Bulusan Volcano |John Seach


Sorsogon Province, Luzon,

12.77 N, 124.05 E
summit elevation 1565 m

Bulusan Volcano is located in Sorsogon Province, 250 km SE of Manila; 70 km SE of Mayon Volcano.

Bulusan volcanic complex is located at the southern extremity of the Bicol arc in the south-east of Luzon. It consists of the active cone of Mt. Bulusan, 11 km wide Irosin caldera, and older dissected volcanic centres that include the Gate Mountains at the
southern tip of the peninsula and Mt. Bintacan to the west.

Bulusan Hydrothermal System
The Bulusan hydrothermal system consists of superheated solfatara at the summit of Mt. Bulusan and hot to warm springs on the volcano flank. All the thermal springs discharge neutral pH waters at temperatures <65°C.

Eruption Hazards
Typical eruptions at Bulusan are Phreatic and Strombolian. A large caldera forming eruption occurred 40,000 years ago. The recent eruptive history of Mt. Bulusan indicates that tephra eruptions and mudflows are the principal volcanic hazards in the area. There is a permanent danger zone within 4km of the summit.

2015 Eruption
A phreatic eruption occurred at Bulusan volcano, Philippines on 17th July 2015. The eruption produced an explosion earthquake which lasted for 11 minutes. Sounds were heard 6km from the summit. The eruption produced a 200 m high ash plume which caused ashfall in nearby areas. Inflation of the volcano was recorded in June and July 2015.

2008 Earthquakes
At least seven small earthquakes occurred near Bulusan volcano on 6-7 January 2008.

2006-07 Eruptions
A summit eruption occurred at Bulusan Volcano on 21st March 2006 after being quiet for 11 years. There were ten explosions up until 28th June 2006. The eruptions in 2006 were the result of small volumes of magma with an overlying water-saturated zone beneath the summit. Explosive eruptions and ashfall occurred between 10th October 2006 and 12th May 2007. On 31st July 2007 an explosion ejected ash to an altitude of 6.6 km.

1994-95 Eruptions
A phreatic eruption occurred at Bulusan volcano on 27th November 1994 which ejected an ash plume 1.5 km altitude. A second ash explosion on 3rd December deposited ash 7 km from the volcano. A strong phreatic explosion on 12th December created a 3 km high ash cloud, and caused ashfall 16 km from the volcano. An eruption on 21st January 1995 was accompanied by rumbling noises, lightning flashes over the summit, and light ashfall at the San Benon Observatory 5 km SW.

1988 Eruptions
On 20th February a small ash eruption occurred at Bulusan volcano. The eruption was accompanied by lightning at the summit. On 24th February 1988 a magnitude 6.9 earthquake occurred 80 km NE of Bulusan. The earthquake possibly caused a landslide which was observed on the volcano's middle to lower flank.

1983 Eruptions
Small phreatic eruptions occurred at the summit crater on 25th and 29th June 1983. Ash was ejected to a height of 1.2 km.

Further reading
Okuno, M., Laguerta, E., Reyes, P.D., Bornas, M.A., Mirabueno, M.H., Arpa, M.C., Bariso, E., Solidum Jr, R., Taguchi, S., Torii, M. and Kobayashi, T., 2011. Eruptions of Bulusan volcano since November 2010. The Journal of the Geological Society of Japan117(12), p.XIV.

Delfin Jr, F.G., Panem, C.C. and Defant, M.J., 1993. Eruptive history and petrochemistry of the Bulusan volcanic complex: implications for the hydrothermal system and volcanic hazards of Mt. Bulusan, Philippines. Geothermics22(5-6), pp.417-434.

Bulusan Volcano Eruptions

2015, 2010-11, 2006-07, 1994-95, 1988, 1983, 1981, 1979-80, 1978, 1933, 1928, 1918-22, 1916, 1894, 1892, 1889, 1886, 1852?