Bagana

Photo of this volcano
Google Earth icon
  Google Earth Placemark
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 6.14°S
  • 155.195°E

  • 1750 m
    5740 ft

  • 255020
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

6 August-12 August 2014

During 6-12 August, DMPGM reported increasing volcanic activity at Bagana volcano. Thin to thick white vapor plumes from Bagana were accompanied on 6, 8 August by reports of rockfalls. On 10 August an ash plume rose to an estimated several hundred meters above the crater drifting SW and W. Moderate ash was reported in Wakovi (6 km W) and decreased downwind. Residents were advised to evacuate to Gotana (9 km SW) if ashfall continued. On 11 August the Darwin VAAC reported ash plumes rose to 3 km (10,000 ft) a.s.l. and drifted up to 55 km SW. On 12 August Darwin VAAC raised the Aviation Color Code to Red as ash plumes rose to 7.6 km (25,000 ft) a.s.l. and drifted up to 167 km SW.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC), Department of Mineral Policy and Geohazards Management (DMPGM)

Index of Weekly Reports


2014: February | March | April | May | June | August
2013: February | March | April | May | June | September | November | December
2012: February | May | June | July | August | September | October | December
2011: March | May | August | October
2010: February | April | May | June | July | August | September
2009: April | May | June | July | August | September | October | November
2008: February | May | September | October | November | December
2007: January | March | May | June | August | September | October | December
2006: March | May | June | November | December
2005: March | May | June | August | September
2004: April | May

Weekly Reports


6 August-12 August 2014

During 6-12 August, DMPGM reported increasing volcanic activity at Bagana volcano. Thin to thick white vapor plumes from Bagana were accompanied on 6, 8 August by reports of rockfalls. On 10 August an ash plume rose to an estimated several hundred meters above the crater drifting SW and W. Moderate ash was reported in Wakovi (6 km W) and decreased downwind. Residents were advised to evacuate to Gotana (9 km SW) if ashfall continued. On 11 August the Darwin VAAC reported ash plumes rose to 3 km (10,000 ft) a.s.l. and drifted up to 55 km SW. On 12 August Darwin VAAC raised the Aviation Color Code to Red as ash plumes rose to 7.6 km (25,000 ft) a.s.l. and drifted up to 167 km SW.

Sources: Darwin Volcanic Ash Advisory Centre (VAAC); Department of Mineral Policy and Geohazards Management (DMPGM)


11 June-17 June 2014

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 11-12 June ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 25-40 km SW and W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


4 June-10 June 2014

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 10 June an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted over 35 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


21 May-27 May 2014

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 27 May an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 65 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


30 April-6 May 2014

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 1 May an ash plume from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted over 45 km SSE.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


19 March-25 March 2014

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 22 March an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 110 km NE.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


12 February-18 February 2014

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 12 February an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 110 km E.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


18 December-24 December 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 22 December an ash plume from Bagana rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted 75 km NE.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


4 December-10 December 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 5-6 December ash plumes from Bagana drifted 55-65 km W. During 9-10 December ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 35-45 km NE and E.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


13 November-19 November 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 14-18 November ash plumes from Bagana rose to an altitude of 2.7 km (9,000 ft) a.s.l. and drifted 35-110 km W and SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


18 September-24 September 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 19 September an ash plume from Bagana rose to an altitude of 2.7 km (8,000 ft) a.s.l. and drifted 75 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


11 September-17 September 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 16-17 September ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 35-55 km NW and SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


12 June-18 June 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 17 June an ash plume from Bagana rose to altitudes of 2.1-2.4 km (7,000-8,000 ft) a.s.l. and drifted over 35 km NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


29 May-4 June 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 4 June an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted over 35 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


22 May-28 May 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 24 May an ash plume from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted over 35 km NW and N.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


1 May-7 May 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 5-6 May ash plumes from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 75-85 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


10 April-16 April 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 10-11 April ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75 km SW and W. On 15 April an ash plume rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted almost 30 km S and W. The next day ash plumes rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 65 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


3 April-9 April 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that on 7 April ash plumes from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted almost 85 km SW and WSW. On 9 April an ash plume rose to an altitude of 4 km (13,000 ft) a.s.l. and drifted almost 75 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


20 March-26 March 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 25-26 March ash plumes from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 45-55 km E.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


13 February-19 February 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 12-14 February ash plumes from Bagana rose to an altitude of 1.5 km (5,000 ft) a.s.l. and drifted 35-55 km SW and NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


6 February-12 February 2013

Based on analyses of satellite imagery and wind data, the Darwin VAAC reported that during 8-12 February ash plumes from Bagana rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted 35-130 km E and NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


12 December-18 December 2012

RVO reported that white vapor from Bagana was emitted during 1 November-12 December. Occasional weak incandescence from the crater was observed at night during 3-8, 10, 17-20, and 29-30 November. An eruption during 1200-1300 on 13 December was followed by light ashfall in Arawa (40 km SE) and heavier ashfall in Manetai (11 km E). A small amount of ashfall was reported in Arawa the next day; the volcano was mostly quiet during 14-15 December.

Source: Rabaul Volcano Observatory (RVO)


3 October-9 October 2012

Based on analyses of satellite imagery, the Darwin VAAC reported that on 3 October an ash plume from Bagana rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted 65 km NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


26 September-2 October 2012

Based on analyses of satellite imagery, the Darwin VAAC reported that on 27 September an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 37 km N.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


1 August-7 August 2012

Based on analyses of satellite imagery, the Darwin VAAC reported that on 2 August ash plumes from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 37 km NW and W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


4 July-10 July 2012

Based on analyses of satellite imagery, the Darwin VAAC reported that on 4 July ash plumes from Bagana rose to altitudes of 2.4-3 km (8,000-10,000 ft) a.s.l. and drifted 55 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


6 June-12 June 2012

Based on analyses of satellite imagery, the Darwin VAAC reported that on 10 June ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 45-130 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


23 May-29 May 2012

According to NASA's Earth Observatory, a satellite image of Bagana acquired on 16 May showed a lava flow on the E flank. Other satellite images indicated that the lava flow was emplaced sometime between March 2011 and February 2012. A plume drifted W.

Source: NASA Earth Observatory


29 February-6 March 2012

Based on analyses of satellite imagery, the Darwin VAAC reported that on 7 March an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 37 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


5 October-11 October 2011

Based on analyses of satellite imagery, the Darwin VAAC reported that during 8-9 October ash plumes from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 45-55 km E and NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


24 August-30 August 2011

Based on analyses of satellite imagery, the Darwin VAAC reported that on 23 August an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 93 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


17 August-23 August 2011

Based on analyses of satellite imagery, the Darwin VAAC reported that on 21 August an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 93 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


18 May-24 May 2011

Based on analyses of satellite imagery, the Darwin VAAC reported that on 21 May an ash plume from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 65 km NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


11 May-17 May 2011

Based on analyses of satellite imagery, the Darwin VAAC reported that on 16 May an ash plume from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 55 km NE.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


23 March-29 March 2011

Based on analyses of satellite imagery, the Darwin VAAC reported that during 25-28 March ash plumes from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 35-100 km NW, W, and SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


16 March-22 March 2011

Based on analyses of satellite imagery, the Darwin VAAC reported that during 18-19 March ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75-110 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


29 September-5 October 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that on 1 October an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75 km NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


11 August-17 August 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that during 13-15 August ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75 km SW and W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


7 July-13 July 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75-150 km SW during 10-11 July.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


30 June-6 July 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. on 4 July and drifted 75 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


9 June-15 June 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that ash plumes from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. during 13-14 June and drifted 75-205 km SW and W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


26 May-1 June 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that ash plumes from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. during 26-28 May and drifted 30-185 km SW and W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


19 May-25 May 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. on 25 May and drifted 55-160 km NW and W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


12 May-18 May 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. on 12 May and drifted 55-75 km W and WSW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


5 May-11 May 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that ash plumes from Bagana rose to altitudes of 2.4-3 km (8,000-10,000 ft) a.s.l. during 6 and 10-11 May and drifted 65 km W and SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


21 April-27 April 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that during 19-20, 23, 25, and 27 April ash plumes from Bagana rose to altitudes of 1.5-3 km (5,000-10,000 ft) a.s.l. and drifted 35-85 km S, SW, W, and NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


17 February-23 February 2010

RVO reported that white vapor from Bagana was emitted during 1-21 February. Ash plumes were seen on 5 February and night-time incandescence was seen on 2, 12, 13, and 19 February. Sulfur dioxide plumes drifted ENE during 11-20 February and NNW on 20 and 21 February.

Source: Rabaul Volcano Observatory (RVO)


10 February-16 February 2010

Based on analyses of satellite imagery, the Darwin VAAC reported that during 11-15 February ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 20-150 km E and NE.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


11 November-17 November 2009

Based on analyses of satellite imagery, the Darwin VAAC reported that on 12 November an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 65 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


14 October-20 October 2009

Based on analyses of satellite imagery, the Darwin VAAC reported that on 15 October an ash plume from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted 55 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


7 October-13 October 2009

Based on analyses of satellite imagery, the Darwin VAAC reported that on 9 October an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 45 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


16 September-22 September 2009

Based on analyses of satellite imagery, the Darwin VAAC reported that during 17-19 September ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 25-45 km NW, W, and SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


9 September-15 September 2009

Based on analyses of satellite imagery, the Darwin VAAC reported that during 12-13 September ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 35-65 km NW and W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


19 August-25 August 2009

Based on analyses of satellite imagery, the Darwin VAAC reported that on 19 August an ash plume from Bagana rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted more than 90 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


5 August-11 August 2009

Based on analyses of satellite imagery, the Darwin VAAC reported that on 10 August a diffuse ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted 55 km NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


15 July-21 July 2009

Based on analyses of satellite imagery, the Darwin VAAC reported that on 19 July an ash plume from Bagana rose to an altitude of 1.8 km (6,000 ft) a.s.l. and drifted 100 km NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


24 June-30 June 2009

Based on analysis of satellite imagery, the Darwin VAAC reported that on 27 June an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 110 km SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


27 May-2 June 2009

Based on analysis of satellite imagery, the Darwin VAAC reported that on 2 June an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 75 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


29 April-5 May 2009

Based on analysis of satellite imagery, the Darwin VAAC reported that on 2 and 4 May ash plumes from Bagana rose to altitudes of 2.4-3 km (8,000-10,000 ft) a.s.l. and drifted 45-55 km NE.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


22 April-28 April 2009

Based on analysis of satellite imagery, the Darwin VAAC reported that on 26 April an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted 28 km S.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


31 December-6 January 2009

Based on analysis of satellite imagery, the Darwin VAAC reported that on 31 December an ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


24 December-30 December 2008

Based on analysis of satellite imagery, the Darwin VAAC reported that on 29 December an ash plume from Bagana drifted about 75 km W. On 30 December an ash plume rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


17 December-23 December 2008

Based on analysis of satellite imagery, the Darwin VAAC reported that on 17 December an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


10 December-16 December 2008

Based on analysis of satellite imagery, the Darwin VAAC reported that on 16 December an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


26 November-2 December 2008

Based on analysis of satellite imagery, the Darwin VAAC reported that on 2 December an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


19 November-25 November 2008

Based on analysis of satellite imagery, the Darwin VAAC reported that on 20 November an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted about 75 km SW. On 26 November a low-level plume drifted W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


8 October-14 October 2008

Based on analysis of satellite imagery, the Darwin VAAC reported that on 8 October low-level ash plumes from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted about 55-110 km WSW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


17 September-23 September 2008

Based on analysis of satellite imagery, the Darwin VAAC reported that during 21-22 September low-level ash plumes from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


10 September-16 September 2008

Based on analysis of satellite imagery, the Darwin VAAC reported that on 16 September a low-level ash plume from Bagana rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


21 May-27 May 2008

Based on observations of satellite imagery, the Darwin VAAC reported that on 22 May a low-level ash plume from Bagana rose to an altitude of 3.7 km (12,000 ft) a.s.l. and drifted S.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


27 February-4 March 2008

Based on observations of satellite imagery and information from RVO, the Darwin VAAC reported that a diffuse plume from Bagana rose to an altitude of less than 3 km (10,000 ft) a.s.l. and drifted SW on 3 March. Later that day an ash-and-steam plume drifted SW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


26 December-1 January 2008

Based on observations of satellite imagery, the Darwin VAAC reported that an ash-and-steam plume from Bagana drifted WSW on 26 December. A plume rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted W on 27 December. RVO advised that intermittent activity was continuing.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


19 December-25 December 2007

Based on observations of satellite imagery and reports from the RVO, the Darwin VAAC reported that a plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SW on 21 December. An ash-and-steam plume was also visible on 26 December and drifted WSW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


12 December-18 December 2007

Based on observations of satellite imagery, the Darwin VAAC reported that a low-level plume from Bagana drifted SW on 10 December and an ash-and-steam plume was observed on 17 December.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


5 December-11 December 2007

RVO reported that during 18 October-10 December white vapor plumes from Bagana were occasionally accompanied by ash plumes generated by rockfalls from the edges of the lava flow on the SE flank. Occasionally, booming and roaring noises were heard and incandescence at the summit was observed. Two explosions were accompanied by ash plumes on 19 and 27 November. Incandescent lava fragments were ejected from the summit on 7 and 9 December. On 9 December, an ash plume rose to an altitude of 2.8 km (9,200 ft) a.s.l. A lava flow became active and was continuously incandescent down the SE flank.

Source: Rabaul Volcano Observatory (RVO)


17 October-23 October 2007

During 1-18 October, white vapor plumes from Bagana were occasionally accompanied by ash plumes that were generated by rockfalls from the edges of the lava flow on the SE flank. Incandescence was noted during most of the reporting period at the summit and occasionally from the lava flow. Based on observations of satellite imagery, the Darwin VAAC reported that ash plumes drifted N then NW on 19 October.

Sources: Rabaul Volcano Observatory (RVO); Darwin Volcanic Ash Advisory Centre (VAAC)


26 September-2 October 2007

RVO reported that white vapor emissions from Bagana's summit crater continued during 24 August-30 September. Forceful emissions on 25 August and 12 September were occasionally accompanied by ash clouds produced by collapses at the edges of a lava flow on the SE flank.

