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地震 ›› 2019, Vol. 39 ›› Issue (4): 172-180.

• • 上一篇    

2012年唐山4.8级地震强震动记录特征及场地相关特性分析

齐玉妍1, 孙丽娜2, 吕国军2, 李慧1   

  1. 1.河北省地震流动测量队, 河北 保定 071000;
    2.河北省地震局, 河北 石家庄 050021
  • 收稿日期:2018-09-28 出版日期:2019-10-31 发布日期:2019-10-30
  • 作者简介:齐玉妍(1981-), 女, 河北海兴人, 高级工程师, 主要从事强震动分析处理及地震中长期预测工作。
  • 基金资助:
    河北省地震科技星火计划项目(DZ20170503011, DZ20180322034)

Strong Motion Records and its Site Characteristics in Tangshan MS4.8 Earthquake on May 28, 2012

QI Yu-yan1, SUN Li-na2, LV Guo-jun2, LI Hui1   

  1. 1.Mobile Survey Team of Hebei, Baoding 071000, China;
    2.Hebei Earthquake Agency, Shijiazhuang 050021, China
  • Received:2018-09-28 Online:2019-10-31 Published:2019-10-30

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摘要： 2012年5月28日河北省唐山市古冶区与滦县交界发生4.8级地震, 国家强震动台网中心在河北、 天津和北京的94个强震动台站记录到了本次地震的加速度。 本文给出了获取记录的强震动台站分布及强震动记录结果, 统计了强震动记录数量随震中距的变化, 给出了3个较小震中距台站记录到的加速度时程; 绘制了空间地震动峰值加速度等值线图及周期0.2 s、 2.0 s加速度反应谱值的等值线, 发现峰值加速度等值线与长周期加速度反应谱等值线极值分布具有明显地域差异, 分析认为是由于厚沉积层对长周期地震动具有放大作用造成的。 通过强震动记录与适用于本区的三个衰减关系对比, 分析了此次地震的峰值加速度衰减特征, 同时研究了周期0.2 s、 2.0 s加速度反应谱值的衰减特征, 周期2.0 s反应谱值随震中距的衰减与衰减关系能较好地对应, 然而在震中距100～130 km沉积层较厚的集中地区, 表现出了实际记录较衰减关系值偏大的现象, 认为同样是由于厚沉积层对地震动加速度反应谱长周期的放大作用导致的。 研究了震中距差别不大的情况下, 场地类型与沉积层厚度对反应谱特征周期的影响, 对比基岩台站与软弱地基土层台站的强震动记录反应谱, 发现软弱土层台站的土层对地震动有一定的放大作用, 导致中长周期地震动被放大, 对比位于沉积层较薄的隆起区台站与位于沉积层较厚的凹陷区台站强震动记录反应谱, 发现厚的沉积层不仅对反应谱长周期有放大的作用, 同时也会使得反应谱特征周期值变大。

关键词: 强震动记录, 峰值加速度, 反应谱, 衰减关系, 特征周期

Abstract: The MS4.8 earthquake occurred on May 28,2012, at the junction area of Guye and Luanxian, Tangshan, Hebei Province. Acceleration records were obtained by 94 digital strong motion stations installed in Hebei province, Tianjin and Beijing. In this paper, the distribution of strong motion stations recording the earthquake is shown, subsequently the count of records within different epicenter distances are analyzed, and the acceleration time history of three typical strong motion records are emphatically displayed within small epicentral distance. Accordingly, the peak ground acceleration contour map is drawn, and the T=0.2 s, 2.0 s response spectrum contours maps are also displayed. By comparing the differences of the three contours maps, it is found that the extreme distribution has obvious regional features, which may be due to the distinct amplification of thick sedimentary layer to the long-period ground motion. The peak ground acceleration also with the T=0.2 s, 2.0 s response spectrum attenuation characteristics are studied by comparing the observed data with the three attenuation relationships applied to this region. The T=2.0 s response spectrum attenuation characteristics with the epicenter distanceis consistent to the attenuation relationship in this region, however, between the epicentral distance of 100 to 130 km, where concentrated by thick sedimentary layers, the response spectrum are larger than the attenuation relationship, which is also because of the distinct amplification of the thick sedimentary layer to the long-period ground motion. In this paper, the characteristic periods of response spectra is also studied by analyzing strong motion recordings on different types of site soil and deposit layers with the similar epicenter distances. Compared response spectra recorded on bedrock stations and on soil stations, it is found that the soft soil site layer at the soil stations has an amplified effect on the ground motion, and it will cause the amplified long-period ground motion. Compared response spectra recorded on thin sedimentary layer stations and on thick sedimentary layer stations, it is found that the thick sediments have amplification effect on the ground motion, as well as make the characteristic periods of response spectra to become larger.

Key words: Strong motion records, Peak ground acceleration, Response spectrum, Attenuation relationship, Characteristic period

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