PVMBG reported that during 7-12 February white plumes rose as high as 400 m above Merapi’s summit lava dome. The volume of the dome was an estimated 407,000 cubic meters on 12 February based on drone photos, similar to 19 November 2019 measurements. An eruption at 0516 on 13 February lasted two and a half minutes and produced an ash plume that rose about 2 km above the summit and drifted NW. Ashfall was reported in areas within a 10-km radius especially to the S, including the villages of Hargobinangun, Glagaharjo, and Kepuharjo. Video of the event showed incandescent material being ejected above the lava dome and lightning in the ash cloud. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to stay outside of the 3-km exclusion zone.

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.

Sources: Balai Penyelidikan dan Pengembangan Teknologi Kebencanaan Geologi (BPPTKG), Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)