Small ash eruptions

Ash eruptions occurred on 3 and 15 November 1991, ejecting columns to a maximum of ~150 m above the crater rim. Since then, an average of 47 shallow earthquakes have been recorded monthly, and a white vapor column continued to rise to ~ 50 m above the crater.

Information Contacts: W. Modjo and W. Tjetjep, VSI.

Information is preliminary and subject to change. All times are local (unless otherwise noted)

December 1982 (SEAN 07:12) Cite this Report

Small ash eruption

VSI reported that an ash eruption began on 17 November at 0615. The ash column rose ~ 1 km and was blown N, causing thin ashfalls on nearby villages. The eruption ended after several hours. As of mid-Jan, no additional activity had been reported. Press sources noted that the eruption was preceded by a moderately strong, felt earthquake on 15 November at about 2300.

Information Contacts: A. Sudradjat and O. Mandraguna, VSI; M. Krafft, Cernay; SinarHarapan, Jakarta.

August 1983 (SEAN 08:08) Cite this Report

Small plume photographed by Space Shuttle astronauts

[Photographs taken on 31 August (figure 1) and] 4 September by astronauts on Space Shuttle mission STS-8 showed small, relatively diffuse plumes long emerging from Iliboleng. [The 31 August plume extended at least 40 km and the 4 September plume was roughly 50-70 km long.]

Information Contacts: C. Wood and R. Underwood, NASA, Houston.

May 1986 (SEAN 11:05) Cite this Report

Explosion; grassfires from ashfall; 570 evacuated

Iliboleng erupted on 28 May at 1735. A single explosion ejected incandescent material and caused ashfall on a nearby plantation and several villages both E and W of the summit (Lamalota, Dua Muda, Tuawolo, and Kiwangona). The incandescent ashfalls caused grass fires in the very dry area (no rain reported since February) that burned 700 hectares of grass W of the volcano and 250 hectares to the E. About 570 people were evacuated from several villages after the initial explosion and grass fires, but returned to their homes 31 May.

On 2 June at 0500, weather had cleared and a white vapor cloud of ~100 m height was reported. B-type earthquakes were recorded in the area on 21 May, but no more seismic data were available.

Information Contacts: A. Sudradjat, L. Pardyanto, and T. Casadevall, VSI.

July 1986 (SEAN 11:07) Cite this Report

800-m eruption cloud

Iliboleng erupted on 18 July at 1234, ejecting a cloud to ~ 800 m above the summit.

Information Contacts: L. Pardyanto, Olas, Kaswanda, Suratman, A. Sudradjat, and T. Casadevall, VSI.

November 1986 (SEAN 11:11) Cite this Report

Renewed explosions after 12 days of seismicity

Explosions occurred 10, 15, and 24 November. A gas and ash column emitted on 24 November at 0712 reached 1,000 m height and was blown NNW, covering 18.7 km² with ~1 mm of ash. There were no casualties. Shallow volcanic seismicity began 30 October, with as many as 60 events/day. Eruption tremor was recorded for 1.5 minutes on 10 November.

Information Contacts: VSI; ANS.

June 1987 (SEAN 12:06) Cite this Report

Earthquakes increase; 300-m-high plume

Since 20 June, a plume has risen as much as 300 m above the summit. The number of shallow volcanic earthquakes increased to ~20/day 20-25 June, compared to 1/day previously. No eruptive activity has been reported since November.

Information Contacts: VSI.

July 1987 (SEAN 12:07) Cite this Report

Volcanic earthquakes decline late in month

During July, white plumes continued to be emitted to 300 m above the peak. Several shallow volcanic earthquakes were recorded daily during early July. In late July, seismic activity had returned to low background levels.

Information Contacts: VSI.

September 1987 (SEAN 12:09) Cite this Report

Explosion deposits ash on nearby village

A large explosion occurred on 2 October at 2252, depositing a light dusting of ash on villages near the volcano.

Information Contacts: VSI.

October 1987 (SEAN 12:10) Cite this Report

Continued seismicity follows explosion

A large explosion on 2 October at 2252 deposited a light dusting of ash in about a 15 km² area around the volcano. During the week of 9-15 October, white fume was continuously present above the crater, rising to heights of 300 m. During that week, about 13 tectonic and 11 volcanic events were recorded/day.

Information Contacts: VSI.

July 1989 (SEAN 14:07) Cite this Report

Fumarolic emissions; felt earthquake

In July, fumarole temperatures in the crater were 60-70°C. On 15 July, an MM II earthquake was felt. The number and types of earthquakes recorded were: 131 distant tectonic, three local tectonic, two volcanic A-type, and 144 volcanic B-type. The volcano's level of activity is slightly higher than normal.

Information Contacts: VSI.

June 1991 (BGVN 16:06) Cite this Report

Vapor and ash emission

Vapor and ash were continuously emitted to 100-850 m height, beginning 8 May and continuing through June. Shallow volcanic earthquakes were recorded 15-25 times/week (figure 2), but no explosion earthquakes were recorded. Tectonic earthquakes averaged 14-24/week.

Information Contacts: W. Modjo, VSI.

February 1992 (BGVN 17:02) Cite this Report

Small ash eruptions

Ash eruptions occurred on 3 and 15 November 1991, ejecting columns to a maximum of ~150 m above the crater rim. Since then, an average of 47 shallow earthquakes have been recorded monthly, and a white vapor column continued to rise to ~ 50 m above the crater.

Information Contacts: W. Modjo and W. Tjetjep, VSI.