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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 13.658°N
  • 123.38°E

  • 1966 m
    6448 ft

  • 273042
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports for Isarog.

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

The Global Volcanism Program has no Bulletin Reports available for Isarog.

Volcano Types


Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Rock Types

Andesite / Basaltic Andesite


Within 5 km
Within 10 km
Within 30 km
Within 100 km

Geological Summary

The broad isthmus between Lagonoy Gulf and San Miguel Bay in SE Luzon is occupied by the isolated Mount Isarog volcano. The 1966-m-high andesitic stratovolcano is truncated by a 2.5-km-wide crater that is breached to the east along a narrow valley drained by the Quinarag River. A major debris avalanche deposit extends northwest to the coast and into San Miguel Bay. Pyroclastic flows originating from lava dome collapses have occurred during the Holocene, one of which has a calibrated radiocarbon date of about 5500 years Before Present. Currently the Maalsom vent displays gas seepages, warm springs, and steaming vents.

Eruptive History

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
3500 BCE ± 125 years Unknown Confirmed   Radiocarbon (corrected)

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.


Feature Name Feature Type Elevation Latitude Longitude
Maalsom Thermal

Photo Gallery

Mount Isarog volcano in the background rises to 1966 m NW beyond the lower flanks of Iriga volcano, which form the sloping terrain in the foreground. Mount Isarog is an isolated stratovolcano occupying the broad isthmus between Lagonoy Gulf and San Miguel Bay. The summit of the volcano is cut by a large crater, which has a prominent, deep and narrow breach on the lower eastern flank.

Photo by Chris Newhall (U.S. Geological Survey).


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.

Fontijn K, Newhall C G, 2013. Reconnaissance geology of Isarog volcano (Luzon, Philippines): evidence for Holocene explosive eruptions and a major edifice collapse. J Volc Geotherm Res, 250: 100-105.

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

PHIVOLCS, 2004-. Volcanoes.

Affiliated Databases

Large Eruptions of Isarog 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.