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
2010 Guatemala City sinkhole 2010 Guatemala City sinkhole The 2010 Guatemala City sinkhole was a disaster in which an area approximately across and deep collapsed in Guatemala City's Zona 2, swallowing a three-story factory. The sinkhole occurred for a combination of reasons, including Tropical Storm Agatha, the Pacaya Volcano eruption, and leakage from sewer pipes. Overall, the risk of sinkholes occurring in Guatemala City is high and unpredictable. One recent, similar sinkhole had collapsed in 2007, forming a pit 100 metres deep. The 2007 Guatemala City sinkhole was formed by fluid from a sewer eroding uncemented volcanic ash, limestone, and other pyroclastic deposits underlying