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以甘肃和山西２ 个区域的历史地震资料为基础,采用地震时序分析方法,研究了这２ 个区域地震活动状态与地震形势．结果表明：（１） 区域７ 级强震在不同层次上活跃与平静交替发生;（２） 中强震在７ 级强震活跃期内伴随７ 级强震发生,在７级强震平静期内或围绕６ 级地震活动或５ 级以上地震丛集发生;（３） 甘肃目前可能正处于７ 级强震平静期以及中强地震平静期内,今后一百年或数百年内发生７ 级强震的可能性不大,十几年内也可能不会发生中强地震 相似文献
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2005年2月15日新疆乌什6.2级地震的地震环境及强震加速度记录 总被引：5，自引：0，他引：5
2005年2月15日7时38分7．5秒，在新疆维吾尔自治区乌什县境内发生了6．2级地震，在4团、乌什设立的强震台记录到了地震加速度记录。本文介绍了乌什地区6级以上地震的历史地震环境，对比分析了衰减公式与实际事件的异同。 相似文献
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2003年1月4日新疆伽师5.4级地震的强震观测与分析 总被引：1，自引：0，他引：1
2003年1月4日新疆伽师县发生了5．4级地震，其宏观烈度为Ⅵ度。布设在伽师县城的强震固定台记录到5．4级主震及1次4．2级余震的加速度，其中一个地震的最大加速度值(水平分量)为66．12gal。初步分析这次强地震运动特性，得出两点结论：(1)强运动记录检验了投入使用的GDQJ-1A型仪器性能良好；(2)加速度时程记录表明垂直向P波初动尖锐、强震持时较长，最长约达7．5s，而水平向P波初动弱、强震持时较短，仅约2．5s。 相似文献
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土耳其伊兹米特地震(1999,M7.4)的强地震动 总被引：1，自引：0，他引：1
介绍了１９９９年８月１７日土耳其伊兹米特地震（Ｍｓ７．４）的强震观测资料。结合工程应用,对烈度分布、加速度峰值衰减关系、加速度反应谱及其特征参数、强地震动持续时间等进行了分析和讨论。 相似文献
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介绍二滩拱坝强震台阵第1次记录的地震要素和记录情况；介绍了台阵记录的强地震动加速度记录的处理过程，包括零线校正，傅氏带通滤波。最后给出处理后各通道的加速度时程曲线和峰值加速度。 相似文献
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强震动观测仪器面临的机遇和挑战 总被引：1，自引：1，他引：0
本文介绍了国内外强震仪、力平衡加速度计、烈度计、MEMS加速度仪等强震动观测仪器的发展历史与现状,概述了强震动记录中典型异常波形产生的原因和力平衡加速度计的仪器响应误差及校正,建议了解决强震仪器缺陷的措施,分析了强震仪在强震动观测发展中面临的机遇和挑战。研究结果如下:① 进行强震动记录异常波形的研究是有针对性改进现有强震仪存在问题的很好途径;② 早期数字强震仪（力平衡加速度计频带范围0至30Hz）获取的强震动记录应进行仪器校正;③ 应跟踪强震动观测新方法和相关领域新技术,发展MEMS加速度仪和光纤加速度仪等新型仪器。 相似文献
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力平衡式加速度计仪器响应误差的校正方法 总被引：2，自引：2，他引：0
于海英 《地震工程与工程振动》2006,26(6):200-203
本文通过对数字强震仪系统使用的力平衡加速度计的仪器响应误差进行分析,提出了一个校正仪器响应失真的处理方法(微分-微分方法),即对未校正记录做低通滤波后运用近似理想微分器做两次微分得到校正加速度记录。针对大亚湾核电站地震仪表系统(K IS)给出了仪器校正示例,并编制了相应计算软件。该方法适用于我国强震动台网数字强震仪获取的加速度记录的仪器响应误差校正处理。 相似文献
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In damage‐based seismic design it is desirable to account for the ability of aftershocks to cause further damage to an already damaged structure due to the main shock. Availability of recorded or simulated aftershock accelerograms is a critical component in the non‐linear time‐history analyses required for this purpose, and simulation of realistic accelerograms is therefore going to be the need of the profession for a long time to come. This paper attempts wavelet‐based simulation of aftershock accelerograms for two scenarios. In the first scenario, recorded main shock and aftershock accelerograms are available along with the pseudo‐spectral acceleration (PSA) spectrum of the anticipated main shock motion, and an accelerogram has been simulated for the anticipated aftershock motion such that it incorporates temporal features of the recorded aftershock accelerogram. In the second scenario, a recorded main shock accelerogram is available along with the PSA spectrum of the anticipated main shock motion and PSA spectrum and strong motion duration of the anticipated aftershock motion. Here, the accelerogram for the anticipated aftershock motion has been simulated assuming that temporal features of the main shock accelerogram are replicated in the aftershock accelerograms at the same site. The proposed algorithms have been illustrated with the help of the main shock and aftershock accelerograms recorded for the 1999 Chi–Chi earthquake. It has been shown that the proposed algorithm for the second scenario leads to useful results even when the main shock and aftershock accelerograms do not share the same temporal features, as long as strong motion duration of the anticipated aftershock motion is properly estimated. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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When measured earthquake accelerations are used as a basis for structural design, then acceleration errors of a few per cent are usually acceptable. However a number of tasks in structural design, and in earthquake engineering research, require measured accelerations with errors limited to a few parts per thousand. Such tasks include those which call for the calculation of angular accelerations, the comparison of acceleration spectra or the calculation of relative displacement Accurate accelerations may be obtained from existing accelerographs by applying the results of an accurate static calibration to an accelerogram, and then applying corrections for the effects of accelerometer resonance. This paper concentrates attention on the correction of static errors, including sensing direction errors and cross-axis interaction errors. For completeness there is a brief discussion of dynamic errors, which depend on accelerometer periods and dampings. It is concluded that earthquake accelerations may be obtained with errors of not much more than 0·001 g, the resolution of a typical accelerograph, at least for periods greater than 0·2 sec. When the accelerations have shorter periods, larger errors may arise due to the limited accuracy of the corrections for dynamic errors The static calibration of accelerographs, and the corresponding record correction procedures, are illustrated by application to the M.O.2 accelerograph. 相似文献
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The Simulation of Ground Motions Using Envelope Summations 总被引：2，自引：0，他引：2
—?The technique of Midorikawa (1993) has been modified to obtain a resultant envelope function at the observation point by placing the rupture causing an earthquake in a layered earth model. The method and its dependency on various modelling parameters are studied in detail. The complete study shows that the generated resultant envelope follows important strong motion characteristics such as directivity and attenuation effects. The simulated resultant envelope is further used for generating synthetic accelerograms by multiplying filtered white noise with the envelope of accelerogram at a particular observation point. Filters through which white noise passes include the effects of geometrical spreading, anelastic attenuation and near-site attenuation at high frequencies.¶Uttarkashi earthquake is among few Indian earthquakes for which strong motion data are available at thirteen different stations. Using the technique presented in this work, envelope function as well as complete acceleration time history during Uttarkashi earthquake has been simulated at these observation points. Comparison of peak acceleration, duration and acceleration response spectra confirms the utility and efficacy of the approach. 相似文献
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For designing a structure to withstand the effects of strong earthquake ground motions, it is necessary to characterize the type of motion that probably affects the structure. The strong-motion accelerograms contain numerous data regarding the source, path, and receiver. Variables such as the Richter magnitude, hypocenter depth, duration of the event, and focal mechanism relate to the source. The soil parameter and distance to epicenter, relate to the path. The application of autoregressive moving average (ARMA) process in modeling an earthquake accelerogram of three different regions of Iran reveals a formulation, which relates the physical variables via a regression analysis. In order to generate time history data of a probable future earthquake, it is recommended to use the regression equations for a specific type of earthquake focal mechanism if the future earthquake mechanism and physical variables are known; otherwise, regional equations are more suitable. 相似文献
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Roberto Paolucci Antonio Rovelli Ezio Faccioli Carlo Cauzzi Daniela Finazzi Manuela Vanini Carola Di Alessandro Giovanna Calderoni 《地震工程与结构动力学》2008,37(5):697-710
