Bulusan

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  • Philippines
  • Luzon
  • Stratovolcano(es)
  • 2011 CE
  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 12.77°N
  • 124.05°E

  • 1565 m
    5133 ft

  • 273010
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

25 April-1 May 2012

PHIVOLCS reported that the Alert Level for Bulusan was lowered to 0 (on a scale of 0-5) on 24 April following a decline in activity after a phreatic eruption on 13 May 2011. The frequency of earthquakes decreased to baseline levels of 0-2 per day, measurements indicated deflation since late November 2011, and steaming activity from the crater and known thermal vents had been frequently weak compared to more moderate steam emissions during periods of unrest. Entry into the permanent danger zone, defined by a 4-km radius around the volcano, remained prohibited.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)



 Available Weekly Reports


2012: April
2011: January | February | March | April | May
2010: November | December
2008: January
2007: January | March | April | May | July | August | October
2006: March | April | May | June | July | August | October | November | December


25 April-1 May 2012

PHIVOLCS reported that the Alert Level for Bulusan was lowered to 0 (on a scale of 0-5) on 24 April following a decline in activity after a phreatic eruption on 13 May 2011. The frequency of earthquakes decreased to baseline levels of 0-2 per day, measurements indicated deflation since late November 2011, and steaming activity from the crater and known thermal vents had been frequently weak compared to more moderate steam emissions during periods of unrest. Entry into the permanent danger zone, defined by a 4-km radius around the volcano, remained prohibited.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


11 May-17 May 2011

On 13 May, PHIVOLCS reported that an explosion from Bulusan's summit crater was accompanied by a rumbling sound audible up to 5 km away. The event was recorded by the seismic network as an explosion-type earthquake lasting for about 10 minutes. Cloud cover prevented observations of the summit area. Field investigation conducted immediately after the explosion confirmed the presence of thin ash deposits (0.5- 2.5 mm) approximately 9 km away from the crater in the NW and SW sectors. Several barangays in the municipalities of Juban and Irosin reported light ashfall. The Alert Level remained at 1 (on a scale of 0-5). Entry into the permanent danger zone, defined by a 4-km radius around the volcano, was prohibited.

During 15-16 May the seismic network detected four earthquakes. Then, on 16 May, the number of earthquakes rapidly increased to 80 in a seven-hour period. On 17 May PHIVOLCS reported that 144 earthquakes were recorded in the previous 24 hours. Steam rose from the active vents.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


20 April-26 April 2011

Based on notices from the Manila airport (RPLL), the Tokyo VAAC reported that on 20, 22, and 26 April ash from Bulusan was observed. PHIVOLCS reported that only diffuse steam rose from the SE vents during 20-23 April. During cloud breaks on 26 April, diffuse steam plumes from the NW and SE vents were observed rising about 50 m and drifting WSW.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


13 April-19 April 2011

During 12-19 April, PHIVOLCS reported that up to six daily volcanic earthquakes at Bulusan were detected by the seismic network. Although cloud cover mostly prevented observations of the summit area, steam was observed rising from NW and SE thermal vents during 15 and 17-18 April. Based on notices from the Manila airport (RPLL) and reports from PHIVOLCS, the Tokyo VAAC reported that ash was observed on 13 and 15 April.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


6 April-12 April 2011

Based on notices from the Manila airport (RPLL), the Tokyo VAAC reported that ash from Bulusan was observed during 7-8 and 11 April. Plumes drifted W on 7 April, and NW and SW on 11 April. PHIVOLCS reported that during breaks in the clouds on 7 April steam plumes were observed rising from the SE and NW thermal vents.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


23 March-29 March 2011

Based on notices from the Manila airport (RPLL), the Tokyo VAAC reported that during 25-26 March ash from Bulusan was observed. PHIVOLCS reported that cloud cover prevented ground-based observations.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


