Vertical land motion (VLM), particularly subsidence in coastal urban environments, poses a significant geohazard to the resilience of transportation infrastructure by exacerbating the frequency and duration of flooding. Moreover, differential subsidence introduces angular distortions that compromise the integrity of rigid structures such as roads, runways, and subway lines. In this study, we applied interferometric synthetic aperture radar (InSAR) analysis to detect and quantify subtle, millimeter-scale elevation changes across New York City (NYC). Our results reveal that several sections of NYC highways are subsiding at rates exceeding 2 mm/yr. Notably, spatially variable, or differential, subsidence along these corridors heightens the geohazard exposure of key transport routes. We estimate economic risk exposure at ~$9.43 billion for 6.07 km of subways and $10.70 billion for 49.14 km of highways affected by subsidence exceeding -2 mm/yr. These findings provide essential input for urban planners and engineers, supporting the development of more resilient transportation systems in NYC.
Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025