Introduction
Mount Pinatubo is located on the island of Luzon in the Philippines which lies on a Destructive plate margin where the Oceanic Plate is subducted by the Eurasian Plate. People, including the Aeta , lived on the slopes because the ash and lava had Created fertile soil, ideal for growing Rice. Mount Pinatubo erupted in 1991 after being dormant for 600 years
Evaluation of effectiveness of volcanic preparation
-Steam emissions reported 2nd April 1991 and Scientists brought in who began onsite monitoring.
-A number of methods were used to monitor Pinatubo:
o Seismic monitoring - The USGS established a network of seven seismometers around the mountain
o Monitoring gas emissions - US Airforce helicopter flights took gas samples using a correlation spectrometer
-examination of previous volcanic history revealed that in last 2000 years, Pinatubo had only erupted 4 or 5 times
o Visual observation - determined number and scale of steam omissions
-the scientists also produced a hazard prediction map, which detailed the likely path of pyroclastic flows, Lahars and other volcanic hazards. As the seismic activity increased phased evacuations were ordered.
-20,000 living within 10km evacuated 3rd of June, 120,000 within 18km radius June 7th and US airforce evacuated + 14’000 staff moved to safe distance
Evaluation of the Volcanic preparations
-continuous monitoring was successful. The final death toll of 850 was small compared to the size of the eruption as well as the around 1 million population. scientists estimated that up to 20,000 lives were saved with most of the Aeta people heeding the warnings and were willing to leave
-The cost of monitoring was around $1.5 million, and evacuations were around $40 million. Philippine and commercial airlines saved 50-100 million
-Hazard prediction map proved largely accurate. However, it underestimated some of the volcanic hazards eg five major lahars were predicted but there was 8
-Typhoon Yunga had heavy rain and ash fall mix. 1000’s of hectares of farmland were buried and over 1 million livestock killed.
Immediate Response
-National Disaster Coordinating Council, mobilised military and civilian resources to respond to the evacuation, rescue and relief needs of the affected population.
-Health advisories were also issued to inform people how to cope and deal with the ashfall.
-However, disease, including malaria and measles was the major issue in the evacuation centres. Eg 30’000 people used the Amoranto Velodrome in for temporary shelter. Estimates suggest that around 600 of the 850 deaths were due to disease caused by poor conditions in the evacuation shelters.
Long Term Response
-a system to monitor and warn of lahars was established. This system has saved hundreds of at Pinatubo since 1991. However, many needed to be resettled and helped to be re-established in their livelihoods
-Additionally, by June 1991, the government had set up a ‘Task Force Mt Pinatubo’, a unit with a six year mandate and a 10 billion peso fund to assist in the establishment of resettlement centres. By 1996, all government departments included post-eruption mitigation strategies in their programmes.
Conclusion
-The preparation and response management to the volcanic activity of Mount Pinatubo in 1991was effective.
-While 850 died following the eruption, the death toll had the potential to be significantly higher had it not been for the thorough preparation and a phased evacuation.
-Although there were issues following the eruption in the evacuation centres with the spread of disease and there continues to be a significant threat posed to life and the built environment due to lahars, the immediate and long-term response management was largely effective
