South Florida sees dozens of luxury high-rises begin to sink

Miami’s barrier islands are home to many high-rise luxury buildings and, according to a study recently published in Earth and Space Science, about three dozen are sinking.

Thirty-five luxury condos and hotels throughout Florida’s Sunny Isles Beach, Surfside, Miami Beach and Bal Harbor have faced landslides over the past several years, the study found.

It was compiled by researchers from the University of Miami, Florida Atlantic University, the University of Houston, the University of Hanover in Germany, the German GFZ Research Center for Geosciences and the California Institute of Technology.

It involved the review of Interferometric Synthetic Aperture Radar data.

According to the researchers, the subsidence of the high-rise reached 2-8 centimeters over a multi-year period from 2016 to 2023.

Tall buildings expect to see “up to several tens of centimeters” of settlement “during and immediately after construction,” the University of Miami’s Rosenstiel School said in a Friday post on its website.

Builders built a “majority” of the affected apartments and hotels after 2014, according to the study.

“We found that subsidence in most tall buildings slows over time, but in some cases, it continues at a steady pace. This suggests that the decline may continue for a long period,” senior author Falk Amelung was quoted as saying.

The study authors had several theories about what was behind the decline, based on their research.

The subsidence “is mainly due to the gradual reconfiguration of sand grains into a denser pack within the interbedded sandstone layers in limestone” in the area, the study said.

The researchers hypothesized a link between construction-related vibrations or groundwater flow and the sinking, according to the study. Other things like daily tidal flow and storm water injection may also have been a factor in this phenomenon.

“The discovery of the extent of subsidence hotspots along the South Florida coastline was unexpected. The study underscores the need for continued monitoring and a deeper understanding of the long-term implications for these structures,” said lead author Farzaneh Aziz Zanjani.

Greater Miami-Dade County had a population of nearly 2.7 million people as of July 2023, according to the U.S. Census Bureau.

More than 27.2 million people visited the area last year, through the Greater Miami Convention and Visitors Bureau.