"A seismograph record shows the volcano erupted twice respectively at 07.30 a.m. and 08.16 a.m.," spokesman of the Bukittinggi Geological and Volcanological Survey and Geological Hazard Mitigation Center (BGPVMB) Warseno said on Sunday.
The volcanic ash moved in the southeasterly direction to Simabur and Pariangan areas in Tanahdatar district, he said.
"Thin ash affected the two areas but it did not endanger residents there. After all, they must remain watchful for the impact of the ash," he said.
The agency still put the 2,891-meter high volcano on the second highest alert status as a number of eruptions were still felt, he said.
"BGPVMB also still recommends a ban on any climbing activity more than three kilometers from the peak," he said.
The volcano began to show signs of increased activity on August 3, 2011 at around 09.00 a.m. It sent sulfur smell of volcanic ash up to 1,000 meters into the sky and the volcanic ash reached a number of areas in West Sumatra, such as Agam, Tanahdatar, Padangpariaman, and Padangpanjang.
To see the volcano`s activity as soon as possible, the agency installed three seismographs at a height of 2,000 meters at Batu Palano area and a digital analog at a height of 1,500 meters at Lasi area.
The volcano last erupted in 2005.
Under normal condition, the volcano always becomes destination of domestic and foreign climbers. (*)