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Iliboleng

Photo of this volcano
  • Country
  • Primary Volcano Type
  • Last Known Eruption
  •  
  • 8.342°S
  • 123.258°E

  • 1659 m
    5443 ft

  • 264220
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Bulletin Report: February 1992 (BGVN 17:02) Citation IconCite 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.

The Global Volcanism Program has no Weekly Reports available for Iliboleng.

Bulletin Reports - Index

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

12/1982 (SEAN 07:12) Small ash eruption

08/1983 (SEAN 08:08) Small plume photographed by Space Shuttle astronauts

05/1986 (SEAN 11:05) Explosion; grassfires from ashfall; 570 evacuated

07/1986 (SEAN 11:07) 800-m eruption cloud

11/1986 (SEAN 11:11) Renewed explosions after 12 days of seismicity

06/1987 (SEAN 12:06) Earthquakes increase; 300-m-high plume

07/1987 (SEAN 12:07) Volcanic earthquakes decline late in month

09/1987 (SEAN 12:09) Explosion deposits ash on nearby village

10/1987 (SEAN 12:10) Continued seismicity follows explosion

07/1989 (SEAN 14:07) Fumarolic emissions; felt earthquake

06/1991 (BGVN 16:06) Vapor and ash emission

02/1992 (BGVN 17:02) Small ash eruptions




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


December 1982 (SEAN 07:12) Citation IconCite 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) Citation IconCite 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.]

Figure (see Caption) Figure 1. Space Shuttle photograph (STS008-60-1840) taken on 31 August 1983 showing Iliboleng emitting a diffuse plume. Note that N is to the upper right; the plume is blowing almost due W. [Adonara Island covers 580 km2 and is 37 km long and 18 km wide. Lomblen Island, with its many volcanoes, is ESE of Adonara Island. To Adonara's west, the E tip of Flores Island is visible; almost due S of Adonara is Solor Island.] Courtesy of C. Wood.

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


May 1986 (SEAN 11:05) Citation IconCite 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) Citation IconCite 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) Citation IconCite 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) Citation IconCite 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) Citation IconCite 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) Citation IconCite 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) Citation IconCite 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) Citation IconCite 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) Citation IconCite 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.

Figure (see Caption) Figure 2. Monthly number of earthquakes at Iliboleng, January 1990-May 1991. Courtesy of VSI.

Information Contacts: W. Modjo, VSI.


February 1992 (BGVN 17:02) Citation IconCite 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.

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Eruptive History

There is data available for 20 confirmed Holocene eruptive periods.

1993 Jun 16 (?) ± 15 days - 1993 Jul 16 ± 15 days Confirmed Eruption Max VEI: 1 (?)

Episode 1 | Eruption Episode
1993 Jun 16 (?) ± 15 days - 1993 Jul 16 ± 15 days Evidence from Observations: Reported

List of 6 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Earthquakes (undefined) Before.
   - - - -    - - - - Earthquakes (undefined)
   - - - -    - - - - Earthquakes (undefined) After.
1993 Jun
(?)
   - - - - VEI (Explosivity Index)

1991 Nov 3 - 1991 Nov 15 Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode
1991 Nov 3 - 1991 Nov 15 Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
1991 Nov 3    - - - - VEI (Explosivity Index)

1991 May 8 - 1991 Jun 30 (in or after) Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode
1991 May 8 - 1991 Jun 30 (in or after) Evidence from Observations: Reported

List of 4 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Ash
   - - - -    - - - - Earthquakes (undefined) Before.
   - - - -    - - - - Earthquakes (undefined)
1991 May 8    - - - - VEI (Explosivity Index)

1987 Oct 2 - 1987 Oct 2 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1987 Oct 2 - 1987 Oct 2 Evidence from Observations: Reported

List of 5 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Earthquakes (undefined) Before.
   - - - -    - - - - Earthquakes (undefined) After.
1987 Oct 2    - - - - VEI (Explosivity Index)

1986 May 28 - 1986 Nov 24 Confirmed Eruption Max VEI: 1

Episode 1 | Eruption Episode
1986 May 28 - 1986 Nov 24 Evidence from Observations: Reported

List of 6 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Seismicity (tremor)
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Earthquakes (undefined) Before.
   - - - -    - - - - Evacuations
1986 May 28    - - - - VEI (Explosivity Index)

1983 May 11 - 1984 Apr 13 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1983 May 11 - 1984 Apr 13 Evidence from Observations: Reported

List of 4 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
1983 May 11    - - - - VEI (Explosivity Index)
1984 Jan 3    - - - - VEI (Explosivity Index)

1982 Nov 17 - 1982 Nov 17 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1982 Nov 17 - 1982 Nov 17 Evidence from Observations: Reported

List of 4 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Earthquakes (undefined) Before.
1982 Nov 17    - - - - VEI (Explosivity Index)

1973 Apr 16 ± 15 days - 1974 Apr 16 ± 15 days Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1973 Apr 16 ± 15 days - 1974 Apr 16 ± 15 days Evidence from Observations: Reported

