Global Volcanism Program

The Global Volcanism Program has no activity reports available for Fonuafo'ou.

The Global Volcanism Program has no Weekly Reports available for Fonuafo'ou.

The Global Volcanism Program has no Bulletin Reports available for Fonuafo'ou.

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude

243050

1936 CE

-17 m / -56 ft

20.32°S
175.42°W

Morphology

Volcano Landform
Composite

Volcano Types
Stratovolcano
Submarine

Rock Types

Major
Andesite / Basaltic Andesite
Dacite

Tectonic Setting

Subduction zone
Oceanic crust (< 15 km)

Population

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

302
302
532
69,016

Geological Summary

The ephemeral Fonuafo'ou island in the central part of the Tonga Islands is also known as Falcon Island, named after the British vessel H.M.S. Falcon, which reported a shoal in 1865. Islands up to 6 km long were formed in 1885 and 1927 eruptions; in 1933 the island had a height of more than 145 m. Passing ships often reported "smoke" issuing from the site. The latest explosive activity was reported in 1936. By 1949 the island had eroded beneath sea level, but the summit remains at shallow depths.

References

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

Baker S W, 1885. A description of the new volcano in the Friendly Islands, near Tongatabu. Trans New Zeal Inst, 18: 41-46.

Hoffmeister J E, Ladd H S, Alling H L, 1929. Falcon Island. Amer J Sci, 18: 461-471.

Lister J J, 1890. A Visit to the Newly Emerged Falcon Island, Tonga Group, South Pacific. Proceedings of the Royal Geographical Society and Monthly Record of Geography, Vol. 12, No. 3 (Mar., 1890), pp. 157-160. https://doi.org/10.2307/1801346

Melson W G, Jarosewich E, Lundquist C A, 1970. Volcanic eruption at Metis Shoal, Tonga, 1967-1968: description and petrology. Smithsonian Contr Earth Sci, 4: 1-18.

Phillips C, 1898. The volcanoes of the Pacific. Transactions and Proceedings of the Royal Society of New Zealand, 31: 510-551.

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

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.

Thomson J A, 1926. Volcanoes of the New Zealand-Tonga volcanic zone--a record of eruptions. New Zeal J Sci Tech, B8: 354-371.

Eruptive History

There is data available for 5 confirmed Holocene eruptive periods.

1936 Jun Confirmed Eruption (Explosive / Effusive) VEI: 2

Episode 1 | Eruption (Explosive / Effusive)

1936 Jun - Unknown

Evidence from Observations: Reported

List of 2 Events for Episode 1

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Explosion
	1936 Jun	- - - -	VEI (Explosivity Index)

1933 Apr Confirmed Eruption (Explosive / Effusive) VEI: 2

Episode 1 | Eruption (Explosive / Effusive)

1933 Apr - Unknown

Evidence from Observations: Reported

List of 2 Events for Episode 1

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Explosion
	1933 Apr	- - - -	VEI (Explosivity Index)

1927 Oct 4 - 1928 Sep (on or after) Confirmed Eruption (Explosive / Effusive) VEI: 2

Episode 1 | Eruption (Explosive / Effusive)

1927 Oct 4 - 1928 Sep (on or after)

Evidence from Observations: Reported

List of 9 Events for Episode 1

Start Date	End Date	Event Type	Event Remarks
- - - -	- - - -	Explosion
- - - -	- - - -	Cinder Cone
- - - -	- - - -	Ash
- - - -	- - - -	Blocks
- - - -	- - - -	Scoria
- - - -	- - - -	Pumice
- - - -	- - - -	Earthquakes (undefined)	Before.
- - - -	- - - -	Island	ephemeral
1927 Oct 4	- - - -	VEI (Explosivity Index)

[ 1921 Nov ] Uncertain Eruption

Episode 1 | Eruption (Explosive / Effusive)

1921 Nov - Unknown

Evidence from Unknown

List of 3 Events for Episode 1

Start Date	End Date	Event Type	Event Remarks
- - - -	- - - -	Explosion	Uncertain
- - - -	- - - -	Island	Uncertain
1921 Nov	- - - -	VEI (Explosivity Index)

[ 1894 Dec ] Uncertain Eruption

Episode 1 | Eruption (Explosive / Effusive)

1894 Dec - Unknown

Evidence from Unknown

List of 3 Events for Episode 1

Start Date	End Date	Event Type	Event Remarks
- - - -	- - - -	Explosion	Uncertain
- - - -	- - - -	Island	Uncertain
1894 Dec	- - - -	VEI (Explosivity Index)

