Mount Pinatubo: Predicting a ...
For 600 years, Mount Pinatubo appeared to be sleeping. Towering 1745 meters (5725 feet) over the Philippine island of Luzon, the seemingly dormant volcano showed no signs of an impending catastrophic eruption. Then, in early April 1991, Pinatubo stirred, sending puffs of steam into the air. Soon after this first event, vulcanologists began measuring vibrations