Open Geosciences (Jul 2023)
Characteristics of the present crustal deformation in the Tibetan Plateau and its relationship with strong earthquakes
Abstract
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 Nepal M S 8.1 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 Wenchuan M S 8.0 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.
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