Shishapangma with 393mm horizontal component and 36mm settlement. Mt. Everest, the world's highest peak, moves 36mm in nearly southward direction with 9mm settlement. The displacements of other peaks of the Himalaya are different with the epicentral distance and azimuth of the 2015 Nepal earthquake sequence.  相似文献   

Improved evaluation of inelastic displacement demands for short‐period masonry structures          下载免费PDF全文

Gabriele Guerrini  Francesco Graziotti  Andrea Penna  Guido Magenes 《地震工程与结构动力学》2017,46(9):1411-1430

This work discusses the simplified estimation of earthquake‐induced nonlinear displacement demands as required by nonlinear static procedures, with particular attention on short‐period masonry structures. The study focuses on systems with fundamental periods between 0.1 and 0.5 s, for which inelastic amplification of the elastic displacement demand is more pronounced; hysteretic force‐displacement relationships characteristic of masonry structures are adopted, because these structures are more commonly found within the considered period range. Referring to the results of nonlinear dynamic analyses of single‐degree‐of‐freedom oscillators, some limitations of the Eurocode 8 and Italian Building Code formulations are first discussed, then an improved equation is calibrated that relates inelastic and elastic displacement demands. Numerical values of the equation parameters are obtained, considering the amount of hysteretic energy dissipation associated with various damage mechanisms observed in masonry structures. Safety factors are also calculated to determine several percentiles of the displacement demand. It is shown that the proposed equation can be extended to more dissipative systems. Finally, the same formulation is adapted to the estimation of seismic displacements when elastic analysis procedures are employed. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

高频GPS和强震仪数据在汶川地震参数快速确定中的初步应用   总被引：2，自引：1，他引：1       下载免费PDF全文

尹昊  单新建  张迎峰  屈春燕  王振杰  刘晓东  张国宏  李彦川 《地球物理学报》2018,61(5):1806-1816

高频GPS可以实时获取地表位移数据,在地震学中有十分重要的现实应用,比如快速获取震中、震级、地震烈度甚至震源破裂过程.本文以汶川地震为例,首先利用近场7个GPS台站数据反演震中位置,由于高频GPS和测震学确认的震相不一致,两种震中结果相距约15.7 km.然后对高频GPS和强震动数据进行了比较分析,我们的统计结果表明,尽管由于工作原理不同,高频GPS数据中的地震动峰值与强震记录相比存在明显差异,但是高频GPS记录的PGA、PGV和PGD同样可以作为计算地震烈度的指标.进而,使用SMBLOC程序对强震记录进行事后的基线偏移校正,得到与实时高频GPS精度相当的地表位移序列.最后,采用移动平均窗口对这些位移数据作平滑,基于最速下降法和OKADA模型,对汶川地震断层破裂的过程进行了回溯性准实时反演.结果表明,汶川地震主断层由西南向东北方向破裂,以14∶28∶04为基准,在震后20 s提供初始震级M_W7.0,震后70 s震级稳定在M_W7.8,但断层仍在破裂,在震后159 s根据位移波形判断事件基本结束.研究表明,实时地表位移数据可以快速准确获取强震震级和破裂方向,从而使得高频GPS将对现有地震预警系统提供很好的补充.  相似文献   

HORIZONTAL MOVEMENT CHARACTERISTICS OF THE ACTIVE SANWEISHAN FAULT AND ITS MECHANISM: CONSTRAINTS ON THE GROWTH OF THE NORTHERN QINGHAI-TIBETAN PLATEAU          下载免费PDF全文

YUN Long  ZHANG Jin  WANG Ju  LING Hui  ZHANG Jing-jia  ZHANG Bei-hang  ZHAO Heng 《地震地质》2019,41(6):1333-1349

