Intra-Frame Deformation Model: Improving the spatial resolution of vertical land motions through InSAR/GNSS integration

Lavoisiane Ferreira, Yehuda Bock, David T. Sandwell, & Aubrey Bennett

Submitted September 7, 2025, SCEC Contribution #14895, 2025 SCEC Annual Meeting Poster #TBD

We are developing an Intra-Frame Deformation Model (IFDM) to account for the deforming regions of the Western U.S. The project is funded by the National Geodetic Survey’s Geospatial Modeling Program as a complement to the new National Spatial Reference System, NATREF2022. We describe our efforts to integrate GNSS and InSAR to create precise weekly vertical displacement grids with spatial resolution (< 1km), finer than available at typical GNSS station spacings (~20-40km). Vertical land motion (VLM) is related to the Earth’s surface response due to natural (earthquakes, landslides and surface water variation) and anthropogenic causes (mining, groundwater injection/extraction and oil/gas exploration). Therefore, VLM often contains significant non-linear features that are difficult to model at sufficient spatial resolution with GNSS-only networks, for example, subsidence in the Central Valley that varies with the increase in groundwater extraction during droughts. We present a weekly time series of high-resolution vertical displacement grids from 2015-2022. The Sentinel-1 InSAR displacements grids were created using a coherence-based SBAS approach. Therefore, we tied the InSAR displacements to the GNSS displacements using SOPAC’s SECTOR utility, removed the horizontal component through the projection of the GNSS horizontal displacement grids in the line of sight from the satellite, and extracted the vertical. Besides its intrinsic scientific value, access to high-resolution grids of transient vertical motion tied to NATREF2022 contributes to a wide range of applications across both private and public sectors, such as flood risk, water management, agriculture, landslide monitoring, and infrastructure safety.

Citation
Ferreira, L., Bock, Y., Sandwell, D. T., & Bennett, A. (2025, 09). Intra-Frame Deformation Model: Improving the spatial resolution of vertical land motions through InSAR/GNSS integration. Poster Presentation at 2025 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy