1985 Nevado Del Ruiz Volcanic Eruption, Colombia
The 1985 Nevado Del Ruiz volcanic eruption in Colombia caused a high death toll of 23000. Despite the indicators, such as increased seismic activities, gas emissions of carbon dioxide and sulfur dioxide and phreatic eruptions, the damage was severe. This was due to several reasons.
- Officials did evacuate the people despite warnings. Authorities did not believe the volcano was going to erupt as it has been inactive for 140 years. Furthermore, there were no trained volcanologists monitoring the volcano.
- The city of Armero had a high population density.
Hence, towns were buried under quick-moving lahars which gave people little time to escape.
2010 Mount Merapi Volcanic Eruption, Indonesia
The 2010 Mount Merapi volcanic eruption caused a death toll of 353 people. About 350,000 people were evacuated. This was after the volcano started spewing lava, hot gases and ash. The volcano had a few minor eruptions prior to the major eruption.
Even though people evacuated, some died due to the following reasons.
- Due to cultural reasons, others did not leave the site. They believed that the volcano would not erupt as long as the gatekeeper to the volcano was alive.
- Even though people were evacuated, some returned to their village check on their livestock and property.
Hence, people were killed by the high temperatures of the pyroclastic flow as the result of the collapse of the ash column. Others were asphyxiated.
1991 Mount Pinatubo Volcanic Eruption, Philippine
The 1991 Mount Pinatubo volcanic eruption caused a low death toll of 800 people. This was a result of houses collapsing due to the weight of wet ash. Despite it being the second largest. eruption in the 20th century, the damage to the human environment was low due to successful prediction and evacuation. This was due to several reasons.
- U.S. GS teamed with scientists from Philippine to monitor the volcanic activities. This was due to the frequent earthquakes and emission of gasses.
- Helicopters were deployed to observe the volcanic activities and more seismometers were used.
- The accurate prediction led to the prompt evacuation of 500,000 people living near Mt Pinatubo.
- It is estimated that they have saved at least 5000 lives and $250 million worth of property.
Despite this, the response strategies were not efficient, leading to an increased number of deaths.
- There was an outbreak of diseases. The evacuation camp was unsanitary. There was insufficient clean water and improper waste disposal. This led to deaths primarily by measles. Other causes of death included diarrhea and respiratory infections.
- There were not enough emergency supplies.
Hence the death toll continued to climb despite effective evacuation .
Prediction estimates the time of a volcanic eruption. This allows for sufficient time for people to evacuate. Prediction strategies can be both short-term and long-term. Short-term methods monitoring of volcanoes for any frequent gas emissions of carbon dioxide and sulfur dioxide, increased seismic activities, phreatic eruptions and ground deformations. Long – term strategies include studying the geologic history of the volcano, such as the intensity and frequency of the volcanic eruptions. One successful example was the 1991 Mount Pinatubo volcanic eruption in Philippine. Despite it being the second largest eruption in the 20th century, the damage to the human environment was low due to successful prediction and evacuation… In contrast, the death toll of the 1985 Nevado Del Ruiz volcanic eruption was high at about 23000 due to unsuccessful evacuation… Hence, prediction needs to be coupled with evacuation to successfully minimize death toll, otherwise it may prove to be ineffective as a standalone strategy.