Nevado Del Ruiz Analysis
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 …show more content…
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:
Approximately 21,000 people were killed in Armero. (out of 28,700)
The eruption caused an estimated 25,000 deaths.
Around 5,000 people were injured.
About 5,000 homes were destroyed.
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.
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; also many of Amero's citizens were unable to read anyway. As the volcano began to erupt the people of Amero remained calm. They were placated by reassuring messages from the mayor over radio and from a local priest over the church public address system. Nevertheless, the Red Cross ordered an evacuation of the town. However, shortly after the evacuation order the ash stopped falling and the evacuation was called off. A storm obscured the summit area so that most citizens were unaware of the pyroclastic eruption that was happening. The authorities had been warned that a moderate eruption would produce " . . . a 100 percent probability of mudflows . . . with great danger for Armero and the lower part of the River Chinchina." However, government officials dismissed the report; they did not want to evacuate people until they were assured of the necessity. Had the authorities taken the scientists and the Red Cross seriously then far fewer people would
have been injured as the town could have been evacuated.
What could be done in future to prevent such damage and death occurring again?
There are many methods to protect towns from lahars. These include: alternate channels, tunnels, and concrete structures. Some of these methods have met with success and others have not. The best preventative measure is to establish a warning system. Warning systems that have been used include seismometers that pick up the signal of a lahar as it moves down valley and rain gauges that collect water and warn when lahars formation is possible. But, as was shown at Nevado Del Ruiz, warning systems are not enough. Evacuation plans and lines of communication must also be established the damage may not be preventable but earlier warning thanks to better communications would enable people to be evacuated to higher ground.
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 …show more content…
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:
Approximately 21,000 people were killed in Armero. (out of 28,700)
The eruption caused an estimated 25,000 deaths.
Around 5,000 people were injured.
About 5,000 homes were destroyed.
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.
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; also many of Amero's citizens were unable to read anyway. As the volcano began to erupt the people of Amero remained calm. They were placated by reassuring messages from the mayor over radio and from a local priest over the church public address system. Nevertheless, the Red Cross ordered an evacuation of the town. However, shortly after the evacuation order the ash stopped falling and the evacuation was called off. A storm obscured the summit area so that most citizens were unaware of the pyroclastic eruption that was happening. The authorities had been warned that a moderate eruption would produce " . . . a 100 percent probability of mudflows . . . with great danger for Armero and the lower part of the River Chinchina." However, government officials dismissed the report; they did not want to evacuate people until they were assured of the necessity. Had the authorities taken the scientists and the Red Cross seriously then far fewer people would
have been injured as the town could have been evacuated.
What could be done in future to prevent such damage and death occurring again?
There are many methods to protect towns from lahars. These include: alternate channels, tunnels, and concrete structures. Some of these methods have met with success and others have not. The best preventative measure is to establish a warning system. Warning systems that have been used include seismometers that pick up the signal of a lahar as it moves down valley and rain gauges that collect water and warn when lahars formation is possible. But, as was shown at Nevado Del Ruiz, warning systems are not enough. Evacuation plans and lines of communication must also be established the damage may not be preventable but earlier warning thanks to better communications would enable people to be evacuated to higher ground.