QUITO (AFP) - Tungurahua, a volcano in southern Ecuador, erupted for a fourth day, burying thousands of farms in ash and threatening to "boil over" and dump lava on a nearby town, officials said. Explosions were heard for days, said Geophysical Institute engineer Pablo Samaniego, who compared the volcanic activity to a "pot of milk waiting to boil over at any moment". Lava threatens to run downhill, toward Banos, with 15,000 residents, he said. "This has happened before and could affect Banos," he said. "The town will have to make its decisions" on whether to evacuate," he said. So far,...