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Schlagwörter:
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Zusammenfassung:
The recent Mw 7.4 Madoi, Tibet earthquake provides a valuable opportunity to assess the contribution of the fully operational global BeiDou Navigation Satellite System (BDS-3) and other Global Navigation Satellite Systems (GNSS) in real-time seismic waveform capture. This event was successfully recorded by 111 1-Hz GNSS stations and 16 200-Hz strong motion stations. All GNSS stations are capable of recording BDS, GPS, GLONASS and Galileo observations. The variometric approach has been expanded to process multi-frequency and multi-GNSS data to estimate velocity, and then the coseismic displacements can be obtained by integrating the velocities. The results indicate that the phase-specific inter-frequency clock bias between BDS and GPS has minimal impact on velocity and displacement estimation, and there is no significant accuracy improvement with the help of a third frequency. Although the velocities derived from BDS are more noisy than those from GPS, the accuracy of integrated horizontal displacements for the regional BDS (BDS-2) shows 20% improvement with the RMS value of 0.5 cm. Compared to BDS-2, the seismic waveforms retrieved from BDS-3 shows nearly 50% better accuracy, due to the higher observation quality and stronger satellite geometry, and the performance can be further improved through fusion with multi-GNSS. The GNSS-derived seismic waveforms are consistent with those from accelerometer data. The inversion of the rapid rupture process indicates that BDS can provide a more reliable estimation of the fault slip distribution than GPS, and the performance can be further improved by using the GCRE observations, which will undoubtedly contribute to seismology applications.
