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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.

Basic Data

Volcano Number

Last Known Eruption



Unknown - Evidence Credible

-65 m / -213 ft


Volcano Types

Pyroclastic cone(s)

Rock Types

Andesite / Basaltic Andesite

Tectonic Setting

Subduction zone
Oceanic crust (< 15 km)


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 following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

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.

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.

Smithsonian Sample Collections Database

There are no samples for Unnamed in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

Affiliated Sites

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).
MODVOLC - HIGP MODIS Thermal Alert System Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.
MIROVA Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.