Indonesian officials said they have declared an emergency response period following frequent eruptions from volcano Mount Sinabung. The period will be effective until the Center for Volcanology and Geological Hazard Mitigation lifts the warning, the Jakarta Post reported. The most recent eruption occurred Tuesday and lasted for 20 minutes, local authorities said. No casualties were reported, and at least 1,700 people from the surrounding area in North Sumatra had been evacuated. Two other eruptions occurred Monday night, the Post said. The volcano began erupting in mid-September after being inactive since August 2010, when several people were killed in an explosion.