Activity in the San Cristobal volcano in Nicaragua has calmed a day after three loud explosions were accompanied by a huge eruption of ash and gas that led officials to evacuate about 3,000 people from nine nearby communities.

Officials say the area remains under an alert.

Nicaragua's geological institute says sporadic explosions have been heard Sunday and occasional ash columns have billowed up to heights between 1,500 meters (4,950 feet) and 5,000 meters (16,500 feet).

On Saturday, the 1,740-meter (5,740-foot) volcano spewed out clouds of ash that traveled 50 kilometers (31 miles).

San Cristobal has been active since 1520.