陕西地区小微震震源机制研究   总被引：4，自引：1，他引：3       下载免费PDF全文

惠少兴  严川  王平  金昭娣 《地震工程学报》2018,40(2):288-293

小微震事件的震源机制是区域应力场及诸多地球动力学研究的基础资料。陕西地区为多个地震带的交汇区,近些年积累了丰富的小微震波形资料。运用新近发展的适用于求解小微震震源机制的广义极性振幅技术(GPAT),结合陕西2015地壳速度模型,求解陕西测震台网2011年4月至2015年12月间记录的121次ML1.5~3.5事件的震源机制。反演结果表明:(1)以上事件的震源机制大部分为走滑及正断类型,其比例占64.5%;逆断型机制占22.3%。(2)反演震源机制得到的震源深度与定位深度具有良好的一致性;矩震级与近震震级间存在差别,且这种差别随事件的变小而增大。(3)对比渭河断陷带相关研究成果,验证了该区域震源机制以正断型为主,具有拉张应力状态。  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 Historical documents in Korea show that event E1 possibly corresponds to the earthquake that occurred in AD 1810 (the Qing Dynasty in Chinese history) in the Ningguta area, which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   

Review on the study of topographic effect on seismic ground motion          下载免费PDF全文

Hong Zhou 《地震科学（英文版）》2018,31(2):110-116

Topographic effect study is a very important research topic in seismology, seismic engineering,earthquake engineering, engineering earthquake construction and engineering seismology. This paper focuses on its present development status. Post-earthquake investigation has found that the existence of topography caused more serious earthquake damage. The actual seismographs also recorded the topographic amplification effect of 6 to 7 times and even more than 10 times. Numerical simulation is an important technique to study topographic effect, which complements the lack of observed records. However researches on 3-D topographic effect are not enough and need to be studied deeper. To find the main influence factors and the quantitative relationship between topography and ground motion are required very urgently. Obviously the achievements not only can be applied in the earthquake resistant design, but also can provide the quantitative pre-earthquake disaster prediction and quantitative post-earthquake disaster evaluation.  相似文献   

相邻两井对大地震的不同水力响应模型研究——页岩影响分析   总被引：1，自引：0，他引：1       下载免费PDF全文

张艳  符力耘  陈学忠  曹呈浩  赵连锋  马玉川 《地球物理学报》2019,62(1):143-158

大地震引起了左家庄和宝坻(相距～50km)两井中截然不同的同震水位响应.我们用水位的气压和潮汐响应来分析解释此现象.结果表明,宝坻井的观测含水层中存在页岩,且此井受裂隙影响很大,储水效应较差.页岩的复杂裂隙或者各向异性可能会导致此井观测含水层处于半封闭状态,从而导致垂直向排水的发生.通过多方计算分析后,我们将这两口井划分为两种模型—1.水平流动模型;2.水平流动+垂直流动的混合流动模型.由于裂隙影响,宝坻井的观测含水层介质与外界的水力沟通性在震前就较强(震前渗透率就比较大),所以宝坻井观测含水层与外界的孔隙压差异较小,导致同震渗透率上升较小甚至没有变化,这些因素是导致该井同震水位变化幅度总是非常微小的原因.  相似文献   

2003年民乐-山丹6.1、5.8级地震灾害损失评估   总被引：1，自引：3，他引：1       下载免费PDF全文

马尔曼  石玉成  高晓明  何文贵 《地震工程学报》2007,29(1):64-68

2003年10月25日在甘肃省民乐-山丹交界处相继发生MS6.1和MS5.8地震,造成10人死亡、46人受伤,近5万人失去住所;村镇民用房屋、水利、生命线工程和学校、卫生院所等公共设施严重破坏。震后采用抽样调查、单项调查、填表调查核实的方法,取得了大量的实际资料,将灾区合理的划分为3个评估区,建立了每个评估区的每类建筑物的破坏比、损失比和基础数据资料,分10个专项进行统计分析,通过计算得出了本次地震灾害的经济损失结果。  相似文献   

