Report on Ijen (Indonesia) — August 2002
Bulletin of the Global Volcanism Network, vol. 27, no. 8 (August 2002)
Managing Editor: Richard Wunderman.
Ijen (Indonesia) Small explosion in late July 2002 accompanies increased seismicity; ash emissions
Please cite this report as:
Global Volcanism Program, 2002. Report on Ijen (Indonesia) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 27:8. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200208-263350
Ijen
Indonesia
8.058°S, 114.242°E; summit elev. 2769 m
All times are local (unless otherwise noted)
During 27 May through at least 8 September 2002 at Ijen, activity was above background levels. Seismicity was dominated by shallow volcanic (B-type) earthquakes. One small explosion occurred on 29 July, accompanying an increase in the number of B-type earthquakes (table 4). Ash was emitted during late July through mid-August. Continuous tremor occurred with a maximum amplitude of 0.5-6 mm. Fog obscured the view during most of the reporting period, but when the summit was visible, plumes were observed reaching up to 125 m above the volcano. Ijen remained at Alert Level 2.
Table 4. Earthquakes and plumes reported at Ijen during 27 May-8 September 2002. Courtesy VSI.
| Date | Deep volcanic earthquakes (A-type) | Shallow volcanic earthquakes (B-type) | Max amplitude of continuous tremor | Small explosion | Tectonic earthquakes | Plume Details |
| 27 May-02 Jun 2002 | -- | 6 | 0.5-4 mm | -- | -- | White-medium plume reached 50-125 m above the summit. |
| 03 Jun-09 Jun 2002 | -- | 10 | 0.5-4 mm | -- | -- | White-medium plume reached 50 m above the summit. |
| 10 Jun-16 Jun 2002 | -- | 12 | 0.5-4 mm | -- | 2 | -- |
| 17 Jun-23 Jun 2002 | 1 | 6 | 0.5-4 mm | -- | 4 | -- |
| 24 Jun-30 Jun 2002 | -- | 2 | 0.5-6 mm | -- | 2 | -- |
| 01 Jul-07 Jul 2002 | -- | 1 | 0.5-5 mm | -- | 2 | -- |
| 08 Jul-14 Jul 2002 | -- | 13 | 0.5-4 mm | -- | 2 | -- |
| 15 Jul-21 Jul 2002 | -- | 23 | 0.5-4 mm | -- | 1 | -- |
| 22 Jul-28 Jul 2002 | -- | 22 | 0.5-4 mm | -- | 10 | -- |
| 29 Jul-04 Aug 2002 | 4 | 40 | 0.5-3 mm | 1 on 29 July | -- | White-gray ash plume ~50 m above summit drifted E. |
| 05 Aug-11 Aug 2002 | -- | 31 | 0.5-6 mm | -- | 2 | White-gray ash plume ~50 m above summit drifted E. |
| 12 Aug-18 Aug 2002 | -- | 34 | 0.5-2 mm | -- | 4 | White-gray ash plume 50-75 m above summit drifted E. |
| 19 Aug-25 Aug 2002 | -- | 47 | 0.5-4 mm | -- | 8 | -- |
| 26 Aug-01 Sep 2002 | 2 | 59 | 0.5-4 mm | -- | 3 | -- |
| 02 Sep-08 Sep 2002 | -- | 65 | 0.5-3 mm | -- | 6 | -- |
Geological Summary. The Ijen volcano complex at the eastern end of Java consists of a group of small stratovolcanoes constructed within the 20-km-wide Ijen (Kendeng) caldera. The north caldera wall forms a prominent arcuate ridge, but elsewhere the rim was buried by post-caldera volcanoes, including Gunung Merapi, which forms the high point of the complex. Immediately west of the Gunung Merapi stratovolcano is the historically active Kawah Ijen crater, which contains a nearly 1-km-wide, turquoise-colored, acid lake. Kawah Ijen is the site of a labor-intensive mining operation in which baskets of sulfur are hand-carried from the crater floor. Many other post-caldera cones and craters are located within the caldera or along its rim. The largest concentration of cones forms an E-W zone across the southern side of the caldera. Coffee plantations cover much of the caldera floor; nearby waterfalls and hot springs are tourist destinations.
Information Contacts: Volcanological Survey of Indonesia (VSI), Jalan Diponegoro No. 57, Bandung 40122, Indonesia (URL: http://www.vsi.esdm.go.id/).
