Extraction of High-Rate GPS Seismic Wave Signals with Wavelet Packets Decomposition

With the development of high-rate GPS receivers, precise orbit and processing technology of GPS data, it is possible to observe the high frequency, transient dynamic displacement by GPS. However, it remains a problem as how to mitigate the error such as multipath errors, and random noise aliasing in geophysical signals so as to extract seismic signals, which in turn limits the high-rate GPS and its geophysical applications. In this paper, an approach based on wavelet packets decomposition (WPD) is presented to extract seismic signals through mitigating the multipath error and random noise of dynamic displacement series from high-rate GPS. With the 1 Hz observation data from 19 stations in Southern California Integrated GPS Network (SCIGN) during the Mexico M7.2 earthquake in 2010, the ground displacement is calculated. Meanwhile, the approach based on WPD is introduced for seismic signal extraction and spectrum analysis. As is shown in results, the approach is accurate and effective in seismic signal extraction to reflect the characteristics of seismic wave propagations and it enjoys an advantage that it does not necessarily involve multiple-day observation.