'Leaning Tower of SF' Is Sinking Faster Than Thought
Satellite images show descent of Millennium Tower
By Elizabeth Armstrong Moore,  Newser Staff
Posted Dec 1, 2016 2:40 PM CST
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Data from the Sentinel-1 satellites acquired between February 2015 and September 2016 show that Millennium Tower in San Francisco is sinking nearly two inches a year.   (ESA/NASA - SOHO/LASCO )

(Newser) – There's no question that the 58-story Millennium Tower in downtown San Francisco is both sinking and tilting. But new satellite images find that its progress into the sand below is nearly twice the pace previously thought—close to two inches a year instead of one, reports NBC News. Since the skyscraper was completed on the edge of the city's Financial District in 2009, it has sunk 16 inches and now leans two inches to the northwest. New York-based Millennium Partners tells the San Francisco Business Times that the skyscraper is just one of several area buildings developed in the Colma Formation of sand, and the European Space Agency images confirm that multiple other buildings are sinking as well.

Millennium Partners first announced the tower was sinking in August, and lawsuits have already been filed by regulators, including the San Francisco City Attorney, as well as homeowners concerned over the sinking value of their investments in the $350 million building. Two homeowners have also filed a civil claim against the city and Transbay Joint Powers Authority over concerns that nearby activity may have removed groundwater, thus making the ground less stable. The "leaning tower of San Francisco" was observed using the ESA's Sentinel-1 satellites, which are in orbit at 400 miles and track fault lines and ground movement, reports Extreme Tech. Some experts suggest the building is shifting because it rests on 950 friction piles buried up to 90 feet deep that don't actually reach bedrock. (Meanwhile, a sinkhole in Japan sinks some more.)
 

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