The Potential of High‐Rate GPS for Strong Ground Motion Assessment

Abstract

We show that high-rate Global Positioning System (GPS) can have a vital role to play in near-real-time monitoring of potentially destructive earthquakes. We do this by investigating the potential of GPS in recording strong ground motions from earthquakes in Switzerland and Japan. The study uses finite-fault stochastic groundmotion simulation based on Fourier amplitude spectra and duration models previously developed for both countries, allowing comparisons in terms of both Fourier and timedomain characteristics (here, the peak ground velocity [PGV]).We find that earthquakes of magnitude M w > 5:8 can be recorded by GPS in real time at 10 km distance, that is, their Fourier spectrum exceeds the noise of the instruments enough to be used in strong-motion seismology. Postprocessing of GPS time series lowers the noise and can improve the minimum observable magnitude by 0.1-0.2. As GPS receivers can record at higher rates (> 10 Hz), we investigate which sampling rate is sufficient to optimally record earthquake signals and conclude that a minimum sampling rate of 5 Hz is recommended. This is driven by recording events at short distances (below 10 km for magnitude 6 events and below 30 km for magnitude 7 events).Furthermore, the maximum ground velocity derived from GPS is compared with the actual PGV for synthetic signals from the stochastic simulations and the 2008 M w 6.9 Iwate earthquake. The proposed model, confirmed by synthetic and empirical data, shows that a reliable estimate of PGV for events of about magnitude 7 and greater can be basically retrieved by GPS in real time and could be included, for instance, in ShakeMaps for aiding postevent disaster management.

Integration of Single-Frequency GNSS and Strong-Motion Observations for Real-Time Earthquake Monitoring

“…Previous studies have shown that 5 Hz GPS data can be used to recover a significant part of PGV values for large earthquakes [33].…”

Effect of Sensor Error on the Assessment of Seismic Building Damage

“…Measurement noise z[k] is considered additive with zero mean, since constant bias is estimated by long term averaging and then subtracted from the measurement [5]. Hence, measured acceleration is expressed by (6). Consequently, measured displacement is shown by (7)- (9).…”

Focal Mechanisms of the 2016 Central Italy Earthquake Sequence Inferred from High-Rate GPS and Broadband Seismic Waveforms

“…By comparing the frequency contents of seismic and high-rate GPS data, Avallone et al [25] inferred that GPS sampling rates greater than 2.5 Hz are required in the near-field region of moderate-magnitude events to provide solutions for the coseismic dynamic displacement that are free of aliasing artifacts [28,29]. Therefore, high-rate GPS data recorded at a sampling rate of 10 Hz were selected for this study.…”