辽宁兴城地区地球物理探测效果评价     

张黎  刘万崧  张晨曦  赵倩 《世界地质》2015,34(1):194-202

以辽宁兴城实验区为重点,详细分析了重力、磁力、大地电磁测深和地震勘探等不同的物探方法对研究区内地质目标的识别作用。根据重力剖面测量、磁力剖面测量、大地电磁测深以及地震勘探等方法对实验区进行野外勘探工作和详细的数据分析。结果表明,重力异常对于构造单元划分、断裂识别、基底起伏的识别等均能发挥重要的作用;磁异常对于断裂识别、不同磁性岩石单元的识别、岩浆活动的分析等方面均能发挥重要的作用;大地电磁测深,在划分构造单元、确定断裂分布、垂向地层分层方面均能提供重要信息;地震勘探横向上可划分出盆地等构造界限,纵向上可分层。  相似文献   

大地震的18.6年周期   总被引：1，自引：0，他引：1       下载免费PDF全文

杜品仁  赵俊猛  高祥林 《地球物理学报》2011,54(9):2256-2262

将全球分为15个研究区,用1900~2009年M_W≥7.0地震目录,统计分析了各区大地震与月球交点运动周期的关系,得出15个研究区中有10个区,大地震存在统计意义上的18.6 a周期:活跃段为12.4 a,平静段为6.2 a;环太平洋地震带北、南、西、东4大区的大地震,不仅有这样的周期,而且其地震活跃段的时间存在一定规律.用第6个18.6 a(1991~2009年)期间的大地震,检验据前5个18.6 a(1900~1990年)地震目录所得18.6 a 周期的稳定性和实用性,发现有这种周期的地区多数的周期性是稳定的.大地震18.6 a周期的可能成因有: (1)18.6 a潮波通过调制日潮和半日潮调制大地震; (2)上地幔内流体的潮汐(地内潮)作用; (3)18.6 a潮波通过影响地球自转变化调制大地震.  相似文献   

南京地区地球物理场与地震构造稳定性   总被引：2，自引：1，他引：1       下载免费PDF全文

熊振  李清河  王良书  周彩霞 《地震学报》2011,33(5):624-636

岩石圈的不均衡状态是地球物理场存在差异的原因,对区域地球物理场进行分析,可以了解岩石圈的不均衡及其构造活动的背景.本文在对南京地区地震地质环境分析的基础上,通过重力异常、地热场、深部速度结构、天然地震层析成像等地球物理资料进行系统分析,研究它们与本区地震构造稳定性的关系;分析研究地震活动,从现今地壳运动速度场与地壳形变...  相似文献   

中国大陆现代构造应力场与强震活动   总被引：11，自引：0，他引：11  

谢富仁  张红艳  崔效锋  杜义 《国际地震动态》2011,(1):4-12

依据应力性状和力源特征,中国大陆现代构造应力场可划分为四级应力区.它们分别是2个一级应力区、4个二级应力区、5个三级应力区和26个四级应力区.通过分析中国大陆现代构造应力分区与强震活动之问的关系,初步获得以下结论:①构造应力作用强烈和复杂的地区是强震频发的地区;②应力区边界是强震集中发生的地带;③应力方向、应力结构类型...  相似文献   

基于大地形变监测的大震预测问题思考     

王双绪 《国际地震动态》2011,(2):8-13

本文以中国西部大地形变监测与地震预测实践为基础, 简要总结回顾了利用大地形变进行强震预测研究的工作思路、方法和一些进展; 进而结合2001年昆仑山口西8.1级、 2008年四川汶川8.0级特大地震前区域地壳运动变形背景和已有的研究结果, 分析和探讨了基于大地形变监测、 并考虑地震构造的差异性来进一步提高大震预测的有效性...  相似文献   

柱顶层间隔震体系增量动力响应研究          下载免费PDF全文

袁梦醒  陈望  刘彦辉  谭平  金建敏 《地震工程学报》2020,42(4):872-880

针对悬臂柱顶有拉梁和无拉梁层间隔震体系的抗震性能问题,运用增量动力分析(IDA)方法进行弹塑性分析,模拟结构从弹性到弹塑性直至最后倒塌的全过程。通过调幅地震动得到相应的层间位移角及峰值加速度,分别绘制单条与多条IDA曲线分析拉梁对隔震结构动力响应的影响,研究两种结构的抗震性能。结果表明:在相同性能点,有拉梁和无拉梁对纤维铰弯矩值和曲率值基本无影响,而在不同性能点,纤维铰状态明显不同;两种体系从正常使用阶段到防止倒塌阶段所需的加速度峰值的差距慢慢增大;在极罕遇地震下,柱顶有拉梁层间隔震体系的下部结构抗震性能要高于柱顶无拉梁层间隔震体系。  相似文献   

Late Holocene slip rate and average recurrence interval of great earthquakes on the Shangzhi segment of the Yilan‐Yitong Fault Zone,northeastern China: Constraints from paleo‐earthquakes and historical written records          下载免费PDF全文

Zhongyuan Yu  Peizhen Zhang  Wei Min  Qinghai Wei  Yugang Liu 《Island Arc》2018,27(1)