Source: Rabaul Volcano Observatory (RVO)


22 August-28 August 2007

RVO reported that an effusive lava flow from Bagana's summit crater began travelling down the SE flank on 6 August and continued flowing through 23 August. Continuous incandescence was visible down the SE flank during 6-10 August. During 6-23 August, white vapor plumes were occasionally accompanied by ash plumes that were generated by rockfalls from lava-flow edges. Based on satellite imagery, the Darwin VAAC reported that a diffuse plume rose to an altitude of 3.7 km (12,000 ft) a.s.l. on 23 August.

Sources: Rabaul Volcano Observatory (RVO); Darwin Volcanic Ash Advisory Centre (VAAC)


6 June-12 June 2007

RVO reported that white vapor emissions from Bagana's summit crater continued during 1-11 June. Based on satellite imagery and information from RVO, the Darwin VAAC reported that a low-level diffuse plume rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted W on 11 June.

Sources: Rabaul Volcano Observatory (RVO); Darwin Volcanic Ash Advisory Centre (VAAC)


23 May-29 May 2007

Based on satellite image observations and information from RVO, the Darwin VAAC reported that a diffuse ash-and-steam plume rose to an altitude of 3.7 km (12,000 ft) a.s.l. on 22 May and drifted W. Another diffuse plume was visible on satellite imagery to an altitude of 3 km (10,000 ft) a.s.l. on 28 May.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


16 May-22 May 2007

RVO reported that white vapor emissions from Bagana's summit crater continued during 10 March-20 May. Emissions were occasionally forceful, and were accompanied by ash clouds during 17 March, 1 April, and 3-5 April. Weak roaring noises were heard on 4 April. Summit incandescence was visible on 20 and 24 March and 17 May. Based on satellite imagery and information from RVO, the Darwin VAAC reported that a diffuse plume rose to an altitude of 3 km (10,000 ft) a.s.l. and drifted SW on 20 May. RVO reported that forceful, white emissions on 21 May produced plumes to an altitude of 2.3 km (8,200 ft) a.s.l. and drifted W.

Sources: Rabaul Volcano Observatory (RVO); Darwin Volcanic Ash Advisory Centre (VAAC)


7 March-13 March 2007

RVO reported that white vapor emissions from Bagana continued during 10 January-9 March. Emissions were occasionally forceful, and on 3 March were accompanied by an ash cloud that drifted E. Summit incandescence was visible on 7 and 8 March. Based on satellite imagery, the Darwin VAAC reported that a diffuse plume rose to an altitude of 2.4 km (8,000 ft) a.s.l. and drifted WSW on 10 March.

Sources: Rabaul Volcano Observatory (RVO); Darwin Volcanic Ash Advisory Centre (VAAC)


3 January-9 January 2007

A diffuse plume from Bagana was visible on satellite imagery drifting SE on 9 January.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


20 December-26 December 2006

Geologic Summary. Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. Bagana is a massive symmetrical lava cone largely constructed by an accumulation of viscous andesitic lava flows. The entire lava cone could have been constructed in about 300 years at its present rate of lava production. Eruptive activity at Bagana is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50-m-thick with prominent levees that descend the volcano's flanks on all sides.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


29 November-5 December 2006

Based on satellite imagery, the Darwin VAAC reported that an ash plume from Bagana rose to an altitude of 3 km (10,000 ft) a.s.l. on 5 December.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


22 November-28 November 2006

A diffuse plume from Bagana was visible on satellite imagery on 22 November. The height and direction of the plume were not reported.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


14 June-20 June 2006

An ash-and-steam plume from Bagana was visible on satellite imagery on 18 June drifting SW. The height of the plume was not reported.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


3 May-9 May 2006

On 4 May, satellite imagery showed an ash plume from Bagana at a height of ~3 km (10,000 ft) a.s.l. extending 4 km W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


29 March-4 April 2006

During 16 February to 31 March, activity at Bagana was at moderate levels. Mostly gas emissions occurred, but on 27 March an ash cloud was emitted. During 15-31 March, observers noted moderate-to-bright incandescence, projections of lava fragments, and a lava flow traveling down the volcano's SSW flank.

Source: Rabaul Volcano Observatory (RVO) via the Darwin Volcanic Ash Advisory Center


21 September-27 September 2005

Ash was emitted from Bagana during 17-18 September and drifted W and NW. During 14-18 September, incandescence from the volcano was visible at night. On the 18th, observers described what could have been cascading volcanic material detached from a possible active lava flow.

Source: Rabaul Volcano Observatory (RVO)


17 August-23 August 2005

During 15-21 August, volcanic activity at Bagana remained at low levels. Variable amounts of thick "white vapor" were emitted from the summit crater. During several nights, dull-to-moderately bright incandescence was visible. On the 20th, lava flowed from volcano's main crater. Incandescent lava avalanches occasionally originated from unstable areas of the lava flow.

Source: Rabaul Volcano Observatory (RVO) via the Darwin Volcanic Ash Advisory Center


10 August-16 August 2005

Based on information from the US Air Force Weather Agency, the Darwin VAAC reported that an ash plume from Bagana was visible at a height of ~3 km (10,000 ft a.s.l.), extending ~40 km SW of the summit. The Darwin VAAC did not see ash on satellite imagery.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


29 June-5 July 2005

A thin plume emitted from Bagana was visible on satellite imagery on 30 June. The height of the plume was not reported.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


15 June-21 June 2005

A plume from Bagana was visible on satellite imagery on 21 June extending W. The height of the plume was not reported.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


8 June-14 June 2005

During 8-10 June, several low-level plumes emitted from Bagana were visible on satellite imagery. They extended predominately to the WSW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


1 June-7 June 2005

A plume from Bagana was observed on satellite imagery on 7 June initially extending 65 km WSW, then W later in the day. The height of the plume was not known.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


11 May-17 May 2005

Satellite imagery taken at 0551 on 13 May revealed a thin plume extending 28 km (15 nm) ESE below 3 km altitude (10,000 feet). Similar plumes, blowing W, were identified at 0537 on the 14th and at 0634 on 15 May.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


16 March-22 March 2005

The Darwin VAAC reported that on 17 March at 0726 a very small plume and hot spot were visible on satellite imagery.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


26 May-1 June 2004

An ash plume from Bagana was visible on satellite imagery during 26-27 May. The plume reached a height of ~3 km a.s.l. and extended ~130 km NW.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)


28 April-4 May 2004

According to a news article, following the emission of new lava from Bagana on 27 April, local volcanologists and a team of provincial disaster delegates conducted an aerial inspection of the area around the volcano on 2 May. The team concluded that the lava flows were not an immediate threat to the safety of villagers near the volcano. A spokesperson for Papua New Guinea's national Disaster Center reportedly said, "the aerial inspection team noted a continual effusion of lava flowing in a south-westerly direction but there is a lot of vegetation in the area which is acting as a buffer."

Sources: Australian Associated Press; Reuters


21 April-27 April 2004

A helicopter pilot reported to RVO that new lava was being emitted from Bagana around 1240 on 27 April. According to information from the village of Torokina, the lava flow was estimated to be about 8-9 km from the village. RVO was uncertain about the local topography between the volcano and Torokina, and therefore could not assess the degree of danger for the residents of the village from the lava flow. RVO has no monitoring equipment at Bagana.

Source: Rabaul Volcano Observatory (RVO)


Index of Monthly Reports

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.

05/1978 (SEAN 03:05) Sluggish lava flow continuing on N flank

09/1978 (SEAN 03:09) N flank lava flow remains active

03/1981 (SEAN 06:03) Lava extrusion continues; small nuées ardentes

05/1983 (SEAN 08:05) Increased vapor emission; sluggish lava flow

09/1983 (SEAN 08:09) Gas measurements on 8 September

12/1983 (SEAN 08:12) Glow, explosions, incandescent boulders

01/1984 (SEAN 09:01) Two active lava flows

03/1984 (SEAN 09:03) Sounds, glow, tephra emissions; but no new lava flows

08/1984 (SEAN 09:08) Lava production continues; SO2-rich plume

10/1984 (SEAN 09:10) Lava flow continues; earthquake swarm

11/1984 (SEAN 09:11) Lava dome grows & spawns avalanches; seismicity builds

12/1984 (SEAN 09:12) Lava extrusion and avalanches from dome; new fumaroles

01/1985 (SEAN 10:01) Bulging dome; ash-laden plume; N lava flow continues

02/1985 (SEAN 10:02) Rockfalls from flank lava flow; strong vapor emission

03/1985 (SEAN 10:03) Activity declines; vapor emission; occasional glow

10/1985 (SEAN 10:10) Continued mild activity

11/1985 (SEAN 10:11) Explosions; weak glow; increased seismicity

12/1985 (SEAN 10:12) Occasional night glow from summit throughout December

02/1986 (SEAN 11:02) New extrusive phase

03/1986 (SEAN 11:03) Increased lava extrusion continues; B-type event

04/1986 (SEAN 11:04) Strong plumes; glow; debris slides from lava flow

05/1986 (SEAN 11:05) Plumes; rockfall events from active lava flow

07/1986 (SEAN 11:07) Ash emission declines, lava flow still active

08/1986 (SEAN 11:08) Continued viscous lava extrusion; small explosions

09/1986 (SEAN 11:09) Small summit exlosion; rockfall events decline

10/1986 (SEAN 11:10) Continued lava extrusion; vapor emissions

11/1986 (SEAN 11:11) Lava extrusion continues

12/1986 (SEAN 11:12) Lava extrusion probably continuing

01/1987 (SEAN 12:01) Lava extrusion probably continuing

02/1987 (SEAN 12:02) Occasional crater glow; vapor and ash emission

03/1987 (SEAN 12:03) Lava flow active; stronger seismicity

04/1987 (SEAN 12:04) Ash emissions and summit glow continue

05/1987 (SEAN 12:05) Activity declines; vapor emission continues

06/1987 (SEAN 12:06) Lava flow remains active

07/1987 (SEAN 12:07) Vapor emissions continue; no incandescence seen

08/1987 (SEAN 12:08) Ash plume; incandescent rockfalls

09/1987 (SEAN 12:09) Pyroclastic avalanches end 12-year lava flow

10/1987 (SEAN 12:10) Continuous vapor emissions; weak glow

11/1987 (SEAN 12:11) Vapor emission still moderate-strong; weak glow

12/1987 (SEAN 12:12) Strong steam emissions; low seismicity

01/1988 (SEAN 13:01) Summit glow and vapor emission

02/1988 (SEAN 13:02) Lava flow from summit dome nears base of volcano

03/1988 (SEAN 13:03) Summit glow above new dome

04/1988 (SEAN 13:04) E flank lava flow continues to advance

07/1988 (SEAN 13:07) Continued lava extrusion and weak seismicity

09/1988 (SEAN 13:09) Increased lava production feeds new lobe

10/1988 (SEAN 13:10) Seismic data indicate continued lava extrusion

11/1988 (SEAN 13:11) Summit lava extrusion continues; seismic swarm

01/1989 (SEAN 14:01) Avalanche breaches summit; lava drains from crater

04/1989 (SEAN 14:04) Lava flow advances; new avalanche deposits

05/1989 (SEAN 14:05) Numerous rockfalls from new lava flow

06/1989 (SEAN 14:06) Explosions; S-flank lava flow remains active

07/1989 (SEAN 14:07) Lava production and vigorous SO2 emission

08/1989 (SEAN 14:08) Rockfalls; glow; vigorous gas emission

09/1989 (SEAN 14:09) Frequent rockfalls from active lava flows

10/1989 (SEAN 14:10) Frequent rockfalls; weak explosions; glow

11/1989 (SEAN 14:11) Lava overflows summit crater; explosions

12/1989 (SEAN 14:12) Lava overflows crater; rockfalls

01/1990 (BGVN 15:01) Continued slow summit lava extrusion; new lava pulses every 4-5 days

02/1990 (BGVN 15:02) White and occasional gray emissions; summit extrusion of blocky lava continues

04/1990 (BGVN 15:04) Rockfalls from blocky lava flow; ash column

05/1990 (BGVN 15:05) Frequent ash emissions, rumbling

06/1990 (BGVN 15:06) Thick ash-laden emission; avalanches from block lava flows

07/1990 (BGVN 15:07) Blocky lava overflows onto SE and E flanks

08/1990 (BGVN 15:08) Summit block lava extrusion and plume emission; reporting problems

01/1992 (BGVN 17:01) Continued extrusion of viscous lava; occasional dome collapse episodes

20/1995 (BGVN 20:08) Vapor emissions produce SO2-rich plume 15-20 km long

01/2003 (BGVN 28:01) Infrared data show nearly continuous activity during 2001-2002

03/2004 (BGVN 29:03) Abundant MODIS thermal alerts during March 2003-February 2004

05/2004 (BGVN 29:05) Block-lava flows descend flanks and raise concern for settlers

06/2004 (BGVN 29:06) MODVOLC thermal alerts peak in July 2003 and April 2004

08/2005 (BGVN 30:08) Lava flows and occasional ash plumes during April-September 2005

05/2006 (BGVN 31:05) Lava flows and ash emission throughout March 2006

04/2007 (BGVN 32:04) Almost daily thermal anomalies over past year; plumes and glow

03/2008 (BGVN 33:03) June 2007-March 2008, ongoing emissions including a pyroclastic flow

11/2008 (BGVN 33:11) Lava flows and ash emissions from March to December 2008

11/2009 (BGVN 34:11) Intermittent ash plumes through November 2009; active lava flow

02/2010 (BGVN 35:02) Occasional thermal alerts from possible lava flows during early 2010

01/2011 (BGVN 36:01) Occasional ash plumes during 11 February-1 October 2010


Contents of Monthly Reports

All information contained in these reports is preliminary and subject to change.

All times are local (= UTC + 10 hours)

05/1978 (SEAN 03:05) Sluggish lava flow continuing on N flank

A sluggish lava flow remained active on the N flank of Bagana, but no explosions have been reported there in the past 2 years.

Information Contact: R. Cooke, RVO.

09/1978 (SEAN 03:09) N flank lava flow remains active

An aerial inspection on 14 September showed that lava continued to flow down the N flank, as it has since late 1976. No explosive activity has been reported during this phase of lava flow extrusion.

Information Contact: R. Cooke, RVO.

03/1981 (SEAN 06:03) Lava extrusion continues; small nuées ardentes

"Moderate to strong emission of white vapour continued throughout March. An active lava flow descending the [established lava channel on] the N slope had reached 2/3 of the way down the mountain. Small nuée ardente-type avalanches caused by collapse of the flow front were observed during an aerial inspection on 9 January."

Information Contact: C. McKee, RVO.

05/1983 (SEAN 08:05) Increased vapor emission; sluggish lava flow

From 5-7 March, the weak white vapor emissions from the summit increased to a thick high-pressure plume rising to 2,000 m above the summit. Vapor release remained high until 21 March, but no glow was reported. Vapor emission was again strong at the end of the month.

Aerial inspections on the mornings of 15, 16, and 17 March revealed a thick but apparently normal plume being released from the lava dome occupying the summit crater. The viscous blocky lava flow on the N flank appeared to be moving extremely slowly, perhaps a few meters per week. At the source of this flow, the maximum lava temperature (measured by a portable infrared optical pyrometer from a helicopter) was only 175°C on the slow-moving, blocky surface.

During 24 hours of seismic monitoring from the W flank at 1,100 m altitude, 540 B-type events and one or two sharp, impulsive, shallow events were recorded.

Information Contact: P. de Saint-Ours, RVO.

09/1983 (SEAN 08:09) Gas measurements on 8 September

[Richard Stoiber, Stanley Williams, and Chris McKee used a COSPEC to measure the rate of SO2 emission from several volcanoes in Papua New Guinea during September (table 1). Plumes at Bagana and Manam were strong, and Ulawun's plume was small. Activity at Langila was weak 11 September, but had intensified during measurements the next day. The quiet-phase data were collected from the ground; all other data were acquired while flying under the plumes.]

Table 1. Rates of SO2 emission at Bagana, Langila, Manam, and Ulawun, Papua New Guinea, September 1983. Airborne COSPEC data from R. Stoiber, S. Williams, and C. McKee.

    Volcano    Date     t/d SO2

    Bagana     08 Sep    3,100
    Langila    11 Sep       74
               12 Sep    1,300
    Manam      12 Sep      920
    Ulawun     11 Sep       71

Information Contacts: C. McKee, RVO; R. Stoiber and S. Williams, Dartmouth College.

12/1983 (SEAN 08:12) Glow, explosions, incandescent boulders

"A marked increase in activity was observed from Bagana in December, with an increase in vapour emission and darkening of the plume early in the month. Bright glow was observed at night on 7 December followed by explosion and rumbling noises on the 8th and the emission of abundant blue vapour. On the 14th, incandescent boulders were observed tumbling down the upper NW flank. By the end of the month activity had decreased again, with no glow at night and the emission of moderate amounts of slightly brownish vapour."

Information Contact: P. Lowenstein, RVO.

01/1984 (SEAN 09:01) Two active lava flows

"The increase of summit activity noted in December resulted in [pulses of lava down the channel on the N flank] of the volcano from 5 January onwards. This lava remained active throughout the month and produced plumes of white and grey vapour."

Information Contact: P. Lowenstein, RVO.

03/1984 (SEAN 09:03) Sounds, glow, tephra emissions; but no new lava flows

"The increased activity continued in February and March. Occasional brown and grey tephra emissions were observed, and rumbling and explosion sounds were heard 17 km away. Nighttime summit glows were occasionally seen.

"New lava flows were reported in January, but aerial inspections have failed to confirm these reports. They indicated a relatively static body of lava extending about 200 m from the summit, but this is an old lava flow. The main development of the known active lava flow at Bagana in recent times has been a sharp change in direction of flow on the lower slopes. The nose of the flow is now abutting the dome on the W foot of Bagana after completing a 60°C turn toward the W from the established flow channel on the N flank."

Information Contact: C. McKee, RVO.

08/1984 (SEAN 09:08) Lava production continues; SO2-rich plume

"The predominately effusive eruption continued. When last observed (21 July), the viscous blocky lava flow on the NW flank had reached an altitude of 1,000 m and had an estimated volume of 1.3 x 106 m3. A moderate plume of dense, white, SO2-rich gases continued to be emitted from the summit crater. Seismicity from the volcano was at a low level, with only a few B-type and explosion earthquakes per day."

Information Contact: P. de Saint-Ours, RVO.

10/1984 (SEAN 09:10) Lava flow continues; earthquake swarm

"An uncharacteristic swarm of shallow tectonic-like earthquakes together with banded low-amplitude harmonic tremor commenced on 19 October about 2000 and continued through October. During the previous week the NW lava flow collapsed to form a well-defined lava channel below the point where the flow turns sharply W. The toe of the lava flow continued to encroach on a satellite dome at the W foot of Bagana. Numerous solfataras have given a distinctive facia to the ESE summit."

Information Contact: K. McCue, Bougainville Island Copper Ltd.

11/1984 (SEAN 09:11) Lava dome grows & spawns avalanches; seismicity builds

"A new eruptive phase started in October 1984. The extrusion of a fresh batch of andesitic magma into the summit crater was accompanied by a marked increase in the volume of vapour rising above the crater, an increase in the area of fumarolic activity in and around the crater, night glows, and incandescent material tumbling down the flanks. Simultaneously, volcanic seismicity increased from fewer than 10 B-type events per day to over 100 per day by 19 October; harmonic tremor appeared on the 12th and became sub-continuous after the 15th. A relative drop in volcano seismicity (24-27 October) was followed by re-intensification. The daily frequency of events was about 1000 by 11 November, and consistently above this after 15 November. Strong tremor was recorded for periods of several hours on 4, 5, 9, 13, 18, 20, and 22 November. Explosion earthquakes were occasionally recorded.

"An aerial inspection by Bougainville Island Copper Ltd. geologists revealed that the dome of viscous andesite had bulged to about 15 m above the crater rim and lava was spilling over the N, E, and W parts of the rim. Debris on these three flanks corroborated the observations of incandescent material avalanching down the sides of the volcano, presumably from collapse of parts of the dome. Paradoxically, the long-established lava flow channel on the N flank of the volcano seems to have been drained, leaving an empty lava channel from the crater rim down to about 1,100 m altitude."

Information Contact: P. de Saint-Ours, RVO; K. McCue, Bougainville Island Copper Ltd.

12/1984 (SEAN 09:12) Lava extrusion and avalanches from dome; new fumaroles

"Eruptive activity was at about the same intensity as in November. Slow effusion of viscous andesitic lava continued in the summit crater, and unstable parts of the crater dome collapsed, causing avalanches of incandescent lava blocks. [Strong fumarolic activity was continuing] on the upper E flank to about 200 m below the crater rim."

Information Contacts: C. McKee, RVO; Bougainville Island Copper Ltd.

01/1985 (SEAN 10:01) Bulging dome; ash-laden plume; N lava flow continues

"Bagana's summit crater dome continued growing through January, to fill 95% of the crater and bulge up to about 30 m above the crater rim. A thick, ash-laden plume was fed by numerous sources in the dome. A large solfataric area on the upper E flank of the volcano was also contributing vapours to the plume. An ash haze was observed stretching horizontally more than 100 km to the NE at about 2,000 m altitude. The steep flanks of the volcano were covered with thin ash deposits and a large number of blocks from avalanches of unstable parts of the dome.

"The long-established N lava flow was still active, and was broadening and thickening on the NW basal slopes at about 900 m altitude. Frequent avalanching was taking place from the [edges of the flow near its terminus]."

Information Contact: P. de Saint-Ours, RVO.

02/1985 (SEAN 10:02) Rockfalls from flank lava flow; strong vapor emission

"Eruptive activity continued at Bagana in February, although summit explosive activity was absent, or sporadic and very weak. Strong vapour emission continued, and the very light ash content in the plume was considered to be an effect of entrainment of dust from occasional avalanches on the sides of the summit lava dome. Frequent rockfalls from the edges of the active lava flow on the [N and] NW flanks of Bagana continued."

Information Contact: C. McKee, RVO.

03/1985 (SEAN 10:03) Activity declines; vapor emission; occasional glow

"Activity at Bagana in March was back to normal, after a period of vigorous activity that began in October 1984. The daily totals of volcanic earthquakes ranged from 0 to 3, and summit glow was observed on only 3 nights: 16, 25, and 31 March. Moderate-to-strong white vapour emission continued."

Information Contact: C. McKee, RVO.

10/1985 (SEAN 10:10) Continued mild activity

"Inspection by Bougainville Island Copper, Ltd. geologists, confirmed the ongoing mild eruptive activity, with extremely slow but sustained progress of the blocky andesite flow active (since [1975]) on the [N and] NW flanks. Weak glow was occasionally observed at night above the summit crater. The viscous lava dome in the crater continued to gently release a faint vapour plume. Seismicity remained weak with a few B-type earthquakes occurring daily."

Information Contact: C. McKee, RVO.

11/1985 (SEAN 10:11) Explosions; weak glow; increased seismicity

"A moderate level of activity was observed during November with occasional reports of weak nighttime glows from the summit crater and occasional audible explosions. Seismic activity increased in the middle of the month to about 50 earthquakes per day. Previous levels were generally less than 10. This level of seismic activity persisted to the end of the month."

Information Contacts: P. Lowenstein, RVO.

12/1985 (SEAN 10:12) Occasional night glow from summit throughout December

"Following moderate activity in November, the seismicity declined to 5-20 events per day. Occasional reports of weak nighttime glow from the summit were received throughout December."

Information Contacts: P. Lowenstein, RVO.

02/1986 (SEAN 11:02) New extrusive phase

"A new extrusive phase from Bagana's summit crater commenced on 16 February. The extrusion was preceded by several days' increase in seismicity, including three periods of 'tremor,' 30 minutes long (on the 5th and 6th) and an increase in the number of B-type events after the 10th. An increase in the amount of vapour released from the crater was also noted from the 7th onward.

"On the 16th, the vapour cloud became thick and coloured, while the seismicity rose suddenly to 140-175 events/day. From that night until the 21st, weak night glow from the crater was observed and extrusions of lava resulted in numerous incandescent avalanches of boulders on the NW, N, and NE flanks of the cone.

"At the end of the month, seismicity was still at a high level (>100 events/day), with periods of 'tremor' (on the 20th, 26th, and 28th), although visible activity had declined.

"Similar phases of extrusive activity occurred in November 1985 and January 1986 and resulted in increased movement of the long-established blocky lava flow down the N flank of the volcano."

Information Contacts: P. Lowenstein, RVO.

03/1986 (SEAN 11:03) Increased lava extrusion continues; B-type event

"The phase of stronger extrusive activity continued into March, and was detected both seismically and visually. There were occasional reports of moderate to strong white to dark brown emissions from the summit, which displayed a weak glow whenever visible at night.

"The seismicity, which increased sharply in mid-February, declined slightly during the first week of March, but rose again steadily to a peak of 145 B-type events/day on the 12th before gradually declining to ~20 events/day at month's end."

Information Contacts: P. Lowenstein, RVO.

04/1986 (SEAN 11:04) Strong plumes; glow; debris slides from lava flow

"Stronger activity continued in April. On most days, strong white to brown emissions from the summit were reported. Weak crater glow was often observed at night, and on one occasion the upper part of the N flank's active lava flow was also observed to be glowing. Occasional debris slides from the flanks of the lava flow produced impressive ash clouds. Seismicity increased from about 20 B-type events/day in early April to about 50-60 events/day at mid-month, staying at that level for the rest of April."

Information Contacts: P. Lowenstein, RVO.

05/1986 (SEAN 11:05) Plumes; rockfall events from active lava flow

"Stronger activity continued through May. Moderate to strong white to brown emissions were reported daily. Weak glow from the summit was visible on five nights. There were 40-70 low-frequency seismic events/day, about the same as during the last half of April. Most of these events are probably due to rockfalls from the margins of the active lava flow."

Information Contacts: P. Lowenstein, RVO.

07/1986 (SEAN 11:07) Ash emission declines, lava flow still active

"The phase of stronger activity weakened during the second half of July. Activity during the first half of the month was similar to that of the latter part of June, with 20-40 seismic events/day (probably rockfalls off the active lava flow). Occasional summit incandescence was reported. Emissions consisted of moderate to strong white vapours and moderate brown ash clouds. For the second half of the month, the activity appeared to be declining as the seismicity decreased to 10-20 events/day.

"During an aerial inspection on the 29th, moderate emissions of off-white vapour were observed. Although voluminous, the emissions were being released gently and no emission column was formed. A faint brown tint in the emission plume suggested that it contained some ash. This ash was not being produced by explosive shattering and fragmentation of lava, but is believed to result from fine comminution of fragments broken off relatively cool blocks on the surface of the active lava mound in the summit crater.

"In contrast to previous reports, no true lava dome was observed in the crater. Several rockfalls from the margins of the active lava flow were observed during the inspection flight. The lava channel on the upper flank was full, and several terraces were observed in the distal parts of the flow where new lava units had overridden older units. Arcuate pressure ridges were common on the distal part of the lava flow.

"During the 1986 phase of stronger activity, spillover of lava from the summit crater has been occurring on the upper E flanks. Two adjacent scree deposits were observed there. This observation tends to confirm occasional reports of incandescence on this part of the volcano."

Information Contacts: J. Mori and C. McKee, RVO.

08/1986 (SEAN 11:08) Continued viscous lava extrusion; small explosions

"The phase of viscous lava extrusion from the summit crater continued into August at a moderate level as evidenced from visual observations and seismicity. Reports suggest that surges of lava into the active flow channel on the N flank took place on 6-7 and 31 August. White to brown emissions were usually quietly released from the crater, which was illuminated by a weak glow at night. Small explosions were reported 17-22 August. Rumbling noises were occasionally heard. Seismicity fluctuated throughout the month from 15 to 75 B-type events/day."

Information Contacts: P. de Saint-Ours and C. McKee, RVO.

09/1986 (SEAN 11:09) Small summit exlosion; rockfall events decline

"The predominately effusive eruption continued, although a decline in seismicity (probably mostly rockfall events from the active lava flow) was registered. Daily totals of volcano-seismic events ranged between 5 and 35, and the month's total was about 500. In August, 10-75 events/day were recorded and the total for the month was 1345.

"One small summit explosion was seen on 9 September. The products of this explosion included lava fragments that were incandescent in daylight. Summit glows were observed on the nights of the 12th, 14th, and 22nd. Emissions from the summit consisted mostly of moderate to strong white vapours or brown-grey vapour and ash clouds."

Information Contacts: C. McKee, RVO.

10/1986 (SEAN 11:10) Continued lava extrusion; vapor emissions

"Seismicity and visual surveys indicated that the viscous extrusive phase from Bagana's summit crater continued into October at a moderate level. [White to brown emissions] were quietly released from the crater, with a weak glow at night. Daily reports of glow on the northern flank of the volcano from 21 to 29 October suggested that new lava was flowing into the active channel. Seismicity remained at 0-25 B-type events/day, the lowest rate since January."

Information Contacts: P. Lowenstein and P. de Saint-Ours, RVO.

11/1986 (SEAN 11:11) Lava extrusion continues

"Seismicity and a bright glow at night from the summit indicated that lava extrusion continued at a low to moderate rate throughout November. Moderate amounts of white to brown emissions were quietly released."

Information Contacts: B. Talai and P. Lowenstein, RVO.

12/1986 (SEAN 11:12) Lava extrusion probably continuing

December observations indicated that the lava extrusion that has been ongoing for most of 1986 was probably continuing. A weak glow was often seen at night. [White and brown emissions] from the summit were moderate to strong.

Information Contacts: J. Mori and P. Lowenstein, RVO.

01/1987 (SEAN 12:01) Lava extrusion probably continuing

Visual observations and seismicity indicated that viscous lava extrusion was probably continuing at a low level in January. Emissions from the summit consisted of moderate to strong white and occasionally brown vapours [and ash]. Weak glow from the summit was often visible at night.

Information Contacts: B. Talai and P. Lowenstein, RVO.

02/1987 (SEAN 12:02) Occasional crater glow; vapor and ash emission

"In February, weak to strong, white to grey emissions were commonly observed, and strong brown emissions were noted once. Crater glow was occasionally seen. Seismic activity appeared to be unchanged from last month's low level."

Information Contacts: P. Lowenstein, RVO.

03/1987 (SEAN 12:03) Lava flow active; stronger seismicity

Eruptive activity continued through March, apparently accompanied by increased seismicity. The summit vent emitted mostly moderate to strong white to brown-gray vapor and ash clouds. Blue vapour emissions were observed 17-19 March. Weak summit glows were reported on most nights and incandescent lava fragments were ejected to ~50 m above the summit on 31 March. Rumbling sounds accompanied the eruption. Rockslides from the edges of the lava flow on the N and NW flanks indicated that effusion was continuing.

Although seismic recordings were intermittent, seismicity appeared to have begun increasing on 11 March [see also 12:4]. The highest daily total of volcanic earthquakes was 110. A total of 333 earthquakes were recorded for the month (the highest total since September 1986) but the actual number of earthquakes could have been significantly higher.

Information Contacts: B. Talai and P. Lowenstein, RVO.

04/1987 (SEAN 12:04) Ash emissions and summit glow continue

The activity level in April appeared similar to that in March. Moderate to strong white, gray, and brown emissions were reported. Summit glow was seen occasionally and was especially bright on 1 April. Seismic recording was patchy in April; recordings were made on only 6 days, down from 16 days in March. Increased seismic activity on 12 and 15 March was followed by a period of stronger activity beginning 27 March that probably persisted through 1 or 2 April. Seismicity was at a low level on 6 April but had increased considerably by 16 April when ~60 events were recorded. Activity then subsided and from 23 to 26 April very few volcanic earthquakes were recorded.

Information Contacts: C. McKee and P. Lowenstein, RVO.

05/1987 (SEAN 12:05) Activity declines; vapor emission continues

Activity appeared to decline in May compared to the previous few months' activity. Moderate to strong brown emissions continued but glow from the summit was noted only once.

Information Contacts: J. Mori and P. Lowenstein, RVO.

06/1987 (SEAN 12:06) Lava flow remains active

Activity continued at a steady moderate level throughout June. Strong white vapour emissions were occasionally tinged with brown or grey ash. Several aerial inspections and close-up ground observations suggested that most of the emitted ash was derived from debris avalanches from the summit area where a mound of lava filled the crater. Rock slides were common at the edges of the active lava flow on the N to NW flanks. Occasional incandescent ejections from the summit were reported by a schoolteacher living near the S base of the volcano. Glow from the summit was reported often, although volcanologists camped at the E base of the volcano on 17-18 June did not observe any summit incandescence.

An experiment with paint marks on the central part of the lava flow and adjacent marks on the levee banks indicated that the speed of the flow at ~1,200 m elevation was only 1-2 m/day. At this elevation the flow channel is ~20-30 m wide and possibly 10 m deep. These measurements indicate a flow rate of 200-600 m3/day or ~105 m3/year. The total volume of the flow since 1975 is ~106 m3.

Information Contacts: C. McKee and P. Lowenstein, RVO.

07/1987 (SEAN 12:07) Vapor emissions continue; no incandescence seen

Activity may have declined in July although moderate to strong, thick, white, vapor emissions were observed throughout the month. No sounds were heard and no night glow from the summit crater was seen. Night glow . . . is thought to be evidence of lava flow activity.

Information Contacts: B. Talai and P. Lowenstein, RVO.

08/1987 (SEAN 12:08) Ash plume; incandescent rockfalls

A moderately thick white to brown plume was continuously released from the summit crater. Plume emission intensified 14-15 August when incandescent rockfalls down the N and W flanks and strong night glow from the summit were reported. On 29 August the summit crater was reported to be completely filled with a smoking lava dome that continued to feed the long-active lava flow on the N flank. Seismicity remained at a low level throughout the month, with 10-20 rockfall events/day.

Information Contacts: C. McKee, P. de Saint-Ours, and P. Lowenstein, RVO.

09/1987 (SEAN 12:09) Pyroclastic avalanches end 12-year lava flow

"On 8 September between 0600 and 0800, a series of pyroclastic avalanches descended the E flank. There were no reports of any explosive activity at the time, but low-level ash clouds were seen on the flanks. Later in the day, a new lava flow was reported on the E side of the summit.

"The cumulative deposit of these avalanches covered an area of ~1 km2. Its outline was complex because about half of the material formed a fan-shaped deposit on a gently sloping bench near the E foot of Bagana. Most of the other material moved 2.5 km from the summit, filling an arcuate depression between Bagana and neighboring Reini volcano. The deposit had a maximum thickness of 10-20 m and is poorly sorted; clast size ranged from fine ash to several-meter-wide blocks. The clasts were andesitic and mostly dense, although some show a slight degree of vesiculation.

"The deposit was still somewhat inflated when inspected on 15 September and numerous rootless fumaroles were active in the central part. The fumaroles were releasing sulphurous gases and depositing sulphur at some vents. The ground around many fumaroles had collapsed, producing craters as large as 1 m across and 20 cm deep. The craters indicated that a considerable amount of gas release had already taken place by 15 September. Crater density was >50% in the central part of the deposit. Near-surface temperatures were measured using a 30-cm-long mercury-in-glass thermometer; the highest temperature recorded was 460°C.

"Eight days before this activity, an increase in high-frequency earthquakes began. By about 5 September, seismicity had built up to several hundred of these events/day. During this time some long-duration (1-5 minute) seismic events occurred that were interpreted as probable rockslides. At the presumed time of the pyroclastic avalanches, a high-frequency tremor was recorded that lasted about 2 hours. Another event of this type, though considerably smaller in amplitude and lasting only half an hour, occurred on 11 September.

"The pyroclastic avalanches may have been caused by mechanical failure of the summit crater wall, which in turn destabilized the active lava dome. The dome then began shedding material in a series of hot avalanches down the E flank . . . . The lack of accompanying explosive activity, the predominantly unvesiculated nature of the clasts, and the lava dome source, suggest that the deposit is of the non-explosive block and ashflow type. These were the first pyroclastic flows recorded at Bagana since the ones that accompanied explosive activity in 1966.

"Within a few days after its appearance the new lava flow showed little activity. At the end of the month, it was ~100-200 m long, 50-100 m wide, and perhaps 10-20 m thick. Activity of the lava flow on the N flank of Bagana has probably ended, 12 years after its commencement."

Information Contacts: J. Mori, C. McKee, and P. Lowenstein, RVO.

10/1987 (SEAN 12:10) Continuous vapor emissions; weak glow

Following the September pyroclastic avalanches, Bagana emitted continuous moderate-strong white vapour for most of October. Weak glow from the summit was visible during the first 2 weeks of the month. Seismicity was at a low level, except from 15-19 October when a total of 75 events were recorded.

Information Contacts: J. Mori, D. Lolok, and P. Lowenstein, RVO.

11/1987 (SEAN 12:11) Vapor emission still moderate-strong; weak glow

Bagana continued to emit moderate-strong white vapors during November. Weak glow from the summit was seen on 6, 13, and 14 November. The number of long-duration seismic events (interpreted as rockfalls from the lava flow) showed a slight increase during the first part of the month to about 40/day, but the activity declined to 10/day by the end of the month.

Information Contacts: P. Lowenstein, RVO.

12/1987 (SEAN 12:12) Strong steam emissions; low seismicity

The summit was often obscured in December, but when visible at mid-month strong white emissions were observed. Seismicity was at a low level of about 10 volcanic earthquakes/day with a recorded maximum of 30/day on 9 December; the seismograph was not operating for part of the month.

Information Contacts: C. McKee and P. Lowenstein, RVO.

01/1988 (SEAN 13:01) Summit glow and vapor emission

Low-level activity continued through January, with the summit area continuously producing moderate to heavy white vapor. Glow from the summit was noted on several nights during the month. Seismicity was at a low level with only 1-10 events recorded/day.

Information Contacts: J. Mori and P. Lowenstein, RVO.

02/1988 (SEAN 13:02) Lava flow from summit dome nears base of volcano

Activity continued at a low level through February, with the summit area continuously producing moderate to strong white vapor. Glow was noted from the summit on several nights during the month. Seismicity was at a low level with only a few (1-10) events recorded/day. During an aerial inspection on the 25th, the new E-flank lava flow had descended to an elevation of ~1,150 m, close to the foot of the volcano. The flow was ~1.5 km long, and its terminus was ~100 m wide and 20-30 m thick.

The lava dome in the summit crater had a flat top but its sides were very steep, particularly noticeable on its SW flank where the dome stood ~30-40 m above [the SW rim] of the summit crater. The lava flow was being fed from the top of the dome and it appeared that the direction of flow could change quite easily.

Information Contacts: P. de Saint-Ours and C. McKee, RVO.

03/1988 (SEAN 13:03) Summit glow above new dome

Low-level activity continued through March, with continuous production of moderate to strong white vapour from the summit area. Summit glow was noted on several nights during the month. Seismicity was at a low level, with only 1-10 events recorded/day.

Information Contacts: P. de Saint-Ours and C. McKee, RVO.

04/1988 (SEAN 13:04) E flank lava flow continues to advance

"April activity was steady with moderate to strong emissions of white vapours from the summit area, and a small number (up to ~15) of seismic events/day. During an aerial inspection on the 26th, the emission plume was dense and white in colour, and rose ~1.2 km above [the] summit. Its length was ~5-10 km.

"The nose of the active lava flow on the E flank had advanced ~50-100 m since the last inspection in late February. It had also widened as it spread out on the more gentle lower slopes of the cone. The flow appeared to be as much as 50 m thick in places and there were occasional slides of unstable material from the edges. The September 1987 pyroclastic avalanche deposit at the E base of the cone was also inspected. Many of the rootless fumaroles were still steaming. The craters and sulphur deposits around many of these fumaroles have been preserved."

Information Contacts: D. Lolok, C. McKee, and B. Talai, RVO.

07/1988 (SEAN 13:07) Continued lava extrusion and weak seismicity

"Mild eruptive activity consisting of non-explosive lava emission continued at Bagana. Volcano-seismicity was weak with only a few events recorded/day."

Information Contacts: C. McKee and P. Lowenstein, RVO.

09/1988 (SEAN 13:09) Increased lava production feeds new lobe

"An aerial inspection . . . on 5 September confirmed seismic evidence of increased lava effusion. A new lava lobe was observed on the S side of the one that had been active since September 1987. When the volcano was last inspected in April 1988, only one lobe (~1 km long) was present. It appears that this lobe had not advanced much beyond its April position. The new lobe was fed directly from the summit and its broad, moderately-sloping nose was ~200-300 m beyond the first lobe's terminus. Rockslides on the lobe's edges were observed . . . and pale-brown dust mantled the nose of the lobe, indicating that rockslides were occurring frequently. This observation confirmed seismic evidence of repeated rockslides. The top of the summit lava dome was flat. Voluminous white vapour emissions were fed from diffuse sources on the dome's upper flanks. The emission plume was 10-20 km long."

Information Contacts: C. McKee and P. Lowenstein, RVO.

10/1988 (SEAN 13:10) Seismic data indicate continued lava extrusion

"Bagana's level of activity in October was steady. From the number of explosive earthquakes (1-12/day) and rockfall-related tremor (90-300 events/day), it is believed that the volcano is still extruding lava from its summit crater at a slow steady rate."

Information Contacts: D. Lolok, B. Talai, and P. Lowenstein, RVO.

11/1988 (SEAN 13:11) Summit lava extrusion continues; seismic swarm

"Seismic activity continued at a steady low level until 7 November when a swarm of 1,500 small explosion-type earthquakes were recorded. Visual reports were obtained of red material sliding or rolling down the E slopes of the volcano on the 6th and pale brown dust/vapour rising from the same area on the 7th. Seismic activity then returned to a normal level with 15 rockfall-related tremor events/day, indicating continued slow steady extrusion of lava from the summit crater. Seismic telemetry to Rabaul stopped on the 14th. Records continued to be obtained at Panguna until the nearby Mt. Kupara repeater station, containing RVO telemetry equipment, was destroyed on 2 December."

