Direct estimation method to extract phase velocities of Rayleigh waves in microtremors using circular arrays
Direct estimation method to extract phase velocities of Rayleigh waves in microtremors using circular arrays
复制标题
利用圆形阵列提取微震瑞利波相速度的直接估计方法
DOI：
10.3124/segj.58.643
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
H. Asanuma
中科院分区：
文献类型：
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作者：
H. Shiraishi;T. Matsuoka;H. Asanuma
本文提出了一种新的用于检测地脉动瑞利波相速度的地脉动圆形台阵分析方法，旨在进行比空间自相关（SPAC）方法更少的地脉动台阵观测。该方法基于Shiraishi和Matsuoka（2005）提出的Rayleigh波复相干函数（CCF）来研究波源与基阵上观测点之间的关系。在该方法中，生成相速度的贝塞尔函数J0（kr）（k：波数，r：观测点之间的距离）的值作为CCF的联立方程的解获得，而在SPAC方法中，它们是根据CCF的方向平均计算的。从理论上研究了这种方法在圆形地震台阵上的应用，发现在地震计对称布置的条件下，地震计在圆周上几乎可以布置在任何位置。现场实验表明，该方法得到的相速度与SPAC方法得到的相速度基本一致。
We propose a new analysis method of microtremor circular arrays for detecting phase velocities of Rayleigh waves in microtremors, aiming to conduct the microtremor array observations with fewer restriction of seismometer arrangement than the spatial autocorrelation (SPAC) method. The method is based on the complex coherence function (CCF) of the Rayleigh waves formulated by Shiraishi and Matsuoka (2005) to study the relationship between wave sources and observation points on an array. In this method, the values of the Bessel function J0 (kr) (k: wave number, r: distance between observation points) that generate phase velocities are obtained as a solution of the simultaneous equations of CCFs, while they are calculated from the directional average of CCFs in the SPAC method. Therefore, our method allows observation points not equally spaced on the circumference.From theoretical studies of this method for a circular array, it was found that seismometers on the circumference could be set at almost any place with the condition of symmetrical seismometer arrangement. Moreover, a field experiment have confirmed that the phase velocity obtained from the proposed method agreed with that of the SPAC method.