Sinking city under observation

An associate research professor of marine geology and geophysics believes Venice, Italy, may be in danger.

The city, founded in A.D. 421, has been under observation for the past six years. Researchers have noticed a steady rise in its sea level – it has been consistently rising 2 millimeters per year since the study started. In addition, the city is sinking at the same rate, resulting in a total 4 millimeters a year increase of water level rising in comparison to the land.

“Today it may not seem like it makes a big difference but in the long run it will with the accumulating effect,” said Shimon Wdowinski, associate research professor of marine geology and geophysics.

The study is among several others Rosenstiel School of Marine and Atmospheric Science (RSMAS) research professors and graduate students undertake in order to examine the effects of long-term coastal living. In this particular study, RSMAS has collaborated with the University of California-Santa Barbara to install GPS instruments in locations across Venice. These monitored the movement of the Earth’s surface. The American researchers conferred with Italy’s Tele-Rilevamento Europa, a company that measures ground deformation. The company set up satellite radars to determine the elevation of the land in relation to other points.

Using data collected from these two instruments, researchers were able to determine that Venice was still sinking despite that prior studies had indicated that it had stabilized. These earlier studies had only used satellite radars to collect data.

“The advantage to using both methods is that we got a very precise idea of the level of sea and land when we combined them,” Wdowinski said.

The GPS instruments also showed that Venice is tilting eastward, according to the study, which was published in Geochemistry, Geophysics, Geosystems, a journal of the American Geophysical Union.

Venice’s rising sea levels are a result of climate change, while its sinking is caused by plate tectonics, according the to the study.

It was determined during the last century that the city was sinking, according to Wdowinski.

“Venice subsided very fast in the 40s, 50s, and 60s when they extracted gas and pumped groundwater,” he said. “They stopped in the 80s but it still continued.”

Currently, a billion-dollar initiative called the MOSE Project, which which stands for Modulo Sperimentale Elettromeccanio and translates to Experimental Electromechnaical Module in English, aims to create a defense system to separate the Venetian Lagoon from the Adriatic Sea, said Wdowinski. Gates will be able to be raised in order to prevent high tides in the city.

NASA recently granted Wdowinski funds to conduct research in Mexico, where water extraction from land below the Earth’s surface has caused the land to sink. He also previously researched land surface movement in New Orleans.