Surface Displacement Monitoring for Natural and Anthropogenic Hazard Applications: From Tectonics to Urban Subsidence

Surface displacement measurements from satellite Synthetic Aperture Radar (SAR) have become a critical observational tool for understanding a wide range of natural and anthropogenic processes, including tectonic deformation, landslides, and coastal subsidence. Increasing revisit frequency and data availability now enable systematic monitoring across diverse spatial and temporal scales.

We present an application-focused assessment of InSAR displacement monitoring across multiple hazard contexts, drawing on examples from California, Texas, Hawaii, Alaska, and New York in the USA. These case studies demonstrate how InSAR time-series observations can disentangle overlapping deformation signals associated with tectonics, slope instability, volcanic unrest, groundwater-related and coastal subsidence. These examples are framed in the context of practical applications by state and federal agencies, including hazard assessment, infrastructure planning, and coastal risk analysis, highlighting the importance of spatially consistent, operationally usable displacement products. Specifically, we show how variable coastal subsidence impacts present and future sea level estimates for policy decision making in California. We assess the exposure of critical infrastructure, such as petroleum above ground storage tanks, to subsidence and flooding during hurricane events in Houston, Texas. In New York City, we demonstrated natural and anthropogenic vertical land motion impacts on local communities. In volcanic settings, displacement time series are being evaluated by volcano observatories for operational use to detect anomalous trends and characterize evolving surface deformation associated with active and re-awakened systems, including Mauna Loa and Kilauea volcanoes in Hawaii, as well as Mount Edgecumbe volcano in Alaska. Lastly, we demonstrate the use of the displacement time-series to map the spatial extent and slope instability of the Palos Verdes landslide in Los Angeles, California, adding additional observational context for informed decision making by local authorities.

This work is performed using OPERA Surface Displacement (DISP) products, which provide spatially consistent, large-scale InSAR displacement fields derived from C-band Sentinel-1 data over North America beginning from 2016. Analyses are supported by advanced and state-of-the-art spatial time-series algorithms designed to support continental-scale processing and a newly developed global tropospheric correction dataset based on the ECMWF High-Resolution Forecast (HRES) numerical weather model. Looking forward, OPERA will incorporate observations from the L-band NASA-ISRO SAR (NISAR) mission, providing continuity and enhanced capability in challenging environments for future displacement monitoring. All OPERA datasets are freely available through NASA archives, and the associated algorithms are developed in open-source repositories, enabling broad scientific reuse, reproducibility, and application.