Papua New Guinea's volatile Ulawun volcano, one of the world's most hazardous, erupted yesterday, spewing lava high in the air and sending residents fleeing. A pilot for Niugini Helicopters, a chartered helicopter service provider, flying near the crater witnessed a column of lava spurting into the sky. Witnesses had reported ash violently spewing out of the 2,334m summit. Ulawun is one of 16 Decade Volcanoes, identified by the International Association of Volcanology and Chemistry of the Earth's Interior, targeted for research because they pose a significant risk of large, violent eruptions. Thousands of people live in the shadow of Ulawun, despite it being one of the most active volcanoes in the country.