大孔径地震台阵噪声互相关函数中体波信号的研究——以ChinArray二期数据为例

本文利用ChinArray二期大孔径台阵677个台站2013年10月至2016年4月期间的垂直分量记录，计算了不同路径上的噪声互相关函数（Noise Cross-correlation Function，NCF），观测到4~8 s和8~12 s频带内的NCF零时附近存在显著的高视速度信号.基于NCF的慢度聚束分析表明，这些信号由背景噪声中的远震P、PP和PKPbc波干涉产生，且以P波能量为主.位置聚束图像表明，P波类型的噪声源主要分布在北大西洋、北太平洋和南大洋凯尔盖朗深海高原，其位置对应于平均海浪波高较高的区域.同时，在阿拉斯加海岸及澳大利亚附近海域也存在P波噪声源.利用已识别的P波噪声源位置，计算了其在NCF中产生的干涉信号理论到时，结果与实际观测一致.

P wave signals in the noise cross-correlation functions of a large-aperture array illustrated by the data of ChinArray Phase II

Using vertical component records of 677 stations of ChinArray Phase Ⅱ from September 2013 to June 2016, we compute the noise cross-correlation functions (NCFs) between the stations of the array. Signals with high apparent velocity near the zero time are observed at the period bands of 4~8 s and 8~12 s, respectively. Using the NCF-based slowness beamforming technique, it is confirmed that these signals are generated by the interference behavior of teleseismic P, PP and PKPbc waves. Furthermore, the sources of P, PP and PKPbc waves are located by the NCF-based location beamforming technique. The results indicate that the persistent P wave sources are mainly distributed in the deep areas of the North Atlantic, the North Pacific and the Southern Ocean, which correspond to the averaged significant wave heights. Some P-wave noise sources also exist in the Alaska Coast and the region near Australian. Using the identified noise sources, arrival times of the interference signals are predicted, consistent with observations.