Report on Semeru (Indonesia) — 6 January-12 January 2016
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 6 January-12 January 2016
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2016. Report on Semeru (Indonesia) (Sennert, S, ed.). Weekly Volcanic Activity Report, 6 January-12 January 2016. Smithsonian Institution and US Geological Survey.
8.108°S, 112.922°E; summit elev. 3657 m
All times are local (unless otherwise noted)
PVMBG reported that during 1 November 2015-4 January 2016 white and gray plumes from Semeru rose as high as 500 m above the crater and drifted E, S, and W; inclement weather sometimes prevented observations. In November nine incandescent avalanches traveled 100-500 m down the flanks. During December 2015-4 January 2016 incandescent material was occasionally ejected above the crater. Seismicity was dominated by signals indicating avalanches and emissions. The Alert Level remained at 2 (on a scale from 1-4); visitors and residents were warned to avoid the SE flank within 4 km of the crater.
Geological Summary. Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano.