Source Parameters of Recent Earthquakes from Sentinel-1 InSAR Data

Karlee M. Rivera, & Gareth J. Funning

Published September 11, 2022, SCEC Contribution #12561, 2022 SCEC Annual Meeting Poster #081

This study presents results of routine modeling of recent, moderate-sized earthquakes (5.6 ≤ M ≤ 6.6) with Sentinel-1 InSAR data. We process interferograms using the ISCE software, and downsample them using a quadtree decomposition. We model the downsampled data, to estimate the fault geometry and other source parameters, using a rectangular dislocation model in an elastic half space with uniform slip. To find the best fitting model, we use a Powell algorithm with multiple Monte Carlo restarts.

We model two earthquakes that occurred in NE Tibet in 2022. This area is controlled by ESE-trending thrust faults and strike slip faults near the Qilian Mountains. The M 6.6 Qinghai earthquake occurred on January 7th. Our results show that the earthquake occurred on an ESE-striking structure with left-lateral strike-slip movement. These results suggest that the over strike-slip movement of the plateau. The M 5.6 Loajunmiao earthquake occurred on January 23rd. Our results show that this earthquake occurred on a NNW-striking structure with right-lateral strike-slip movement. We interpret this as a secondary, conjugate fault.

We model two earthquakes from the SE Zagros of Iran from the past 12 months. The M 6.4 Bandar Abbas earthquake occurred on November 14th, 2021. Our modeling results show an ENE-striking structure with thrust movement, which follows the overall change of strike in the area. The M 6.0 Bandar-e Lengeh event occurred on July 1st, 2022. The preliminary results show a shallow north-dipping, ESE-striking thrust, which may be reflective of the change of strike in the SE Zagros fault zone. We modeled both nodal planes but favored the shallower dipping model due to its better misfit overall.

The M 5.9 Hualien City earthquake occurred on June 20, 2022 in eastern Taiwan, an area dominated by reverse faulting. Our preliminary models show that both nodal planes fit the data approximately equally well. However, the proximity to the active Chihshang fault zone suggests that the SE-dipping nodal plane is likely the source fault.

The M 6.0 Khost earthquake occurred on June 21th, 2022 in eastern Afghanistan, part of the Indian-Eurasian plate boundary zone. Our preliminary model shows that the event occurred on the shallow portion of a NNE-striking fault with left-lateral strike-slip. The strike of the fault is oblique to the local plate boundary motion suggesting that there may be local slip partitioning.

Key Words
InSAR, Source Parameters

Citation
Rivera, K. M., & Funning, G. J. (2022, 09). Source Parameters of Recent Earthquakes from Sentinel-1 InSAR Data. Poster Presentation at 2022 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy