Nevado del Ruiz is a stratovolcano, with a history of generating deadly lahars from relatively small eruptions (SDSU, 2006). The Nevado del Ruiz volcano stands at an elevation of 5, 389 meters above sea level. It is the tallest volcano of any Columbian Mountain. It is also the most northern of any stratovolcano in the area. Nevado del Ruiz is part of the Andes Volcanic Chain of western South America. It is located approximately 500 kilometers from the equator and its summit is covered with 25 square meters of snow and ice (SDSU, 2006). The Nevado del Ruiz volcano usually has only steam eruptions, with minimal to no pyroclastics ejected. It is also famous for starting lahars (mudflows) that generate to great speeds, knocking anything down in their path.


There were many precursors leading up to the 1985 eruption of Nevado del Ruiz. Small earthquakes and fumaroles that spew gas and steam were detected near the summit. There were also small eruptions detected along the summit that contained small magma explosions (Suite101, 2009). These precursors signaled the 1985 eruption. On November 13, 1985, the Nevado del Ruiz volcano started with a small eruption at 3:06pm and two hours later pumice fragments and ash were showering down on Armero, the town 74 kilometers below. At 7:00pm the town started an evacuation and at 9:08pm molten rock began to erupt from the summit for the first time, previous eruptions were only steam explosions (SDSU, 2006). The eruption also generated deadly lahars that started at 11:35pm and moved downwards at speeds of 24 feet per second or 50 kilometers per hour (Suite101, 2009). The ice and snow on the summit of the volcano melted from the heat and sent large amounts of water and mud/materials picked up, speeding down the side towards Armero and hit within an hour.


Although Armero was 74 kilometers from the crater of Nevado del Ruiz, it took only two and a half hours for the lahars to reach to village, after the eruption began. The town of Armero was nearly destroyed. Over 23, 000 people died directly from the lahars and molten rocks that were thrown from the volcano during eruption. Many people later died because of smoke inhalation and starvation, etc. (Scribd, 2010). Approximately 15, 000 animals died and this eruption is said to be one of the ten deadliest eruptions in South American history.

References

Unknown Author. (2009). Nevado del Ruiz. Retrived: October 12, 2010 from Wikipedia website; http://en.wikipedia.org/wiki/Nevado_del_Ruiz.

Camp, Vic. (2005). How Volcanoes Work: Nevado del Ruiz 1985. Retreived: October 19, 2010 from How Volcanoes Work website; http://www.geology.sdsu.edu/how_volcanoes_work/index.html.

Camp, Vic. (2005). How Volcanoes Work: Nevado del Ruiz 1985. Retreived: October 19, 2010 from How Volcanoes Work website; http://www.geology.sdsu.edu/how_volcanoes_work/Nevado.html.

Fleury, Maureen K. (2005). Eruption of Nevado del Ruiz 1985: Devastating Volcano in Colombia, South America.  Retrived: October 19, 2010 from Suite101 website; http://www.suite101.com/content/eruption-of-nevado-del-ruiz-1985-a100396.

Staff Writer. (2008). Overview Charity Challenge in Guatemala. Retrived: November 20, 2010 from GVI website; http://www.gvi.co.uk/projects/central-america/guatemala/volunteer-charity-challenge-guatemala/home.

Staff Writer. (unknown date). Nevado del Ruiz Summary. Retrieved: Novemeber 10, 2010 from Global Volcanism Program website; http://www.volcano.si.edu/world/volcano.cfm?vnum=1501-02=.

Topinka, Lyn. (2008). Colombia Volcanoes and Volcanics. Retrrived: November 10, 2010 from USGS website; http://vulcan.wr.usgs.gov/Volcanoes/Colombia/framework.html.

Staff Writer. (2008). No apparent danger : the true story of volcanic disaster at Galeras and Nevado del Ruiz. Retrieved: October 19, 2010 from Amazon.ca website;
http://www.amazon.ca/No-apparent-danger-volcanic-disaster/dp/B002MRMWR8/ref=sr_1_12?ie=UTF8&s=books&qid=1290024574&sr=1-12.

Unknown Author. (2000). Eruption of the Nevado Del Ruiz Volcano, Colombia, on 13 November 1985: Gas Flux and Fluid Geochemistry. Retrieved: October 12, 2010 from Jstor website; Eruption of the Nevado Del Ruiz Volcano, Colombia, on 13 November 1985: Gas Flux and Fluid Geochemistry.

Staff Writer. (2010). The Erutpion of Nevado Del Ruiz Volcano Colombia, South America, November 13, 1985. Retrieved: October 29, 2010 from The National Academic Press; http://www.nap.edu/openbook.php?record_id=1784&page=79.

Finding Dulcinea Staff. (2010). On This Day: Mudslide in Colombia Kills 23,000. Retrieved: November 20, 2010 from Finding Dulcinea website; http://www.findingdulcinea.com/news/on-this-day/November/On-this-Day--Mudslide-in-Colombia-Kills-23-000.html.

Unknown Author. (2006). Nevado del Ruiz. Retrieved: November 1, 2010 from Solar Net International; http://www.solarnet.tv/forum/index.php?topic=30188.0;all.

Unknown Writer. (2009). Nevado del Ruiz. Retrieved: November 1, 2010 from Blogger.com;  http://nevadodelruiz.blogspot.com/2009/03/type-of-volcanoe.html.

Staff Writer. (2010). Volcan Nevado Del Ruiz. Retrieved: Nevember 23, 2010 from Libertad y Orden website;  http://intranet.ingeominas.gov.co/manizales/IntroNevadoRuiz.

Pahopin. (2008). The Eruption of the Nevado del Ruiz Volcano - Colombia 1985. Retreived: November 1, 2010 from YouTube; http://www.youtube.com/watch?v=3XMS-quxdGg&feature=channel.

Staff Writer. (unknown date). Nevado del Ruiz Case Study. Retreived: November 1, 2010 from Scribd.com website; http://www.scribd.com/doc/14806257/Nevado-Del-Ruiz-Case-Study-Copy.  

Hyndman, D., Hyndman, D., Catto, N. (2009). Natural Hazards and Disasters. Toronto, Ontario: Nelson Education Ltd.