Report on Colo (Indonesia) — September 1983
Scientific Event Alert Network Bulletin, vol. 8, no. 9 (September 1983)
Managing Editor: Lindsay McClelland.
Colo (Indonesia) Satellite observations of July-August eruption clouds
Please cite this report as:
Global Volcanism Program, 1983. Report on Colo (Indonesia) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 8:9. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198309-266010
Colo
Indonesia
0.162°S, 121.601°E; summit elev. 404 m
All times are local (unless otherwise noted)
Since late August, no explosions have been reported by ground observers or seen on satellite imagery. Yosihiro Sawada searched all July and August images from the GMS satellite and provided table 1.
Table 1. Una Una eruption cloud data extracted from GMS satellite images. Data are tentative; some apparent plumes may have been weather clouds. Times are the beginnings of image scans, which are completed in about 25 minutes. Images are returned 14 times/day at intervals ranging from 30 minutes to 3 hours. New explosions are indicated in the remarks column. Data shown in parentheses are for plumes that are detached from the volcano because explosive activity had (apparently) stopped. A new plume was sometimes ejected before remnants of the previous explosive pulse had dissipated; dimensions of the old plume are then listed in parentheses below data on the new activity. Coldest temperatures at the tops of plumes are shown. Courtesy of Yosihiro Sawada.
| Date | Time | Length (km) | Width (km) | Temp (°C) | Comment |
| 23 Jul 1983 | 1631 | 100 | 90 | -74 | -- |
| 23 Jul 1983 | 1801 | -- | -- | -76 | -- |
| 23 Jul 1983 | 1831 | 320 | 200 | -- | -- |
| 23 Jul 1983 | 1931 | 560 | 180 | -- | -- |
| 25 Jul 1983 | 2331 | 30 | 30 | -70 | New explosion |
| 26 Jul 1983 | 0131 | 210 | 160 | -- | -- |
| 26 Jul 1983 | 0431 | (520) | (160) | -- | -- |
| 27 Jul 1983 | 1931 | 60 | 20 | -- | New explosion |
| 28 Jul 1983 | 0131 | 160 | 20 | -- | -- |
| 28 Jul 1983 | 0431 | 170 | 50 | -- | -- |
| 28 Jul 1983 | 0631 | 290 | 70 | -- | -- |
| 28 Jul 1983 | 0731 | 260 | 40 | -- | -- |
| 28 Jul 1983 | 1031 | 500 | 70 | -- | -- |
| 28 Jul 1983 | 1331 | 550 | 60 | -- | -- |
| 28 Jul 1983 | 1631 | 710 | 80 | -- | -- |
| 28 Jul 1983 | 1831 | 650 | 70 | -- | -- |
| 28 Jul 1983 | 1931 | 500 | 30 | -- | -- |
| 28 Jul 1983 | 2331 | (340) | (20) | -- | -- |
| 30 Jul 1983 | 1631 | 80 | 40 | -73 | New explosion |
| 30 Jul 1983 | 1801 | -- | -- | -80 | -- |
| 30 Jul 1983 | 1831 | 260 | 110 | -- | -- |
| 30 Jul 1983 | 1931 | 370 | 120 | -- | -- |
| 30 Jul 1983 | 2331 | 190 (340) | 50 (320) | -- | New explosion |
| 31 Jul 1983 | 0131 | 250 | 130 | -- | -- |
| 31 Jul 1983 | 0431 | (260) | (100) | -- | -- |
| 31 Jul 1983 | 1801 | -- | -- | -70 | New explosion |
| 31 Jul 1983 | 1831 | 60 | 30 | -71 | -- |
| 31 Jul 1983 | 1901 | -- | -- | -71 | -- |
| 31 Jul 1983 | 1931 | 160 | 50 | -71 | -- |
| 31 Jul 1983 | 2331 | (150) | (80) | -- | -- |
| 01 Aug 1983 | 0131 | (160) | (110) | -- | -- |
| 01 Aug 1983 | 0431 | (130) | (50) | -- | -- |
| 02 Aug 1983 | 0431 | 70 | 50 | -72 | -- |
| 02 Aug 1983 | 0601 | -- | -- | -65 | -- |
| 02 Aug 1983 | 0631 | 160 | 70 | -63 | -- |
| 02 Aug 1983 | 0701 | -- | -- | -72 | -- |
| 02 Aug 1983 | 0731 | 240 | 80 | -75 | -- |
