SUBMARINE VOLCANIC ACTIVITY IN THE SOUTH WEST PACIFIC...
Transcript of SUBMARINE VOLCANIC ACTIVITY IN THE SOUTH WEST PACIFIC...
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