ON JUNE 24, 2021, at about 1:22 a.m. in the oceanside Miami suburb of Surfside, Florida, a 12-story beachfront condominium named Champlain South partially collapsed, killing 98 people.
Back then, I warned through Philippine media that Champlain South was 40 years old, and that over time its concrete slowly absorbed salty sea air that rusted its steel reinforcing bars. This caused “concrete cancer,” fatally weakening it. Strong vibrations from pile-driving during construction of the Eighty Seven Park condo next door have also been blamed.
My worry was that much construction in Metro Manila uses much Pinatubo lahar sand, which is exceptionally porous. Furthermore, any construction on Manila Bay reclamations would doubtless also use Pinatubo sand, and the salty bay breezes would especially threaten those structures.
I have warned for many years about the dangers that confront people who build and live on reclaimed nearshore: land subsidence, earthquake-generated liquefaction and tsunamis, storm surges and waves from the strong typhoons that climate change is making more frequent.
Now, news from Miami has yet another serious implication for reclaimed land along Manila Bay.
It is described in a recent CNN report (“Dozens of luxury condos and hotels in Florida are sinking, study finds”: cnn.com/2024/12/23/climate/florida-condos-hotels-sinking/index.html). The title of the scientific study that CNN reported on says it all: “InSAR Observations of Construction-Induced Coastal Subsidence on Miami’s Barrier Islands, Florida” (emphasis mine).
In short, buildings already standing on reclaimed land will subside or suffer damage as construction of new buildings as far away as 320 meters cause the land to vibrate, expel the water between sediment grains, and settle.
Along the 15-mile (24-kilometer) stretch from Golden Beach South to Miami Beach, 35 buildings in which tens of thousands of people live, have subsided an average of 2.6 inches per decade from 2016 to 2023. These buildings include two massive Trump edifices, and both Ritz-Carlton Residences and Surf Club Towers. The underlying rocks are young coralline limestone with interfingered sandy layers; not the best foundation, but with more strength and structural integrity than Manila Bay reclamations.
The multinational research was conducted by marine, earth, and atmospheric scientists of the University of Miami, the California Institute of Technology, the University of Houston, and several German institutions. It was led by the University of Miami’s Dr. Falk Amelung. How the ground subsided was monitored from space with satellites using “InSAR” – Interferometric Synthetic Aperture Radar.
This is the same technique that Filipino scientists collaborating with Dr. Amelung used to evaluate land subsidence in the Metro Manila region (published in 2020 as Eco, Rodrigo C., Kelvin S. Rodolfo, Jolly Joyce Sulapas, A. M. Morales Rivera, A. M. F. Lagmay, and F. Amelung, “Disaster in slow motion: Widespread land subsidence in and around Metro Manila, Philippines quantified by InSAR time-series analysis.” JSM Environmental Science & Ecology 8, no. 1.)
The 2021 Champlain South disaster has also been blamed on strong vibrations from pile-driving during construction of the Eighty Seven Park condo next door.
What this all means is that structures built on Manila Bay reclamations may not even need natural forces to damage or destroy them: vibrations and subsidence from newer structures being built hundreds of meters away can do the job.
I have given up my efforts to convince the powers-that-be to stop the reclamations. Instead, I appeal to the common sense of would-be investors.
If you want to buy or build on reclaimed land, first make sure you can buy damage insurance.
If you cannot get insurance, be forewarned.
If the financial backers of reclamation are so certain such investments are safe, surely they will be glad to be the insurers themselves.
If they refuse to do so, what does that tell you?
Have a happy, environmentally, ecologically, and financially sound New Year!
Kelvin S. Rodolfo, PhD is the professor emeritus of Earth & Environmental Sciences at the University of Illinois, Chicago and a senior research fellow at the Manila Observatory.