16 March-22 March 2011

Based on notices from the Manila airport (RPLL) and analyses of satellite imagery, the Tokyo VAAC reported that on 18 and 20 March ash from Bulusan was observed. PHIVOLCS reported that cloud cover prevented ground-based observations during 18-20 March.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


2 March-8 March 2011

During 2-8 March, PHIVOLCS reported that up to four daily volcanic earthquakes at Bulusan were detected by the seismic network. Although cloud cover mostly prevented observations of the summit area, steam was observed rising from thermal vents during 2-4 and 7-8 March. Based on notices from the Manila airport (RPLL) and satellite image observations, the Tokyo VAAC reported that during 3-4 March ash was observed.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


23 February-1 March 2011

During 24 February-1 March, PHIVOLCS reported that up to five daily volcanic earthquakes at Bulusan were detected by the seismic network. There were 13 lahar-related seismic signals detected during 27-28 February. Continuous heavy rain caused small lahars on the flanks and in river channels, including the Cogon and Monbon rivers to the SW. Cloud cover prevented observations of the summit area during 24-28 February.

Based on notices from the Manila airport (RPLL), the Tokyo VAAC reported that on 24 and 28 February ash was observed. However, ash was not identified in satellite imagery.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


16 February-22 February 2011

During 17-20 February, PHIVOLCS reported that up to three daily volcanic earthquakes at Bulusan were detected by the seismic network. Cloud cover mostly prevented observations of the summit area, although steam rose from NW thermal vents on 19 February. An explosion on 21 February produced a gray ash plume that rose 3 km above the crater and drifted SW. Rumbling sounds were heard up to 10 km away in the town of Juban (NW). The event was recorded by the seismic network as an explosion-type earthquake lasting for about 19 minutes. Field investigations confirmed ash deposits in the towns of Irosin (up to 5 mm), 8 km SSW, and Bulan (up to 3 mm), 22 km SW. Traces of ashfall were also reported in the municipalities of Juban and Magallanes (24 km WNW), and in Masbate City (70 km SW), Masbate. According to news articles, about 2,000 people evacuated. During 21-22 February 16 volcanic earthquakes were detected by the seismic network. The Alert Level remained at 1 (on a scale of 0-5).

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Xinhua


26 January-1 February 2011

During 25-27 and 29-30 January, PHIVOLCS reported that up to five daily volcanic earthquakes at Bulusan were detected by the seismic network. Cloud cover prevented observations of the summit area. A deformation survey conducted during 25-29 January showed slight deflation relative to a December 2010 survey. The Alert Level remained at 1 (on a scale of 0-5).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


19 January-25 January 2011

During 18-19 January, PHIVOLCS reported that 11 volcanic earthquakes at Bulusan were detected by the seismic network. From 20 to 25 January up to five volcanic earthquakes per day were detected. Cloud cover mostly prevented observations of the summit area. Diffuse steam plumes rose from vents on 20 and 22 January. The Alert Level remained at 1 (on a scale of 0-5).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


12 January-18 January 2011

During 11-17 January, PHIVOLCS reported that up to 2 daily volcanic earthquakes at Bulusan were detected by the seismic network. Cloud cover prevented observations of the summit area. An explosion on 18 January was accompanied by a rumbling sound audible in Monbon, a barangay (neighborhood) in the municipality of Irosin, to the S. Cloud cover prevented observations of the crater. Trace amounts of ashfall were observed in Monbon. The Alert Level remained at 1 (on a scale of 0-5).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


5 January-11 January 2011

During 4-10 January, PHIVOLCS reported that 2-8 daily volcanic earthquakes at Bulusan were detected by the seismic network. Clouds usually prevented observations, but on 5 or 6 January steam was seen rising from a known NW thermal vent. The Tokyo VAAC reported that on 6 and 7 January ash was observed according to notices from the Manila airport (RPLL). The Alert Level remained at 1 (on a scale of 0-5).

