Dozens of luxury beachfront condos and hotels in Surfside, Bal Harbour, Miami Beach and Sunny Isles are sinking into the ground at rates that were “unexpected,” with nearly 70 percent of the buildings in northern and central Sunny Isles affected, research by the University of Miami found.

The study, published Friday night, identified a total of 35 buildings that have sunk by as much as three inches between 2016 and 2023, including the iconic Surf Club Towers and Faena Hotel, the Porsche Design Tower, The Ritz-Carlton Residences, Trump Tower III and Trump International Beach Resorts. Together, the high rises accommodate tens of thousands of residents and tourists. Some have more than 300 units, including penthouses that cost millions of dollars.

“Almost all the buildings at the coast itself, they’re subsiding,” Falk Amelung, a geophysicist at the University of Miami’s Rosenstiel School of Marine, Atmospheric and Earth Science and the study’s senior author, told the Miami Herald. “It’s a lot.”

Preliminary data also shows signs that some buildings along the coasts of Broward and Palm Beach are sinking, too.

A new study by University of Miami researchers shows a string of beachside high rises in Sunny Isles, the skyline shown here, along with Bal Harbour, Surfside and Miami beach have been sinking into the ground at unexpected rates.

 

Sinking Condos in Miami-Dade

A new University of Miami study found that these 35 high-rise towers in Miami-Dade were sinking several inches into the ground between 2016-2023.

Experts called the study a “game changer” that raises a host of questions about development on vulnerable barrier islands. For starters, experts said, this could be a sign that rising sea levels, caused by the continued emission of greenhouse gases, is accelerating the erosion of the limestone on which South Florida is built.

“It’s probably a much larger problem than we know,” Paul Chinowsky, a professor of civil engineering at the University of Colorado Boulder, told the Herald.

Initially, researchers looked at satellite images that can measure fractions of an inch of subsidence to determine whether the phenomenon had occurred leading up to the collapse of Champlain Towers in Surfside, the 2021 catastrophe that killed 98 people and led to laws calling for structural reviews of older condos across the state. The researchers did not see any signs of settlement before the collapse “indicating that settlement was not the cause of collapse,” according to a statement.

 

 

Instead, they saw subsidence at nearby beachside buildings both north and south of it.

 

Surprising findings

“What was surprising is that it was there at all. So we didn’t believe it at the beginning,” Amelung said, explaining that his team checked several sources that confirmed the initial data. “And then we thought, we have to investigate it,” he said.

In total, they found subsidence ranging between roughly 0.8 and just over 3 inches, mostly in Sunny Isles Beach, Surfside, and at two buildings in Miami Beach – the Faena Hotel and L’atelier condo – and one in Bal Harbour.

It’s unclear what the implications are or whether the slow sinking could lead to long-term damage, but several experts told the Herald that the study raises questions that require further research as well as a thorough on-site inspection.
 

“These findings raise additional question which require further investigation,” Gregor Eberli, a geoscience professor and co-author of the study, which was published Friday in the journal Earth and Space Science, said in a statement. Lead author Farzaneh Aziz Zanjani pointed to the need for “ongoing monitoring and a deeper understanding of the long-term implications for these structures.”

Though the vast majority of affected buildings were constructed years or decades before the satellite images were taken, it is common for buildings to subside a handful of inches during and shortly after construction — a natural effect as the weight of the building compresses the soil underneath.

And sinking doesn’t necessarily create structural issues.

“As long as it’s even, everything’s fine,” Chinowsky said, placing his hands next to each other, “the problems start when you start doing this,” he said, then moving one hand down faster than the other.

But such uneven sinking, known as differential subsidence, can cause significant damage to buildings, he said. “That’s where you can get structural damage,” he said. More research is needed to determine whether the buildings are sinking evenly or not.

High-rise building dominate the skyline of the coast of Miami-Dade County, from Sunny Isles Beach down to Miami Beach. A new study by University of Miami researchers shows at least 35 buildings in the stretch have sunk by as much as three inches between 2016 and 2023.

 

An uncertain impact

“Sometimes it can be dangerous, sometimes not – it will have to be evaluated,” said Shimon Wdowinski, a geophysicist at Florida International University, told the Herald. Wdowinski worked on a different 2020 study that showed that the land surrounding the Champlain Towers – not the buildings themselves – had been subsiding back in the nineties, though that alone couldn’t have led to the collapse. The National Institute of Standards and Technology (NIST) has yet to release a final report on the cause but a Herald investigation pointed to design and construction flaws as well as decades of maintenance issues.