This eruption occured on Wednesday,13th November in 1985

In the Nevado del Ruiz, South America and latitude (DMS) of 4° 54' 0 N and longtitude (DMS)75° 17' 60 W. It occured due to the eastward subduction of the Nazca oceanic plate South American continental plate. The magnitude of the event is estimated to be 3 on the Volcanic Explosivity Index due to it meeting the criteria of the scale, being 10,000,000 m3 in volume of ejecta and a plume height of 3-15 km.A total of four towns in the Andes region, and estimated total of 23,000 people, have been reported to be buried when hot volcanic ash melted part of the ice-cap on the volcano's summit, triggering debris flows, which swept down valleys and buried everything in its path, including the villages as well as fallen bridges and impassable roads.Another 4,500 people were injured and about 8,000 made homeless,the estimated cost of disaster is $1,000,000,000. The event had initially shown warning signs such as minor earthquakes and steam eruptions for 51 weeks prior to the eruption, however, some government officials dissmissed this as "too alarming" and did not want to want to evacuate anyone unless they were assured of the necessity and now, the government has asked the United Nations for help.