Near-source attenuation of peak horizontal acceleration
Near-source attenuation of peak horizontal acceleration
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发表时间：
1981-12
影响因子：
3
通讯作者：
K. Campbell
中科院分区：
文献类型：
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作者：
K. Campbell
利用距破裂带50 km范围内的强震记录资料，研究了全球范围内5.0 ~ 7.7级地震水平峰值地面加速度的近源衰减特征。该数据库由27次地震记录的峰值加速度的229个水平分量组成，包括1979年10月15日的帝王谷地震。发现这些数据可以用函数关系PGA = a exp（B M）[ R + C（M）] − d来充分表示，其中PGA表示从每个记录的两个水平分量缩放的峰值的平均值，M是里氏震级，R是距断层破裂带的距离。峰值加速度被认为是对数正态分布的标准误差表示增加了45%的中位数估计。回归分析从统计学上证实了地震模拟研究的结果，这些研究预测峰值加速度在近场与震级和距离无关。一项广泛的敏感性研究表明，基于我们的衰减关系的预测是稳定的合理的模型和参数变化。用残差分析法研究了峰值加速度随地震、场地和记录参数的变化规律，发现：（1）在土壤和岩石上记录的加速度水平相似，（2）在浅土层或陡峭地形的场地上记录的加速度大于平均加速度，（3）在高海拔地区记录的加速度大于平均加速度，（4）在高海拔地区记录的加速度大于平均加速度。（3）大于与逆断层机制地震相关的平均加速度;（4）低于大型嵌入式结构记录的平均加速度。
Strong-motion data recorded within 50 km of the rupture zone were used to study near-source attenuation characteristics of horizontal peak ground acceleration for worldwide earthquakes of magnitudes 5.0 to 7.7. The data base consisted of 229 horizontal components of peak acceleration recorded from 27 earthquakes, including the 15 October 1979, Imperial Valley earthquake. These data were found to be adequately represented by the functional relationship PGA = a exp ( b M ) [ R + C ( M ) ] − d where PGA represents the mean of the peak values scaled from the two horizontal components of each recording, M is Richter magnitude, and R is distance from the fault rupture zone. Peak acceleration was found to be lognormally distributed with a standard error representing a 45 per cent increase in the median estimate. The regression analysis statistically confirmed the results of earthquake simulation studies that have predicted peak acceleration to become independent of magnitude and distance in the near field. An extensive sensitivity study showed that predictions based on our attenuation relationships are stable with respect to reasonable model and parameter variations. An analysis of residuals was used to investigate the behavior of peak acceleration with respect to various earthquake, site, and recording parameters, the more significant findings being: (1) a similarity in the level of acceleration recorded on soil or rock; (2) larger than average accelerations recorded at sites located on shallow soils or in areas of steep topography; (3) larger than average accelerations associated with earthquakes having reverse fault mechanisms; and (4) lower than average accelerations recorded in large embedded structures.