🌋VolcanoAtlas

Bulusan

Luzon's Southernmost Volcanic Sentinel

Elevation

1,535 m

Last Eruption

2025

Type

Stratovolcano(es)

Country

Philippines

Location

Loading map...

Volcanic Hazards & Risk Assessment

Primary Hazards

  • Pyroclastic flows
  • Lava flows
  • Volcanic bombs and ballistics
  • Lahars and mudflows

Risk Level

Population at RiskHigh
Infrastructure RiskHigh
Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary
Unknown
Silica Content
Varied composition

Tectonic Setting

Unknown
Intraplate setting with hotspot or regional volcanic activity.

Age & Formation

Epoch
Unknown
Evidence
Unknown

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent Activity1 years agoVery RecentCurrently active

Monitoring & Alert Status

Monitoring Networks

Global Volcanism Program
International eruption database

Current Status

Active
Recent volcanic activity detected. Continuous monitoring in place.

Authority Sources

Smithsonian GVP
Official volcano database

Related Volcanoes

All Philippines Volcanoes
Explore by country
Stratovolcano(es) Volcanoes
By volcano type
Sorsogon Province, Bicol Region, Luzon
Regional volcanoes

Other Volcanoes in Philippines

Interesting Facts

🌋

Bulusan is built within the 11-km-wide Irosin caldera, which formed approximately 36,000 years ago during a massive dacitic-to-rhyolitic eruption.

🌋

The volcano has erupted 10 times since 2006, making it one of the most frequently active volcanoes in the Philippines during the 21st century.

🌋

Most of Bulusan's modern eruptions are phreatic (steam-driven) explosions that occur with little warning, producing sudden ash plumes and ballistic projectiles.

🌋

A 4-km-radius permanent danger zone around the summit is maintained by PHIVOLCS, prohibiting permanent settlement within this zone.

🌋

The summit crater is 300 m wide and 50 m deep, one of the most actively modified craters in the Philippines due to frequent phreatic explosions.

🌋

Mount Jormajan, a large lava dome on Bulusan's southwest flank, is one of several intracaldera volcanic features that demonstrate the complex's multi-vent nature.

🌋

Heavy tropical rainfall in Sorsogon Province makes lahars a persistent hazard, as water mobilizes volcanic ash deposits into destructive mudflows along river channels.

🌋

Bulusan Volcano Natural Park protects dense tropical rainforest on the volcano's flanks, including habitat for the critically endangered Philippine eagle.

🌋

Approximately 50,000 people live within the broader hazard zones of Bulusan, primarily in the municipalities of Irosin, Juban, and Bulusan.

🌋

The Irosin caldera that hosts Bulusan was produced by one of the largest Pleistocene eruptions in the Philippines, ejecting dacitic to rhyolitic ignimbrites across a wide area.

Frequently Asked Questions

Is Bulusan an active volcano?
Yes, Bulusan is one of the most active volcanoes in the Philippines. It last erupted in April 2025 and has produced 10 eruptions since 2006 alone. The volcano has 26 confirmed eruptions in its record. Most modern activity consists of phreatic (steam-driven) explosions that generate ash plumes and lahars. PHIVOLCS continuously monitors Bulusan with seismic stations, gas sensors, and webcams, and maintains a permanent danger zone around the summit.
What type of eruptions does Bulusan produce?
Bulusan predominantly produces phreatic (steam-driven) eruptions, which occur when groundwater is heated by magma and flashes to steam, causing explosive decompression. These events generate ash plumes typically reaching 1–3 km above the summit, ballistic ejection of rocks near the crater, and lahars (volcanic mudflows) when ash mixes with heavy tropical rainfall. The strongest recorded eruptions in 1979–1981 reached VEI 3 and involved magmatic material beyond the typical phreatic activity.
How tall is Bulusan?
Bulusan rises to 1,535 m (5,036 ft) above sea level. It is the southernmost volcano on Luzon island and the most prominent peak in Sorsogon Province. For comparison, nearby Mayon volcano, approximately 80 km to the northwest, stands at 2,462 m (8,077 ft). Bulusan is built within the much larger 11-km-wide Irosin caldera, so its actual cone rises from the caldera floor rather than from sea level.
What is the Irosin caldera?
The Irosin caldera is an 11-km-diameter volcanic collapse structure formed approximately 36,000 years ago during a catastrophic eruption that produced voluminous dacitic-to-rhyolitic ignimbrites (pyroclastic flow deposits). Bulusan and several other volcanic edifices — including Mount Jormajan and Sharp Peak — were subsequently built within and along the rim of this caldera. The caldera's flat moat is now occupied by agricultural land and settlements. The event that formed the Irosin caldera was one of the largest Pleistocene eruptions in the Philippines.
Is Bulusan dangerous?
Bulusan poses moderate to high risk to surrounding communities. Approximately 50,000 people live within the broader hazard zones in Sorsogon Province. Frequent phreatic eruptions can occur with little warning, and the resulting ash and lahars affect communities along river drainages. Heavy tropical rainfall amplifies lahar hazards. PHIVOLCS maintains a 4-km permanent danger zone and issues evacuation orders when eruption risk is elevated. The 1979–1981 VEI 3 eruptions demonstrated that more powerful explosive events are possible.
When did Bulusan last erupt?
Bulusan's most recent eruption occurred in April 2025. Prior to that, the volcano erupted in June 2022 (VEI 2), June 2017 (VEI 1), twice in 2016 (February and June, both VEI 2), and May 2015 (VEI 2). This pattern of eruptions every one to three years has been characteristic of the volcano since 2006 and shows no signs of abating. PHIVOLCS anticipates continued intermittent phreatic activity.