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


29 December-4 January 2011

Based on notices from the Manila airport (RPLL), the Tokyo VAAC reported that on 29 and 30 December ash from Bulusan was observed. PHIVOLCS noted that inclement weather prevented views of the summit area during 29-31 December. Eight volcano-tectonic earthquakes were detected by the seismic network during 30-31 December.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


22 December-28 December 2010

On 23 December, PHIVOLCS reported that an explosion from Bulusan's summit crater was recorded by seismographs as an explosion-type earthquake following tremor that lasted for almost 31 minutes. A grayish steam-and-ash plume rose to about 500 m above the crater rim and drifted S-SW. Based on information from PHIVOLCS, the Tokyo VAAC reported that on 24 December an ash plume rose to an altitude of 2.1 km (7,000 ft) a.s.l. and drifted SW.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Tokyo Volcanic Ash Advisory Center (VAAC)


15 December-21 December 2010

On 17 December, PHIVOLCS reported that an explosion from Bulusan, recorded for about 3 minutes by seismographs, produced an ash-and-steam plume that rose 500 m above the crater and drifted SW. Steam rose from the NW and SE vents, and again from NW vents on 19 December.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


8 December-14 December 2010

During 8-12 December, PHIVOLCS reported that 1-2 volcanic earthquakes from Bulusan were detected by the seismic network. Cloud cover prevented visual observations. On 13 December, 7 volcanic earthquakes were detected. Steam rose from the crater and known thermal vents. The Alert Level remained at 1 (on a scale of 0-5).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


1 December-7 December 2010

PHIVOLCS reported that volcanic earthquakes from Bulusan were detected during 1-6 December; no earthquakes were recorded on 7 December. Steam from known thermal vents rose 100 m and drifted SW on 1 December. Cloud cover prevented visual observations during 2-4 and 6-7 December. Diffuse steam rose from the crater and from known vents on 5 December. The Alert Level remained at 1 (on a scale of 0-5).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


24 November-30 November 2010

On 24 November, PHIVOLCS reported that an explosion from Bulusan, recorded for almost six minutes by seismographs, produced an ash plume that rose 1 km above the crater, drifted SW, and dissipated. Ashfall was not observed outside of the permanent danger zone, defined as a 4-km radius from the summit, suggesting that ashfall was confined to the upper flanks. On 26 November steam was emitted from known thermal vents and the crater. A steam plume rose 150 m above the NW vent and drifted SW. Later that night an explosion-type earthquake was recorded by the seismic network; cloud cover prevented visual observations of the crater. On 28 November steam rose from the SE and SW vents. During 29 November-1 December steam rose from both the NW vents and thermal vents.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


17 November-23 November 2010

On 16 November, white steam rose from Bulusan's NW vent, but no steaming was observed from the crater and SE vent. Cloud cover prevented observations the next day. On 18 November weak steaming from the crater and known thermal vents produced plumes that drifted downslope to the SW. Cloud cover obscured views of the crater during 19-20 November. An explosion-type earthquake on 21 November was coincident with rumbling sounds and an ash plume that rose 2 km above the crater. Ashfall up to 3 mm thick was reported in multiple areas. According to news reports, about 500 families evacuated and some local roads were impassable. Steam was emitted from the crater and known thermal vents during 22-23 November.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Philippine Daily Inquirer, Malaya Business Insight


10 November-16 November 2010

During 10-11 November, PHIVOLCS reported that 18 volcano tectonic earthquakes from Bulusan were detected by the seismic network. On 11 November white steam plumes rose 150 m above the crater and drifted ENE. During an aerial survey, scientists saw that recent explosions resulted in the joining of two of the 2006-2007 craters into one. They also noted that deposits from an explosion on 9 November did not contain juvenile material. On 12 November an ash explosion produced an ash-and-steam plume that rose 700 m above the crater and drifted SW. Multiple neighborhoods to the W and SW reported light ashfall. Four volcano-tectonic earthquakes were detected during the previous 24 hours. Steam plumes rose to a maximum height of 100 m above the crater. Some steaming was seen during 13-14 November. White steam rose from the NW vent, but no steaming was observed from the crater and SE vent on 14 and 15 November. An explosion late at night on 15 November was followed by ashfall in nearby neighborhoods. Cloud cover prevented observations of the summit area the next morning. The Alert Level remained at 1 (out of 5).

