Abstract:Using GPS continuous observation data from the CORS network of Qinghai province, we obtain the coseismic deformation field and the state of surface movement during the 2021 Maduo MW7.4 earthquake. The results reveal that the near-field stations on the south and north sides of the fault show southeast and northwest movements respectively, which is consistent with the left-lateral strike-slip mechanism. The coseismic permanent deformation is concentrated within 300 km of the epicenter. The sites within epicentral distance of 150 km captured centimeter-level displacements; the maximum horizontal displacement is 28.3 cm, occurring at the JDUO station. The permanent displacement extracted by the high-rate GPS kinematic deformation is approximately equivalent to the static calculation result, and the maximum peak value of the deformation waveform is 49.9 cm, which occurred at the KANQ station. Based on the epicenter distance and the initial motion time of the waveform, the estimated seismic wave velocity is 2.8-4.9 km/s. The estimated velocity at the eastern end of the fault is higher than that of other sites, which may be related to the directionality or the propagation velocity of the rupture. According to the empirical formula of magnitude, the estimated magnitudes of the deformation waveforms are in the range of M6.8-7.6, and the fitted average magnitude is M7.35±0.15. If data were processed real time, the robust magnitude could be derived within 70 s after the rupture initiated.
XIONG Shizhao,LIU Gang,LIN Mu et al. Coseismic Static and Kinematic Deformation Field of 2021 Maduo MW7.4 Earthquake Derived by GPS[J]. jgg, 2022, 42(10): 1041-1046.