Information Contacts: I. Itikarai and P. Lowenstein, RVO.

01/1989 (SEAN 14:01) Avalanche breaches summit; lava drains from crater

"A minor collapse took place near the summit early on 22 January. The summit was reported to be glowing bright red at about 0430, then changed from red to yellow as it became even brighter. This activity culminated in an avalanche of incandescent boulders down the SE flank . . . . Shortly afterward, a large plume of ash and vapour developed. Inspections . . . on 28 January and 3 February revealed that structural failure had occurred at the outflow point of the lava flow on the E edge of the summit. The breach that was formed allowed rapid drainage of lava, forming a crater at Bagana's summit. The lava in the crater has a flat surface and appears to be flowing freely through the breach.

"It is concluded that the bright glow from the summit seen on 22 January resulted from the emergence of a pulse of hotter, more fluid lava which destabilized the edge of the dome and initiated the breaching."

Information Contacts: C. McKee, H. Patia, and P. de Saint-Ours, RVO.

04/1989 (SEAN 14:04) Lava flow advances; new avalanche deposits

"Observer reports and recorded seismicity indicate that increased activity . . . is continuing. Inspections on 3 and 4 March by personnel from Bougainville Island Copper Ltd. revealed that a new deposit of avalanche debris was present on the SE flank. The deposit was dark in colour and extended from the summit . . . to the mid-flank level (~1,000 m altitude). Vegetation around the edges of the deposit had been killed. The avalanche occurred sometime between 3 February and 3 March. The profile of E flank lava flow's terminus had changed, suggesting overriding of older parts of the flow by new lobes and possible advance of the flow nose.

"On 18 March, the pilot of a passing aircraft reported a lava flow on the SE flank and copious ash around and above the volcano. However, an inspection on 12 April indicated that the deposit was probably formed by a rockfall from the inactive nose of of the E flank lava flow (at ~880 m altitude). The proximal part of the flow was still active. It appeared that a new thin lobe was overriding older lava in the main flow channel. An ash mantle on the upper E flank indicated that rockfalls (detected seismically) were occurring in this area. The flow was bent to the S at ~1,150 m altitude. It may be significant that the first lobe of this now compound flow terminated at about this point.

"Since 8 March (when seismic recording . . . was restored) seismicity has been dominated by relatively long-duration, low-frequency, spindle-shaped events. This activity is attributed to rockfalls on the margin of the active lava flow. Daily totals of these events ranged between ~90 and 300. Summit activity has continued to consist of moderate to strong emission of white vapour rich in sulphur dioxide."

Information Contacts: C. McKee, RVO.

05/1989 (SEAN 14:05) Numerous rockfalls from new lava flow

"Observer reports indicated that the increased level of activity was continuing. Emissions were moderate to strong and consisted of white-grey (with occasional brown) ash and vapour clouds. Ashfalls around the summit area, due to rockfalls from a new lava flow on the S flank, were reported 7-11 and 25 May. Glows from the active lava flow were seen 2-3, 16-17, 22, and 24 May. Rumbling noises, correlating well with rockfalls, were heard 1-5, 12-14, and 23 May.

"Seismic monitoring . . . lapsed at the beginning of May because of an inability to maintain telemetry equipment during the current period of civil disturbance on Bougainville Island."

Information Contacts: H. Patia and C. McKee, RVO.

06/1989 (SEAN 14:06) Explosions; S-flank lava flow remains active

"Bagana is currently the most active volcano in Papua New Guinea. Unfortunately, civil disturbance on Bougainville Island Island prevents proper monitoring. The observer reported fluctuating night glows from the summit and from the new (blocky) lava flow on the S flank. Incandescent rockfalls were frequent on all flanks, accompanied by rumbling sounds. Explosions and incandescent projections over the crater were reported 10 and 12-15 June. The thick, white to brown plume . . . produced occasional light ashfalls downwind."

Information Contacts: P. de Saint-Ours and B. Talai, RVO.

07/1989 (SEAN 14:07) Lava production and vigorous SO2 emission

Quoted material is from RVO, with additional information on SO2 flux supplied by S. Williams. "Moderate eruptive activity continued . . . throughout July. The summit crater released moderate to strong volumes of thick white and sometimes grey emissions. Intermittent low rumbling sounds with occasional mild explosions were heard at the observation post ~10 km S of Bagana. Occasional night glows from the summit were observed, and rockfalls continued on the active lava flow(s). The effusive activity was not clearly seen during the aerial inspection, although voluminous white emissions on the S flank . . . probably originated from a steaming lava flow."

During an SO2 monitoring flight on the 27th from 0830 to 0910, a strong convoluted white cloud emanated from Bagana's summit, rising only slightly before being blown ~25-30 km downwind. The plume contained no ash but varied in size and opacity. Four traverses yielded SO2 flux measurements of 4,870, 4,800, 1,930, and 2,390 t/d. The large measured variations corresponded well with visual estimates of variation in the plume size. Based on the duration of the observations and the relative times of the traverses, the estimated weighted average of the flux data was 3,230 t/d. The September 1983 data were similar (yielding a mean value of 3,100 t/d) but showed less variation (2,300, 3,000, 4,200, 2,800, 3,000 t/d) suggesting a more steady state of degassing at that time.

Information Contacts: B. Talai and C. McKee, RVO; S. Williams, Louisiana State Univ.

08/1989 (SEAN 14:08) Rockfalls; glow; vigorous gas emission

"Activity was at a moderate level during August. The summit crater released moderate to strong volumes of thick white and occasionally grey emissions. Rumbling noises were heard from time to time throughout the month, sometimes accompanied by small explosions. Night glows were observed 29-30 August. Rockfalls were observed on the S flank of the volcano, and on the 28th and 30th, light ashfalls were observed on the W flank."

Information Contacts: I. Itikarai and C. McKee, RVO.

09/1989 (SEAN 14:09) Frequent rockfalls from active lava flows

"Activity continued at a moderate-strong level in September. Strong emission of thick white vapours continued from the summit area. The emissions were reportedly grey on a few days. Rumbling and explosion noises were heard occasionally at the observation post, ~8 km S of Bagana.

"Rockfalls from active lava flows were observed frequently in a broad area on Bagana's S flank. A visit to the seismic transmitter site (~2 km SW on the summit) by staff of Bougainville Island Copper Limited in late September revealed that rockfalls had occurred nearby.

"Seismic monitoring . . . resumed 28 September. Consistent with visual observations, the seismograms contain a large number of rockfall events, on the order of 100-120/day. A few A- and B-type events were also recorded daily."

Information Contacts: C. McKee, RVO.

10/1989 (SEAN 14:10) Frequent rockfalls; weak explosions; glow

"Activity was at a relatively low level during October. The summit steadily released thick white vapour of moderate volume, with occasional grey clouds associated with reported weak explosions. Weak glow was occasionally seen at night over the summit, and rockfalls continued on the flanks. Seismicity was dominated by rockfall events (6-70/day), but occasional B-type events (0-8/day) were also recorded."

Information Contacts: C. McKee, RVO.

11/1989 (SEAN 14:11) Lava overflows summit crater; explosions

"Mild sustained eruptive activity continued throughout November. Aerial reconnaissance on the 10th and 11th revealed that the summit, fully occupied by blocky lava, was overflowing on several sides. A main lava flow, active since 1987, extended to the foot of the volcano on the E flank (13:02). Lava also progressed slowly into the channel of the N lava flow (inactive since 1987), into the upper part of the prominent [1966-75] lava channel on the S flank, and spread over the upper NW flank. Very frequent rockfalls or avalanches occurred on all sides below the summit, producing short-lived red glow at night.

"An SO2-laden vapour plume, formed by numerous fumaroles in cracks in the lava-filled crater and the weathered upper flanks, quietly drifted as much as 20 km downwind. Slow and quiet lava effusion was only disturbed by occasional explosions (3, 16, and 25 November) which generated a black cloud above the summit. The seismicity continued to be dominated by rockfall events (2-94/day) and a few B-type events (0-4/day)."

Information Contacts: D. Lolok and P. de Saint-Ours, RVO.

12/1989 (SEAN 14:12) Lava overflows crater; rockfalls

"Mild, sustained, eruptive activity continued throughout December. Numerous rockfalls or avalanches occurred from the unstable blocky flows that slowly spilled over all sides of the summit crater, producing short-lived, red incandescence at night. The seismicity continued to be dominated by rockfall events (several tens/day), with only a few B-type events and occasional swarms of discontinuous tremor (1/2 hour on the 18th and 3 hours on the 21st)."

Information Contacts: P. de Saint-Ours, RVO.

01/1990 (BGVN 15:01) Continued slow summit lava extrusion; new lava pulses every 4-5 days

"Mild but steady eruptive activity continued as a result of slow extrusion of blocky lava in the summit crater. The main visible activity consisted of frequent rockfalls of (night-glowing) rock avalanches from the summit onto all flanks of the volcano. New pulses of lava were seen spilling onto the SE flank and into the [1966-75] lava channel at 4-5-day intervals. Abundant fumaroles are present within the crater which is weakly glowing at night. Two low explosions were reported on the 10th and 27th. Seismicity continued to be dominated by rockfall events (several tens/day), but occasional B-type events were also recorded. Seismic monitoring . . . ceased on the 24th, due to the loss of telemetry as the result of the current civil disturbance . . . ."

Information Contacts: I. Itikarai and P. de Saint-Ours, RVO.

02/1990 (BGVN 15:02) White and occasional gray emissions; summit extrusion of blocky lava continues

"Mild eruptive activity continued in February. Regular reporting of observations ceased on the 12th but it appears that the more-or-less steady extrusion of viscous blocky lava continued through the month. Frequent rockfalls occurred on the W, S, and E flanks. Glow from the summit area was seen occasionally. Emissions were mostly white vapours, but grey emission clouds were reported on a few days."

Information Contacts: C. McKee, RVO.

04/1990 (BGVN 15:04) Rockfalls from blocky lava flow; ash column

"In the current period of social unrest on Bougainville Island Island, no instrumental data is being recorded, and the only information on Bagana's activity is from visual observations from a site 15 km SSW of the volcano.

"When observations resumed on 3 April, Bagana was in a fairly high level of activity. Thick, white, ash-laden vapour was being forcefully emitted from the summit area. [An explosion in the summit crater] on the 3rd produced a black column, and loud rumbling noises were heard until the 4th.

"Numerous rockfalls (including daytime glowing avalanches) were observed in early April on the SE and E flanks of the cone, where a slowly progressing blocky lava flow has been active since 1987. This activity together with the reportedly stronger vapour and ash emission may suggest that a new pulse of viscous lava extrusion took place in the summit crater in the first few days of April.

"The mountain was often covered by atmospheric clouds or rainstorms, but a weak, night, summit glow was intermittently observed until the 21st, with occasional (night-glowing) rockfalls occurring until the 24th."

Information Contacts: P. de Saint-Ours and C. McKee, RVO.

05/1990 (BGVN 15:05) Frequent ash emissions, rumbling

"Bagana was at a fairly high level of activity throughout May. On most days, thick white or grey clouds were emitted from the summit area and loud rumbling noises were heard. On the 6th, 8th, 20th, 21st, 23rd, and 26th, 1-3 explosions produced dark ash-laden columns to 2 km above the summit. Weak red glow was observed on most nights during the last 3 weeks of the month.

"The blocky lava flow being slowly extruded from the summit crater was seen to overflow on several days onto the upper E, SE, and SW flanks. Small to moderate rockfalls were reported daily on the E and S sides of the volcano."

Information Contacts: P. de Saint-Ours and C. McKee, RVO.

06/1990 (BGVN 15:06) Thick ash-laden emission; avalanches from block lava flows

"Activity was at a fairly high level throughout June. On most days, thick white clouds were emitted from the summit area and rumbling noises were heard. One to three explosions [per day] occurred on 14, 16, 22, and 24 June, producing thick ash-laden columns to 6 km above the summit. A red glow was observed on all nights when the summit was clearly visible.

"The blocky lava flow being slowly extruded from the summit crater was seen on occasion to overflow onto the upper E, SE, and SW flanks, and rockfalls or debris avalanches (some glowing) were reported daily on the E and SE sides of the volcano."

Information Contacts: P. de Saint-Ours and C. McKee, RVO.

07/1990 (BGVN 15:07) Blocky lava overflows onto SE and E flanks

"Activity continued at a steady level in July. White and grey emissions were released during most days from the summit, accompanied by low rumbling noises. Explosions occurred on 3, 13, 16-18, 20, 25, and 26 July, producing brown to black plumes. A weak red glow was observed over the crater on most nights.

"The blocky lava flow being slowly extruded from the summit crater was seen on two occasions to overflow onto the SE and E flanks, with rockfalls reported on most days."

Information Contacts: H. Patia and C. McKee, RVO.

08/1990 (BGVN 15:08) Summit block lava extrusion and plume emission; reporting problems

"Due to social unrest and political isolation on Bougainville Island Island, instrumental data is no longer being recorded and no reliable reports of visual observation were received. From the sparse reports of observations received between 12 and 27 August, it is presumed that the volcano is still extruding a blocky lava flow from its summit crater with accompanying moderate to strong white to grey plumes, summit night glow, and numerous rockfalls."

Information Contacts: I. Itikarai and C. McKee, RVO.

01/1992 (BGVN 17:01) Continued extrusion of viscous lava; occasional dome collapse episodes

"Socio-political unrest on Bougainville Island Island has prevented transmission of any reports of Bagana's activity since late July 1990. However, Bagana's former observer recently arrived in Rabaul and confirmed that the volcano has remained active, with slow, continuous extrusion of sluggish lava into the summit crater and onto the volcano's flanks. A significant change occurred on the night of 14 January 1991, when part of the summit lava dome collapsed onto the SE flank of the volcano, and initiated a new lava channel between the 1966-75 and 1987-90 lava flows. Apparently, the blocky lava flow is slowly advancing in the saddle between Bagana and the nearby Pleistocene Reini Volcano. Other minor collapses of the summit dome occurred occasionally onto the SW flank (and possibly other parts of the volcano). The current activity is apparently similar to that reported up to mid-1990, with release of a brownish white plume from the dome, extremely slow extrusion of lava, and frequent tumbling of rocks down the flanks of the volcano."

