## 1 Introduction  
On 22 May 2021, an earthquake (98.3\({}^{\circ}\) E and 34.59\({}^{\circ}\) N) struck Maduo town in Qinghai province, occurring along a relatively obscure secondary fault within the block. This seismic event reached a moment magnitude of Mw 7.4, which is the most significant event in the Chinese mainland since the 2008 Wenchuan earthquake [1; 2; 3]. Many earthquake research institutions reported that the epicenter of this event was situated in a sparsely populated area. Studies from field reconnaissance, aftershock distributions, and Interferometric Synthetic Aperture Radar (InSAR) unwrapping images from both ascending and descending orbits suggest that this event may have been caused by a sinistral strike-slip rupture along the Kunlun Pass-Jiangcuo Fault (KPJF) [4]. Previous studies have shown that this event resulted in a significant surface rupture with a length varying from 150 to 210 km [1; 2; 3; 4; 5; 6; 7; 8; 9] (Figure 1b). The Bayan Har block is well-known for its strong seismicity and frequent earthquakes in the northern Tibetan Plateau. The Kunlun Fault forms the northern edge of the BayanHar block, while the Ganzi-Yushu-Xianshuihe Fault (GYXF) defines the southern edge of the block. Its eastern boundary is the Longmen Mountain orogenic belt, adjacent to the Sichuan Basin (Figure 1a). Since the 1990s, most earthquakes (>Mw 7) in the Chinese mainland have occurred on the boundaries of the block [10; 11; 12], except for this event, which occurred within the interior of the block. Therefore, this earthquake provides a valuable opportunity for studying intrablock faulting behavior and evaluating regional seismic risk in the future. Space geodetic data, e.g., Global Navigation Satellite System (GNSS) and Interferometric Synthetic Aperture Radar (InSAR), have been conventional methods for investigatingoseismic deformation and postseismic time series [10; 11; 12; 13; 14]. Field geological investigations indicate that this event occurred on the KPJF, which is characterized by a sinistral strike-slip motion [1; 2]. Relocating the aftershock sequence after the mainshock suggests that the seismogenic fault exhibited an asymmetric bilateral rupture on a near-vertical fault plane and revealed a clear bifurcation geometry feature at the end of the surface trace [4; 5]. Many studies reported that the peak coseismic slip ranged from 3.6 m to 9.3 m [3; 7; 8; 9; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25]. The Maqin-Maqin segment, in particular, may have a higher potential seismic risk, and should be carefully monitored in the future [8; 9; 15; 17; 18; 19; 22; 23; 25]. Based on the seismic data, strong-motion acceleration waveforms, and high-rate (1 Hz) GNSS observations, some studies revealed a nearly bilateral slip-pulse rupture caused by the event [17; 26] and demonstrated the interactions on the stress triggering between the different asperities [15]. Compared to the coseismic deformation, postseismic displacement caused by a large earthquake usually occurs over a wider range and exhibits non-linear decay over time [13; 14; 27]. Space geodetic data, especially the InSAR time series with high spatio-temporal resolution, are crucial for investigating transient deformation after a strong earthquake, e.g., the Wenchuan earthquake [28; 29], the Nepal earthquake [13; 30; 31; 32], and the Yushu earthquake [33]. [PERSON] et al. [28] found that a shallow afterslip effectively explained the near-field deformation caused by the Wenchuan earthquake and was inversely correlated with the coseismic slip distribution. [PERSON] et al. [33] demonstrated that short-term afterslip associated with the Yushu earthquake likely contributed to the low-amplitude postseismic deformation observed along the main rupture zone. Some early studies on the 2021 Maduo earthquake have shown that afterslip occurs on the shallow portion of the seismogenic fault [20; 21; 23].