The Nevado del Ruíz volcano in central Colombia remains on orange alert after the Colombian Geological Service – SGC – released last Wednesday an “extraordinary bulletin” regarding seismic activity in the interior of the mountain. According to the SGC, daily seismic activity began to increase sharply as from March 24 when more than 9,400 “incidents” were recorded. On Saturday, this number increased above 11.000 and highest recorded since the 1985 eruption.
The orange alert, and declaration by the SGC of an imminent eruption, possibly “within days or weeks” of this 5,321-meter-high mountain has been accompanied by the temporary closure of the PNN National Park Los Nevados, as well as preventive evacuation of some 40,000 residents who live near the summit of the active volcano. An estimated 30 communities along a volcanic belt that extends through the departments of Tolima, Caldas and Antioquia could be affected by the eruption, including towns in the Magdalena River basin.
On Sunday, seismic activity lowered slightly to 10.000 as emergency plans were issued by the Ministries of Health and Communications. The Governor of Caldas, Luis Carlos Velásquez, called to the residents of the department to be prudent with information regarding the volcano’s activity and not generate panic on social media. “We are very ready and willing to work jointly with all institutions on contigency plans,” he stated.
The area with the most seismicity is located on the southwestern flank of the volcano, some two to five kms from the Arenas crater. The SGC also highlighted that citizens should “remain calm, but be attentive to information on the evolution of the state of the volcano.”
Known also as La Mesa de Herveo, the volcano was first ascended by the Swiss geologist Augusto Gansser-Biaggi and mountaineer W.Cunet during an expedition in 1936. The Nevado del Ruíz’s eruption on November 13, 1985, resulted in country’s worst natural disaster. A mud flow caused by heat at the summit melting the ice cap broke banks of local rivers. The lahar devastated the city of Armero, in the department of Tolima, killing 22,000 residents.