Information Contacts: H. Patia, P. de Saint-Ours, and B. Talai, RVO.

20/1995 (BGVN 20:08) Vapor emissions produce SO2-rich plume 15-20 km long

Although one of Melanesia's youngest and most active volcanoes, reports on Bagana are infrequent. Bagana sits along Bougainville's axial highlands ~140 km NW of the 16 August, M 7.8 earthquake's epicenter. Following the earthquake, a report from the Buka Passage Administration Office described a change in activity. Specifically, the report mentioned "black thick clouds coming out of the volcano" and stated that "lava had fallen along the SW coastline." The report included a request for RVO to carry out an inspection. As a result, Chris McKee (RVO) flew around the volcano on 22 August.

McKee noted moderate-to-strong vapor emissions forming a 15-20 km long plume. While the plume looked white near Bagana's summit, downwind a prevailing brown color suggested high SO2 concentrations in the emissions. No ash was noted in the plume. The summit, a region occupied by a blocky lava dome, fed the plume from numerous sources. There was no appreciable force in the emissions and the plume rose only slightly above the summit.

A lava flow that has been active for several years was observed on the volcano's SW flank. In late August the flow's front was estimated to have reached 580 m elevation. In overview, conditions at the volcano appeared stable. There was no indication of recent explosive activity.

Although reports documenting activity have been absent since early 1991, reported Bagana eruptions in the interval 1972-87 described activity that included long-term lava effusion and slow dome growth, coupled with moderate explosive activity ending with dome destruction. After destruction there was a return to dome growth and lava flows.

Information Contacts: Patrice de Saint-Ours and Ben Talai, RVO.

01/2003 (BGVN 28:01) Infrared data show nearly continuous activity during 2001-2002

Throughout 2001 and 2002, MODIS detected quasi-continuous thermal alerts at Bagana (figure 1). The most recent report is from August 1995 (BGVN 20:08). The MODIS data are presented here as valuable objective evidence of more recent activity. MODIS thermal alerts were recorded on 16 September, 3, 19, and 26 November, and 10, 12, 28, and 30 December 2000. The 2001-2002 MODIS anomalies were relatively stable with an average alert ratio of -0.63 and generally they consisted of 1 or 2 alert pixels. The maximum alert ratio detected (-0.51) occurred on 21 November 2002 when the number of alert-pixels was at its two-year maximum of 5. This is likely to indicate a higher degree of activity than usual, in which case it is likely to represent effusion of a new lava flow or a pyroclastic flow in the act of emplacement. Coordinates of alert pixels generally clustered tightly around the summit, with a slight preference towards the NW (figure 2). Activity may be genuinely concentrated on this part of the cone, but another explanation would be a 300-m error in the supposed location of the summit relative to the MODIS geocoding. However, the 5-pixel alert of 21 November 2002 is strung out towards the E, which is likely to represent an eastward-flowing lava (or pyroclastic) flow ~2 km long.

Figure 1. MODIS thermal alerts on Bagana during 2001-2002. Courtesy of Diego Coppola and David Rothery, The Open University.
Figure 2. Locations of MODIS alert-pixels on Bagana during 2001-2002. Courtesy of Diego Coppola and David Rothery, The Open University.

Information Contacts: Diego Coppola and David A. Rothery, Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom (Email: d.coppola@open. ac.uk, d.a.rothery@open.ac.uk).

03/2004 (BGVN 29:03) Abundant MODIS thermal alerts during March 2003-February 2004

Continued MODIS thermal alerts during March 2003-February 2004 (table 2) suggests that activity continued over the year ending February 2004. No corroborative reports of activity have been received from the Rabaul Volcano Observatory or the Darwin Volcanic Ash Advisory Centre.

Table 2. Nights on which MODIS thermal alerts were recorded for Bagana, for the year ending February 2004. Thermal alerts recorded in daylight hours have been omitted for data reliability reasons (one case on 23 October 2003). Data courtesy HIGP MODIS Thermal Alert System.

    Month       Days with Thermal Alerts

    Mar 2003    13, 19, 26, 31
    Apr 2003    2, 11, 18, 25
    May 2003    18, 20
    Jun 2003    19, 26
    Jul 2003    21, 23, 25
    Aug 2003    4, 6, 8, 13, 24, 29
    Sep 2003    16
    Oct 2003    2, 4, 07, 13, 18, 27
    Nov 2003    5, 10, 12
    Dec 2003    3
    Jan 2004    13, 15, 20, 24, 31
    Feb 2004    5

Information Contact: HIGP MODIS Thermal Alert System, Hawaii Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawaii at Manoa (URL: http://modis.higp.hawaii.edu/).

05/2004 (BGVN 29:05) Block-lava flows descend flanks and raise concern for settlers

The Rabaul Volcano Observatory (RVO) received a report on 28 April from a pilot of the Hevi Lift helicopter company stating that new lava had come from Bagana volcano the day before. RVO has had no monitoring equipment at Bagana since 1989. Although they hope to again install monitoring instruments in the future, they could not confirm the visual observations instrumentally.

Bagana has been in long-term eruption since 1972, although reports ceased in 1995 because of political and economic unrest. MODIS satellite observations began in 2000, and almost monthly thermal alerts have been recorded since September 2000.

According to a news article, on 2 May local volcanologists and a team of provincial disaster delegates conducted an aerial inspection of the area around Bagana. At that time, the team concluded that the lava flows were not an immediate threat to the safety of villagers near the volcano. According to news reports a spokesperson for Papua New Guinea's national Disaster Center said the aerial inspection team noted a continual effusion of lava flowing in a southwesterly direction, but there was a great deal of vegetation in the area which acted as a buffer.

A later news article also noted that in the long term the lava flows could expose local hamlets to danger. The hamlets were constructed in the 1990s by people displaced by civil unrest.

RVO staff sent a series of photos and brief notes regarding their visit. Ima Itikarai commented that during his trip clouds affected the quality of the photos. Figure 3 shows a hamlet, which sits 3 km from the active block-lava flow front and 6.5 km from the summit, well within reach of pyroclastic flows similar to those in 1952, 1960, and 1966.

Figure 3. An overview of the scene on the SW region surrounding Bagana illustrating a potentially threatened hamlet and the erupting volcano and block-lava flow in the background. Courtesy of Ima Itikarai, RVO.

At about the same time but in clearer weather, another photographer, Peter Mildner, took the photo in figure 4. It shows Bagana's summit and the active block-lava flow at a point where the levees had become 'bank full.' Figure 5 shows the lava flow pouring over the levees at various points. The lava flow's toe was also being overridden.

Figure 4. Bagana summit and upper flanks as seen in April 2004 showing the active block-lava flow on the SW side (steaming, at left center). A second block-lava flow path may have begun to descend the leveed banks on the right (note abundant steam on upper right-hand slopes). Copyrighted photo by Peter Mildner provided courtesy of Ima Itikarai, RVO.
Figure 5. Closer view of the block-lava flow down Bagana's SW flank taken in April or May 2004, on a day with considerable low clouds. The initially confined lava flow followed the leveed path and then began to escape at several places. The fresh block lava's darker color stands in mild contrast to sparsely vegetated, older levee banks, which have a speckled appearance. Courtesy of Ima Itikarai, RVO.

Information Contacts: Ima Itikarai and Herman Patia, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea (Email: hguria@global.net.pg); Papua New Guinea Post-Courier; The National; The Australian.

06/2004 (BGVN 29:06) MODVOLC thermal alerts peak in July 2003 and April 2004

MODVOLC alerts occurred at the same rate as in 2001-2002 (BGVN 28:01), with quasi-continuous alerts from January 2003 to May 2004 (figure 6). These were mostly one- or two-pixel alerts with an average alert ratio of -0.712. On 21 July 2003 activity appeared to have intensified, with an alert ratio of -0.328 and three alert pixels detected. By 13 August 2003 activity was back to 'normal' levels. Then on 18 April 2004, activity picked up again, with a maximum alert ratio for this period of -0.135, along with a maximum number of four alert pixels on 22 April (Aqua satellite) and 6 May 2004 (Terra satellite).

Figure 6. MODIS thermal alerts from Bagana for 1 January 2001-31 May 2004. Thermal alerts collated by Charlotte Saunders and David Rothery; data courtesy of the Hawaii Institute of Geophysics and Planetology's MODIS thermal alert team.

Data acquisition and analysis. Reports from Diego Coppola and David A. Rothery provided analyses of MODIS thermal alerts during 2001 and 2002 (using the MODVOLC alert-detection algorithm) extracted from the MODIS Thermal Alerts website (http://modis.hgip.hawaii.edu/) maintained by the University of Hawaii HIGP MODIS Thermal Alerts team (BGVN 28:01). Rothery and Charlotte Saunders provided updates to 31 May 2004. MODVOLC data are now routinely available from the Aqua satellite (equator crossing times 0230 and 1430 local time) in addition to the original Terra satellite (equator crossing times 1030 and 2230 local time).

Information Contacts: David A. Rothery and Charlotte Saunders, Department of Earth Sciences, The Open University, Milton Keynes, MK7 6AA, United Kingdom (Email: d.a.rothery@open.ac.uk).

08/2005 (BGVN 30:08) Lava flows and occasional ash plumes during April-September 2005

Bagana was last reported on in June 2004 (BGVN 29:06) summarizing MODIS thermal alerts during 1 January 2001-31 May 2004. Lava flows, which had erupted at an unknown time, were described in BGVN 29:05. Bagana has been in long-term eruption since 1972, but the volcano's remote location and intervals of separatist conflict on the island had restricted access by observatory staff, and subsequent reports remained infrequent. Several Rabaul Volcano Observatory (RVO) reports addressed Bagana volcanism during March-September 2005, revealing conditions seen on the ground. There were numerous MODVOLC thermal alerts posted for Bagana during the reporting interval. The rest of the reports relied on satellite-based observations of plumes produced for the purpose of aircraft safety.

RVO noted that during April 2005 Bagana continued its effusive eruption of lava. The summit crater released weak to moderate volumes of thick white vapor on most days. Occasional gray to brown ash plumes were reported. White vapor was visible in some areas of the SW flank. Summit glow was visible on most nights when it was clear, associated with the active lava flow on the upper S flanks. White vapor visible on the upper SW flank during daytime was also associated with a lava flow. Occasional loud roaring noises like jet engines and booming noises were heard on 17, 19, and 30 April. Some of the noises accompanied emission of thick, dark gray ash clouds.

According to the Darwin Volcanic Ash Advisory Centre (VAAC), on 17 March 2005 at 0726 a very small plume to ~ 2.4 km altitude and hot spot were visible on satellite imagery. Satellite imagery at 0551 on 13 May revealed a thin plume extending 28 km ESE below 3 km altitude. Similar plumes, blowing W, were identified at 0537 on 14 May and at 0634 on 15 May.

A plume from Bagana was observed in satellite imagery for 8 June. Darwin VAAC stated that the plume initially extended 65 km WSW, then W later in the day. The height of the plume was not stated. US Air Force Weather Agency analysts indicated that at 0955 local time on 8 June (2355 UTC on 7 June) the plume extended at least ~ 38 km W, rising up to ~ 3 km, and the MODIS image they provided showed four volcanoes in the region all emitting plumes (figure 7).

Figure 7. A DMSP image highlighting a Bagana plume seen on 20 June 2005. For scale, near its broad SE end, Bougainville island is ~50 km wide (measured in the NE-SW direction). Both images provided courtesy of NASA and the US AFWA.

During 13-19 June, Bagana was relatively quiet with variable amounts of white vapor emitted from the crater. Weak projections of incandescent lava were visible until 17 June. During 8-10 June, several low-level plumes emitted from Bagana were visible on satellite imagery extending mainly to the WSW. A plume from Bagana visible on satellite imagery on 21 June extended W. The height of the plume was not reported. A thin plume emitted from Bagana was visible on satellite imagery on 30 June. The height of the plume was not reported.

During 10-16 August, the Darwin VAAC reported that satellite observations showed an ash plume from Bagana visible at a height of ~ 3 km, extending ~ 40 km SW of the summit. Ash was not visible on the image.

During 15-21 August, volcanic activity at Bagana remained at low levels. Variable amounts of thick white vapor were emitted from the summit crater. During several nights, dull-to-moderately bright incandescence was visible. Occasional low roaring noises were heard on 15 and 20 August. At night dull to moderately bright glow was visible on 16, 18, 20, and 21 August. On 20 August, lava flowed from the main crater. Incandescent lava avalanches occasionally originated from unstable areas of the lava flow.

Between 22 and 28 August 2005, Bagana was quiet. The summit crater released variable amounts of white vapor throughout. Continuous roaring noises were heard during a 30-minute period on 23 August, and bright glow was visible the nights of 23 and 24 August. There was a single expulsion of a thick dark ash plume on 24 August.

During 12-18 September 2005, occasional small volumes of ash escaped, and emissions consisted chiefly of weak to moderate volumes of white vapor. Beginning on 17 September occasional sub-continuous booming noises commenced. Some of the booming noises were accompanied by forceful emissions of whitish-brown ash clouds. This activity continued on 18 September. Ash plumes from the activity drifted to W and NW resulting in fine ashfall in downwind areas. Occasional sub-continuous jet-like noises began to occur on 18 September along with a reported lava flow. Glow was observed at night on 14 and 18 September. This could have been associated with cascading lava detached from steep portions of an active lava flow.

The seismograph remained off from 15 August onward through the reporting period due to technical problems.

Information Contacts: Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea ; Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, Northern Territory 0811, Australia (URL: http://www.bom.gov.au/info/vaac/).

05/2006 (BGVN 31:05) Lava flows and ash emission throughout March 2006

Little activity had been recorded at Bagana since 18 September 2005, when forceful emissions of whitish-brown ash occurred, accompanied by ash fall in downwind areas and large booming noises. From the end of January to mid-April 2006 there were brief periods of effusive activity. The summit crater released moderate to dense white vapor throughout this time.

