An Efficient Algorithm to Identify Strong-Velocity Pulses in Multicomponent Ground Motions
An Efficient Algorithm to Identify Strong-Velocity Pulses in Multicomponent Ground Motions
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DOI：
10.1785/0120130191
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发表时间：
2014-10
影响因子：
3
通讯作者：
S. Shahi;J. Baker
中科院分区：
文献类型：
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作者：
S. Shahi;J. Baker
具有强速度脉冲的地震动是结构工程师特别关心的问题。我们描述了一个有效的和定量的方法来识别这样的地面运动。以前的算法来分类这些脉冲状的地面运动考虑在一个单一的方向，这使得分类脉冲在任意方向的地面运动。我们提出了一种算法，可以识别脉冲在任意方向的多分量地震动，与一个单一的方向计算很少的额外的计算成本。我们使用连续小波变换的两个正交分量的地面运动，以确定最有可能包含脉冲的方向。然后，小波变换的结果被用来提取脉冲从选定的方向，并提出了一种新的分类标准的基础上支持向量机。由于我们最感兴趣的是前向方向性脉冲，这是早期发现的时间历程中，一个标准，以拒绝脉冲到达时间历程中的晚。该过程用于对下一代衰减-West 2数据库中的地面运动进行分类（Eschereta等人，2013年）。然后使用震源到场地几何形状和场地条件手动过滤脉冲状地面运动列表，以找到最可能由方向性效应引起的脉冲。提供了脉冲状地震动和方向性地震动的列表，沿着脉冲的周期和脉冲最强的方向。使用分类结果，新的模型来预测的概率脉冲和脉冲周期为一个给定的未来地震的情况下开发。在线资料：下一代衰减-West 2数据库中识别的所有脉冲状地面运动的表格，以及源到站点几何形状的HTML文件，记录的时间历史，提取的脉冲和每个识别脉冲的其他方向性参数。
Ground motions with strong velocity pulses are of special concern for structural engineers. We describe an efficient and quantitative method to identify such ground motions. Previous algorithms to classify these pulse-like ground motions con- sidered the ground motion in a single orientation, which made classifying pulses in arbitrary orientations difficult. We propose an algorithm that can identify pulses at arbitrary orientations in multicomponent ground motions, with little extra computa- tional cost relative to a single-orientation calculation. We use continuous wavelet transforms of two orthogonal components of the ground motion to identify the ori- entations most likely to contain a pulse. The wavelet transform results are then used to extract pulses from the selected orientations, and a new classification criterion based on support vector machines is proposed. Because we are mostly interested in forward directivity pulses, which are found early in the time history, a criterion to reject pulses arriving late in the time history is also proposed. The procedure was used to classify ground motions in the Next Generation Attenuation-West2 database (Ancheta et al., 2013). The list of pulse-like ground motions was then manually filtered using source- to-site geometry and site conditions to find the pulses most likely caused by directivity effects. Lists of both pulse-like ground motions and directivity ground motions are provided, along with the periods of the pulses and the orientations in which the pulses were strongest. Using the classification results, new models to predict the probability of a pulse and pulse period for a given future earthquake scenario are developed. Online Material: Table of all the pulse-like ground motions identified in the Next Generation Attenuation-West2 database, and HTML files of source-to-site geometry, the recorded time history, extracted pulse, and other directivity parameters for each identified pulse.