Miami’s barrier islands are home to many tall 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 across Florida’s Sunny Isles Beach, Surfside, Miami Beach and Bal Harbour have faced subsidence in the past handful of years, the study found.
It was authored by researchers from the University of Miami, Florida Atlantic University, University of Houston, University of Hanover in Germany, GFZ German Research Centre for Geosciences and California Institute of Technology.
It involved reviewing Interferometric Synthetic Aperture Radar data.
The sinking of the high-rises amounted to 2-8 centimeters over a multiyear span running 2016 through 2023, according to the researchers.
High-rises expect to see “up to several tens of centimeters” of settlement “during and immediately after construction,” the University of Miami Rosenstiel School said in a Friday post on its website.
Builders constructed a “majority” of the affected condos and hotels after 2014, according to the study.
“We found that subsidence in most high-rises slows down over time, but in some cases, it continues at a steady rate. This suggests that subsidence could persist for an extended period,” senior author Falk Amelung was quoted as saying.
The study authors had some theories about what was behind the subsidence, based on their research.
The sinking “is primarily due to the gradual reconfiguration of the sand grains into a denser packing within sandy layers interbedded in the 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 stormwater injection could also have factored into the phenomenon.
“The discovery of the extent of subsidence hotspots along the South Florida coastline was unexpected. The study underscores the need for ongoing monitoring and a deeper understanding of the long-term implications for these structures,” lead author Farzaneh Aziz Zanjani said.
The broader 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, per the Greater Miami Convention and Visitors Bureau.