The northern margin of the Qinghai-Tibet Plateau is currently the leading edge of uplift and expansion of the plateau. Over the years, a lot of research has been carried out on the deformation and evolution of the northeastern margin of the Qinghai-Tibet Plateau, and many ideas have been put forward, but there are also many disputes. The Altyn Tagh Fault constitutes the northern boundary of the Qinghai-Tibet Plateau, and there are two active faults on the north side of the Altyn Tagh Fault, named Sanweishan Fault with NEE strike and Nanjieshan Fault with EW strike. Especially, studies on the geometric and kinematic parameters of Sanweishan Fault since the Late Quaternary, which is nearly parallel with the Altyn Tagn Fault, are of great significance for understanding the deformation transfer and distribution in the northwestward extension of the Qinghai-Tibet Plateau. Therefore, interpretation of the fault landforms and statistical analysis of the horizontal displacement on the Sanweishan Fault and its newly discovered western extension are carried out in this paper. We believe that the Sanweishan Fault is an important branch of the eastern section of the Altyn Tagh fault zone. It is located at the front edge of the northwestern Qinghai-Tibet Plateau and is a left-lateral strike-slip and thrust active fault. Based on the interpretation of satellite imagery and microgeomorphology field investigation of Sanweishan main fault and its western segments, it's been found that the Sanweishan main fault constitutes the contact boundary between the Sanweishan Mountain and the alluvial fans. In the bedrock interior and on the north side of the Mogao Grottoes, there are also some branch faults distributed nearly parallel to the main fault. The main fault is about 150km long, striking 65°, mainly dipping SE with dip angles from 50° to 70°. The main fault can be divided into three segments in the spatial geometric distribution:the western segment(Xizhuigou-Dongshuigou, I), which is about 35km long, the middle segment(Dongshuigou-Shigongkouzi, Ⅱ), about 65km long, and the east segment(Shigongkouzi-Shuangta, Ⅲ), about 50km long. The above three segments are arranged in the left or right stepovers. In the west of Mingshashan, it's been found that the fault scarps are distributed near Danghe Reservoir and Yangguan Town in the west of Minshashan Mountain, and we thought those scarps are the westward extension of the main Sanweishan Fault. Along the main fault and its western extension, the different levels of water system(including gullies and rills)and ridges have been offset synchronously, forming a series of fault micro-geomorphology. The scale of the offset water system is proportional to the horizontal displacement. The frequency statistical analysis of the horizontal displacement shows that the displacement has obvious grouping characteristics, which are divided into 6 groups, and the corresponding peaks are 3.4m, 6.7m, 11.4m, 15m, 22m and 26m, respectively. Among them, 3.4m represents the coseismic displacement of the latest ancient earthquake event, and the larger displacement peak represents the accumulation of coseismic displacements of multi-paleoearthquake events. This kind of displacement characterized by approximately equal interval increase indicates that the Sanweishan Fault has experienced multiple characteristic earthquakes since the Late Quaternary and has the possibility of occurrence of earthquakes greater than magnitude 7. The distribution of displacement and structural transformation of the end of the fault indicate that Sanweishan Fault is an "Altyn Tagh Fault"in its infancy. The activities of Sanweishan Fault and its accompanying mountain uplift are the result of the transpression of the northern margin of the Qinghai-Tibet Plateau, representing one of the growth patterns of the northern margin of the plateau.  相似文献   

基于同震位移的隧道抗震设计及其工程应用          下载免费PDF全文

黄禄渊  王成虎  杨树新 《地震工程学报》2019,41(1):29-35

首次在隧道抗震设计中考虑地震同震位移场,通过搜集历史地震破裂信息估计工程区地震位错,采用"分裂节点法"获得隧道周边的同震位移场,并联合拟静力隧道抗震设计方法,成功应用于某公路隧道。研究表明:基于同震位移的隧道抗震设计方法能够为我们估算未来可能的地震灾害提供有力的定量分析工具;当地层自振周期和基岩反应谱未知,可以利用同震位移场估算远场剪应变开展隧道拟静力抗震设计;例如对于云南某隧道,如果龙陵—澜沧断裂带发生地震,隧道南北两端强制位移约为6 cm。如果龙陵—瑞丽断裂发生地震,由于强制位移导致隧道南北部分出现反向运动,将会对隧道中部产生剪切作用,且隧道出现明显的横向和垂向差异运动。  相似文献   

