T

he volcanic activity of Mount Dempo in Pagaralam, South Sumatra, has been increasing recently, with at least 79 tremors recorded last week.

Eight deep volcanic quakes and one surface quake were recorded between Oct. 25 and 31, Mt. Dempo observation post chief Slamet said.

He said Mt. Dempo was different to other volcanoes in Indonesia, particularly because of its wide and vast crater.

“This means there can be changes in its volcanic activity at any time,” Slamet said.

Dempo erupted in 1838, creating a lava lake covering an area of around 3,000 square meters.

Despite that only volcanic tremors had been recorded, Slamet said, residents living on Dempo’s slopes needed to be on the alert because of its unpredictable nature.

In anticipation of a possible eruption, Pagaralam city administration has prepared a disaster mitigation team comprising volunteers and search and rescue members.

“We have shown residents the disaster preparedness system, which is especially important when the volcano starts showing an increase in activity,” a member at the city administration said.

He added that evacuation zones had also been designated in north, central and south Dempo regions, with room for thousands of refugees.

Separately, the Meteorology, Climatology and Geophysics Agency’s (BMKG) Sultan Mahmud Badaruddin II Palembang office has predicted frequent heavy rains in the Bangka Strait as a result of the Anggrek tropical cyclone from the southwest of Sumatra at speeds of 5 to 10 knots.

“The rain is intensifying,” BMKG observation and information section chief Agus Satosa said.

Agus also said waves of between 1.5 and 2 meters could occur in the strait, potentially disrupting transportation.

“Although the sea is still relatively safe for sailing, they’d better be cautious,” Agus said.

BMKG Kenten Palembang chief Muhammad Irdham said the impact from Anggrek were now visible, as shown by intensifying rainfalls.

Rains during October reached 350 millimeters over 24 days, he said.

“Conditions in the Karimata Strait need to be monitored closely because there is also a low pressure system. This can cause bad weather,” he said.