While studying satellite data from the 1990s, FIU earth sciences professor Shimon Wdowinski discovered evidence that parts of Miami Beach and Surfside have been gradually sinking for decades. In a video interview produced by FIU, Wdowinski said that included the precise spot of Thursday's building collapse.
Wdowinski's study was published last year in the Ocean & Coastal Management journal.
In the video interview Wdowinski said the findings in Surfside were unexpected. While the western part of the barrier island was built on reclaimed wetland, which is more susceptible to sinking, the eastern side was built on a rockier, more solid foundation. Nevertheless, Wdowinski said he and his team noticed an unusual pocket of movement underneath the 12-story condo building, which is on the eastern side along the oceanfront.
According to the satellite data Wdowinski collected, the condo was sinking at a rate of about 2 millimeters per year from 1993 to 1999.
Authorities still don't know the cause of the devastating collapse at Champlain Towers, which was built in 1981. Atorod Azizinamini, chair of FIU's engineering college, also appears in the interview clip; he noted that an investigation into the cause of the collapse could take months.
While the gradual sinking in and of itself is unlikely to have caused the collapse, Wdowinski said, any time a building and the ground underneath it start to move, it's alarming.
A separate study conducted by Wdowinski and also published in 2020 found structural damage at several other sinking areas in Miami, mostly around Biscayne Bay. The study showed cracks on structures at Matheson Hammock Park, Morningside Park, Haulover Park, and FIU's Kovens Conference Center, all of which were built between 1930 and 1960 on reclaimed marshland.
Images included in the study show cracks in sidewalks, stairs, and seawalls at the locations. While the researchers didn't warn of imminent danger at those sites, they noted that the damage suggests Florida's southeast coast is gradually sinking in various places around Miami-Dade County.
The process of gradual sinking is known as land subsidence. In South Florida, it's often caused when developers build upon reclaimed wetlands. Buildings and cement structures press down on the underlying rock, squashing it in a process called sediment compaction and placing it under intense pressure over time. In some parts of Florida, the process can cause sinkholes.
Wdowinski's study concluded that the double whammy of sea-level rise and land subsidence may lead to further property damage and flood risk in South Florida in the future. Wdowinski believes the satellite technology used in his studies can help detect vulnerable buildings and prevent future disasters.