| 02 Aug 1983 | 1031 | 420 | 100 | -79 | -- |
| 02 Aug 1983 | 1331 | 50 (340) | 15 (240) | -60 | New explosion |
| 02 Aug 1983 | 1631 | 60 (420) | 20 (320) | -56 | -- |
| 02 Aug 1983 | 1831 | (130) | (20) | -- | -- |
| 02 Aug 1983 | 1931 | (450) | (320) | -- | -- |
| 02 Aug 1983 | 2331 | 80 | 30 | -71 | -- |
| 03 Aug 1983 | 0131 | (120) | (60) | -- | -- |
| 03 Aug 1983 | 0431 | (110) | (20) | -- | -- |
| 03 Aug 1983 | 0631 | (130) | (15) | -- | -- |
| 04 Aug 1983 | 1031 | 80 | 40 | -73 | -- |
| 04 Aug 1983 | 1331 | 150 | 110 | -73 | -- |
| 04 Aug 1983 | 1631 | 190 | 120 | -63 | -- |
| 04 Aug 1983 | 1831 | (190) | (160) | -- | -- |
| 04 Aug 1983 | 1931 | (210) | (130) | -- | -- |
| 04 Aug 1983 | 2331 | 90 | 100 | -79 | New explosion |
| 05 Aug 1983 | 0131 | 170 | 100 | -81 | -- |
| 05 Aug 1983 | 0431 | 280 | 200 | -73 | -- |
| 05 Aug 1983 | 0601 | -- | -- | -61 | -- |
| 05 Aug 1983 | 0631 | 170 | 170 | -60 | -- |
| 05 Aug 1983 | 0701 | -- | -- | -64 | -- |
| 05 Aug 1983 | 0731 | 30 | 30 | -70 | New explosion |
| 05 Aug 1983 | 1031 | 60 | 60 | -61 | -- |
| 05 Aug 1983 | 1331 | 100 | 90 | -63 | -- |
| 05 Aug 1983 | 0131 | 30 | 20 | -64 | -- |
| 06 Aug 1983 | 0131 | 30 | 20 | -64 | New explosion |
| 06 Aug 1983 | 0431 | 110 | 60 | -- | -- |
| 06 Aug 1983 | 0631 | 190 | 90 | -- | -- |
| 06 Aug 1983 | 0731 | 200 | 130 | -- | -- |
| 06 Aug 1983 | 1631 | 60 | 50 | -73 | New explosion |
| 06 Aug 1983 | 1801 | -- | -- | -69 | -- |
| 06 Aug 1983 | 1831 | 110 | 70 | -- | -- |
| 06 Aug 1983 | 1931 | (130) | (80) | -- | -- |
| 07 Aug 1983 | 1331 | 190 | 80 | -75 | New explosion |
| 07 Aug 1983 | 1631 | 320 | 110 | -79 | -- |
| 07 Aug 1983 | 1801 | -- | -- | -77 | -- |
| 07 Aug 1983 | 1831 | 190 | 150 | -75 | -- |
| 07 Aug 1983 | 1931 | 240 | 160 | -- | -- |
| 07 Aug 1983 | 2331 | 150 | 70 | -- | -- |
| 08 Aug 1983 | 0131 | (190) | (60) | -- | -- |
| 08 Aug 1983 | 0431 | 30 | 15 | -- | New explosion |
| 08 Aug 1983 | 0631 | 60 | 15 | -- | -- |
| 08 Aug 1983 | 0731 | (70) | (20) | -- | -- |
| 10 Aug 1983 | 0131 | 30 | 20 | -- | (obscure) |
| 10 Aug 1983 | 0431 | 30 | 10 | -- | (obscure) |
| 10 Aug 1983 | 0631 | 50 | 15 | -- | (obscure) |
| 11 Aug 1983 | 1331 | 290 | 80 | -69 | -- |
| 11 Aug 1983 | 1631 | (510) | (110) | -- | -- |
| 11 Aug 1983 | 1831 | (680) | (160) | -- | -- |
| 12 Aug 1983 | 0131 | 140 | 60 | -73 | New explosion |
| 12 Aug 1983 | 0431 | 460 | 100 | -- | -- |
| 22 Aug 1983 | 1331 | 20 | 15 | -- | (obscure) |
| 22 Aug 1983 | 1631 | 150 | 110 | -- | (obscure) |
| 22 Aug 1983 | 1831 | (260) | (110) | -- | -- |
| 22 Aug 1983 | 1931 | (300) | (140) | -- | -- |
| 26 Aug 1983 | 1331 | -- | -- | -- | New explosion; almost circular plume |
| 26 Aug 1983 | 1631 | -- | -- | -- | Cloud detected |
Geological Summary. Colo volcano forms the isolated small island of Una Una in the middle of the Gulf of Tomini in northern Sulawesi. The broad, low volcano contains a 2-km-wide caldera with a small central cone. Three eruptions have been recorded since the late 1800's, but two of those caused widespread damage over the island. The last eruption, in 1983, produced pyroclastic flows that swept over most of the island shortly after all residents had been evacuated.
Information Contacts: Y. Sawada, MRI, Tsukuba.
