The Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG) reported that the eruption at Merapi (on Java) continued during 29 November-5 December. Seismicity remained at high levels. The SW lava dome produced 84 lava avalanches that traveled as far as 1.8 km SW down the Bebeng drainage, eight that traveled SW down the Krasak drainage, and one that traveled 500 m W down the Senowo drainage. At 1642 on 5 December a pyroclastic flow descended 1.4 km along the Krasak drainage for nearly two minutes. Morphological changes to the SW lava dome resulted from continuing effusion and collapses of material. The SW dome grew larger and was an estimated 3,272,300 cubic meters based on an analysis of webcam images. The volume of the main crater was stable at an estimated 2,361,800 cubic meters. The Alert Level remained at 3 (on a scale of 1-4), and the public was warned to stay 3-7 km away from the summit, based on location.

Geological Summary. Merapi, one of Indonesia's most active volcanoes, lies in one of the world's most densely populated areas and dominates the landscape immediately north of the major city of Yogyakarta. It is the youngest and southernmost of a volcanic chain extending NNW to Ungaran volcano. Growth of Old Merapi during the Pleistocene ended with major edifice collapse perhaps about 2,000 years ago, leaving a large arcuate scarp cutting the eroded older Batulawang volcano. Subsequent growth of the steep-sided Young Merapi edifice, its upper part unvegetated due to frequent activity, began SW of the earlier collapse scarp. Pyroclastic flows and lahars accompanying growth and collapse of the steep-sided active summit lava dome have devastated cultivated lands on the western-to-southern flanks and caused many fatalities.

Source: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG)