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Post-Earthquake Fold Growth Imaged in the Qaidam basin, China, With InSAR
  • Simon Daout,
  • Barry E. Parsons,
  • Richard Thomas Walker
Simon Daout
Department of Earth Sciences, University of Oxford

Corresponding Author:[email protected]

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Barry E. Parsons
University of Oxford
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Richard Thomas Walker
University of Oxford
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Abstract

Questions regarding the development of folds and their interactions with the seismic faults within thrust systems remain unanswered. However, estimating fault slip and earthquake hazards using surface observations and kinematic models of folding requires an understanding of how the shortening is accommodated during the different phases of the earthquake cycle. Here, we construct 16-years of InSAR time series across the North Qaidam thrust system (NE Tibet), where three Mw 6.3 earthquakes occurred along basement faults underlying shortened folded sediments. The analysis reveals spatio-temporal changes of post-seismic surface displacement rates and patterns, which continue more than ten years after the seismic events. The decomposition of the Sentinel-1 ascending and descending LOS velocities into vertical and shortening post-seismic components indicates that long-term transient uplift and shortening coincide spatially with young anticlines observed in the geomorphology and cannot simply be explained by elastic slip along dislocations. These findings provide evidences for fold buckling during the post-earthquake phase and highlight the contribution of distributed aseismic deformation to the growth of topography.