On 6 March PVMBG lowered the Alert Level for the Dieng Volcanic Complex to 1 (on a scale of 1-4) due to decreased carbon dioxide emissions. During the first half of January carbon dioxide emissions were elevated at Timbang Crater and then significantly increased in mid-January; recent measurements indicated a decreasing trend. On 22 February a mobile instrument measured 112,000 ppm CO2 at the crater, though the concentration dropped to 9,200 ppm at a distance of less than 10 m from the crater rim. Measurements at the multi-gas station indicated concentration of 1,500-1,900 parts per million (ppm). The public was warned to stay 500 m away from Sileri Crater and to stay out of Timbang Crater, and to take caution when digging in the ground as gasses could be released from the soil.

Geological Summary. The Dieng plateau in the highlands of central Java is renowned both for the variety of its volcanic scenery and as a sacred area housing Java's oldest Hindu temples, dating back to the 9th century CE. The Dieng Volcanic Complex consists of multiple stratovolcanoes and more than 20 small Pleistocene-to-Holocene craters and cones over a 6 x 14 km area. Prahu stratovolcano was truncated by a large Pleistocene caldera, which was subsequently filled by a series of cones, lava domes, and craters, many containing lakes. Lava flows cover much of the plateau, but observed activity has been restricted to minor phreatic eruptions. Gas emissions are a hazard at several craters and have caused fatalities. There are abundant thermal features and high heat flow across the area.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)