
A new study led by scientists at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science reveals significant subsidence patterns affecting coastal buildings in South Florida. Using advanced satellite-based Interferometric Synthetic Aperture Radar (InSAR) technology, researchers documented vertical displacements ranging from 2 to 8 centimeters over a seven-year period (2016–2023). The study highlights 35 buildings, particularly along Sunny Isles Beach, Surfside, and Miami Beach, as experiencing ground sinking, with the most pronounced effects observed in Sunny Isles Beach.
Subsidence in the region stems from the geological composition of South Florida’s barrier islands, which feature layers of sand interbedded within porous limestone. This natural characteristic, combined with the weight and vibrations of high-rise construction, contributes to gradual settlement. Construction-induced vibrations, groundwater pumping for underground facilities, tidal flows, and stormwater injection exacerbate the sinking. Notably, while most subsidence slows over time, some sites exhibit steady rates of sinking, raising long-term concerns for structural stability.
The study found no evidence of ground displacement before the tragic 2021 collapse of the Champlain Towers South condominium in Surfside, which claimed 98 lives. However, subsidence in other areas highlights risks to older buildings, especially when nearby construction disturbs sandy subsurface layers. In Sunny Isles Beach, where newer developments dominate, subsidence often aligns with recent construction, impacting both the new structures and nearby buildings.
The findings underscore the importance of ongoing monitoring to mitigate potential risks. Researchers recommend using satellite-based systems to track subsidence and establishing a public database to inform residents and authorities of subsidence rates and affected areas. Such efforts can enable timely inspections and proactive measures, such as reinforcing foundations.
The study also emphasizes the need for further investigation into differential settlement, where parts of a building sink at varying rates, which can cause internal stresses and long-term structural damage. Researchers propose drilling sediment cores and testing limestone samples to better understand the mechanics of subsidence and its interaction with local geology.
These insights, published in the journal Earth and Space Science, highlight the critical need for Florida officials and residents to prioritize structural monitoring and consider potential risks as coastal development continues. The innovative use of satellite technology demonstrates its potential as a tool for improving the safety and resilience of urban infrastructure in vulnerable regions.