Report on Sangeang Api (Indonesia) — September 1985
Scientific Event Alert Network Bulletin, vol. 10, no. 9 (September 1985)
Managing Editor: Lindsay McClelland.
Sangeang Api (Indonesia) 30 July eruption plume seen on satellite images
Please cite this report as:
Global Volcanism Program, 1985. Report on Sangeang Api (Indonesia). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 10:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198509-264050.
8.2°S, 119.07°E; summit elev. 1912 m
All times are local (unless otherwise noted)
GMS images showed plumes from the initial 30 July activity (figure 1). Digital data analyses of temperatures at the tops of the plumes compared with radiosonde altitude profiles suggested that they reached a maximum altitude of 14.1 km (table 1), below the tropopause. However, Yosihiro Sawada notes that for both this and other eruptions, altitudes calculated with this technique seem to be consistently higher than estimates from ground observers.
|Figure 1. Surface temperatures (in °C) of eruption clouds from Sangeang Api (left), 30 July 1985, 1400 (top) and 1700 (bottom) Zones of plume surface from Sangeang Api (right) with temperatures|
|Date||Time||Length (km)||Width (km)||Min Temp||Max Alt (km)||Remarks|
|30 Jul 1985||1400||135||105||-71°C||14.1||emerging from volcano|
|30 Jul 1985||1700||315||100||-50°C||11.8||detached from volcano|
|30 Jul 1985||1800||385||150||-37°C||10.2||detached from volcano|
|30 Jul 1985||1830||405||160||-30°C||9.4||detached from volcano|
|30 Jul 1985||1900||425||130||-24°C||8.5||detached from volcano|
Geologic Background. Sangeang Api volcano, one of the most active in the Lesser Sunda Islands, forms a small 13-km-wide island off the NE coast of Sumbawa Island. Two large trachybasaltic-to-tranchyandesitic volcanic cones, Doro Api and Doro Mantoi, were constructed in the center and on the eastern rim, respectively, of an older, largely obscured caldera. Flank vents occur on the south side of Doro Mantoi and near the northern coast. Intermittent historical eruptions have been recorded since 1512, most of them during in the 20th century.
Information Contacts: Y. Sawada, MRI, Tsukuba.