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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 21.15°S
  • 175.75°W

  • -65 m
    -213 ft

  • 243011
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports for Unnamed.

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

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

Volcano Types

Pyroclastic cone(s)

Tectonic Setting

Subduction zone
Oceanic crust (< 15 km)

Rock Types

Andesite / Basaltic Andesite


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

Geological Summary

A large submarine volcano rises to within 65 m of the sea surface west of Tongatapu Island. The volcano was informally named Volcano #1 by the scientists on the bathymetric survey that discovered the submarine volcano in 2003. The summit of the andesitic-to-dacitic volcano is cut by a large 7 x 4.5 km wide caldera, with two young scoria cones forming the high point of the seamount. A chain of explosion craters up to 100 m deep cut the flank of one of the scoria cones, and thick deposits of ash and scoria blanket the caldera floor nearby. The lack of organic sediments between volcaniclastic deposits exposed in one portion of the caldera wall suggest it was constructed within the past 200 years. Diffuse low-temperature hydrothermal vents and vigorous gas discharge occurs near the explosion craters.

The Global Volcanism Program is not aware of any Holocene eruptions from Unnamed. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the Unnamed page in the LaMEVE (Large Magnitude Explosive Volcanic Eruptions) database, a part of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

The Global Volcanism Program has no synonyms or subfeatures listed for Unnamed.

The Global Volcanism Program has no photographs available for Unnamed.


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.

Hekinian R, Muhe R, Worthington T J, Stoffers P, 2008. Geology of a submarine volcanic caldera in the Tonga Arc: dive results. J Volc Geotherm Res, 176: 571-582.

Stoffers P, Worthington T J, Schwarz-Schampera U, Hannington M D, Massoth G J, Hekinian R, Schmidt M, Lundsten L J, Evans L J, Vaiomo'unga R, Kerby T, 2006. Submarine volcanoes and high-temperature hydrothermal venting on the Tonga arc, southwest Pacific. Geology, 34: 453-456.

Affiliated Databases

Large Eruptions of Unnamed 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.