Studying volcanic eruptions in the 1980s has resulted in better monitoring through expendable instruments that can operate remotely and be optimally placed , increased knowledge of individual volcanic history , and distinctive tremor patterns . "Our biggest improvement has been in our own heads," said Peter Lipman, a volcanologist with the U.S. Geological Survey in Menlo Park. Eruptions at Alaska 's volcano in 1989 and the Philippines ' volcano , which began giving signs of activity two months ago after 600 years , were both forecast . Pinatubo 's evacuation was expensive , considering the hazards , factory shutdowns , and unattended crops and livestock ; but only 101 lives have been lost so far . At Colombia 's Nevado del Norte eruption six years ago , officials were warned but did n't order evacuation , resulting in 22,000 deaths .
Studying volcanic eruptions in the 1980s has resulted in better monitoring through expendable instruments that can operate remotely and be optimally placed , increased knowledge of individual volcanic history , and distinctive tremor patterns . Eruptions at Alaska 's volcano in 1989 and the Philippines ' volcano , which began giving signs of activity two months ago after 600 years , were both forecast . Pinatubo 's evacuation was expensive , considering the hazards , factory shutdowns , and unattended crops and livestock ; but only 101 lives have been lost so far . At Colombia 's Nevado del Norte eruption six years ago , officials were warned but did n't order evacuation , resulting in 22,000 deaths .