Report on Merapi (Indonesia) — 17 April-23 April 2019
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 17 April-23 April 2019
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2019. Report on Merapi (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 17 April-23 April 2019. Smithsonian Institution and US Geological Survey.
7.54°S, 110.446°E; summit elev. 2910 m
All times are local (unless otherwise noted)
PVMBG reported that during 15-21 April the lava dome at Merapi continued to grow slowly, with any extruded material channeled into the SE-flank Gendol River drainage. White emissions rose 70 m. Block-and-ash flows traveled as far as 1.5 km in the Gendol drainage on 21 April. The Alert Level remained at 2 (on a scale of 1-4), and residents were warned to remain 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.