Although previous studies had found that Venice has stabilized, new measurements indicate the historic city continues to slowly sink, and even to tilt slightly to the east.
“Venice appears to be continuing to subside at a rate of about 2 millimeters a year,” said Dr. Yehuda Bock, a research geodesist with Scripps Institution of Oceanography at the University of California, San Diego. “It’s a small effect, but it’s important.”
Bock worked with colleagues from the University of Miami’s Rosenstiel School of Marine & Atmospheric Science and Italy’s Tele-Rilevamento Europa, a company that measures ground deformation, to analyze data collected by GPS and space-borne radar (InSAR) instruments regarding Venice and its lagoon. TheGPSmeasurements provide absolute elevations, while the InSAR data are used to calculate elevations relative to other points. By combining the two datasets from the decade between 2000 and 2010, Bock and his colleagues found that Venice was subsiding an average of 1 to 2 millimeters a year (0.04 to 0.08 inches per year). They also found the patches of land in Venice’s lagoon (117 islands in all) are sinking.
Image courtesy of GeoEye.