Based on the GPS data in the northeastern edge of Qinghai-Tibet Plateau, the velocity field and the extension change rate of baseline between stations are analyzed. The crustal movement characteristics and their dynamic changes in this region are discussed. The result indicates that the baseline in the regions demonstrates an overall characteristic of shrinking in the NE direction and extending in the NW direction; The extrusion of Bayan Har Block in SE direction since 2009 has amplified obviously, which leads to the enhancement of correlated movement in SE direction in the NW side of Longmenshan Fault. In addition, Tianzhu empty regions and the area near the epicenter of Menyuan Ms6.4 earthquake in 2016 are right in the boundary of this differentiated movement. Recently, a certain amount of strain energy might have been accumulated in the nearby area of the northern margin of Alkin Fault Zone, west boundary of Erdos Block and west to105°N on Northern Xiqinling Fault. The seismic risk in the west and east section of the intersecting area between Bayan Har Block and Qaidam Block is high. The west section of Northern Xiqinling Fault belongs to the inner ring of clockwise vortex and possesses medium-strong seismic risk.

To determine the crustal deformation and the stress–strain accumulation characteristics preceding the $Mw$ 7.3 Maduo earthquake and the seismic potential of the Maqin–Maqu fault segment, the seismic data from small earthquake events and Global Positioning System (GPS) observations stations are collected. The b‐value, the GPS velocity field, the GPS baseline, and the GPS strain parameters for multiple areas are calculated and analyzed. The results show a low b‐value anomaly in the epicenter and its adjacent areas before the earthquake, which suggest that the stress level of the medium in this area was high before the earthquake. The regional GPS velocity field indicates that the earthquake epicenter is in an area where strain energy accumulates at varying slip rates and orientations. The deformation rates of the northeast‐oriented baselines on the east side of the fault and the northwest‐oriented baselines on the west side of the fault are lower than those observed near the three near north–south‐oriented baselines, reflecting a small compressive deformation that occurred at the epicenter before the earthquake. Meanwhile, the motion of baselines QHYS‐QHMD, QHYS‐QHMQ, and QHGE‐SCSP noticeably decreased, indicating that the area near the fault had already stored a great deal of strain energy prior to the earthquake. The rate of plane strain reduced in the epicenter region before the earthquake gradually since the second half of 2019, illustrating the deficit points to high stress conditions in the epicenter area. Furthermore, the area near the epicenter was characterized by high strain accumulation before the earthquake. The Maqin–Maqu segment of the East Kunlun fault is likely to be capable of generating strong earthquakes in the near future, because the current state of the area is similar to that of the Maduo epicenter before the onset of the earthquake.

To study the characteristics of the present crustal movement in the Tibetan Plateau and explore its relationship between strong earthquakes with magnitudes of 8 and above, the velocity field size was analyzed based on the global position system (GPS) campaign observations and the time series of site north-ward displacement and long baseline were discussed using the GPS continuous observations. The results show that the velocity field size in the Tibetan Plateau decreases from southwest to north, northeast, and southeast, and the value of the velocity in the west is significantly greater than that in the east in the same dimension. The maximum value is located in the southwest and the minimum value is located in the east. The Wenchuan earthquake is located in the mutation region, where the rate and the direction of the crustal movement are quite different. The crustal deformation extent is large in the region close to the seismic source before the earthquake, reflecting that the regional stress accumulation is fast and its required time is relatively short. However, the crustal deformation extent is relatively small in the region away from the seismic source before the earthquake, reflecting that the regional stress accumulation is slow and its required time is relatively long. The N-ward movement became significantly strong after NepalM_S8.1 earthquake; the occurrence of this earthquake may have caused the unlocking of large-scale faults near the seismic source, which further intensified the NE-ward subduction and collision of the Indian Plate. The compression of the Indian Plate to the Tibetan Plateau slowed down after the 2008 WenchuanM_S8.0 earthquake, and increased significantly after 2015, which boosted strain accumulation in the Tibetan Plateau, and attention needs to be paid continuously to strong earthquake risk in this region.

To clarify the relationship between GNSS (Global Navigation Satellite System) crustal deformation and the preparation of strong earthquakes in the western Chinese Mainland, a series of methods including velocity field, strain rate field, and strain parameter time series are adopted based on the GNSS observation data from the CMONOC (Crustal Movement Observation Network of China). The abnormal characteristics of crustal deformation movement before the M ≥ 5 earthquakes in the area since 1999 are studied. The corresponding variety of the crustal movement before earthquakes is discussed in combination with the seismogenic structure of earthquakes. The abnormalities of the GNSS velocity field, strain field, and strain parameter time series before earthquakes with different magnitudes are proposed. Finally, the anomaly criterion before medium-strong-large earthquakes in the western Chinese Mainland is proposed according to the GNSS and its combination with the characteristics of geological structure. The results can provide a basis for the forecasting of the trend and location of medium-strong-large earthquakes in the western Chinese Mainland.

A M_S6.2 earthquake struck Jishishan Country in Gansu Province on 18 December 2023. The earthquake occurred on the eastern branch of the Northern Lajishan fault (NLJSF) which has never experienced such a violent seismic event in recorded history. In this study, multiple periods of GNSS campaign observation data and continuous observation data are collected to reveal the crustal deformation evolution characteristics of the eastern branch of the NLJSF before the earthquake, focusing on the dynamic behavior of the causative fault, regional strain parameter features, and the variation of GNSS baselines across the NLJSF. Velocity field data show that the differential movement on both sides of the fault zone before the earthquake accumulated energy for the occurrence of the earthquake. Cross-fault profile analyses indicate a noticeable weakening of horizontal shortening on both fault flanks, suggesting a nearing fault lockup. The baseline time series and strain parameter time series results both show that the study area is mainly NEE-trending compression deformation. In addition, before the earthquake, multiple baseline results and strain parameter time series deviated from the linear trend and gradually flattened, indicating a strain accumulation in the study area. The overall crustal deformation evolution shows a relatively high earthquake risk before the Lajishan earthquake.