Emissions were forceful on 27 February, and on 3, 5, 7, 13, 22, 24, and 29 March. Denser emissions of pale gray ash clouds were reported on 27 March. Rumbling and roaring noises were heard on 15-16, 22, and 26-28 March. Moderate to bright glow was accompanied by projections of lava fragments and the advance of a lava flow down the S-SW flank, which was visible from 15 March until the end of the month. During April, the summit crater continued to release white vapor. A forceful emission was recorded on 8 April. A weak glow was visible on 9 April. Occasional weak rumbling noises were heard on 12-13 and 15 April. On 4 May, there was an ash plume visible on satellite imagery at a height of ~ 3 km (10,000 ft) altitude that extended 4 km W. On 18 June there was an ash-and-steam plume drifting SW; the height of the plume was not recorded.

Information Contacts: Ima Itikarai and Herman Patia, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea.

04/2007 (BGVN 32:04) Almost daily thermal anomalies over past year; plumes and glow

Brief periods of effusive activity took place during January to mid-April 2006 (BGVN 31:05), with ash-and-steam emissions reported as late as 18 June 2006. Activity has continued since that time through early June 2007, with evidence coming from either MODIS thermal satellite data, observations of glow, or plume observations from the ground or satellites (figure 8). It appears that there were three episodes of increased plume generation, two periods of frequent glow observations, and almost daily MODIS anomalies over that one-year time frame.

Figure 8. Summary of daily activity at Bagana, 18 June 2006-5 June 2007. Plumes are all varieties (steam or ash) reported by RVO or Darwin VAAC; glow as reported by RVO; MODIS data indicates days with at least one thermal pixel detected. Compiled from MODIS/HIGP data, Darwin VAAC reports, and RVO reports.

The Rabaul Volcano Observatory (RVO) noted that between 18 September and 4 December 2006 only white vapor was released; some of these emissions were forceful. Jet engine-like roaring noises were heard on 11 and 20 November. Variable glow was visible on 25-26 September, 15, 20, and 29 October, 15-21 November, and 4 December. The lava flow on the S flank was active only on 15 October.

There were no aviation warnings after June until a diffuse plume became visible on satellite imagery on 22 November. Based on satellite imagery, the Darwin Volcanic Ash Advisory Centre (VAAC) reported subsequent plumes on 5 December (ash), 21-22 December (ash-and steam), and 9 January 2007.

RVO reported that white vapor emissions from the summit crater continued during 10 January-21 May 2007. Emissions were occasionally forceful and were accompanied by ash clouds on 3 and 17 March, as well as 1 and 3-5 April. Summit incandescence was visible on 7, 8, 20, and 24 March, and 17 May. Based on satellite imagery, the Darwin VAAC reported diffuse plumes to altitudes of 2.4 and 3 km on 10 March and 20 May, respectively. Forceful, white emissions on 21 May produced plumes that rose to an altitude of 2.3 km and drifted W. Diffuse ash-and-steam plumes were seen in satellite images again on 22 and 28 May, rising to altitudes of 3.7 and 3 km, respectively.

Moderate Resolution Imaging Spectroradiometers (MODIS) satellite thermal anomaly data reported by the Hawai'i Institute of Geophysics and Planetology (HIGP) revealed frequent thermal anomalies during 20 June-24 July 2006, 16 August-3 October 2006, 9 November 2006-23 January 2007, and 13 February-2 June 2007.

Information Contacts: Herman Patia, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea; Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, Northern Territory 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Hawai'i Institute of Geophysics and Planetology (HIGP) Hot Spots System, University of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).

03/2008 (BGVN 33:03) June 2007-March 2008, ongoing emissions including a pyroclastic flow

Lava flows, pyroclastic flows, loud noises, and repeated forceful emissions were witnessed during June 2007-March 2008. Previously, there were brief periods of effusive activity and almost daily thermal anomalies during June 2006 through May 2007 (BGVN 32:04). Emissions during June 2007 consisted largely of steam of variable density.

On 12 June, there was a particularly forceful emission. Glow was observed on the night of 14 June. This kind of behavior continued into July. On 8 July observers saw glow and watched a single forceful release of pale gray ash.

On 14 July, Bagana generated a particularly forceful release that generated a pyroclastic flow. The release spewed out thick, dark-gray ash. The pyroclastic flow descended the S flank of the volcano stopping at the base near a small hot-spring-fed lake located at the head of the Torokina river. Since that event, rock falls from the edge of the active lava flow triggered thin ash clouds of light brown color from the S flank. This was accompanied by a loud roaring noise persisting into 15 July.

On 6 August, some emissions occasionally contained gray ash. The lava flow from the summit crater on the SE flank became active again and continued through 23 August. Thick white plumes escaped forcefully during 13-16 August. Ash clouds seen then were attributed to rock falls from collapse at the edges of the active lava flow. The Darwin VAAC reported that a diffuse plume rose to an altitude of 3.7 km on 23 August.

A particularly forceful emission occurred on 25 August and 12 September and the latter generated thin gray ash clouds directed over the SE flank.

Into October, the summit continued to release gentle emission of thin to thick white vapor. A weak to bright fluctuating glow was visible at night from 2-5 October and a continuous rumbling noise that lasted about an hour was heard on 5 October. On 6 October, there was a particularly forceful emission and the lava flow on the SE flank became active. Observers saw the lava flow emitting glow as it passed down the SE flank on 6-7, 10-12, and 17 October. Occasional thin pale gray ash clouds observed at the edges of the active lava flow were visible on 9-10, and 14-15 October. Based on satellite imagery, the Darwin VAAC reported that ash plumes drifted N then NW on 19 October.

White vapor escaped through November and into December. It was occasionally accompanied by plumes containing ash that were generated along the lava flow.

Two explosions sent forth ash plumes on 19 and 27 November. The SE-flank lavas descended almost continuously and lava fragments vented at the summit on 7 and 9 December. On 9 December an ash plume rose to an altitude of 2.8 km; another on 17 December rose to uncertain height; and one on 26-27 December rose to 3 km altitude and drifted W.

Activity in January through March was generally weak but persistent, with earthquakes absent. Satellite imagery and information from RVO led the Darwin VAAC to report a diffuse plume on 3 March. It rose to an altitude of less than 3 km and drifted SW. Later that day, an ash-and-steam plume drifted SW.

Throughout the reporting period, the MODVOLC satellite system typically detected multiple thermal anomalies monthly. The system uses MODIS (the Moderate Resolution Imaging Spectroradiometer) and a processing algorithm and staff at HIGP (see Information Contacts, below).

Information Contacts: Herman Patia, Rabaul Volcano Observatory (RVO), P.O. Box 386, Rabaul, Papua New Guinea; Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, Northern Territory 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Hawai'i Institute of Geophysics and Planetology (HIGP) Hot Spots System, University of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).

11/2008 (BGVN 33:11) Lava flows and ash emissions from March to December 2008

Lava flows, pyroclastic flows, and repeated forceful ash emissions were noted at Bagana (figure 9) from June 2007 through March 2008 (BGVN 33:03). Lava flows and ash emissions continued from the end of May 2008 through 16 December 2008. No reports were received for April 2008.

Figure 9. Map of Bougainville Island showing adjacent islands and key cities, including Arawa, the disputed capital and largest settlement of the province. Panguna is the location of an enormous gold- and silver-bearing porphyry-copper deposit in the volcanic highlands (Sillitoe, R. H., 1997), and the site of an open-pit mine which closed in 1989. A decade of civil war surrounding the mine hampered reporting on Bougainville's volcanoes. Base map modified from Lightbody and Wheeler (1985).

In May 2008 the Rabaul Volcanological Observatory (RVO) noted that sluggish lava flowed from the summit towards the S and the Torokina River, along with small ash emissions from the summit that rose a few hundred meters. Smaller dust clouds formed from the lava flow fronts. Night glow was common, as were booming and rumbling noises. On 15 May 2008 the lava flows accelerated and the glow brightened. Activity was low during June. RVO noted variable volumes of white vapor from the summit crater. Occasional loud booming noises were heard, and on the night of 8 June, a weak glow was visible. RVO reports for August through much of December were absent.

Based on observations of satellite imagery, the Darwin Volcanic Ash Advisory Center published aviation advisories for Bagana. From May through December, eight low level ash plumes were observed (table 3). The highest was noted on 22 May, when the plume rose to 3.7 km altitude and drifted S at about 23 km/hour.

Table 3. Darwin VAAC advisories describing ash plumes from Bagana during May 2008 to December 2008.

    Date           Altitude    Drift    Remarks

    22 May 2008    3.7 km      S        ~23 km/hour
    16 Sep 2008    2.4 km      SW       --
    22 Sep 2008    2.4 km      SW       --
    08 Oct 2008    3 km        WSW      Extended 55-110 km
    20 Nov 2008    3 km        SW       Extended 75 km
    26 Nov 2008    --          W        --
    02 Dec 2008    3 km        NW       --
    16 Dec 2008    3 km        SW       --

MODVOLC. These satellite-derived infrared alerts were consistent with ongoing Bagana eruptions. As previously reported, MODIS/MODVOLC thermal alerts were abundant during 2006-2007 (BGVN 32:04) and through March 2008 (BGVN 33:03). Thermal alerts continued to be detected from April through the end of December 2008. During this time, the alerts were issued 4-12 times per month. The system, using MODIS (the Moderate Resolution Imaging Spectroradiometer) and the MODVOLC algorithm, is processed by the staff at the Hawaii Institute of Geophysics and Planetology (HIGP).

References. Sillitoe, R. H., 1997, Characteristics and controls of the largest porphyry copper-gold and epithermal gold deposits in the circum-Pacific region: Australian Journal of Earth Sciences, v. 44, no. 3, p. 373-388.

Lightbody, M., and Wheeler, T., 1985, Papua New Guinea, a travel survival kit: Lonely Planet Publications, 256 p., ISBN 0 908086 59 8.

Information Contacts: Rabaul Volcanological Observatory (RVO), Dept of Mining, Private Mail Bag, Port Moresby Post Office, National Capitol District, Papua New Guinea (Email: hguria@global.net.pg, URL: http://www.pngndc.gov.pg/Volcano Bulletins.htm); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).

11/2009 (BGVN 34:11) Intermittent ash plumes through November 2009; active lava flow

The eruptive activity at Bagana that began in September 2000 continued through late 2009. As previously reported, lava flows and ash emissions occurred during 2008 through at least mid-December (BGVN 33:03 and 33:11). Similar activity, confirmed by visual observations and satellite data, continued through the end of 2009.

Based on analysis of satellite imagery, the Darwin VAAC reported ash plumes on 17 and 29-31 December 2008. Intermittent ash plumes continued to be reported throughout 2009 based on both satellite imagery and visual observations (table 4). Thermal anomalies identified in MODIS data (figure 10) were also intermittent throughout 2009. The frequency and number of daily alert pixels was higher during 1 June-10 August.

Table 4. Ash plumes from Bagana seen on satellite imagery or by visual observations during 2009. Courtesy of the Darwin VAAC and RVO.

    Date           Altitude    Direction    Remarks

    17 Dec 2008     3 km            W       --
    29 Dec 2008      --             W       Extended 75 km
    30 Dec 2008     2.4 km         NW       --
    31 Dec 2008     2.4 km         --       --
    26 Apr 2009     2.4 km          S       Extended 28 km
    02 May 2009     3 km           NE       Extended 55 km
    04 May 2009     2.4 km         NE       Extended 45 km
    02 Jun 2009     2.4 km          W       Extended 75 km
    27 Jun 2009     2.4 km         SW       Extended 110 km
    19 Jul 2009     1.8 km         NW       Extended 100 km
    20 Jul 2009      --            --       Dense gray ash clouds
    26 Jul 2009      --            --       Dense gray ash clouds
    30 Jul 2009      --            --       Dense gray ash clouds
    10 Aug 2009     3 km           NW       Diffuse ash plume extended 55 km
    19 Aug 2009     2.1 km          W       Extended 90 km
    09 Sep 2009      --            --       Light-gray ash emissions
    10 Sep 2009      --            --       Light-gray ash emissions
    12 Sep 2009     2.4 km         NW       Extended 37 km
    13 Sep 2009     2.4 km          W       Extended 65 km
    16 Sep 2009      --            --       Light-gray ash emissions
    17 Sep 2009     2.4 km        W, SW     Extended 46 km
    18 Sep 2009     2.4 km       SW, NW     Extended 37 km
    19 Sep 2009     2.4 km         NW       Extended 28 km
    09 Oct 2009     2.4 km         SW       Extended 45 km
    15 Oct 2009     2.1 km         SW       Extended 55 km
    12 Nov 2009     3 km           SW       Extended 65 km
Figure 10. Maximum number of daily thermal alert pixels at Bagana as identified by the MODVOLC system during 2009. Data comes from MODIS instruments on both Aqua and Terra satellites; the total shown is the maximum pixels per satellite per pass on a given day (UTC). Courtesy of Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System.

Activity continued at a low level during February 2009 with white vapor emissions from the summit. Occasional loud booming noises were heard between 6 and 13 February. Collapses from the edge of an active lava flow resulted in glowing lava fragments moving down the SW flank that were visible at night on 7 February.

During April both the Main Crater and the Northwest Vent released moderate volumes of white vapor. The emissions from Northwest Vent ceased on 14 April. A single moderately loud booming noise was heard on 23 April from the Main Crater. Intermittent ash plumes extending in various directions were reported by the Darwin VAAC on 26 April, on 2 and 4 May, and again on 2 and 27 June.

July 2009 emissions from the summit crater consisted of white vapor. Single loud booming noises were heard on 15, 16, and 20 July. An ash plume reported by the Darwin VAAC extended 100 km NW on 19 July, and RVO noted dense gray ash clouds on 20, 26, and 30 July. A weak glow was visible on most nights during the month. The lava flow was reported active only on 1 July, when collapses from the leading edge resulted in rapid movement of glowing lava fragments on the SW flank.

During August the Darwin VAAC reported ash plumes on the 10th and 19th. RVO noted that the summit was obscured by atmospheric clouds throughout the first week of September. After that it was clear on most days until the end of October. Activity consisted of dense white emissions, except for 9, 10, and 16 September when small amounts of light gray ash were released. Occasional weak glow was observed on the 9th, but moderately bright glow was seen during 16, 19, 21, and 26 September. More ash plumes were seen in satellite imagery during 12-13 and 17-19 September.