再生混凝土的低温抗震性变化对比分析          下载免费PDF全文

关宏洁  王群  田晶 《地震工程学报》2019,41(2):326-331

再生混凝土作为建筑材料在被使用前,需要对其低温抗震性能做出分析。但目前我国是全球新建筑数量最多的国家,再生混凝土成本低、需求量大,建筑方根据对普通混凝土的印象,直接将再生混凝土应用到建筑工程建设中,其中存在低温抗震性能不明确的问题。针对这个问题,提出再生混凝土的低温抗震性变化对比分析,通过再生混凝土的材料配比及实验搭建设计再生混凝土低温抗震结构模型。根据其指标对其低温抗冻性能、加速度变化、损伤指标、刚度稳定性、层位移变化等几个方面进行变化对比分析。对比实验结果表明:再生混凝土当含气量在逐渐降低时,其保温效果降低,强度在降低,抗冻性也在降低,耐久性和稳定性较差,并且在地震后楼层间的位移和加速度变化较大,不能保证楼层的稳定性;位移角无法降低到最小;随着位移和负载地震力不断增加,再生混凝土逐渐产生开裂变化,刚度减小速度较快,刚度退化程度较大,低温抗震性能较差。  相似文献   

建筑结构的屈曲约束支撑对其抗震加固性能的影响          下载免费PDF全文

冯冲冲  朱南海  贺小玲 《地震工程学报》2019,41(2):353-359

当前方法采用伸臂桁架加固建筑结构时,未考虑建筑结构的屈曲约束支撑力的影响,伸臂桁架与建筑结构的连接不牢固,导致其对建筑结构的抗震加固性能较差。故此,深入分析建筑结构的屈曲约束支撑对其抗震加固性能的影响,设计建筑结构抗震加固方案,利用高强螺栓节点经由连接钢板实现屈曲约束支撑与建筑结构的铰接固定。分别从支撑变形同建筑结构层间位移的关系、建筑结构支撑承载力、多遇地震影响下屈曲约束支撑框架的位移验算,以及罕遇地震影响下屈曲约束支撑的弹塑性位移验算方面,分析屈曲约束支撑对建筑结构抗震加固性能影响。经实验分析得出,建筑结构加入屈曲约束支撑后第一扭转周期同第一平动周期的比值降低0.14,X、Y两个方向的砌体墙同建筑结构的刚度比值降低6.9、8.0,最大顶点位移值降低15.4 mm、29.3 mm,抗震加固性能大大提高。  相似文献   

水平地震作用下建筑顶层重力荷载能力研究          下载免费PDF全文

袁慧子  许浒 《地震工程学报》2019,41(3):613-618

地震灾害的发生给人们的生命财产安全带来了极大的威胁,为了保障在地震发生时建筑的安全,需要时刻对试件的荷载、初始刚度、延性系数、建筑模型的竖向位移等信息进行检测,一旦重力荷载高于峰值荷载,建筑安全将不能得到保障。为分析水平地震作用下建筑的顶层重力荷载能力,首先建立用于实验的一榀三层三跨式的房屋建筑模型,检测这种模型处于重力荷载作用情况下的侧向刚度,用来了解在建筑顶层结构在处于水平地震作用情况下重力荷载对其检测刚度的影响程度。然后从模型中选取5个试件,对这些试件的材料属性、实验结果、荷载位移进行分析,再通过实验模型的重力荷载位移曲线确定建筑的峰值荷载为700 kN,即当建筑顶层的峰值荷载超过700 kN时,建筑的安全性将难以保证。  相似文献   

钢筋混凝土框架结构自复位加固研究     

陈盈  盛飞翔  张文学 《震灾防御技术》2019,14(3):574-583

为减小结构震后残余位移,提高框架结构的震后可修复性,本文提出1种自复位耗能加固方法。以一典型框架结构为例,对比传统框架结构和采用自复位耗能装置加固框架结构的地震响应,并研究自复位耗能装置各参数对加固后结构抗震性能的影响。结果表明:采用自复位耗能装置加固框架结构可有效减小残余位移,但有可能增大结构内力响应;结构的残余位移随着弹簧刚度的增大而减小,结构的内力响应也随之增大;预拉力越大,结构内力响应增加越小,在实际工程中应对自复位加固装置的弹簧刚度和预拉力进行优化以获得最优的自复位加固效果。  相似文献