PREDICTING VOLCANIC ERUPTIONS 1. Study of past eruptions from records and observations. 2. Seismographic monitoring. Rising magma sets off earth tremors. When the frequency and intensity of these begins to increase, the magma is approaching the surface. 3. Tiltmeters measure changing ground shape. 4. Measuring gas and steam emissions using correlation spectrometers. Increasing emissions of hydrogen sulphide and hydrogen chloride may indicate an eruption is likely. 5. Increased temperature in a crater lake may suggest magma is nearer the surface. 6. Magnetic anomalies 7. Gravity anomalies 8. Electrical anomalies Why is volcanic hazard prediction more likely to occur in countries like the United States and Japan than in Central Africa or Latin America? What signs do you think local people might recognise as suggesting the mountain is about to erupt? PATH OF A KILLER VOLCANO This video is about Mount Pinatubo in the Philippines. Although the Philippines is an LEDC, the volcano was well-monitored because the Americans had a large air force base close by. 1. List the ways in which the volcano was being monitored. 2. Record the events of the following dates 28th May 31st May 2nd June 3rd June 5th June 6th June 7th June LEVEL 4 DECLARED 8th and 9th June 10th June 12th June 14th June 15th June Following days 3. How many casualties were there? 4. What other effects did the people suffer? 5. What effect did the eruption have on global climates?