The first was at 9:30 a.m. local time, followed by the second 13 minutes later both with a strong pressure.
The volcanic ash from the mountain which is 2,891 meters high above sea level spouted for about 10 minutes some 100-200 meters from the peak of the crater.
The volcanic ash is carried by the wind as far as 5 kilometers north of the mountain, and fell on its slopes.
Before spewing volcanic ash, from 8 am it had been constantly spouting white fumes 100 meters high from the cauldron.
A Bukinttinggi Volcanology and Geological Disaster Mitigation Center (PVMBG) official Warseno said he was still determining level II of the status of the mountain.
"PVMBG was still recommending alert level II and called on climbers not to go further than 3 kilometers from the peak," he said.
The volcano has started raising its activities on August 3, 2011. Everyday it spouted white fumes and volcanic ash.
One of the active mountains in West Sumatra on August 3, 2011 spewed sulphuric ash 1,000 meters high reaching several parts of West Sumatra like Agam, Tanahdatar, Padangpariaman, and Padangpanjang. (*)