Geology of Colombia: Earthquakes in Colombia, Impact craters of Colombia, Mining in Colombia, Oil fields of Colombia, Volcanoes of Colombia, Nevado del Ruiz, Andean Volcanic Belt, Mineral industry of Colombia, Cerrejón Formation, Galeras, Cerro Machín

Source: Wikipedia. Pages: 23. Chapters: Earthquakes in Colombia, Impact craters of Colombia, Mining in Colombia, Oil fields of Colombia, Volcanoes of Colombia, Nevado del Ruiz, Andean Volcanic Belt, Mineral industry of Colombia, Cerrejón Formation, Galeras, Cerro Machín, Nevado del Huila, 1999 Armenia, Colombia earthquake, 1868 Ecuador earthquakes, List of earthquakes in Colombia, 1875 Cúcuta earthquake, 2008 El Calvario earthquake, 1906 Ecuador-Colombia earthquake, Doña Juana, Caño Limón oilfield, List of volcanoes in Colombia, El Totumo, 1994 Paez river earthquake, Nevado del Quindío, Nevado del Tolima, Doña Juana-Cascabel Volcanic Complex, Ministry of Mines and Energy, Cerro Bravo, Vichada Structure, Santa Isabel, Puracé, Cumbal Volcano, Azufral, Cerro Negro de Mayasquer, Sotará, Romeral, Chiles. Excerpt: The Nevado del Ruiz, also known as La Mesa de Herveo (English: ) or Kumanday in the language of the local pre-Columbian indigeous people, is a volcano located on the border of the departments of Caldas and Tolima in Colombia, about 129 kilometers (80 mi) west of the capital city Bogotá. It is a stratovolcano, composed of many layers of lava alternating with hardened volcanic ash and other pyroclastic rocks. Nevado del Ruiz has been active for about two million years, since the early Pleistocene or late Pliocene epoch, with three major eruptive periods. The current volcanic cone formed during the "present" eruptive period, which began 150 thousand years ago. The Nevado del Ruiz usually generates Plinian eruptions, which produce swift-moving currents of hot gas and rock called pyroclastic flows. These eruptions often cause massive lahars (mud and debris flows), which pose a threat to human life and the environment. On November 13, 1985, a small eruption produced an enormous lahar that buried and destroyed the town of Armero in Tolima, causing an estimated 23,000 deaths. This event later became known as the Armero tragedy¿the deadliest lahar in recorded history. Similar but less deadly incidents occurred in 1595 and 1845, consisting of a small explosive eruption followed by a large lahar. The volcano is part of Los Nevados National Natural Park, which also contains several other volcanoes. The summit of Nevado del Ruiz is covered by large glaciers, although these have retreated significantly since 1985 because of atmospheric warming. The volcano continues to pose a threat to the nearby towns and villages, and it is estimated that up to 500,000 people could be at risk from lahars from future eruptions. Map of the major Colombian volcanoesNevado del Ruiz, which lies about 129 kilometers (80 mi) west of Bogotá, is part of the Andes mountain range. The volcano is part of the Ruiz¿Tolima volcanic massif (or Cordillera Central), a group of five ice-capped volcanoes which inc