Mount Agung volcano spewed ash and stream on the Indonesian island of Bali on Tuesday, its first eruption since 1963.   National Disaster Mitigation Agency spokesman Sutopo Purwo Nugroho said the minor explosion started around 5 p.m. and created a plume that rose roughly 2,300 feet from the volcano. Bali’s international airport remained open. Volcanologists say the eruption was caused by

magma heating water, which is called a phreatic eruption, rather than a generally more dangerous eruption of magma itself, Nugroho said. Agung’s alert status was recently lowered to the second-highest warning level after several weeks at the highest level. More than 140,000 people evacuated the region around the volcano when it was on high alert, though authorities urged some to return home who had left areas not in the official danger zone. READ MORE