The Russian city of Berezniki was built atop an undergound mine during the dark days of Soviet-era madness, so it’s constantly prone to rapidly forming sinkholes capable of swallowing people or buildings whole. In order to safeguard the more than 150,000 residents, scientists constantly monitor the situation with a dizzying array of surveillance cameras. But even that may not be enough to save the burg. From Andrew E. Kramer in the New York Times:
“Mining engineers first tried to maintain the supports by pumping in saltwater, intending to raise the salinity of the floodwater to the saturation point before the structure collapsed, but that did not work.
After that, the local government adopted the policy in effect today, of careful observation and early warning: geologists, surveyors and emergency personnel use a panoply of high-technology monitors. These include the video surveillance system, seismic sensors, regular surveys and satellite monitoring of the changes in altitude of roofs, sidewalks and streets.
‘We will fight the holes with science,’ the mayor, Sergei P. Dyakov, said in an interview. The city will not need to relocate, he said, because engineers believe that no new holes will open. Much of the mine was filled before the flood, he said, and the sinkholes occurred in an anomalous area that had not been filled in.
But federal officials and company executives are debating whether to relocate the entire city to the opposite bank of the Kama River, where the bedrock is solid.”