Increased seismic activity around an active volcano in Colombia has forced residents to leave ahead of a possible eruption. The Nevado del Ruiz volcano sits about 80 miles west of Bogotá, and according to Colombia’s Geological Survey, an earthquake swarm has increased to levels not seen since a disastrous eruption in the 1980s killed at least 25,000 people. According to Colombian officials, there have been 18 orange alerts since 1985, with none leading to a major eruption