Glow was observed on 3 October, which seems to have been associated with the dislodging of lava fragments from the active flow. Discrete booming noises were heard on 2, 4, and 9 October. The Darwin VAAC reported ash plumes on 9 and 15 October, and 12 November.

Information Contacts: Rabaul Volcano Observatory (RVO), PO Box 386, Rabaul, Papua New Guinea (Email: hguria@global.net.pg); Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/), Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).

02/2010 (BGVN 35:02) Occasional thermal alerts from possible lava flows during early 2010

A report issued in October 2009 (Arumba, 2009) described Bagana as the most active in Papua New Guinea due to its sub-continuous effusive activity, which continued in 2009. "The effusive emissions of lava from the summit crater rolled down the western flanks of the volcano. The volume of lava was too insignificant to cause any alarm." The volcano is andesitic and its lava flows tend to be ten's of meters thick. Parks (1948) photographed Bagana in eruption, and Blake (1968) discussed its geology.

Emission of lava flows, intermittent ash plumes, and thermal anomalies that were evident through December 2009 (BGVN 34:11). Reports from the Rabaul Volcano Observatory (RVO) indicated activity continuing through February 2010.

According to RVO the S-flank lava flow resumed in January 2010, and there was occasional roaring and booming from the main vent. On 5 February observers saw dense gray eruption clouds, presumably signifying ash. Weak glow was seen on the nights of 2, 12, 13, and 19 February. For the rest of the month, variable volumes of white vapor were released from the summit vents;no noises were heard.

MODIS/MODVOLC thermal alerts continued. Alerts were recorded on 13, 24, 29, and 31 January; 7, 10, 14, and 19 February; and 16 March 2010. On 16 March, the Terra satellite recorded four hot pixels.

References. Arumba, J., 2009, Agenda Item 3, Coordinating Committee for Geoscience Programmes in East and Southeast Asia (CCOP), 46th CCOP Annual Session, 18-23 October 2009, Vungtau, Vietnam; Member Country Report of Papua New Guinea, October 2009, Annual member country report, 16 p.

Blake, D.H., 1968, Post Miocene volcanoes on Bougainville Island, territory of Papua and New Guinea: Bull. Volcanology, v. 32(1), p. 121-138.

Parks, F.L. (photographer), 1948, Volcano erupts–A crater on Bougainville obliges high-ranking amateur photographer: Life Magazine, November 29, 1948, p. 42.

Information Contacts: Ima Itikarai, Rabaul Volcano Observatory (RVO), PO Box 386, Rabaul, Papua New Guinea (Email: hguria@global.net.pg); Hawai'i Institute of Geophysics and Planetology (HIGP) Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/).

01/2011 (BGVN 36:01) Occasional ash plumes during 11 February-1 October 2010

This report discusses thermal anomalies and occasional ash plumes at Bagana during February into October 2010, with some satellite thermal data (MODVOLC) as late as early 2011. Our previous report (BGVN 35:02) also noted small lava flows, occasional ash plumes, and thermal anomalies from October 2009 through February 2010.

Historical records describe frequent eruptions since 1842. Bagana lacks instrumental monitoring and sits far from population centers. Many recent observations are remote-sensing based, although the Rabaul Volcano Observatory (RVO) produces reports with direct air- and ground-based observations. Bagana's flanks are covered with andesitic lava flows up to 50 m thick (Blake, 1968). The flows typically descend the mid-slope within the confines of tall lava levees, but emerge from the levees on the outer flanks to form sub-circular flow fields. Bagana's thick lava flows are visible in two photos below (figures 18 and 19).

Figure 18. This false-color satellite image was acquired on 15 November 2010 from the ASTER instrument on NASA's Terra satellite. It illustrates the large pyroclastic flow along the Gendol River S of Merapi. Scale at lower left corner. Courtesy of Natural Hazards NASA Earth Observatory. Data, caption, and interpretation credit to NASA/GSFC/METI/ERSDAC/JAROS, and the U.S./Japan ASTER Science Team and Robert Simmon.
Figure 19. An International Space Station photo taken on 2 April 2007 showing a diffuse white vapor plume extending SSW from Bagana's summit. The volcano is known for ongoing activity and lava flows of noteworthy thickness (~ 50 m thick). In colored versions of this photo, the brown-to-olive colors of the volcano stand out amidst the green of tropical rain forest. Astronaut Photo ISS014-E-18844. Courtesy NASA.

Activity. Between 10 February 2010 and 1 October 2010, the Darwin Volcanic Ash Advisory Center (VAAC) reported one or a few ash plumes per month from Bagana. Many rose to ~3 km and drifted from 20-205 km (table 2). According to RVO, ash plumes were seen on 5 February and night-time incandescence was seen on 2, 12, 13, and 19 February. White vapor was emitted during 1-21 February. Sulfur dioxide plumes drifted ENE during 11-20 February and NNW on 20 and 21 February. Consistent with the thick lava flows, MODVOLC detected well over 100 thermal anomalies at Bagana in the year ending 10 February 2011.

Table 2. Summary of ash plumes from Bagana reported during 1 February-October 2010. Courtesy of the Darwin Volcanic Ash Advisory Centre (VAAC).

Date
(2010)
Altitude
(km)
Drift
(distance and direction)
11-15 Feb 2.4 18-150 km E, NE
19-20, 23, 25 and 27 Apr 1.5-3 35-85 km S, SW, W, NW
06, 10-12 May 2.4-3 55-75 km W, SW, WSW
25-28 May 3 30-185 km NW, W, SW
13-14 Jun 3 75-205 km SW, W
04 Jul 2.4 75 km W
10-11 Jul 2.4 75-150 km SW
13-15 Aug 2.4 75 km SW, W
01 Oct 2.4 75 km NW

Reference. Blake D H, 1968. Post Miocene volcanoes on Bougainville Island, Territory of Papua and New Guinea. Bull Volc, 32: 121-140

Information Contacts: Darwin Volcanic Ash Advisory Centre (VAAC), Bureau of Meteorology, Northern Territory Regional Office, PO Box 40050, Casuarina, NT 0811, Australia (URL: http://www.bom.gov.au/info/vaac/); Rabaul Volcano Observatory (RVO), PO Box 386, Rabaul, Papua New Guinea; NASA Earth Observatory (URL: http://earthobservatory.nasa.gov/); Hawai'i Institute of Geophysics and Planetology (HIGP) MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://hotspot.higp.hawaii.edu/); Image Science and Analysis Laboratory, NASA-Marshall Space Flight Center (URL: http://eol.jsc.nasa.gov, http://www.flickriver.com/photos/); VolcanoWallpapers (URL: http://www.volcanowallpapers.com/Volcano-Smoke/mount-bagana-volcano/).

Bagana volcano, occupying a remote portion of central Bougainville Island, is one of Melanesia's youngest and most active volcanoes. Bagana is a massive symmetrical, roughly 1750-m-high lava cone largely constructed by an accumulation of viscous andesitic lava flows. The entire lava cone could have been constructed in about 300 years at its present rate of lava production. Eruptive activity at Bagana is frequent and is characterized by non-explosive effusion of viscous lava that maintains a small lava dome in the summit crater, although explosive activity occasionally producing pyroclastic flows also occurs. Lava flows form dramatic, freshly preserved tongue-shaped lobes up to 50-m-thick with prominent levees that descend the volcano's flanks on all sides.

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2000 Sep 16 2014 Jun 12 (continuing) Confirmed 2 Historical Observations
1972 1995 (continuing) Confirmed 2 Historical Observations
1970 May 21 ± 15 days 1971 Aug (in or after) Confirmed 2 Historical Observations
1968 Aug 1968 Aug Confirmed 2 Historical Observations
1966 Mar 20 1967 Nov 30 Confirmed 3 Historical Observations
1964 Apr 24 1965 Confirmed 2 Historical Observations
1962 Feb 15 1963 Confirmed 2 Historical Observations
1961 Jul 26 Unknown Confirmed 2 Historical Observations
1959 (?) 1960 May Confirmed 2 Historical Observations
1956 Unknown Confirmed 2 Historical Observations
1953 Jun 1953 Sep Confirmed 3 Historical Observations
1952 Feb 29 1952 Oct Confirmed 4 Historical Observations
1948 Dec 1 ± 30 days 1951 Dec 1 ± 30 days Confirmed 3 Historical Observations
1945 1947 Confirmed 2 Historical Observations
1943 Apr 7 (in or before) Unknown Confirmed 1 Historical Observations
1939 Jan 30 (?) Unknown Confirmed 2 Historical Observations
1938 May 15 Unknown Confirmed 3 Historical Observations
1937 Sep 7 Unknown Confirmed 3 Historical Observations
[ 1909 Jul ] [ Unknown ] Uncertain    
1908 Jul 15 Unknown Confirmed 2 Historical Observations
1899 Unknown Confirmed   Historical Observations
1897 May 16 (?) Unknown Confirmed 2 Historical Observations
1894 1895 Confirmed 2 Historical Observations
1883 Dec 31 ± 30 days Unknown Confirmed 3 Historical Observations
1865 ± 3 years 1883 Confirmed 2 Historical Observations
1842 Mar 15 Unknown Confirmed 1 Historical Observations

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.



Synonyms
Bogana
The beautiful caldera lake of Billy Mitchell provides a dramatic setting for unvegetated Bagana volcano, one of the most active in Papua New Guinea. The Solomon Sea can be seen in the distance to the SW. Two major explosive eruptions from Billy Mitchell, one about 900 and the other about 370 years ago, produced pyroclastic-fall deposits that cover most of the northern half of Bougainville Island and pyroclastic-flow and -surge deposits that extend 25 km to the eastern coast. The younger eruption may have been responsible for formation of the summit caldera.

Photo by Wally Johnson, 1988 (Australia Bureau of Mineral Resources).
A very strong steam plume rises above the summit lava dome on Bagana on June 18, 1987. On the righthand side of this view from the flanks of Reini volcano, NE of Bagana, one of the old lava flows from Bagana is visible. Long-term extrusion of viscous andesitic lava flows from Bagana has occurred throughout much of the 20th century, and has been almost continuous since 1972.

Photo by Wally Johnson, 1987 (Australia Bureau of Mineral Resources).
Steam clouds rise from a spectacular, but very slow-moving andesitic lava flow descending the NW flank of Bagana on April 26, 1988. The flow at that time had been moving for about 3 or 4 years, and is typical of the long-term lava effusion that began in 1972. The massive symmetrical lava cone, one of the most active volcanoes in Papua New Guinea, was largely constructed by an accumulation of viscous andesitic lava flows. At its present rate of effusion, the volcano could have been constructed in about 300 years.

Photo by Wally Johnson, 1988 (Australia Bureau of Mineral Resources).
Bagana volcano is seen here on October 7, 1964 from the south. The 1964 lava flow, darker in color than other lava flows, is descending the western flank. About half way down the flank the flow divides into four branches, two of which flow to the west and the other two toward the camera to the south. The 1964 eruption began with explosive activity on April 24. Lava extrusion soon began, and continued into 1965.

Photo by C.D. Branch, 1964 (courtesy of Ben Talai, Rabaul Volcano Observatory).
Bagana volcano, on Papua New Guinea's Bougainville Island, is characterized by the extrusion of thick, viscous andesitic lava flows. This dramatic photo shows a massive lava flow, bound by prominent lateral levees, descending from the summit and ponding against ruggedly dissected forested hills at the base of the volcano. Bagana is constructed almost entirely of overlapping lava-flow lobes. Slow lava extrusion, occasionally accompanied by explosive activity, has been continuing since 1972.

Photo by Wally Johnson, 1988 (Australia Bureau of Mineral Resources).
Much of the left side of this NASA image with north to the upper left is covered by volcanic products from Tore volcano in the Emperor Range on NW Bougainville Island. The Tore massif lies to the left of the light-colored area at the center of the image, Balbi volcano. Two Pleistocene ignimbrites from Tore formed a broad fan that extends the coastline to the west (lower left). The dark-colored caldera lake of Billy Mitchell volcano is at the right, above an ash plume originating from Bagana volcano.

NASA Space Shuttle image ISS001-358-32, 2001 (http://eol.jsc.nasa.gov/).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

Blake D H, 1968. Post Miocene volcanoes on Bougainville Island, Territory of Papua and New Guinea. Bull Volc, 32: 121-140.

Blake D H, Miezitis Y, 1967. Geology of Bougainville and Buka Islands, New Guinea. Aust Bur Min Resour Geol Geophys Bull, 93: 1-56.

Bultitude R J, 1976. Eruptive history of Bagana volcano, Papua New Guinea, between 1882 and 1975. In: Johnson R W (ed) {Volcanism in Australasia}, Amsterdam: Elsevier, p 317-336.

Bultitude R J, 1979. Bagana volcano, Bouganiville Island geology, petrology and summary of eruptive history between 1875 and 1975. Geol Surv Papua New Guinea Mem, 6: 1-35.

Bultitude R J, 1981. Literature search for pre-1945 sightings of volcanoes and their activity on Bougainville Island. Geol Surv Papua New Guinea Mem, 10: 227-242.

Bultitude R J, Cooke R J S, 1981. Note on activity from Bagana volcano from 1975 to 1980. Geol Surv Papua New Guinea Mem, 10: 243-248.

Cooke R J S, Johnson R W, 1978. Volcanoes and volcanology in Papua New Guinea. Geol Surv Papua New Guinea Rpt, 78/2: 1-46.

Fisher N H, 1957. Melanesia. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 5: 1-105.

Rogerson R J, Hilyard D B, Finlayson E J, Johnson R W, Mckee C O, 1989. The geology and mineral resources of Bougainville and Buka Islands, Papua New Guinea. Geol Surv Papua New Guinea Mem, no 16.

Volcano Types

Lava cone
Lava dome

Tectonic Setting

Subduction zone
Crustal thickness unknown

Rock Types

Major
Andesite / Basaltic Andesite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
198
404
7,861
115,257

Affiliated Databases

Large Eruptions of Bagana Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.