New approach to detect seismic surface waves in 1Hz-sampled GPS time series

Area of Science:

• Geodesy
• Seismology
• Earthquake Engineering

Background:

• Co-seismic seismic source characterization using Global Positioning System (GPS) measurements has yielded significant results.
• Accuracy in ground displacement measurement from GPS phase residuals is limited by satellite distribution.
• Existing methods struggle with intrinsic GPS measurement errors.

Purpose of the Study:

• To introduce and test a novel method for detecting 3D co-seismic ground shaking.
• To enhance the accuracy of ground displacement measurements during seismic events.
• To overcome limitations posed by satellite geometry in GPS measurements.

Main Methods:

• Utilizing double-difference (DD) computations of Line of Sight (LOS) measurements.
• Employing a quasi-analytical approach to minimize intrinsic GPS errors.
• Benchmarking the method with data from the Hokkaido Earthquake (2003) using GEONET GPS stations.

Main Results:

• The DD method successfully detects 3D co-seismic ground shaking.
• DD amplitudes generated by seismic waves were 4 and 7 times stronger than background noise.
• The method demonstrated robustness despite potential satellite distribution issues.

Conclusions:

• The developed DD method offers a more accurate way to characterize co-seismic ground motion.
• This technique is effective in identifying 3D seismic shaking, improving upon existing GPS-based methods.
• The study validates the DD method's performance using real-world earthquake data.