高频GNSS形变波的震相识别：模拟实验与实例分析

Recognition of seismic phases recorded by high-rate GNSS measurements:Simulation and case studies

高频GNSS震时形变波震相及识别是GNSS地震学的重要内容.在实时数据处理基础上,本文利用振动台的高频GNSS观测实验,并结合近期部分大震的高频GNSS形变波震相特征进行研究.数据处理结果表明,实时处理与事后处理的精度在同一量级,且与采样率无关.通过与同址观测强震仪和地震计记录的对比及特定震相的频谱分析,发现高频GNSS可完整记录P波、S波、Love波及Rayleigh波震相,影响震相记录的主要因素是GNSS定位精度与震级,而仅当震中距很小时,采样率将产生一定影响.研究结果得出:基于地震波传播规律,利用高频GNSS台阵记录的形变波空间分段特征,结合震相运动轨迹及其他地震波记录,可实现实时高频GNSS形变波的震相识别.

Recognition of seismic phases measured by real-time high-rate GNSS plays an important role in GNSS seismology.By comparison between the RTDD and KPPP,we find the precisions of two results having the same order and independence of sampling rates.Through analysis of time series of high-rate GNSS measurements on the testing shake table and large earthquakes,we demonstrate that the high-rate GNSS has ability to retrieve almost all kinds of seismic phases including P-,S-,Love and Rayleigh waves.The main factors that limit its performance are the uncertainty of the high-rate GNSS tracking and the magnitude of an earthquake.The sampling rate of a GNSS receiver located in short epicentral distance affects to some extent the recognition of recorded seismic waves.We conclude that propagation paths of seismic waves,spatial configuration of the high-rate GNSS array,spatial traces of seismic phases,and incorporation of seismographs are all useful to retrieve seismic phases from high-rate GNSS time-series.