Moutohora Island

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 37.858°S
  • 176.98°E

  • 354 m
    1161 ft

  • 241815
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Moutohora Island.

The Global Volcanism Program has no Weekly Reports available for Moutohora Island.

Index of Monthly Reports

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

03/1990 (BGVN 15:03) CO2-rich gases from thermal area


Contents of Monthly Reports

All information contained in these reports is preliminary and subject to change.

03/1990 (BGVN 15:03) CO2-rich gases from thermal area

The following observations, made by scientists from the USSR and New Zealand during a cruise of the RV Vulkanolog, were reported by W.F. Giggenbach and I. Menyailov.

"...Thermal activity manifests itself largely in areas of hydrothermally altered, steaming ground. The major thermal feature is a vigorously boiling pool near sea level in Sulphur Bay (Ramsay and Hayward, 1971). As indicated by the occurrence of bubble zones (Glasby, 1971), submarine thermal activity extends well SW of the island.

"During both the 1988 and 1990 cruises of the RV Vulkanolog, gas and water samples were collected from the main pool. The waters are essentially acid sulfate (4,000 mg/kg; Cl, 20 mg/kg), steam-heated, initially non-saline groundwater. Compositions of 1988 gases are compared in table 1 with those of 1974 samples from Sulphur Bay spring and the seafloor at 34 m depth (Lyon and others, 1977).

Table 1. Chemical composition of gases collected from vents on and near Whale Island (in mmol/mol of dry gas), March 1974 (Lyon and others, 1977) and during the September 1988 cruise of the RV Vulkanolog.

    Vent   Seafloor (34 m depth)    Island (pool)
    Date   10 Sep 74   10 Sep 74    10 Sep 74   10 Mar 88   10 Mar 88

    C          15          15           99           99           99
    CO2       734         680          967          935          937
    H2S        --          --           --         12.5         12.2
    He         --          --           --       0.0028       0.0010
    Ne         --          --           --      0.00004     0.00006
    Ar        1.2         0.8         0.07         0.04         0.03
    H2        0.1         0.3          3.2         11.2          9.7
    O2       14.1         7.5        <0.01        <0.03        <0.03
    N2        131         119           11           13           11
    CH4       120         193           18           28           30

"All gases reflect a hydrothermal origin, and their major component is CO2. The seafloor gases are contaminated with air, probably after sampling. Their higher CH4 and lower H2 contents suggest longer residence at lower temperatures compared to the island samples. The composition of the latter has remained essentially unchanged over the last 14 years."

References. Glasby, G.P., 1971, Direct observation of columnar scattering associated with geothermal gas bubbling in the Bay of Plenty, New Zealand: New Zealand Journal of Marine and Freshwater Research, v. 5, p. 483-496.

Lyon, G.L., Giggenbach, W.F., Singleton, R.J., and Glasby, G.P., 1977, Isotopic and Chemical composition of submarine geothermal gases from the Bay of Plenty, New Zealand: New Zealand Department of Scientific and Industrial Research Bulletin, v. 218, p. 65-67.

Ramsay, W.R.H., and Hayward, B.W., 1971, Geology of Whale Island: Tane, v. 17, p. 9-32.

Information Contacts: I. Menyailov and A. Ivanenko, IV, Petropavlovsk; W. Giggenbach, DSIR Chemistry, Petone.

Moutohora (Whale) Island forms the summit of a largely submerged Pleistocene dacitic-andesitic complex volcano that lies 11 km offshore from Whakatane in the Bay of Plenty. The island is 15 x 5 km wide and elongated E-W. The 354-m-high central dome complex is flanked by East Dome, which forms the eastern tip of the island and is the oldest of the domes, and Pa Hill lava dome, which forms the NW tip of the island. Acid hot springs, steaming ground, and fumaroles are located primarily between the central cone and East Dome. The central cone and east dome are both older than the roughly 42,000 before present (BP) Rotoehu Tephra, and Pa Hill dome is overlain by the 9000 years BP Rotoma Ash but may be considerably older. It was included in the Catalog of Active Volcanoes of the World (Nairn and Cole, 1975) based on its thermal activity.

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

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.



Synonyms
Motuhora Island | Whale Island


Domes
Feature Name Feature Type Elevation Latitude Longitude
Central Dome Dome 354 m 37° 51' 30" S 176° 58' 30" E
East Dome Dome 37° 51' 30" S 176° 59' 0" E
Pa Hill
    West Dome
Dome 37° 51' 0" S 176° 58' 0" E


Thermal
Feature Name Feature Type Elevation Latitude Longitude
Sulphur Valley Thermal
Moutohora (Whale) Island is the elongated island 11 km offshore from the city of Whakatane at the mouth of the Whakatane River in the center of this Landsat image. The 354-m-high central dome complex on the 15 x 5 km wide island is flanked by two lava domes, Pa Hill Dome (also known as West Dome) at the NW tip of the island and East Dome at the opposite end. Eruptive activity ceased during the Pleistocene, but thermal activity continues. Rurima Rocks and Moutoko Island lie WNW, and the large bay at the lower right is Ohiwa Harbour.

NASA Landsat image, 2000 (courtesy of Hawaii Synergy Project, Univ. of Hawaii Institute of Geophysics & Planetology).

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.

Burt R M, Cole J W, Vroon P Z, 1996. Volcanic geology and geochemistry of Motuhora (Whale Island), Bay of Plenty, New Zealand. New Zeal J Geol Geophys, 39: 565-580.

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

Nairn I A, Cole J W, 1975. New Zealand. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 22: 1-156.

Volcano Types

Complex
Lava dome(s)

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Affiliated Databases

Large Eruptions of Moutohora Island 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.