Using records from co‐located broadband and digital strong motion (SM) instruments, it is first shown that the displacement waveforms obtained by double integration of the accelerogram need not be free of unrealistic baseline drift to yield reliable spectral ordinates up to at least 10 s. Secondly, to provide objective criteria for selecting reliable digital SM records for ground motion predictions at long periods, a set of synthetic accelerograms contaminated by random long‐period noise has been used, and the difference between the original accelerograms and the spurious ones in terms of response spectra has been quantified, by introducing a noise index that can be easily calculated based on the velocity waveform of the record. The results of this study suggest that high‐pass filtering the digital acceleration record from a cutoff period selected to suppress baseline drifts on the displacement waveform appears to be in most cases too conservative and unduly depletes reliable information on long‐period spectral ordinates. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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In this paper, the method presented by Lee and Trifunac (1985) for generating synthetic torsional accelerograms has been extended to the estimation of synthetic rocking accelerograms and of their response spectra. Results from our previous regression analyses for the characterization of strong shaking in terms of (1) earthquake magnitude and epicentral distance, or (2) Modified Mercalli Intensity at the site are utilized here again. The effects of geologic environment, in terms of site parameters or the representative depth of sediments, which influence amplification, and the dispersive properties of ground motion are also included. The synthetic rocking accelerogram is then constructed from the horizontal and vertical acceleration components. 相似文献
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A Simplified Technique for Simulating Wide-band Strong Ground Motion for Two Recent Himalayan Earthquakes 总被引：1，自引：0，他引：1
A simplified technique for simulation of wide-band strong motion based on simple regression relations and Empirical Greens Function (EGF) technique by Irikura (1986) is presented in this paper. The method uses the acceleration envelope as a shaping window for a filtered white Gaussian noise, to get the synthetic accelerogram from each subfault. Correction factors for slip of large and small events and transmission factors at each boundary of different layers are included in this synthetic accelerogram. The synthetic accelerogram obtained from each subfault is used as the Greens function to get resultant records. Simulations are made for the confirmed models of the Uttarkashi and the Chamoli earthquakes at a number of stations to get wide-band strong ground motion. The comparison of synthetic with the observed records over a wide range of frequencies for two different Himalayan earthquakes establishes the efficacy of the present technique. 相似文献
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简要评述了现有强震记录仪器响应失真校正方法的优点和存在的不足。在文献[1]的基础上，提出了对强震记录进行仪器响应失真校正的权函数方法，并推导建立了相应的计算公式。通过设计真实地震动为已知的算例，对加速度摆和速度摆强震仪的未校正记录，和用不同方法获得的校正记录的精度（或误差）进行了对比分析。理论和算例分析表明，本文方法简单、实用，具有很高的计算机精度且无稳定性问题。 相似文献
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The potential of a particular ground accelerogram to inflict damage to asymmetric strongly-inelastic systems is studied in the paper. An idealised analogue, the rigid block with frictional contact on an inclined base, is adopted as the generic representation of such systems. The inclined base (of (a sufficiently steep) angle) is shaken with numerous strong records bearing the effects of forward-directivity and/or fling-step. The accumulated slippage, D, of the block caused by each record is taken as the induced “damage” to the system. The relevance of a variety of ‘Intensity Measures’ of each accelerogram (ranging from PGA and PGV to Housner’s and Arias’ Intensities) in predicting this damage, is investigated statistically. It is shown that only a few of these ‘Intensity Measures’ are reasonably successful and their use could therefore be recommended, but only for statistical inference. A detailed deterministic analysis presented in the paper for one of these successful measures, Arias Intensity, reveals the unacceptably poor predictive power of this measure. Upper-bound curves of slippage provided in closed-form expressions, are an improvement over the state-of-practice Makdisi & Seed diagrams. 相似文献