This study presents a systematic uncertainty quantification of the two-track InSAR three-dimensional (3D) deformation field of the 2025 Dingri earthquake (Mw 7.1). Using Sentinel-1 ascending and descending track data, a 3D coseismic displacement field was constructed via least-squares inversion. The results revealed that the earthquake produced a north–south-striking normal fault rupture, with the vertical component reaching a maximum subsidence of −403.3 mm and a maximum uplift of +621.1 mm, and the east–west component reaching a maximum westward displacement of −592.3 mm and an eastward displacement of +332.1 mm. Uncertainty analysis reveals a divergence between formal errors and actual accuracy: formal error propagation yields 1σ uncertainties of 1.09 mm and 1.38 mm for the vertical and east–west components, respectively; a realistic error budget based on Monte Carlo simulations indicates that the actual errors are approximately 13.8 mm for the vertical component and 17.2 mm for the east–west component, with systematic error contributions far exceeding random noise. Cross-validation against an independent Sentinel-1 processing chain supports the above error assessment: the correlation coefficient R for ascending track line-of-sight (LOS) displacement is 0.88, whereas it is 0.62 for the descending track; for the three-dimensional components, R reaches 0.88 for the vertical component and 0.59 for the east–west component, with discrepancies arising primarily from the greater sensitivity of the east–west component to processing strategies and observation geometry. This study demonstrates that formal error propagation underestimates the actual uncertainty of two-track InSAR inversion and that systematic error sources contribute far more than random noise does.
Zhangdi Xie (Tue,) studied this question.