Armero Tragedy - Background

Background

Armero, located 48 kilometers (30 mi) from the Nevado del Ruiz volcano and 169 kilometers (105 mi) from Colombia's capital of Bogotá, was the third largest town in Tolima Department, after Ibague and Espinal. A prominent farming town before the eruption, it was responsible for roughly one-fifth of Colombia's rice production, and for a large share of the cotton, sorghum, and coffee crops. Much of this success can be attributed to Nevado del Ruiz, as the fertile volcanic soil had stimulated agricultural growth. Built on top of an alluvial fan that had been host to historic lahars, the town was previously destroyed by a volcanic eruption in 1595 and by mudflows in 1845. In the 1595 eruption, three distinct Plinian eruptions produced lahars that claimed the lives of 636 people. During the 1845 event, 1,000 people were killed by earthquake-generated mudflows near the Magdalena River.

Nevado del Ruiz has undergone three distinct eruptive periods, the first beginning 1.8 million years ago. During the present period (beginning 11,000 years ago), it has erupted at least twelve times, producing ashfalls, pyroclastic flows, and lahars. The historically recorded eruptions have primarily involved a central vent eruption (in the caldera) followed by an explosive eruption, then the formation of lahars. Ruiz's earliest identified Holocene eruption was in about 6660 BC, and further eruptions occurred around 1245, 850, 200 BC and in about 350, 675, in 1350, 1541 (perhaps), 1570, 1595, 1623, 1805, 1826, 1828 (perhaps), 1829, 1831, 1833 (perhaps), 1845, 1916, December 1984 through March 1985, 1987 through July 1991, and possibly in April 1994. Many of these eruptions involved a central vent eruption, a flank vent eruption, and a phreatic (steam) explosion. Ruiz is the second-most active volcano in Colombia after Galeras.

One week before the eruption, the Palace of Justice siege took place. The assailants (M-19 guerrilla fighters) planned to hold a trial involving Colombian President Belisario Betancur. He refused to participate and sent the national army into the building. The attackers were holding several hundred hostages, including the 24 Supreme Court justices and 20 other judges. In the ensuing battle between the two forces, more than 75 hostages died (including 11 judges). This disaster, coupled with the Armero tragedy, spurred the Colombian government to predict and prepare for a broad range of threats.