Image From Space Shows Downtown San Francisco 'Slowly Sinking'

The sinking Millennium Tower has been a source of concern for San Francisco officials and residents for the past five years.

Now, one researcher says space-based observations have confirmed that not only is the city's most recognizable building sinking, but the entire downtown area surrounding it is sinking too.

“I looked at every building in the Bay Area, so just under a million buildings,” U.S Geological Survey research geophysicist Tom Parsons told NBC Bay Area. “Clearly, the most density and the tallest buildings are centered in that downtown San Francisco area, and that's where we see the most calculated cumulative settlement from all of those buildings together."

At an estimated 686 million pounds, the Millennium Tower is the third heaviest building in the city. While the top nine all weigh more than 300 million pounds, the Millennium is the only one that's sinking and leaning significantly.

According to NBC Bay Area, the tower's developers believe groundwater loss from nearby construction can be blamed for the problems. However, geotechnical experts say that the key is the building's foundation not being rooted in bedrock.

The sinking area shows up clearly in images captured by the European Space Agency's Sentinel 1 satellite.

Luckily, the San Andreas fault runs offshore before it gets to the city so Parsons says these problems will not likely have seismic implications.