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


3 November-9 November 2010

PHIVOLCS reported an explosion-type earthquake at Bulusan on 6 November coincident with a steam-and-ash plume that rose 600 m above the crater at 0811. Trace amounts of ashfall were reported in multiple areas 6-10 km NW. The Alert Level was raised from 0 to 1 (out of 5), and PHIVOLCS reminded the public not to enter the permanent danger zone, defined as a 4-km radius around the volcano. White steam plumes were observed rising 200 m above the crater before 1400, when cloud cover prevented observations. On 7 November, PHIVOLCS noted that seismic activity had increased during the previous 24 hours. A phreatic explosion on 8 November was produced a brownish-to-light-gray plume that rose 700 m above the crater. Several neighborhoods to the NW, W, and WSW reported ashfall. Steam rose from the crater after the explosion. On 9 November two consecutive ash explosions, accompanied by rumbling sounds, produced ash plumes that rose as high as 1 km above the crater and drifted SW. Ashfall up to 2 mm thick was reported in areas to the SW and WNW.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


2 January-8 January 2008

According to a news article, at least seven minor earthquakes near Bulusan during 6-7 January prompted authorities to enforce the no-entry policy within the permanent danger zone, defined by a 4-km radius around the volcano. The Alert Level remained at 1 (out of 5).

Source: GMA News


3 October-9 October 2007

Based on seismic interpretation, PHIVOLCS reported two explosions from Bulusan on 4 October. Thick clouds obscured observations of the summit. According to news articles, ashfall was reported in several villages.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Agence France-Presse (AFP)


1 August-7 August 2007

An explosion from Bulusan on 31 July produced an ash plume that rose to an altitude of 6.6 km (21,700 ft) a.s.l. The plume drifted WSW and WNW, causing light ashfall. According to a news article, white steam plumes rose from active craters and fissures on 2 August. The Alert Level remained at 1 (out of 5).

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Agence France-Presse (AFP)


11 July-17 July 2007

On 13 July, PHIVOLCS lowered the Alert Level for Bulusan from 2 to 1 (out of 5) due to a decline in activity including decreased seismicity, below baseline sulfur dioxide output, and deflation relative to the previous survey. Steam plumes from active vents and fissures were observed.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


23 May-29 May 2007

According to news articles, scientists from PHIVOLCS conducted an aerial investigation of Bulusan and discovered lahar deposits and three steaming fissures. Lahars were previously reported from the municipalities of Irosin and Juban on 22 May. Scientists also observed steam plumes that rose to altitudes of 1.6-1.7 km (5,200-5,600 ft) a.s.l. and drifted NW and NE. PHIVOLCS reported that the S flank inflated 3 mm.

Sources: GMA News, ABS-CBN News


16 May-22 May 2007

PHIVOLCS reported on 20 May that seismicity from Bulusan remained high following the explosion on 12 May. Ground deformation measurements conducted on 17 May on the NE flank revealed 4 mm of inflation compared to the previous measurement on 7 April. The Alert Level was raised from 1 to 2 (out of 5) due to the increased seismicity and inflation.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


9 May-15 May 2007

PHIVOLCS reported that an explosion from Bulusan on 12 May produced an ash plume that rose to an altitude of 5.6 km (18,400 ft) a.s.l. and drifted WSW and WNW. The activity was accompanied by rumbling sounds and was recorded by the seismic network as an explosion-type earthquake that lasted about 35 minutes. An increase in seismicity was noted during 9-12 May. Ashfall (trace-2 mm thick) was reported in 11 barangays from the municipalities of Irosin and Juban.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


18 April-24 April 2007

PHIVOLCS reported on 17 April that seismicity from Bulusan increased significantly during 16-17 April. Ground deformation surveys conducted in March and April indicated 4 mm of inflation on the NNE flank. Steam plumes from the crater and fissures rose to altitudes of 1.8 km (5,900 ft) a.s.l. and drifted WSW.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


4 April-10 April 2007

According to news articles, eruptions from Bulusan on 8 April produced ash plumes that rose to altitudes of 3.1-6.6 km (10,200-21,700 ft) a.s.l.

