Update: October 11, 2006

THE EARTH?

By Pam Eastlick for THE DEEP on line

Welcome to The Deep science and technology column where we cover topics from the deep sea to deep space and beyond. 

Whenever anyone gives me a blank stare when I tell them I live on Guam, I usually add “It’s a small island in the Pacific.”  Since virtually everyone knows where the Pacific Ocean is, people nod and smile, because they now know where I live.

Most of them are completely unaware that my explanation actually narrows my exact location down to about half the planet’s surface.  We are land creatures and the mind of most people absolutely refuses to wrap around the size of the Pacific Ocean.  We who live on Guam certainly have some idea of how big it is as we drone across endless miles of it on our way to anywhere else.

But in reality, there is NO Pacific Ocean and there is no Atlantic Ocean and there is no Caribbean or Mediterranean or Arctic or Indian Ocean or any South China Sea or Philippine Sea or any of the other literally hundreds of designations for the lapping salt water waves.  There is the Ocean.  Period.  One world Ocean that laps every single saltwater beach.  It covers ¾ of this planet and our world is misnamed.  Its name is not Earth; it is Ocean.

We are all connected by this heaving mass of liquid as the people who live on the east coast of Africa discovered in December of 2004 when their coastlines were inundated by a gigantic wave generated thousands of miles away.  That tsunami generated a tidal bore in the Thames River in England and indeed, in nearly every river on the planet.

The water carries everything that enters it to unknown destinations.  The most radioactive fish caught in the Ocean after the atomic bomb tests of the ‘50’s, was caught thousands of miles away, right here, off the coast of Guam.  Sneakers, oil, packing peanuts, fishing floats, messages in bottles: they go in and they end up somewhere else as they ride the currents of the global Ocean.  But the waves themselves do interesting and somehow frightening things as scientists recently discovered. 

It’s no secret that global warming is carving vast icebergs off the coast of Antarctica.  The Ross Ice Shelf is a huge mass of snow and ice that sits on the side of a mountain range in Antarctica.  Six years ago, an iceberg called B15 calved (broke off) from the Ross Ice Shelf to become the largest iceberg ever recorded.  In 2003, a large piece of B15 broke off and headed for open water.  It became the world’s largest free-floating object.  How big was it?  B15A, as it was designated, was 76 miles long and 17 miles wide, or about twice as big as Guam. In 2005, B15A, got stuck on a projecting ice tongue in the Antarctic coast and caused a mountain of problems for scientists since it prevented ocean currents and winds from assisting in the 2004–2005 summer break-up of the sea ice in McMurdo Sound, and was an obstacle to the annual resupply ships to three research stations.

Then, something really bizarre happened.  Daily satellite images show that on a clear, calm day, 27 October 2005, for no apparent reason, this gigantic mountain of snow and ice shattered into half a dozen pieces. Scientists were understandably puzzled and they’ve been trying to figure out what happened to B15A for the last year.  Seismometers had been planted on the iceberg and after a rather heroic plane trip; scientists retrieved them. The seismometer record showed movement in the iceberg started 12 hours before it broke up and continued for three days.

Although there were no surface waves, scientists detected the seismic traces of long rolling swells that moved the iceberg up and down and sideways.

Storms cause this kind of swell and scientists were able to use their data to estimate the distance to the storm.  They were astounded to find that the waves were generated at least 8,000 miles away.  They searched the weather records and discovered that the first big winter storm of the season had developed six days before the breakup of B15A . . . . in the Gulf of Alaska.

The waves were small when they hit the coast of Antarctica.  The scientists estimate that the iceberg moved up and down only an inch and four inches from side to side as the waves passed.  So . . . why did it break apart?

B15A had run aground near Cape Adare before the swell hit.  Scientists think that B15A was in just the right position for the waves to be fatal.  The iceberg shattered just a wine glass when a soprano hits high C. This set the scientific team to digging, and they discovered that distant storms in the tropics and both the Northern and Southern Hemispheres correlated with all 38 seismological events recorded on their seismometers from December 2004 to March 2005. Did Supertyphoon Pongsona generate waves that impacted Antarctica?  Absolutely!  Could the continued breakup of Artic and Antarctic ice affect us here?  Without question!  It is a World Ocean and we neglect that fact to our peril. Cruise on over to the Deep Website at www.thedeepradioshow.com to learn more about our planet Ocean and many other topics.  Enjoy!

Supertyphoon Ponsona over Guam.  December 2002