Nevado Del RUIZ Shamon Rhodes jr
Nevado del Ruiz, the highest active volcano in the Andes Mountains of Colombia, suffers a mild eruption that generates a series of lava flows and surges over the volcano’s broad ice-covered summit. Flowing mixtures of water, ice, pumice, and other rock debris poured off the summit and sides of the volcano, forming “lahars” that flooded into the river valleys surrounding Ruiz. The lahars joined normal river channels, and massive flooding and mudslides was exacerbated by heavy rain. Within four hours of the eruption, the lahars traveled over 60 miles, killing more than 23,000 people, injuring over 5,000, and destroying more than 5,000 homes. Hardest hit was the town of Armero, where three quarters of the 28,700 inhabitants died.
Nevado del Ruiz covers more 200 sq km and it is composed by 3 major andesitic and dacitic edificed of lavas and tuffs. The present-day cone is composed by lava domes built within the summit caldera of the older Ruiz volcano. Its summit contains the 1-km-wide and 240-m-deep Arenas crater.
The prominent La Olleta flank cone on the SW flank was probably built in historic time. Nevado del Ruiz has repeatedly produced large mud flows lahars, triggered by melting of the summit glacier during eruptions. Deposits of these mud flows are found on its broad flanks and these events have been known since the 16th century.