guagua pichincha has devastated quito, the capital, several times, so scientists monitor emissions ofulfur gas with gat conrn. in 1985, a massive eruption in neighboring colombia melted snowfields, causing mudflows that killed more than 23,000 people. throughout south america, scientists study the tragedy and vow to prevent the next one. they may get their chance here, in ecuador. the ngurahua volcano threatens a town of 17,000 at the base of the mountain. it is called baños. although baños is very near the equator, its elevation in the andes gives it a mild climate. add spectacular scenery and soeothermal hosprings and you have aibrant urist economy. on the surrounding hillsides, adequate rainfall and fertile volcanic soils sustain agriculture. but the same natural forces that sustain the economy are also a source of danger. hoping to avoid a agedy, geographer patty mothes maps and monitors several volcanoes for ecuador's geophysica institute,nclu tungurahua. she is looking for any changes that might signal an eruption. moes and one of these ways thate hat is to put a prism that's hi