List of 5 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
   - - - -    - - - - Earthquakes (undefined)
   - - - -    - - - - Property Damage
1973 Apr    - - - - VEI (Explosivity Index)

1951 Jul 2 ± 182 days Confirmed Eruption Max VEI: 2 (?)

Episode 1 | Eruption Episode
1951 Jul 2 ± 182 days - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
1951    - - - - VEI (Explosivity Index)

1950 Mar 16 ± 15 days - 1950 Aug 16 (?) ± 15 days Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1950 Mar 16 ± 15 days - 1950 Aug 16 (?) ± 15 days Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
1950 Mar    - - - - VEI (Explosivity Index)

1949 Jun 12 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1949 Jun 12 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
1949 Jun 12    - - - - VEI (Explosivity Index)

1949 Feb 4 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1949 Feb 4 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
1949 Feb 4    - - - - VEI (Explosivity Index)

1948 Apr 29 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1948 Apr 29 - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion weak or small
   - - - -    - - - - Blocks
1948 Apr 29    - - - - VEI (Explosivity Index)

1944 Aug - 1944 Oct Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1944 Aug - 1944 Oct Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash weak or small
1944 Aug    - - - - VEI (Explosivity Index)

1927 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1927 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion Uncertain
1927    - - - - VEI (Explosivity Index)

1925 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1925 - Unknown Evidence from Observations: Reported

List of 3 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Ash
1925    - - - - VEI (Explosivity Index)

1909 Nov 9 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1909 Nov 9 - Unknown Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
1909 Nov 9    - - - - VEI (Explosivity Index)

1904 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1904 - Unknown Evidence from Observations: Reported

List of 4 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Ash
1904    - - - - VEI (Explosivity Index)

1888 Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1888 - Unknown Evidence from Observations: Reported

List of 4 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
   - - - -    - - - - Lava flow
   - - - -    - - - - Ash
1888    - - - - VEI (Explosivity Index)

1885 Sep - 1885 Oct Confirmed Eruption Max VEI: 2

Episode 1 | Eruption Episode
1885 Sep - 1885 Oct Evidence from Observations: Reported

List of 2 Events for Episode 1

Start Date End Date Event Type Event Remarks
   - - - -    - - - - Explosion
1885 Sep    - - - - VEI (Explosivity Index)
Deformation History

There is no Deformation History data available for Iliboleng.

Emission History

There is no Emissions History data available for Iliboleng.

Photo Gallery

Iliboleng volcano at the SE end of Adonara Island, east of Flores Island, is a symmetrical stratovolcano with many partially overlapping summit craters. Iliboleng is seen here from Bukit Tomu, north of the volcano. Explosive eruptions from the summit crater have been recorded since 1885. Only one historical eruption, in 1888, produced a lava flow.

Photo by Willem Rohi, 1994 (Volcanological Survey of Indonesia).
Iliboleng volcano rises above the Boleng strait between Adonara and Lomblen Islands, at the eastern end of the Lesser Sunda (Nusa Tenggara) Islands. The symmetrical volcano, which occupies the SE corner of Adonara, is seen here from the NE tip of the island. The 1659-m-high stratovolcano, the only historically active volcano on the island, is one of the most active in the Lesser Sundas.

Photo by O. Rukman, 1985 (Volcanological Survey of Indonesia).
Four volcanoes are seen in this NASA International Space Station image (with north to the upper left) of Solor (lower left), Adonara (upper left), and Lembata (right) Islands. Ililabalekan volcano on SW Lembata (formerly Lomblen) Island is the only one of these without historical eruptions, although fumaroles are found near its summit. A satellitic cone was constructed on the SE flank of the steep-sided volcano, and four craters, one of which contains a lava dome and two small explosion pits, occur at the summit of Mount Labalekan.

NASA International Space Station image ISS009-E-7480, 2004 (http://eol.jsc.nasa.gov/).
An eruption at Iliboleng began on 11 May 1983 when an ash plume rose to 500 m. Ash and incandescent ejecta was reported on 13 July and fine ash occasionally fell from the plume on 15 July. On 4 September space shuttle astronauts photographed this small diffuse plume 50-70 km long, and an ash plume was reported again on 22 September. A 500 m ash plume was seen for a few minutes on 24 November, and additional plumes were emitted on 3 January and 13 April 1984 to a maximum height of 1 km.

NASA Space Shuttle image STS008-50-1840, 1983 (http://eol.jsc.nasa.gov/).
The summit craters of Iliboleng are near the center of this May 2019 Planet Labs satellite image monthly mosaic (N is at the top). The larger crater is approximately 500 x 700 m.

Satellite image courtesy of Planet Labs Inc., 2019 (https://www.planet.com/).
GVP Map Holdings

The maps shown below have been scanned from the GVP map archives and include the volcano on this page. Clicking on the small images will load the full 300 dpi map. Very small-scale maps (such as world maps) are not included. The maps database originated over 30 years ago, but was only recently updated and connected to our main database. We welcome users to tell us if they see incorrect information or other problems with the maps; please use the Contact GVP link at the bottom of the page to send us email.

Smithsonian Sample Collections Database

There are no samples for Iliboleng in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

External Sites