Analysis of Seismic Cycle Deformation for the Ms7.1 Wushi Earthquake in Xinjiang Based on Geodetic Data

On January 23, 2024, an Ms7.1 earthquake struck Wushi County, Aksu Prefecture, Xinjiang. While resulting in relatively limited casualties and economic losses, the event posed a certain threat to the geological safety of the Tianshan region. The Tianshan seismic belt has a history of intense seismic activity, with 17 recorded earthquakes of magnitude 7 or greater since 1716, including four exceeding magnitude 8. Notably, the Wushi earthquake is the largest event in this belt since the 1992 Ms7.3 Suusamyr earthquake in Kyrgyzstan. The 1992 Suusamyr earthquake was the first in the Tianshan region recorded by broadband digital seismographs, whereas the recent Wushi earthquake presents a valuable opportunity for a detailed case study using modern high-precision geodetic techniques. Occurring at the junction of the South Tianshan and the Wushi Basin, this event provides a crucial chance to investigate the deformation characteristics of strong earthquakes within the Tianshan seismic belt and to reveal the associated seismogenic structures and mechanisms. This research carries significant implications for understanding fault activity absorption mechanisms within the Tianshan Mountains and the characteristics of active deformation along the boundary between the Tianshan orogen and its foreland basin.For the Wushi earthquake area, we acquired Sentinel-1 satellite data and GNSS data covering the region. Pre-seismic data collection included 200 frames from Sentinel-1 ascending track (T56) and 208 frames from descending track (T136). For co-seismic deformation analysis, data from tracks T56, T136, and T34 were utilized. Post-seismic data comprised 44 frames from track T56 and 36 frames from track T136. Time-series InSAR and D-InSAR methods were employed to derive regional deformation. The co-seismic results show significant line-of-sight surface deformation in both ascending and descending tracks, with a maximum displacement of approximately 75 cm. Fault slip distribution inversion indicates that the earthquake occurred on a northwest-dipping, left-lateral strike-slip fault with a variable strike and a thrust component. Co-seismic slip was primarily concentrated at depths between 4 and 25 km. Post-seismic deformation results suggest that short-term deformation was mainly induced by an Ms5.7 aftershock. Pre-seismic GNSS deformation results reveal differential crustal activity between the eastern and western sections of the Maidan Fault Zone within the study area, with higher activity observed in the eastern segment where the Wushi earthquake occurred.Future work will involve analyzing pre-seismic InSAR deformation results to obtain long-term, large-scale seismic cycle deformation fields for the Tianshan earthquake region. The co-seismic slip motion consistency model will be applied to analyze the seismogenic structure and mechanism of the Wushi earthquake. Furthermore, numerical simulations will be employed to elucidate the coupling mechanisms of various post-seismic deformation effects, such as afterslip, viscoelastic relaxation, and pore rebound, following the Wushi earthquake. This integrated approach aims to establish a more systematic understanding of the earthquake's seismogenic mechanism and its post-seismic deformation processes.