Performance‐based design using structural optimization     

S. Ganzerli  C. P. Pantelides  L. D. Reaveley 《地震工程与结构动力学》2000,29(11):1677-1690

A new methodology for seismic design is proposed based on structural optimization with performance‐based constraints. Performance‐based criteria are introduced for the seismic design of new buildings. These criteria are derived from the National Guidelines for Seismic Rehabilitation of Buildings (Reference [19], Federal Emergency Management Agency (FEMA), ‘NHERP Guidelines for seismic rehabilitation of buildings’, Report Nos 273 and 274, Washington, DC, 1997) for retrofitting existing structures. The proposed design methodology takes into account the non‐linear behaviour of the structure. The goal is to incorporate in the design the actual performance levels of the structure, i.e. how much reserve capacity the structure has in an earthquake of a given magnitude. The optimal design of the structure minimizes the structural cost subjected to performance constraints on plastic rotations of beams and columns, as well as behavioural constraints for reinforced concrete frames. Uncertainties in the structural period and in the earthquake excitation are taken into account using convex models. The optimization routine incorporates a non‐linear analysis program and the procedure is automated. The proposed methodology leads to a structural design for which the levels of reliability (performance levels) are assumed to be quantifiable. Furthermore, the entire behaviour of the structure well into the non‐linear range is investigated in the design process. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

新疆乌什、阿合奇台地倾斜异常图像与中强地震     

刘辉  赖爱京  王志宽  祝军 《内陆地震》2005,19(2):136-141

统计分析了1988-1998年期间乌什台和阿合奇台地倾斜记录到的异常图像,发现其与周围250km范围尤其是柯坪块体上发生的4级以上地震有较好的对应关系。异常图像特征以葫芦串、错动、抖动等为主,异常持续时间为1—74天,主要集中在震前3天。最后对异常图像形成的可能机制作了初步的讨论。  相似文献   

中、强震前川滇块体遥感红外辐射异常分析——以宁蒗M5.7地震和鲁甸M6.5地震为例          下载免费PDF全文

路茜  张铁宝  崔静  杨星 《地震工程学报》2021,43(3):565-574,582

许多研究表明中强地震前出现了红外辐射异常。近年来,川滇块体中、强地震频发,利用遥感数据对其红外辐射异常变化开展深入分析十分必要。结合13年MODIS/Terra遥感红外数据,采用空间距平分析法、辐射增强阈值面积指数法及辐射亮温均值低频时间序列法,对2004年4月—2017年6月红外亮温数据进行深入分析,研究川滇块体及周边构造断裂M≥5.5地震的震前异常信息。结果表明:(1)M≥6.0地震在震前3～6个月川滇块体会出现较为明显的红外辐射增强异常现象;(2)震前红外异常并非随机分布,而可能是受到相关块体的控制;(3)以宁蒗M5.7地震和鲁甸M6.5地震为例研究发现,震前辐射增强较高的小范围区域与震中位置存在一定关联。  相似文献   

山东及邻区地震重新定位及其与活动构造的关系     

李霞  刘希强  李亚军  董晓娜  张慧峰 《中国地震研究》2013,27(4):512-526

Earthquakes taking place from 1975 to 2010 in and around Shandong Province are relocated using double-difference （HypoDD） and Hypoinvers 2000 （Hypo2000） methods, after correction of the onset times of seismic phases. The results show that the relocated seismicity is clearly associated with regional tectonics in space, and is also in agreement with the existence of deep faults imaged by wide-angle and deep seismic reflection profiling ; most of the focal depths are in the range of 5 - 25km, and there are clearly two predominant depths： 10km and 16km, which are inferred to be on the bottom of the upper crust and in the middle crust, respectively. The pattern of seismic activity indicates that moderate and strong earthquakes are likely to occur in the brittle-ductile transition zone between the upper and the lower crust, as the outcome of the deep tectonic dynamic process and the movement and deformation of faults in the upper and shallow crust under the regional stress field.  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