SUBMARINE VOLCANIC ACTIVITY IN THESOUTH WEST PACIFIC:

BEING IN THE RIGHT PLACE AT THE RIGHT TIME

Paul Taylor, Murray Ford, Brad ScottTaaniela Kula and Rennie Vaiomounga

Pacific Community, Auckland University, GNS NZ,Lands Survey and Natural Resources Tonga

What the presentation will cover

Outline of volcanism in the SW Pacific

Examples of typical submarine activity

The Tofua Volcanic Arc (TVA) submarine activity

2017 Submarine Vol III activity

Previous activity

Characteristics of the area

1991-92 Metis Shoal activity

Previous activity

Details of regional phenomena – no activity reported

Aerial photos of activity occurring June 1991

Implications and way ahead

The South West Pacific

Pacific Ocean

Lau

Basin

South Fiji

Basin

North Fiji

Basin

Woodlark

Basin

FIJI

SAMOA

TONGA

SOLOMON

ISLANDS

VANUATU

Submarine Volcanism in the Pacific

Kavachi, Solomon Islands

2000

Metis Shoal, Tonga, 1995

Character of the Tofua Volcanic Arc (TVA), Tonga

Lau Basin

• Typical oceanic island arc

system.

• Comprised of both

subaerial and submarine

centres.

• Subaerial centres include:

Late, Fonualei, Tofua.

• Predominantly submarine

centres.

• Frequent periods of

activity occur.

• Ephemeral islands often

formed during activity

that only weeks or

months.

Submarine Volcano III

Known Eruptive History

• 1911: Submarine activity.

• 1923: Submarine activity;

eruption column observed

• 1970: Submarine activity;

discoloured water

observed

• 1998-9 Submarine activity; shoal

formed, pumice produced

• 2007: Submarine activity;

discoloured water, strong

sulphur odour in area.

Any other eruptive

activity???

Photos: Hutchins 1999

Submarine Eruption27 January 2017

Sentinel 2A - ESA

Landsat 8 – USGS/NASA

• Activity may have started on or after 23 Jan

• Activity continued for unknown period

• Entirely submarine eruption

• Plume produced that moved the west then

north

• Island was not formed

• Sight was visited but not subaerial features

were observed

Submarine Volcano III – Subsurface Detail

Arculus, 2004

Metis Shoal – Submarine Volcano

Known Activity• 1781: Island observed

• 1851: Submarine activity

• 1852: Submarine activity

• 1858: Explosive activity, island observed

• 1878: Explosive activity, island observed

• 1886: Explosive activity, island observed

• 1894: Explosive activity, island present

• 1967/8: Explosive activity, island formed

• 1979: Explosive activity, island formed, pumice

rafts produced

• 1995: Explosive/effusive activity, island formed

Possible Volcanic Phenomena in the Tonga Fiji Region 1990 - 1992

1990 Oct-Nov Air Pacific pilots reported floating pumice SW of Fiji; these reports could not be confirmed by a further investigation. Pumice was reported on Koro Island; these reports could not be confirmed by a further investigation.

1992 Jan Two narrow, elongate pumice rafts were reported in the Kadavu Passage, 30 km SE of Suva; further rafts were also reported at other localities in the Kadavu Passage and to the NW of Viti Levu.Pumice reported floating in the Suva Passage and along the high-tide line along the Suva Peninsula; pumice was gravel-sized, up to 4 cms across; the pumice was weathered and many fragments included living barnacles; the age of the barnacles was estimated to be between 15-25 weeks; the pumice was estimated to have moved at 12 km/day.

The Possible Culprit – Metis ShoalSubmarine Activity

1991 June 24Submarine activity; observations of aerial photographs taken on this date indicate that a submarine eruption was in progress, the resultant submarine plume moved to the N and then to the NE before dispersing; pumice rafts are apparent on the aerial photographs moving out from the site of eruption in a W-NW direction, no reports of subaerial activity are known.

Implications

Unobserved submarine activity creates a significant hazard to regional maritime transport.

Implications (continued)

Kick ‘em Jenny volcano

GRENADA

CARRIACOU

Island Queen

Providence Mark

Ronde

Caille

12o00’N

12o30’N

kms

0 10 20

61o30’W

Mystery of the “Island Queen”

Duquesne Bay

During the night of 5 August 1944, thewooden schooner “Island Queen”, with over60 people on board, went missing betweenGrenada and St Vincent.

“My last recollection of seeing the Island Queen waswhen we were close to Duquesne Bay. The “IslandQueen” could be seen with its light on a mast very faraway and appeared to be on the horizon……..I repeatthat was the last place I recall having seen the “IslandQueen”.

The “Island Queen” was 4-8 nautical milesnorth of the “Providence Mark” when it waslast seen. The “Island Queen” was never seenagain, and nothing at all was ever recovered.

Kick ‘em Jenny submarine volcano lies 5-6

nautical miles north of Duquesne Bay.

Did the “Island Queen” sink over Kick‘em Jenny volcano during a

period of unknown activity?

Another Example

The Tragedy of the Kaiyo-maru No.5 - 1952

Eruption of Myojin-Sho,

23 September 1952

• 17 Sept 1952 - activity first

observed,

• 18-24 Sept - frequent explosions,

island formed and destroyed by

explosions,

• late-morning 24 Sept - temporary

lull in activity,

• late-morning 24 Sept - Kaiyo-

maru No.5 arrives to observe

activity, sails over inactive vent • 12:20 24 Sept - strong explosive eruption

totally destroys Kaiyo-maru, killing all on

board, no wreckage found.

A Way Ahead

2015Thank You

• There is a need for the development of a process to monitor

volcanic arcs that exhibit predominantly submarine activity

• Conduct of comprehensive risk assessments of know

submarine volcanic centres in such environments

• Due to the remoteness of many centres this may be difficult.

What techniques can be used?

• Period tasking of locally available aircraft to monitor;

• Periodic but regular tasking of satellite systems