Report on Mahawu (Indonesia) — July 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 7 (July 1987)
Managing Editor: Lindsay McClelland.
Mahawu (Indonesia) White plume present, 1977 activity reviewed
Please cite this report as:
Global Volcanism Program, 1987. Report on Mahawu (Indonesia) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 12:7. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198707-266110
1.352°N, 124.865°E; summit elev. 1299 m
All times are local (unless otherwise noted)
White fume was continuously present above the crater rim to 100 m heights. Fewer than five volcanic earthquakes were recorded/day. Some tectonic earthquakes were also recorded.
In 12:4 we reported that the temperature of the crater lake rose to 70°C in January 1978 without an eruption. However, Nairn and Bachri (1978) report that on 16 November 1977, the crater lake, 800 m in diameter and 10 m deep, was gray colored and turbid with strong central upwelling and had a temperature of 85.5°C [but see 12:8]. Moderately loud explosions were heard every 5-10 minutes followed by 2-3-m-high spearhead projections of water and lake-floor debris. Along the NE shore fine gray mud was deposited to 20 m above the lake. A strong H2S odor was present.
Reference. Nairn, I. and Bachri, S., 1978, Several annotations about Mahawu's crater activities in recent times: Berita Direktorat Geologi, v. 10, no. 5, p. 55.
Geological Summary. The elongated Mahawu volcano immediately east of Lokon-Empung volcano is the northernmost of a series of young volcanoes along a SSW-NNE line near the margin of the Quaternary Tondano caldera. Mahawu is capped by a 180-m-wide, 140-m-deep crater that sometimes contains a small crater lake, and has two pyroclastic cones on its N flank. Historical activity has been restricted to occasional small explosive eruptions recorded since 1789. In 1994 fumaroles, mudpots, and small geysers were observed along the shores of a greenish-colored crater lake.
Information Contacts: VSI.