Frequency dependent polarization analysis of ambient seismic noise recorded at a broadband seismometer in the central United States
Frequency dependent polarization analysis of ambient seismic noise recorded at a broadband seismometer in the central United States
复制标题
DOI：
10.1007/s11589-010-0743-5
复制
发表时间：
2010-10
影响因子：
1.2
通讯作者：
K. Koper;Veronica L. Hawley
中科院分区：
文献类型：
--
作者：
K. Koper;Veronica L. Hawley
本文提出了一种新的三分量地震计记录的地震噪声极化分析方法。它是基于统计分析的频率相关的粒子运动特性确定从大量的时间窗口，通过特征分析的3乘3，厄米特，频谱协方差矩阵。我们应用该算法记录在2009年的地震站SLM，位于北美中部的连续数据。观察到各种各样的噪声源。在低频率（<0.05 Hz）下，我们观察到倾斜相关信号，该信号显示出水平面上的一些椭圆运动。在0.05- 0.25Hz的微震带内，我们观测到了来自东北方向的瑞利波能量，但不是典型的单频和双频峰，而是三个明显的峰。在0.5-2.0 Hz的中频，噪声主要由非基模瑞利能量，最有可能的P和Lg波。在最高频率（>3 Hz），瑞利型能量再次以附近文化活动产生的Rg波的形式占主导地位。对噪声功率随时间变化的分析表明，至少0.02-1.0 Hz的频率范围（远大于微震带）对每年的气象引起的噪声源敏感。
We present a new approach to polarization analysis of seismic noise recorded by three-component seismometers. It is based on statistical analysis of frequency-dependent particle motion properties determined from a large number of time windows via eigenanalysis of the 3-by-3, Hermitian, spectral covariance matrix. We applied the algorithm to continuous data recorded in 2009 by the seismic station SLM, located in central North America. A rich variety of noise sources was observed. At low frequencies (<0.05 Hz) we observed a tilt-related signal that showed some elliptical motion in the horizontal plane. In the microseism band of 0.05–0.25 Hz, we observed Rayleigh energy arriving from the northeast, but with three distinct peaks instead of the classic single and double frequency peaks. At intermediate frequencies of 0.5–2.0 Hz, the noise was dominated by non-fundamental-mode Rayleigh energy, most likely P and Lg waves. At the highest frequencies (>3 Hz), Rayleigh-type energy was again dominant in the form of Rg waves created by nearby cultural activities. Analysis of the time dependence of noise power shows that a frequency range of at least 0.02–1.0 Hz (much larger than the microseism band) is sensitive to annual, meteorologically induced sources of noise.