Introduction
The following is a summary of the events that occurred in 1985 regarding the Nevado Del Ruiz eruption and the consequential lahars that followed. The exceptional circumstances that surrounded this event will be covered as well as related information and events. Sources will be provided at the end of the passage.
Overview
The Nevado Del Ruiz eruption of 1985 is a testament that the worst natural disasters do not need to be the most violent or spectacular of occurrences, but ones in which there is suffering and a large loss of life. The populations that resided below Nevado were completely unprepared. On November 14th of the previously mentioned year, The Nevado Del Ruiz erupted, melting glacier ice that sat on top of it and causing huge lahars. Most of the people in the town down below were either asleep or unaware of the eruptions. This was due to several reasons, but the two most significant being the cloud cover that day and the lack of warning people. This was because the city officials wrongfully assumed there was nothing to be alarmed about. The cloud cover that day prevented anyone from physically seeing the volcanic activity from the city. And since the local officials were telling everyone the ash falling from the sky was nothing to be alarmed about, nobody worried, and everyone that was asleep was left to their imminent doom. The mud flows were sudden, and by the time anyone would have realized what was going on, it was too late. The entire town of Armero was left in ruins. As many as 23,000 people from Armero and the surrounding areas lost their lives. Many people didn’t just die from the slide itself, but from being stranded, starved, or buried under heavy debris.
How the Eruption Became a Disaster
Generally the volcano is capped with ice, but when lava started to flow the ice melted extremely quickly. The volcano has been active for a long time, and the fact that it is covered with ice proves to be a deadly combination. The new abundance of water quickly mixes with the surrounding sediment and begins to pour down violently. When the lahars hit the city it became the worst natural disaster associated lava flow. These volcanic debris flows were caused mainly because of the ice melting, creating mud, gathering rocks, and eventually trees, homes, and cars into a violent wake of destruction and travels as fast as 17 meters a second. It happened quicker than a flash flood, and in the middle of the night to add to the terror.
Possible Prevention and the Aftermath
The engineering practices of the locals did practically nothing to avert this type of disaster. The local geologists and engineers also did very little, if anything, to prepare them for this disaster. So even though there may have been warning signs and doable engineering practices, neither was done. For example, a report by a French geologist called Bernard Chouet predicted that the volcano was ready to blow. The terrible thing is that with a proper local government and a warning system, the people would have been evacuated and hardly anyone would have died. The vulnerable areas can be seen in figure A. A bit of history that should be remembered is that a disaster of this magnitude and type occurred in the exact same spot twice before. And it even occurred after. But why is disaster not being averted in the Nevado Del Ruiz region? The simple answer is that the areas around Nevado Del Ruiz are poor and that without money there are less public service and therefore an unreliable local government, which didn’t even pay attention to the report by Chouet. Because of the lack of money in the area, an engineering project is out of the question. No one would be able to undertake such an expensive project, not even the Columbian government. If such a project could be undertaken, however, there are a few things that could be done. If soil were moved in a large scale, the lahars that would form in the future could be redirected away from the city. A wide scale alarm system would wake people if disaster occurred in the middle of the night. Unfortunately, in a poor area like that, all of these things are out of reach. Even after the disaster occurred in 1985, the heavy rain, secluded nature of the area, and the high altitude all work to complicate the jobs of the rescue workers, also worsening the death toll. Since the tragic disaster in 1985, however, great efforts have been made by Chouet to prevent so many people from dying again. By analyzing seismographs, Bernard Chouet incorporates a method to discover volcanic activity early, so that people can be evacuated well ahead of time.
Background on Nevado Del Ruiz
Nevado el Ruiz is an active volcano that is located 17,457 feet above sea level in Columbia. The cone of the volcano is made from pyroclastic material, heavy in silicon, so it is extremely viscous. This thick viscosity allows for gasses to build up pressure so high that when it finally gives, it explodes. Nevado Del Ruiz is a vulcanian type of volcano - so its character is to explode upwards and rain ash from the sky. Because of the ice, lahars are a constant threat. This volcano is so active that it erupts every year up to three times. Specifically, Nevado Del Ruiz is a stratovolcano, and what this tells us about its structure is that it is composed of layers of lava flows, which tend to include ash and other varied debris. Tall and steep, Nevado Del Ruiz allows for the melting ice and mud to gain great velocity as it runs down the steep edge. This can be observed in the topographic map, figure B. By the time the lahars hit the populated areas; they have grown substantially in size, and picked up a lot of debris. Nevado Del Ruiz maintains a volcanic explosivity index of 1 to 6. So the real danger isn’t the eruption itself, but the consequential landslides.


Conclusion
Nevado Del ruiz is an unfortunate example of how money can play a big role in the well being of the people. Without large scale engineering projects and help from the Columbian government, the people of the Nevado Del Ruiz region are left vulnerable to disaster as has been repeated in history over and over.



map_ruiz_hazard_zones[1].gif
Figure A (above)

2fig12[1].gif
Figure B (Above)


Sources Cited

1. ProQuest – CSA http://md1.csa.com/partners/viewrecord.php?requester=gs&collection=ENV&recid=9206272&q=Nevado+del+Ruiz+eruption&uid=788562201&setcookie=yes

2. BBC International
http://www.bbc.co.uk/science/horizon/2001/volcanohell.shtml

3. Smithsonian National Museum of Natural History
http://www.volcano.si.edu/world/volcano.cfm?vnum=1501-02=

4. US Geological Survey
http://vulcan.wr.usgs.gov/Volcanoes/Colombia/Ruiz/description_eruption_lahar_1985.html


5. NASA
http://www.giss.nasa.gov/research/briefs/stothers_06/