Subsidence affecting many new builds, raising questions about sustainability of skyscrapers in coastal areas

Miami’s oceanfront skyscrapers are sinking. In 2021 the devastating collapse of the Champlain Towers South condominium in Miami’s Surfside resulted in the loss of 98 lives, and prompted closer inspection of the city’s high-rise shoreline. Now a study has identified unexpected levels of subsidence among many of Miami’s high-rise buildings, including prominent luxury properties such as the Porsche Design Tower, Trump Tower III and Trump International Beach Resort.

Using satellite data gathered between 2016 and 2023, researchers observed between 2cm and 8cm of sinking of buildings along Miami’s beachfront area. One beachfront – Sunny Isles Beach – recorded continuous subsidence in more than 70% of its new builds. The findings, published in Earth and Space Science, show the majority of affected buildings were recently constructed high-rises. Which means it is possible the subsidence is a consequence of their own construction. The combination of hefty high-rise buildings, vibration from construction, groundwater movement and tidal flows are potentially triggering the subsidence, with the worst-affected areas being those with a sandy layered limestone underlying them.