## 4 Discussion
### Spatial Relationship between Coseismic Slip, Afterslip, and Aftershocks
The driving relationship between aftershocks and afterslip still needs to be verified by additional observations, such as continuous GPS and more seismic data in the future. The Effects of Coulomb Failure Stress Triggered by Coseismic Rupture and Aseismic Slip on Surrounding Faults  
The large earthquakes can be viewed as a release of interseismically accumulated stress, inevitably causing stress disturbances and redistribution in the surrounding crustal medium. We then estimated the Coulomb Failure Stress changes (\(\Delta\)CFS) to evaluate seismic risk on adjacent faults as follows [56; 57]:  
\[\Delta\text{CFS}=\Delta\tau+\mu^{\prime}\Delta\sigma_{\text{n}} \tag{2}\]  
\(\Delta\)CFS is the change in Coulomb stress on the receiver fault, \(\Delta\tau\) is the change in shear stress, \(\mu^{\prime}\) represents the effective friction coefficient, and \(\Delta\sigma_{\text{n}}\) is the change in normal stress. An increase in Coulomb stress of 0.01 MPa on the fault is typically regarded as the threshold to trigger a rupture [57]. We used the PSGRN/PSCMP codes to calculate the \(\Delta\)CFS triggered by the coseismic rupture and afterslip on the surrounding major faults due to this event [58]. In this study, the Crust 2.0 model was used to set up a multi-layered lithospheric model. Additionally, on the fault plane, our study set the effective friction coefficient to 0.4 [15; 16; 57]. The coseismic \(\Delta\)CFS notably increased on the Yushu segment in the GYXE, as well as the Tuosuo Lake segment and the Maqin-Maqin segment in the EKF, exceeding the threshold of 0.01 MPa (Figure 12a), consistent with previous  
Figure 11: On the fault plane, we present spatial distribution of coseismic slip, aftershocks, and afterslip with respect to depth. Black circles represent aftershocks. The hypocenter is represented by a blue star. The black contours show the coseismic slip at 0.6 m intervals. The histogram shows the number of aftershocks along the strike at 5 km intervals. The colored rectangles indicate the cumulative afterslip during the 450 days after the earthquake. studies [23; 57; 58]. The western Dari Fault (DF) also experienced a notable \(\Delta\)CFS increase, which slightly differs from the results of [PERSON] et al. [57]. This discrepancy may be due to the different coseismic slip models used by [PERSON] et al. [57] and in our study. In this paper, the \(\Delta\)CFS triggered by afterslip was also estimated on the surrounding faults during the 450 days following the mainshock (Figure 12b). In general, The co- and postseismic \(\Delta\)CFS show a similar pattern, but the magnitude of the postseismic \(\Delta\)CFS is much lower (\(<\)0.01 MPa). The postseismic \(\Delta\)CFS is increased to 0.002 MPa on the Maqin-Maqin segment in the EKF and to 0.003 MPa on the western part of the DF. However, the postseismic  
Figure 12: (**a**) The coseismic \(\Delta\)CFS caused by the event. (**b**) The postseismic \(\Delta\)CFS caused by the afterslip during the 450 days following the mainshock. The surface traces of the fault geometry are represented as the bold red lines and are shown in (**a**,**b**). Beach balls represent the focal mechanism solutions related to the 2021 Maduo event. \(\Delta\)CFS decreased on the western Tuosuo Lake segment in the EKF and the southeast of the DF [23]. On the Yushu segment in the GYXF, afterslip did not cause the obvious changes in Coulomb stress during the 450 days after the mainshock. Previous studies have suggested there is a seismic gap on the Maqin-Maqu segment in the EKF [20; 41]. The study of [PERSON] et al. [59] indicated that on the Maqin segment, the elapsed time since the most recent seismic event is approximately 400 years, approaching the most recent paleoseismic recurrence cycle of 600 \(\pm\) 100 years; meanwhile, on the Maqu segment, the elapsed time is about 1000 years, significantly exceeding the latest recurrence interval of 650 \(\pm\) 150 years.