Real-Time High-Rate GNSS Displacements: Performance Demonstration during the 2019 Ridgecrest, California, Earthquakes

Cite this article as Melgar, D., T. I. Melbourne, B. W. Crowell, J. Geng, W. Szeliga, C. Scrivner, M. Santillan, and D. E. Goldberg (2019). Real-Time HighRate GNSS Displacements: Performance Demonstration during the 2019 Ridgecrest, California, Earthquakes, Seismol. Res. Lett. XX, 1–9, doi: 10.1785/ 0220190223. Traditional real-time (RT) seismology has relied on inertial sensors to characterize ground motions and earthquake sources, particularly for hazards applications such as warning systems. In the past decade, a revolution in high-rate, RT Global Navigation Satellite Systems (GNSS) displacement has provided a new source of data to augment traditional measurement devices. The Ridgecrest, California, earthquake sequence in 2019 provided one of the most complete recordings of RT-GNSS displacements to date, helping aid in an initial source characterization over the first few days. In this article, we analyze and make available the archived RT displacement streams and compare their performance to postprocessed results, which we also provide. We find good agreement for all stations showing a noticeable signal. This demonstrates that simple modeling in RT, such as peak ground displacement scaling, would be practically identical to postprocessed results. Similarly, we find good agreement across the full spectral range, from the coseismic offsets (∼0 Hz) to the Nyquist frequency. We also find low latency between the measurement acquisition at the field site and the position calculation at the data center. In aggregate, the performance during the Ridgecrest earthquakes is strong evidence of the viability and usefulness of RT-GNSS as a monitoring