The Nevado Del Ruiz

The Nevado Del Ruiz: 1985 eruption

Location?

Nevado del Ruiz is a volcano in Colombia, the northenmost and highest Colombian volcano, located at the in the northern most tip of the Andes in South America. Nevado Del Ruiz is a broad, glacier-covered volcano that covers more than 200 square kilometers.

Has the volcano erupted before?

In 1595 and 1845 summit eruptions melted snow and ice and produced mudflows that traveled tens of miles from the volcano, these mudflows were confined to the valleys that drain the volcano. The 1595 eruption sent a lahar sweeping down the valleys of the River Guali and the River Lagunillas, killing 636 people. In 1845, another immense lahar flooded the upper valley of the River Lagunillas, killing over 1000 people. It continued for 70 kilometers downstream before spreading across a plain in the lower valley floor. The village of Armero was built directly on top of the 1845 mudflow deposit.

What damage did it cause? How many people died/ were injured?

The 1985 eruption of Ruiz, although only moderately explosive, produced hot pyroclastic flows and hot volcanic ash. These melted part of the ice cap on the volcano's summit, triggering debris flows (lahars) that swept down river valleys and overran villages in their path. These reached the town of Armero:

Ð'* Approximately 21,000 people were killed in Armero. (out of 28,700)

Ð'* The eruption caused an estimated 25,000 deaths.

Ð'* Around 5,000 people were injured.

Ð'* About 5,000 homes were destroyed.

Ð'* The entire town was swamped with mud which was up to 40 meters thick, and was traveling at speeds of up to 50km/h when it swept the town away.

Ð'* It was the fourth largest single-eruption death toll in history

Was it inevitable that so many people died/were injured? Could more have been done to save the people/ property?

Scientists had accurately predicted the tragic eruption weeks before it happened. The volcano had been showing signs of unrest for some time and was being monitored by scientists using seismographs. The map below shows which areas would be at risk should the volcano erupt, Armero is clearly in a high risk area even though it is over 25 miles from the volcano. Many of the town's people were unaware of this. The maps were provided over a month before the eruption however they weren't taken seriously and weren't circulated thoroughly;