"He's someone who eats it up," said Randy White, Harlow's friend and colleague at the U.S. Geological Survey in Menlo Park. "He's able to totally concentrate in those sorts of situations."; The eruptions at Mount Pinatubo finally gave Harlow the chance to put his skills and experience to work saving lives. When Harlow went to Mount St. Helens in Washington state in 1980, geologists were still learning how to read the telltale earthquakes. Bureaucratic delays kept Harlow from arriving at Nevado de Ruiz in Colombia until a day after its 1985 eruption. Harlow and his team predicted the 1989 eruption of Redoubt Volcano in Alaska, but few lives were threatened in the remote area.; Three weeks ago, Harlow joined a team of five U.S. Geological Survey scientists who worked with 10 Filipino scientists to try to forecast the eruption of the volcano, which had been dormant for about 600 years. One crew gathered evidence of Pinatubo's earlier eruptions as clues to its potential power.; Harlow's team set up a ring of a half-dozen seismographs around the volcano to measure the deep tremors caused by molten lava slowly pushing to the surface and the shallower tremors that follow when the eruption is imminent.; Pinatubo followed an almost textbook pattern over the past six weeks. Gradually building earthquakes were followed by the release of gas, the buildup of magma and finally the huge explosions that sent ash clouds more than 75,000 feet into the sky and sent avalanches of hot ash pouring down the narrow valleys west of the volcano.; Philippine and U.S. Air Force officials ordered evacuations Monday.; Since late Tuesday, Harlow's colleagues have not been able to get through on the single phone line into the bunker at Clark Air Base, but do not believe the team is in danger. The eruption is on the west side of the mountain, with the summit shielding Clark. Prevailing winds are also away from the base.; "I'm not so concerned," said Pauline Lord, Harlow's wife. "My husband is not unaccustomed to danger."; Lord said Harlow's love affair with volcanoes began when he was an undergraduate student at Dartmouth College and his professor took the entire class to observe an eruption in Guatemala.; "He's somebody who's fascinated by that kind of energy," said Lord, a psychotherapist who has accompanied Harlow to several volcanoes. "It's wonderful to see that lava sloshing around."; Harlow's 5-year-old daughter, Megan, is not worried about her father.; "She knows Daddy is in the Philippines and that he's fixing a volcano," Lord said.
David Harlow is one of the few volcano seismologists in the world. He has been studying volcanoes for over 40 years, and he was a member of the team that discovered the first known earthquake on Mount St. Helens. Pinatubo erupted according to the predictions by Harlow and the team, blowing ash 75,000 feet into the air and sending rivers of molten ash down its slope. The accurate prediction enabled the evacuation of 84,000 people from the area. Evacuees included personnel and dependents from the U.S. Clark Air Force Base. The base may have to be abandoned.