Report on Semeru (Indonesia) — April 1991
Bulletin of the Global Volcanism Network, vol. 16, no. 4 (April 1991)
Managing Editor: Lindsay McClelland.
Semeru (Indonesia) Continued explosions and seismicity
Please cite this report as:
Global Volcanism Program, 1991. Report on Semeru (Indonesia) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 16:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199104-263300.
8.108°S, 112.922°E; summit elev. 3657 m
All times are local (unless otherwise noted)
Explosions continued during April, with column heights averaging 300-400 m, and explosion earthquakes recorded an average of 112 times/day . . . . Seismographs also recorded 2-3 daily avalanches of material off the lava flow erupted 17 February. A total of one deep volcanic earthquake and 18 tectonic events were recorded.
Geologic Background. 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.
Information Contacts: W. Modjo, VSI.