1885 Oct 12 (?) - 1886 Confirmed Eruption (Explosive / Effusive) VEI: 3

Episode 1 | Eruption (Explosive / Effusive)

1885 Oct 12 (?) - 1886

Evidence from Observations: Reported

On the night of 12 October 1885, following an earthquake the previous day, a flash of light and detonations were reported. Explosive eruptions were observed by the H.M.S. Sandfly the following day that ejected steam and black columns along a fissure reported to be 3 km long. An island reported to be 4-6 km long was seen on 14 October, and explosions produced columns to about 3 km height (Baker, 1885). The eruption continued into 1886. In October 1889 the island was a nearly symmetrical oval, with a conical hill (about 1/3 the estimated size of the island when the eruption ended) truncated by an eroding cliff on one side and volcanic bombs scattered over the slope, along with steaming and a sulfur odor; the other part of the island consisted of a flat area about 3-4 m above high tide level (Lister, 1890). Over the next six years (by 1896) Hoffmeister (1929) reported that the island had been reduced to about 800 m diameter, and three years after that (1898) there was just a shoal about 100 m in diameter.

List of 9 Events for Episode 1

Start Date	End Date	Event Type	Event Remarks
- - - -	- - - -	Explosion
- - - -	- - - -	Eruption cloud
- - - -	- - - -	Ash	violent, strong, or large
- - - -	- - - -	Blocks
- - - -	- - - -	Scoria
- - - -	- - - -	Earthquakes (undefined)	Before.
- - - -	- - - -	Earthquakes (undefined)
- - - -	- - - -	Island	ephemeral
1885 Oct 12 (?)	- - - -	VEI (Explosivity Index)	VEI 3

1877 Confirmed Eruption (Explosive / Effusive) VEI: 2

Episode 1 | Eruption (Explosive / Effusive)

1877 - Unknown

Evidence from Observations: Reported

"Smoke" was seen issuing from the sea in 1877 by the H.M.S. Sappho (Thomson, 1926).

List of 2 Events for Episode 1

	Start Date	End Date	Event Type	Event Remarks
	- - - -	- - - -	Explosion
	1877	- - - -	VEI (Explosivity Index)

[ 1865 ] Uncertain Eruption

Episode 1 | Uncertain

1865 - Unknown

Evidence from Unknown

A breaking reef was reported in 1865. No specific mention was made of an eruption. The CAVW treats the event as a submarine eruption, although other compilers do not.

List of 1 Events for Episode 1

	Start Date	End Date	Event Type	Event Remarks
	1865	- - - -	VEI (Explosivity Index)

[ 1781 ] Uncertain Eruption

Episode 1 | Uncertain

1781 - Unknown

Evidence from Unknown

"Culebras Bank" was first reported at this location in 1781 by the vessel Maurelle (CAVW). No specific mention was made of eruptive activity, although the CAVW (p. 14) treats the event as an island-forming eruption. Other compilers such as Thomson (1926) do not list an eruption in this year.

List of 1 Events for Episode 1

	Start Date	End Date	Event Type	Event Remarks
	1781	- - - -	VEI (Explosivity Index)

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

Fonua Fo'ou | Culebras Bank (?) | Kahe Kahe | Fefina | Falcon Island

Photo Gallery

The active crater of Fonuafo'ou (formerly known as Falcon Island) through the SE breach and a plume that is dispersed to the NW by dominant SE Trade Winds. The ephemeral island in the central part of the Tonga Islands had been named after the British vessel H.M.S. Falcon, which reported the shoal in 1865. This volcano has been the site of eruptions on at least two occasions since the 19th century. By 1949 the island had eroded beneath sea level, but the summit of the volcano remains at shallow depths.

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

Smithsonian Sample Collections Database

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

External Sites

Copernicus Browser

The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions.

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.

MODVOLC Thermal Alerts

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.

WOVOdat
   Single Volcano View
   Temporal Evolution of Unrest
   Side by Side Volcanoes

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.

GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments.

Volcanic Hazard Maps

The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter.

IRIS seismic stations/networks

Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Fonuafo'ou. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice.

UNAVCO GPS/GNSS stations

Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Fonuafo'ou. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player.

DECADE Data

The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO₂ to the atmosphere, but installing CO₂ monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere.

Large Eruptions of Fonuafo'ou

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).

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).