Source: GMA News


14 March-20 March 2007

Based on news articles, ash fell on the SW slopes and villages near Bulusan on 15 March. According to the interpretation of a resident volcanologist, the ashfall was not caused by explosions, instead voluminous steaming during 12-15 March "agitated the ash deposits on the crater wall."

Source: The Philippine Star


24 January-30 January 2007

PHIVOLCS reported that an explosion from the summit of Bulusan on 24 January lasted about 10 minutes based on seismic interpretation. Observation was inhibited due to cloud cover. Ashfall was reported from areas SW.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


20 December-26 December 2006

According to a news report, a plume of gas and "white ash" was emitted from Bulusan on 22 December.

Source: News Balita


13 December-19 December 2006

According to new articles, Bulusan emitted ash that was accompanied by rumbling noises and lightning flashes on 20 December. Clouds hindered a view of the summit. Ash deposits up to 4 mm thick were noted in several villages at the foothills.

Source: Associated Press


1 November-7 November 2006

On 1 November, PHIVOLCS reported two explosion-type earthquakes from Bulusan at 1914 and 2345 on 31 October. Trace amounts of ashfall was reported from neighborhoods in the municipalities of Casiguran, Malapatan, and Irosin.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


25 October-31 October 2006

PHIVOLCS reported that during 25-26 October, a lahar from Bulusan deposited sediments 15 cm (6 in) thick along a tributary leading to the Gulang-gulang River. According to news articles, the lahar mobilized boulders as large as trucks and caused at least 96 people to evacuate. During 30-31 October, ash explosions generated a light gray ash-and-steam plume that rose to 2.3 km (7,400 ft) a.s.l. and drifted NNE. Later field inspection revealed ashfall (trace to 1 mm) in the N sectors of the volcano, including areas in the municipalities of Casiguran and Gubat.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Inquirer.net


18 October-24 October 2006

PHIVOLCS reported an explosion from Bulusan on 19 October. The following day, steam plumes drifted W and WSW. On 23 October, an explosion produced a brownish ash plume that rose to about 2.6 km (8,400 ft) a.s.l. and drifted SE and SW. Light ashfall (trace to 0.5 mm thick) from both explosions was reported from neighborhoods in the municipality of Irosin.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


11 October-17 October 2006

PHIVOLCS reported that an explosion from Bulusan on 10 October produced an ash-and-steam plume that rose to 4.5 km (15,000 ft) a.s.l. and drifted mainly SE and SSW. Light ashfall (1.5-5.0 mm thick) was reported in neighboring towns downwind. Based on seismic data, the activity lasted for 9 minutes. On 11 and 12 October, steam plumes drifted SW and SSW.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


4 October-10 October 2006

On 10 October, an eruption plume from Bulusan that was visible on satellite imagery reached altitudes of 3 km (10,000 ft) a.s.l. and drifted SW and SSE.

Source: Tokyo Volcanic Ash Advisory Center (VAAC)


30 August-5 September 2006

PHIVOLCS reported that steam plumes from Bulusan reached up to 350 m above the summit (6,300 ft a.s.l.) on 30 August and 1 September. The plumes drifted NW and SE, respectively.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


26 July-1 August 2006

On 29 July, PHIVOLCS reported that the Alert Level at Bulusan was lowered from 2 to 1 (out of 5 levels) due to a gradual decrease from 28 June of all monitored parameters to near-baseline levels.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


28 June-4 July 2006

Based on interpretations of seismic data, small explosions occurred at Bulusan on 28 and 29 June. No ashfall was reported.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


