Cristian Lopez a contractor for the Institute of Seismology has reported an increase in Activity of the volcano. He added that this does not mean increasing the alert level, which has been yellow since October 2010.
The newspaper La Patria of Manizales yesterday reported that a tour group could not access the National Park of Los Nevados. "Our role is to monitor and it's decision to grant the park to limit access to certain parties," added Lopez.
Due to the changes that have been occurring near the Volcano, Governors Luis Carlos Delgado Tolima and Caldas Rock Guido Etcheverry have been made aware of the situation and planned accordingly.
In a flyby that took place yesterday from 6:00 in the morning with officials and Simológico Volcano Observatory of Manizales and the Colombian Air Force over the volcano Nevado del Ruiz observed a gas column height of approximately 400 thousand meters above the summit, originating from various emission sources within the crater Arenas, showing changes in temperature.
Also verified the presence of ash on the glacier of the volcano, near the crater rim and to the east. The Observatory indicates that you may be associated with small explosions recorded since February 22.
The Centre's director, Gloria Patricia Cortez said the volcano alert will remain on yellow, which was declared in September 30, 2010, and could spend many months in this alert, according to the evolution of the activity. Snowy access is maintained unless the Alert changes to Orange.
At this time they have put in restriction on tourism, which means a decrease in the load car. On the other hand Gloria Serna, head of Nevados Park , said that the implications of this decision will be announced in the afternoon. Source
Nevado del Ruiz, also known as La Mesa de Herveo (Stratovolcano)
Elevation 5,321 m (17,457
Prominence 2,035 m (6,677 ft)
129 kilometers (80 mi) west of the capital city Bogotá, Colombia
November 13, 1985, a small eruption produced an enormous lahar that buried and destroyed the town of Armero in Tolima, causing an estimated 25,000 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 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.
(Lahars) 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)