基于GPS的2021年玛多MW7.4地震同震静、动态形变场

利用青海省CORS网GPS连续观测数据获取2021年玛多M_W7.4地震的同震形变场以及震时地表运动状态。结果表明，断层南北两侧的近场测站分别展现出南东向和北西向运动，符合左旋走滑机制。同震形变集中在震中距300 km范围内，震中距150 km以内的站点均能反映出cm级的位移，最大水平向位移为28.3 cm(JDUO站)。高频GPS动态形变提取出的永久位移与静态解算结果相当，其动态波形最大峰值为49.9 cm(KANQ站)。依据震中距和波形初动时间估计得到地震波速为2.8~4.9 km/s，断层东端的站点估算速度大于其他站点，可能与此次破裂的方向性或者破裂传播速度有关。依据震级经验公式，动态波形估算震级在M6.8~7.6区间，拟合平均震级为M7.35±0.15。若在实时条件下，震后70 s内可得到稳定的震级。

Coseismic Static and Kinematic Deformation Field of 2021 Maduo MW7.4 Earthquake Derived by GPS

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 M_W7.4 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.