21 June-27 June 2006

According to news reports, on 24 June rocks and large boulders that were mobilized on the flanks of Bulusan by heavy rains prompted 100 residents of Cogon village to evacuate. On 26 June, lahars occurred along a tributary leading to the Gulang-Gulang River in Irosin town.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Associated Press


14 June-20 June 2006

An explosion from a fissure W of the summit vent of Bulusan lasting approximately 13 minutes on 13 June produced an ash-and-steam cloud that reached a height of 1.5 km above the summit (10,100 ft a.s.l.) and drifted NW. Ashfall up to 7 mm thick accumulated in neighborhoods in the municipality of Juban. On 18 June, an ash producing explosion that lasted approximately 11 minutes produced an ash-and-steam cloud that also reached a height of 1.5 km above the summit (10,100 ft a.s.l.) and drifted W. Ash up to 5 mm thick fell on a W flank village. On 20 June, a mild ash-and-steam explosion lasted approximately 17 minutes. Close to 900 people were evacuated due to the 18 June activity. On 20 June, officials declared a state of disaster for Irosin, Casiguran, and Juban towns in Sorsogon province. Bulusan remained at Alert Level 2 (out of 5 levels) during 14-20 June.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Reuters, Canada.com (Postmedia Network), Philippine Information Agency


7 June-13 June 2006

According to PHIVOLCS, an ash-and-steam cloud from Bulusan on 7 June reached a height of approximately 2 km above the summit (11,700 ft a.s.l.) and drifted N and NW. Light ashfall was reported 5 km N and trace amounts as far as 20 km N. The Alert Level was raised to 2 (scale 0 to 5), which means restricted entry within 4 km of the summit. On 10 June, an ash-and-steam cloud reached a height of ~1 km above the summit (8,400 ft a.s.l.) and drifted N and NE. A news article reported one death caused by an asthma attack from exposure to ash.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), Associated Press, Manila Standard Today


31 May-6 June 2006

PHIVOLCS reported that an ash-and-steam cloud emitted from Bulusan on 31 May reached a height of 1.5 km above the summit (10,100 ft a.s.l.). Light ashfall, from trace amounts to 1.5 mm thickness, fell in areas W and NW of the volcano. Bulusan remained at Alert Level 1, with a Permanent Danger Zone of 4 km around the summit.

Sources: Philippine Institute of Volcanology and Seismology (PHIVOLCS), The Manila Times


24 May-30 May 2006

A phreatic ash explosion was recorded by the seismograph network at Bulusan between 2117 and 2130 on 25 May. Light ashfall ranging from trace amounts to deposits 2 mm thick was reported from the W and SW villages of Bacolod, Sankayon, Puting Sapa, Rangas, Mapili, Caladgao, and Buraburan in the municipality of Juban and Bolos in the municipality of Irosin.

PHIVOLCS reported that the ash explosion was more-or-less typical of activity at Bulusan during its current period of unrest and they expect more explosions to occur. Bulusan was at Alert Level 1, with a Permanent Danger Zone of 4 kilometers around the summit.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


26 April-2 May 2006

According to news reports, on 29 April at 1044 an explosion at Bulusan produced an ash plume that rose ~1.6 km above the volcano (or 10,400 ft a.s.l.). Ash fell on nearby villages. People are not permitted to enter within 4 km of the volcano's crater.

Sources: Agence France-Presse (AFP), INQ7.net


15 March-21 March 2006

On 21 March at 2258, a modest ash explosion occurred at Bulusan's summit crater. The phreatic explosion produced an ash cloud that rose ~1.5 km above the volcano (or 10,050 ft a.s.l.). Based on interpretations of seismic data, the event lasted ~20 minutes. It was accompanied by lightning and rumbling sounds. Ash drifted N, W, and SW of the volcano, and ~1 hour after the explosion light ash fell (producing ~5-mm-thick deposits) in Barangays (neighborhoods) Cogon, Tinampo, Gulang-Gulang, and Bolos in the town of Irosin. Ash also fell in Barangays Puting Sapa and Bura-Buran of Juban town, and other neighboring barangays under the municipalities of Irosin and Juban, Sorsogon. Three explosion-type earthquakes were also recorded on the 21st, at 2330, 2332, and 2337, but the accompanying eruptive events were not observed because the summit was obscured.

