Fonualei

Photo of this volcano
Google Earth icon
  Google Earth Placemark
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 18.02°S
  • 174.325°W

  • 180 m
    590 ft

  • 243100
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

3 October-9 October 2001

The Laboratoire de Géophysique reported that explosive volcanic activity may have occurred at Fonualei volcano during late September. On 27, 28, and 30 September numerous short T waves were received by the French Polynesian Seismic Network. The preliminary location of the seismicity was determined to be near the Tonga archipelago at 18.18°S (well constrained) and 174°W (not as well constrained). The hydro-acoustic activity was interpreted to be volcanic and explosive and could not be related to seismic activity at the Tonga Trench. According to the Laboratoire de Géophysique, the hydro-acoustic source could be near Fonualei volcano.

Source: Laboratoire de Géophysique

Index of Weekly Reports


2001: October

Weekly Reports


3 October-9 October 2001

The Laboratoire de Géophysique reported that explosive volcanic activity may have occurred at Fonualei volcano during late September. On 27, 28, and 30 September numerous short T waves were received by the French Polynesian Seismic Network. The preliminary location of the seismicity was determined to be near the Tonga archipelago at 18.18°S (well constrained) and 174°W (not as well constrained). The hydro-acoustic activity was interpreted to be volcanic and explosive and could not be related to seismic activity at the Tonga Trench. According to the Laboratoire de Géophysique, the hydro-acoustic source could be near Fonualei volcano.

Source: Laboratoire de Géophysique


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.

02/1974 (CSLP 25-74) Reported emission of steam, foam, and rocks

07/1979 (SEAN 04:07) Steam emissions observed

12/1979 (SEAN 04:12) Fumarolic activity noted during July

11/2001 (BGVN 26:11) Typical steam emissions observed in August 2000


Contents of Monthly Reports

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

All times are local (= UTC + 13 hours)

02/1974 (CSLP 25-74) Reported emission of steam, foam, and rocks

Card 1802 (21 February 1974) Reported emission of steam, foam, and rocks

Captain J. Jenkins of the S.S. Union South Pacific reported by radio to Nuku`Alofa, Tonga, the following observation: "Fonualei Island, Tonga, position 18°01' S, 174°19' W (18.02°S, 174.32°W) was emitting small quantities of steam, foam, and rocks all around the crater at 1900 GMT, 15 February 1974."

Tom Simkin indicates that this activity could be a normal geothermal process, but the fact that rocks were being thrown out suggests that the activity is probably significant.

Information Contacts: J. Jenkins, S.S. Union South Pacific, Union Steamship Co. of New Zealand; T. Simkin, Smithsonian Institution.

07/1979 (SEAN 04:07) Steam emissions observed

Geologists aboard the RV Bulikula inspected the volcanoes along the Tonga Arc between 3 and 21 July. . . . Fonualei . . . was emitting steam when viewed . . . in mid-July.

Information Contact: R. Richmond, Mineral Resources Dept., Fiji.

12/1979 (SEAN 04:12) Fumarolic activity noted during July

Most of the reported eruption sites were investigated during the 11-18 July cruise of the Fijian research vessel RV Bulikula.... Large fluctuations in the intensity of fumarolic activity were observed at both Fonualei and Tofua.

Information Contacts: D. Woodhall and R. Richmond, Mineral Resources Dept., Fiji; D. Tuni, Ministry of Natural Resources, Solomon Islands.

11/2001 (BGVN 26:11) Typical steam emissions observed in August 2000

In February 1974 a ship's captain reported that Fonualei was "emitting small quantities of steam, foam, and rocks all around the crater" (CSLP Card 1802). Large fluctuations in fumarolic activity were observed by geologists in July 1979 (SEAN 04:12).

On 19 August 2000, Jeff and Raine Williams, aboard the S/Y Gryphon, passed Fonualei enroute from Tonga to Wallis Island. They noted that the lower part of the island was covered with lush tropical vegetation, but the upper parts were scarred brown and gray, and steam was venting from the top of the island. Along the coast were rugged volcanic cliffs and black sand beaches.

