Beyond Receiver Functions: Green's Function Estimation by Transdimensional Inversion and Its Application to OBS Data
Beyond Receiver Functions: Green's Function Estimation by Transdimensional Inversion and Its Application to OBS Data
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DOI：
10.1029/2018jb016499
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发表时间：
2019-02
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影响因子：
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通讯作者：
T. Akuhara;M. Bostock;A. Plourde;M. Shinohara
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文献类型：
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作者：
T. Akuhara;M. Bostock;A. Plourde;M. Shinohara
通过从对应的SV（或径向）分量对地震波波形的P（或垂直）分量记录进行去卷积来计算的接收器函数已被广泛用于获得近似形式的接收器侧绿色函数。然而，由于反褶积的数值不稳定性和P分量上的强多次波，常规的接收函数方法经常失败。在高频分析和使用海底地震仪（OBS）数据时，这些问题变得严重。我们提出了一种新的技术来估计接收端结构的绿色函数，从接收端P波形。在该方法中，假设形成一系列脉冲的绿色函数的两个分量在单个方程中直接相关，而无需显式反卷积。基于该方程，我们构建后验概率分布的脉冲的数量，它们的时间，和幅度内的transdimensional贝叶斯框架。为此，我们使用了可逆跳马尔可夫链蒙特卡罗方法，并进一步利用并行回火方法来实现快速收敛。综合测试和应用安装在大和盆地，日本海的OBS，表明所提出的方法可以估计径向分量绿色的功能比传统的接收函数方法更准确。我们认为，高频绿色函数估计的新方法可以用来揭示细尺度（约100米）的海底沉积物的结构。
Receiver functions, calculated by deconvolving P (or vertical) component records of teleseismic waveforms from the corresponding SV (or radial) components, have been widely used to obtain receiver‐side Green's functions in an approximate form. Conventional receiver function methods, however, often fail due to numerical instability of the deconvolution and strong multiples on the P components. These problems become severe when analyzing in high frequency and using data from ocean bottom seismometers (OBSs). We present a novel technique to estimate Green's functions of receiver‐side structure from teleseismic P waveforms. In this method, two components of Green's functions, which are assumed to form a series of pulses, are directly related in a single equation without explicit deconvolution. Based on the equation, we construct posterior probability distributions regarding the number of pulses, their timing, and amplitudes within a transdimensional Bayesian framework. A reversible‐jump Markov chain Monte Carlo method is used for this purpose, and we further utilize a parallel tempering method to achieve rapid convergence. Synthetic tests and application to an OBS installed at the Yamato Basin, the Sea of Japan, show that the proposed method can estimate radial‐component Green's functions more accurately than conventional receiver function methods. We suggest that the high‐frequency Green's functions estimated by the new method can be used to reveal fine‐scale (in order ~100 m) structure of the seafloor sediment.