Although the Millennium Tower's developer, Millennium Partners, continues to insist the condo building is safe for occupancy and could withstand an earthquake, satellite data shows the tower sunk 1.75 inches over a recent one-year period and almost double that amount —2.95 inches — over its 17-month observation period. Petar Marinkovic, founder and chief scientist of PPO Labs, analyzed Sentinel-1's satellite radar imagery for the ESA along with Norway-based research institute Norut. Sentinel-1 orbits the Earth about 435 miles up.
"What can be concluded from our data, is that the Millennium Tower is sinking at a steady rate," Mr Marinkovic said. "There is quite a steady subsidence."
Millennium Partners spokesman PJ Johnston said he had no direct comment on the satellite data but issued a statement saying the Millennium Tower is a "state-of-the-art building" that was "designed and constructed to the extraordinarily high standards" mandated by San Francisco.
He reiterated the developers' blame for the tower's problems on the city's construction of an adjacent railway station, which they say removed ground water from beneath the Millennium Tower that caused it to sink and tilt.
San Francisco Transbay Joint Powers Authority blames the building's "inadequate foundation" which is not anchored to bedrock. The tower is supported by piles driven 60 to 89 feet into landfill. Engineers hired by the building and its developers have drilled deep holes around the building to test soil samples to determine if the building has stopped sinking.
Owners, developers, and the city are trying to figure out a fix.