[Sections about seismicity and pumice rafts have been moved. Later investigations showed that they probably originated from an unnamed submarine volcano in the Tonga Islands.]

Information Contact: Jeff and Raine Williams, P.O. Box 729, Funkstown, MD 21734, USA (Email: j40@attglobal.net, URL: http://pws.prserv.net/j40/).

The small, less than 2-km-wide island of Fonualei contains a fumarolically active crater, which is breached to the SW with a fresh lava flow extending to the sea and forming a rugged shoreline. Steep, inward-facing scarps mark the rim of a partially exposed caldera which contains a pyroclastic cone that is breached to the east and forms the 180-m-high summit of the island. Blocky lava flows from this cone fill much of the northern caldera moat and reach the sea through notches in the northern and eastern caldera rims. In contrast to the andesitic and basaltic rocks of other islands of the Tonga arc, Fonualei lavas are of dominantly dacitic composition. Eruptions have been recorded since 1791, with the largest taking place in June 1846, when explosive eruptions produced large pumice rafts, and ashfall damaged crops on the island of Vavua (56 km away) and fell on vessels up to 950 km distant. In 1939 explosive and effusive activity occurred from summit and flank vents, and water spouts were reported 1.6 km SE of the island.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
[ 1974 Feb 16 ] [ Unknown ] Uncertain 1  
1957 Jun Unknown Confirmed   Historical Observations
1951 Aug 21 Unknown Confirmed 2 Historical Observations North-central part of the island
1939 Jun Unknown Confirmed 2 Historical Observations Summit, west and SE sides
1906 Mar Unknown Confirmed   Historical Observations
1846 Jun 11 (?) 1846 Oct 10 (in or after) Confirmed 4 Historical Observations
1791 Unknown Confirmed 2 Historical Observations
[ 1780 (in or before) ] [ Unknown ] Uncertain    

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
Fanua Lai | Amargura | Gardners Island
Seen from the NE, Fonualei volcano has an upturned saucer profile. The small, less than 2-km-wide island of Fonualei contains a fumarolically active crater, which is breached to the SW with a fresh lava flow extending to the sea and forming a rugged shoreline. Blocky lava flows from a central pyroclastic cone have reached the sea through notches in the rim of a small caldera. Eruptions at Fonualei have been recorded since 1791, with the two largest taking place in October 1846 and July 1847.

Photo by Paul Taylor (published in Taylor and Ewart, 1997).

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.

Brodie J W, 1970. Notes on the volcanic activity at Fonualei Tonga. New Zeal J Geol Geophys, 13: 30-38.

Bryan W B, Stice G D, Ewart A, 1972. Geology, petrology, and geochemistry of the volcanic islands of Tonga. J Geophys Res, 77: 1566-1585.

Ewart A, Bryan W B, Gill J B, 1973. Mineralogy and geochemistry of the younger volcanic islands of Tonga, southwest Pacific. J Petr, 14: 429-465.

Richard J J, 1962. Kermadec, Tonga and Samoa. Catalog of Active Volcanoes of the World and Solfatara Fields, Rome: IAVCEI, 13: 1-38.

Spennemann D H R, 2003. The June 1846 eruption of Fonualei volcano, Tonga, an historical analysis. Charles Sturt Univ, The Johnstone Centre Rpt, 196: 1-30.

Taylor P W, Ewart A, 1997. The Tofua Volcanic Arc, Tonga, SW Pacific: a review of historic volcanic activity. Aust Volc Invest Occ Rpt, 97/01: 1-58.

Volcano Types

Stratovolcano
Caldera
Pyroclastic cone

Tectonic Setting

Subduction zone
Oceanic crust (< 15 km)

Rock Types

Major
Dacite
Andesite / Basaltic Andesite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
71
71
91
17,857

Affiliated Databases

Large Eruptions of Fonualei 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.