The Yilan‐Yitong Fault Zone (YYFZ) is considered to be the key branch of the Tancheng‐Lujiang Fault Zone (TLFZ) in northeastern China. Although the Mesozoic and early Cenozoic deformation of the YYFZ has been studied intensively over the past century, few estimates of slip rate and recurrence interval of large earthquakes in the late Quaternary, which are the two most important parameters for understanding the potential seismic hazard of this crucial structure, were obtained. Based on integrated interpretations of high resolution satellite images and detailed geologic and geomorphic mapping, linear landforms were identified, including fault scarps and troughs, along the Shangzhi segment of the YYFZ, which exceeds 25 km in length. Synthesized results of trench excavations and differential GPS measurements of terrace surfaces indicate that two events (E1, E2) occurred along the Shangzhi segment during the late Holocene, which resulted in 3.2 ±0.1 m of total vertical co‐seismic displacement with clear features of thrust motion. ¹⁴C dating of samples suggests that event E1 occurred between 440 ±30 years BP and 180 ±30 years BP and that event E2 occurred between 4 090 ±30 years BP and 3 880 ±30 years BP, which indicates that the minimum vertical slip rate of the Shangzhi segment of the YYFZ has been approximately 0.8 ±0.03 mm/year during the late Holocene. Constraints from paleo events and the slip rate suggest that the average recurrence interval of major earthquakes on the YYFZ is 3 800 ±200 years. Historical documents in Korea show that event E1 possibly corresponds to the earthquake that occurred in AD 1810 (the Qing Dynasty in Chinese history) in the Ningguta area, which had surface‐wave magnitude (Ms) of 6.8–7.5. Studies of kinematics show that the right‐lateral strike‐slip with a reverse component has been dominant along the YYFZ during the late Holocene.  相似文献   

Influence of earthquake ground‐motion duration on damage estimation: application to steel moment resisting frames          下载免费PDF全文

Andre R. Barbosa  Filipe L. A. Ribeiro  Luis A. C. Neves 《地震工程与结构动力学》2017,46(1):27-49

This paper presents an analytical study evaluating the influence of ground motion duration on structural damage of 3‐story, 9‐story, and 20‐story SAC steel moment resisting frame buildings designed for downtown Seattle, WA, USA, using pre‐Northridge codes. Two‐dimensional nonlinear finite element models of the buildings are used to estimate the damage induced by the ground motions. A set of 44 ground motions is used to study the combined effect of spectral acceleration and ground motion significant duration on drift and damage measures. In addition, 10 spectrally equivalent short‐duration shallow crustal ground motions and long‐duration subduction zone records are selected to isolate duration effect and assess its effect on the response. For each ground motion pair, incremental dynamic analyses are performed at at least 20 intensity levels and response measures such as peak interstory drift ratio and energy dissipated are tracked. These response measures are combined into two damage metrics that account for the ductility and energy dissipation. Results indicate that the duration of the ground motion influences, above all, the combined damage measures, although some effect on drift‐based response measures is also observed for larger levels of drift. These results indicate that because the current assessment methodologies do not capture the effects of ground motion duration, both performance‐based and code‐based assessment methodologies should be revised to consider damage measures that are sensitive to duration. Copyright © 2016 John Wiley & Sons, Ltd  相似文献   

2014年鲁甸M_S6.5地震前后地震活动性          下载免费PDF全文

侯金欣  王宝善 《地球物理学报》2017,60(4):1446-1456

2014年 8月3日在云南省鲁甸县发生M_S6.5地震，造成了巨大的人员伤亡和财产损失.关于鲁甸地震的起因，特别是鲁甸地震与溪洛渡水库之间的关系存在一些争议.分析中强地震前后地震活动性的变化可以为判断主震起源提供一定的依据.然而，由于鲁甸地震震中附近固定台站数目少、台站距离震中远及主震后尾波干扰等因素的影响，会造成地震目录的缺失，从而可能影响地震活动性的可靠分析.为了获得更加完备的地震目录，本文采用模板匹配方法对鲁甸地震前后小地震进行了搜索和识别.以台网目录中的541个事件作为模板，在主震之前33天到主震后5天的连续波形中识别出991个未在目录中列出的地震，使余震的完备震级从1.8降低到1.3.根据检测目录得到主震前33天内的b值为1.04±0.18，余震的b值在震后5天内由0.5左右逐渐上升至0.9附近并保持稳定；根据2009年到主震发生前的台网目录得到该区域的背景b值为0.93±0.04.即鲁甸地震前后区域地震活动b值均与背景b值接近，这与典型水库诱发的中强震具有的b值特征不相符.同时通过进一步分析台网目录，未发现溪洛渡水库蓄水前后研究区域内的地震活动性存在明显变化，这也与典型水库诱发地震区域的地震活动性特征不相符.综合以上结果，我们认为2014年鲁甸M_S6.5地震不具有典型水库诱发地震的特征.  相似文献   

Limit states and failure mechanisms of viscous dampers and the implications for large earthquakes     

H. Kit Miyamoto  Amir S. J. Gilani  Akira Wada  Christopher Ariyaratana 《地震工程与结构动力学》2010,39(11):1279-1297

Fluid viscous dampers are used to control story drifts and member forces in structures during earthquake events. These elements provide satisfactory performance at the design‐level or maximum considered earthquake. However, buildings using fluid viscous dampers have not been subjected to very large earthquakes with intensities greater than the design and maximum considered events. Furthermore, an extensive database of viscous damper performance during large seismic events does not exist. To address these issues, a comprehensive analytical and experimental investigation was conducted to determine the performance of damped structures subjected to large earthquakes. A critical component of this research was the development and verification of a detailed viscous damper mathematical model that incorporates limit states. The development of this model and the laboratory and simulation results conclude good correlation with the new model and the damper limit states and provide superior results compared with the typical damper model when considering near collapse evaluation of structures. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献