背景噪声中地震信号的可识别判据及量化验算

Criterion for distinguishing seismic signal from steady background noise visually:its quantification and verification

背景噪声与地震信号的强度或周期差异决定地震震相是否可从视觉上有效识别。为寻找平稳背景噪声中地震信号的视觉可识别判据,研究能反映两者频率差异及强度差异的参量用于上述两种信号对比,得到背景噪声中地震信号视觉可识别条件的量化判据,并用实际观测资料及仿真数据进行验证。在此基础上,针对功率谱计算过程中的校正环节进行讨论,利用A1buquerque实验室给出的测试实例阐明USGS标准中功率谱计算的规范步骤及细节。

Small seismic event waves and weak teleseismic signals are always buried in background noise and cannot be identified visually; the difference both in strength and frequency between background noise and seismic signal decides whether the seismic signal can be distinguished from steady background noise.For searching a parameter which can indicate the difference both in strength and frequency between background noise and seismic signal,a criterion for distinguishing seismic signal from steady background noise visually are worked out and then demonstrated by practical data and its simulation.Furthermore,which kind of amending steps should be used in calculation of power spectral density are argued and then the normal way of USGS standard for power spectral density calculation is detailed and demonstrated by an example of Albuquerque seismological laboratory.