Challenges of interpreting geodetic deformation in low strain rate regions: Insights from the 2021 MW 7.4 Maduo earthquake

Rutland, Conor, Bie, Lidong, Johnson, Jessica H., Ou, Qi and Mildon, Zoë K. (2026) Challenges of interpreting geodetic deformation in low strain rate regions: Insights from the 2021 MW 7.4 Maduo earthquake. Tectonophysics, 929. ISSN 0040-1951

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Abstract

Interseismic deformation and strain rates derived from Global Navigation Satellite Systems (GNSS) or Interferometric Synthetic Aperture Radar (InSAR) data are often used to assess a fault’s earthquake potential. Deformation rates, commonly derived from short-term geodetic observations, are assumed to be indicative of long-term strain accumulation, and variations in strain rate throughout the interseismic period are poorly studied. Many regions have limited spatial and temporal coverage of GNSS data, and using InSAR presents challenges on low strain rate faults, where the signal-to-noise ratio is low. As a case study, we examine the interseismic period prior to a large intraplate left-lateral strike-slip earthquake: the 2021 MW 7.4 Maduo Earthquake. Using InSAR, we derive eastward velocities and maximum shear strain rates, whilst minimising the influence of near-field GNSS data, for two-year, three-year and six-year time periods. We investigate the sensitivity of geodetic deformation rate to the temporal observation window, and find that transient variations in deformation vary in a spatial pattern that cannot be unequivocally attributed to tectonic motion, given the uncertainty of InSAR data in the region. We do, however, observe a consistently low strain rate on the seismogenic fault. This study highlights the challenges faced when trying to obtain meaningful geodetic measurements on low strain rate faults, bringing to question the utility of strain rate as a proxy for seismic hazard in continental block interiors.

Item Type:	Article
Additional Information:	Data availability: The datasets S1–S30 listed in the supporting information are available at: https://doi.org/10.5281/zenodo.14773362. The interferograms used in the study are available from LiCSAR (Lazecký et al., 2020). Time series processing was carried out using LiCSBAS (Morishita et al., 2020). InSAR frames were mosaiced and decomposed using code developed by Ou et al. (2022b). GNSS eastward velocities were obtained from the following studies: Liang et al., 2013, Diao et al., 2019, Wang and Shen, 2020. Moment tensor solutions are available at the Global Centroid Moment Tensor project (Dziewonski et al., 1981, Ekström et al., 2012). Historical earthquake data are available from USGS (2024). DEM grid files use SRTM1 data and are available from GMTSAR at: https://topex.ucsd.edu/gmtsar/demgen/. Figures were made with Matplotlib version 3.8.4 (Hunter, 2007). Maps were created using Generic Mapping Tools (GMT) version 6 (Wessel et al., 2019). Figures and maps use Scientific Colour Maps (Crameri, 2023).
Uncontrolled Keywords:	interseismic deformation,insar,maduo earthquake,tibetan plateau
Faculty \ School:	Faculty of Science > School of Environmental Sciences
UEA Research Groups:	Faculty of Science > Research Groups > Geosciences
Depositing User:	LivePure Connector
Date Deposited:	26 May 2026 08:49
Last Modified:	26 May 2026 08:49
URI:	https://ueaeprints.uea.ac.uk/id/eprint/103138
DOI:	10.1016/j.tecto.2026.231170

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