NR-1 Sinkhole NR-1 Sinkhole The NR-1 Sinkhole is a giant underwater sinkhole located in the Straits of Florida southwest of Key West, Florida. It is found at an approximate depth of of water at the foot of the Pourtales Escarpment, an area of Quaternary sediment. It was discovered in October 1994 during a survey conducted by the American submarine NR-1, a U.S. Navy nuclear research submarine, and is named for the submarine. It was first identified via side-scan sonar and near-bottom echo sounder data, prompting a second survey in May 1995 to confirm the finding. Discovery of the NR-1 Sinkhole prompted scientific
2007 Guatemala City sinkhole on the city's aging sewerage system, and have speculated that more piping failures are likely to develop unless action is taken. Several rainstorms also contributed to the sinkhole's collapse, as stormwater percolated into the ground, further dissolving the rocks beneath Guatemala City. Citizens of Guatemala City near the sinkhole also reported hearing rumblings a few weeks before its collapse. The INSIVUMEH (Guatemala's seismology institute) had placed a seismic meter there before the disaster; a robotic camera system was supposed to enter the cavity, but the disaster occurred first. On February 23, 2007, the sinkhole collapsed, forming a very large, deep