News Home Video Gallery Newsletters Photo Gallery Cruising Int
Sail-World.com : The disappearing Sandy Island - Scientist may have the answer.
The disappearing Sandy Island - Scientist may have the answer.


'Sandy Island on an old chart'    .    Click Here to view large photo

Sandy Island location - but no more -  .. .  
Where did the Coral Sea's Sandy Island go? This was the question posed by us in an article last November (see Sail-World story) when some Australian scientists aboard the RV Southern Surveyor went to where Sandy Island was meant to be and found only 1400m of water. Now, the mystery of the disappearing island may be solved.

The island, in the meantime, is having an extended obituary: The island has been removed from the latest version of the GSHHS coastline database (version 2.2.2) and from the latest satellite?derived topography (Smith and Sandwell

It will be removed in the next GEBCO release, according to the GEBCO Web site. Google Earth™ has deleted the big black polygon over Sandy Island, as well as its name. Data from the recent cruise will be made available to the National Geophysical Data Center database so that further data sets can be updated.

While the island, which was noted by Captain Cook on the Endeavour and again by the ship Velocity in 1876 more than a hundred years later, is now generally accepted to be non-existent, the mystery remained as to how the error could have started and then persisted for so many years.

Part of the answer lies in technology and the way in which digital information is translated, but the other part of the answer is more fascinating as described by the latest research.

The question which the recent study by the American Geophysical Union has tried to answer is: What actually DID the captain and crew of the Velocity observe in 1876 at the location of Sandy Island? - and what had Captain Cook observed some 100 years before? Some have suggested through online discussions that the captain observed an island that has since been eroded to wave base.

However, this is unlikely as the measured depths over Sandy Island are greater than 1400 metres and satellite imagery does not indicate shallow water over the Sandy Island region. Although the answer to what was originally observed may lie in a simple navigational and/or transcription error, one intriguing possibility is that they spotted a pumice raft.

A recent study of the 2001–2002 eruption of a volcano along the Tofua Arc off Tonga found that sea-rafted pumice associated with this eruption traveled more than 3000 kilometers westward, reaching the eastern Australia shoreline within a year after eruption.

Many cruising sailors have come across such floating pumice islands, some even reporting that their vessels skin fittings became clogged with the pumice as they came across it at night. Ships have also reported such sightings.

Pumice Island as sighted by cruising sailors -  .. .  

Pumice Island with yacht’s wake -  .. .  

For the scientists, an analysis of the pumice trajectory revealed that rafts passed within 20 kilometers of Sandy Island, approximately 200 days after the initial eruption. A study of coral migration from Tonga to the Great Barrier Reef found pumice rafts to be the mode of transportation, with a predicted path consistent with the earlier study. It is believed that wind and ocean surface currents in the area combine to funnel pumice rafts through the area between Fiji and New Caledonia on their way to Australia.

The formation of this 'pumice raft superhighway,' which passes by the location of Sandy Island, lends weight to the idea that the Velocity - and the Endeavour - may have captured a moment when some sea-rafted pumice was traversing the area.

For the full study in EOS by the American Geophysical Union, click here.


by Nancy Knudsen

  

Click on the FB Like link to post this story to your FB wall

http://www.sail-world.com/index.cfm?nid=108617

3:38 AM Sat 20 Apr 2013GMT


Click here for printer friendly version
Click here to send us feedback or comments about this story.

Click for further information on
Environment and the ocean

Related News Stories:

19 Apr 2013  Planetsolar - crossing oceans again, for science, for education.
01 Apr 2013  Planning a sail to the Antarctic any time soon? - check this out!
30 Mar 2013  Solar sailer PlanetSolar heads to sea again.
15 Mar 2013  The question of Turtles
23 Feb 2013  At 86 knots, enter the Cigarette - the world's fastest electric boat
16 Feb 2013  Windfarms to populate UK's sailing seas - the debate rages
27 Jan 2013  Rockefeller Mermaid Mission: Rescuing our seas in 2013
26 Jan 2013  Tres Hombres: slow cargo but sustainable, an early success
07 Jan 2013  DVD offers tips on keeping our seas healthy
02 Jan 2013  Farley the fin whale is staying put
MORE STORIES ...






Cruising USA







Barnacle Busting by Neil and Ley Langford,


From Penguins to Polar Bears by Cherie Winner,




Polar research: Six priorities for Antarctic science by Mahlon C. Kennicutt II and colleagues,




NCI granted dedicated VHF Channel by National Coastwatch,


Positive news for cruising boats in Greece by The Cruising Association,




















Risks to penguin populations continues by British Antarctic Survey,




Follow these tips when anchoring by Alex and Daria Blackwell,


Galley Guys meet the Spice Lady by Greg Nicoll, Andy Adams and John Armstrong,




If all else fails read the instructions!! by Stuart Carruthers, RYA Cruising Manager,




Phuket Yacht Show: new kid on the block taking on PIMEX? *Feature by Guy Nowell, Sail-World Asia and Phuket Yacht Show,






Flags at Sea, an infographic by John Tissott by Anna Parker and the Sail-World Team,








Teen names latest RNLI Shannon class lifeboat in Poole + Video
Fascinating opportunity with OceansWatch
Fake GPS signals detected when cruising the high seas
Our new Cruising Editor editor remembers his first offshore adventure
Blue Planet Odyssey - Jimmy Cornell playing catch up on North West Pa
World ARC 2014 reaches Australia
Venezuelan Port Control lift recent port restrictions.
Seismic survey ship operating north of Aruba and Curacao
Predictwind helps you pick the best time to depart
Watch this whale lift a Kayak clear out of the water
World ARC reaches half-way point in Australia
Northern Scotland: Voyage to Orkney and Shetland Isles (Part 2) *Feature
Drowning or electric shock? What you need to know to help save a life
Costa Concordia - the $2.25 billion salvage operation ready to begin
Northern Scotland: Voyage to Orkney and Shetland Isles, more photos *Feature
Fort Lauderdale International Boat Show - New location and attractions
Long Island waters could become more taxing this summer
4.8 million Legos all at sea
Tranquil, colourful and funky, Genoa Bay is a must stop for West Coast *Feature
Scientist pioneered tracer to reveal hidden ocean flows
Sail-World 2.0 - the Beta version- Please take a look   
Dredging activity near corals can increase frequency of diseases   
World ARC heading out of the Pacific   
Understanding the Ocean's role in Greenland Glacier melt   
Desolation Sound added to Salish Sea Pilot free cruising guides   
Three Defensive Docking Strategies for Sailors   
Revealing report on Search for American yacht Nina released *Feature   
PredictWind's Weather Routing opens your navigation options - try it!   
Sail-World Cruising Founding Editor Nancy Knudsen says farewell   
Book review: Weather - you like it or not   
Vaavud launches generation 2 wind meter   
The drama begins - North West Passage sailors rescued from ice   
Entering an unfamiliar bay - decision time   
Baby Nemos finding their way home   
High Latitude Sailing - Book of the Week   
Will the Olympics make a difference to Rio pollution? *Feature   
Blue Planet Odyssey, around world rally, begins   
Africa Europe Cruising Challenge now open for entries   
The real ‘Supermoon’ story   
Warm and noisy welcome for Oceans of Hope in La Rochelle   


For this week's complete news stories select    Last 7 Days
   Search All News
For last month's complete news stories select    Last 30 Days
   Archive News







Sail-World.com  


















Switch Default Region to:

Social Media

Asia

Australia

Canada

Europe

New Zealand

United Kingdom


http://www.sail-world.com/event_images/image/Twitter_logo_small.png http://www.sail-world.com/event_images/image/FaceBook-icon.png  

United States

Cruising Northern

Cruising Southern

MarineBusiness World

PowerBoat World

FishingBoating World

 

Contact

Commercial

News

Search

Contact Us

Advertisers Information

Submit news/events

Search Stories/Text

Feedback

Advertisers Directory

Newsletter Archive

Photo Gallery

 

Banner Advertising Details

Newsletter Subscribe

Video Gallery

Policies

 

 

 

Privacy Policy

 

 


Cookie Policy

 

 



This site and its contents are © Copyright TetraMedia and/or the original author, photographer etc. All Rights Reserved.  Photographs are copyright by law.  If you wish to use or buy a photograph contact the photographer directly.
XLXL NEW Cru USA
LocalAds   DE  ES  FR  IT