T

he alert status in the Dieng Plateau region of Banjarnegara, Central Java, has since Monday evening increased one level higher from Normal to Waspada (cautious) due to the discovery of the toxic levels of carbon dioxide (CO2) in the area.

The decision was made by the Volcanology and Geological Disaster Mitigation Center (PVMBG) following the increase in CO2 concentration in the Timbang crater area in Batur district since Sunday.

“Because the level of the gas is toxic and endangers humans, people are not allowed within a radius of 500 meters of the crater,” said Dieng observation post head Tunut Pujiraharjo when contacted by The Jakarta Post on Tuesday.

Tunut said that visual observations had indicated an increase in the volcanic activities in the area and at 5:30 a.m. on Sunday, the concentration of CO2 in Timbang crater was recorded at a volume of 0.71 percent, higher than the safe level for human contact, which is 0.05 percent volume.

This accounts for why — at 9:30 p.m. on Monday — the PVMBG decided to increase the Dieng alert status to cautious, the third level on the four-level monitoring system. At this alert level, evacuation is not yet needed but people are banned from approaching the area deemed dangerous. Dieng is popular with local and foreign tourists.

In Bandung, PVMBG chief Surono said only the Timbang crater had showed increased activities while other craters — Sileri, Sinila, Siglagah, Condrodimuko and Sikidang — had not shown any visual changes.

He said that the team had found dead cats, birds and rabbits near the crater, adding that CO2 had seeped some 200 meters from the crater and was expected to head south.

“Residents should also be cautious if digging more than one meter into the ground due to the potential of gas,” he said.

Surono called on all residents to stay calm and to coordinate with the Dieng observation post in Karang Tengah, which can be contacted on 0286-3342202.

Responding to the increase of the Dieng alert status, Banjarnegara Regency Disaster Mitigation Agency (BPBD) called on the public to be cautious about the possible emergence of the gas in their
neighborhoods.

Head of the BPBD’s daily management, Tursiman, said he had called people of Sumberejo subdistrict, especially of Simbar village and the surroundings, to be extremely cautious when they had to pass by around the Timbang crater.

“We have prepared personnel and equipment as well in case the alert status is further increased,”
Tursiman said.

On May 30, 2011, the alert status in the area was increased to Siaga (standby), the second highest, due to the same reason. Some 600 people living near the Timbang crater, which belonged to the two neighboring regencies of Banjarnegara and Wonosobo, were also evacuated.

CO2 gas killed 149 people in Dieng Plateau area on Feb. 20, 1979, remembered as the Sinila tragedy. They were trying to flee but inhaled CO2 seeping from the cracks in the ground along the road they escaped along. They died on their way to a safer place.

As conditions eventually cooled down and normal levels were reached again, the alert status was returned to normal.