Source: Philippine Institute of Volcanology and Seismology (PHIVOLCS)


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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
2010 Nov 6 2011 May 13 Confirmed 2 Historical Observations Summit crater
2006 Oct 10 2007 Oct 4 Confirmed 2 Historical Observations
2006 Mar 21 2006 Jun 28 Confirmed 2 Historical Observations
1994 Nov 27 1995 Jan 28 (in or after) Confirmed 2 Historical Observations
1988 Feb 20 1988 Mar 8 Confirmed 2 Historical Observations
1983 Jun 25 1983 Jun 29 Confirmed 2 Historical Observations
1981 Apr 9 1981 Apr 27 Confirmed 3 Historical Observations
1979 Dec 27 1980 Sep 28 Confirmed 3 Historical Observations
1978 Jul 29 1978 Aug 14 Confirmed 2 Historical Observations
1933 Dec 25 Unknown Confirmed 2 Historical Observations
1928 Jun Unknown Confirmed 2 Historical Observations
1918 Oct 1922 May Confirmed 2 Historical Observations
1916 Jan 18 1916 Jan 22 Confirmed 2 Historical Observations
1894 Unknown Confirmed 2 Historical Observations
1892 Unknown Confirmed 2 Historical Observations
1889 Unknown Confirmed   Historical Observations
1886 Unknown Confirmed 2 Historical Observations
[ 1852 ] [ Unknown ] Uncertain    
0950 (?) Unknown Confirmed   Radiocarbon (uncorrected)
3050 BCE (?) Unknown Confirmed   Radiocarbon (uncorrected)

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. 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. Additional discussion of data sources can be found under Volcano Data Criteria.

Bautista L P, 1988. The 1988 Bulusan volcano activity. Phivolcs Observer, 4: 1-3.

Catane S G, Taniguchi H, Goto A, Givero A P, Mandanas A A, 2005. Explosive volcanism in the Philippines. CNEAS Monograph Ser, Tohoku Univ, 18: 1-146.

COMVOL, 1981. Catalogue of Philippine volcanoes and solfataric areas. Philippine Comm Volc, 87 p.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

McDermott F, Delfin F G Jr, Defant M J, Turner S, Maury R, 2005. The petrogenesis of volcanics from Mt. Bulusan and Mt. Mayon in the Bicol arc, Philippines. Contr Mineral Petr, 150: 652-670.

Mirabueno M H T, Okuno M, Nakamura T, Laguerta E P, Newhall C G, Kobayashi T, 2007. AMS radiocarbon dating of a charcoal fragment from the Irosin Ignimbrite, Sorsogon Province, southern Luzon, Philippines. Bull Volc Soc Japan (Kazan), 52: 241-244.

Neumann van Padang M, 1953. Philippine Islands and Cochin China. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 2: 1-49.

Newhall C G, Dzurisin D, 1988. Historical unrest at large calderas of the world. U S Geol Surv Bull, 1855: 1108 p, 2 vol.

PHIVOLCS, 2004-. Volcanoes. http://www.phivolcs.dost.gov.ph/Volcanolist/.

Luzon's southernmost volcano, Bulusan, was constructed along the rim of the 11-km-diameter dacitic-to-rhyolitic Irosin caldera, which was formed about 36,000 years ago. Bulusan lies at the SE end of the Bicol volcanic arc occupying the peninsula of the same name that forms the elongated SE tip of Luzon. A broad, flat moat is located below the topographically prominent SW rim of Irosin caldera; the NE rim is buried by the andesitic Bulusan complex. Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of 1565-m-high Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank. Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century.