He said it was the biggest quake anywhere in the world since one near the coast of Peru in 2001. The 8.4-magnitude temblor on June 23, 2001 killed 74 people, the U.S. Geological Survey said.
Sinadinovski said large earthquakes were common in the Macquarie Rise region, occurring every one or two years, but Friday's was the strongest quake there since 1924.
Macquarie Island is the exposed crest of the undersea Macquarie Ridge, at the meeting of two tectonic plates, and is the only place on earth where rocks from the earth's mantle _ which normally is six kilometers (four miles) below the ocean floor _ are exposed above sea level, according to the Australian Antarctic Division's Web site.
An earthquake with a preliminary magnitude of 8.1, the year's strongest, shook the ocean floor today about 1,000 miles southwest of New Zealand, with the potential to release tsunamis that were unlikely to reach Pacific coastlines.
TO - TSUNAMI WARNING SYSTEM PARTICIPANTS IN
FROM - WEST COAST AND ALASKA TSUNAMI WARNING CENTER/NOAA/NWS
SUBJECT - TSUNAMI INFORMATION BULLETIN
BULLETIN NUMBER 1
ISSUED 12/23/2004 AT 1520 UTC
...THIS TSUNAMI INFORMATION BULLETIN IS FOR ALASKA - BRITISH
COLUMBIA - WASHINGTON - OREGON AND CALIFORNIA ONLY...
NO - REPEAT NO - WATCH OR WARNING IS IN EFFECT.
PRELIMINARY MAGNITUDE - 7.9
LOCATION - 50.1S 161.1E - NORTH OF MACQUARIE ISLAND
TIME - 0559 AST 12/23/2004
0659 PST 12/23/2004
1459 UTC 12/23/2004
BASED ON LOCATION AND MAGNITUDE THE EARTHQUAKE WAS NOT
SUFFICIENT TO GENERATE A TSUNAMI DAMAGING TO CALIFORNIA -
OREGON - WASHINGTON - BRITISH COLUMBIA OR ALASKA. SOME AREAS MAY
EXPERIENCE SMALL SEA LEVEL CHANGES. IN AREAS OF INTENSE
SHAKING LOCALLY GENERATED TSUNAMIS CAN BE TRIGGERED BY SLUMPING.
THE PACIFIC TSUNAMI WARNING CENTER WILL ISSUE TSUNAMI BULLETINS
FOR HAWAII AND OTHER AREAS OF THE PACIFIC.
THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT BY THE
WEST COAST AND ALASKA TSUNAMI WARNING CENTER UNLESS CONDITIONS
WARRANT. REFER TO THE INTERNET SITE WCATWC.ARH.NOAA.GOV...
FOR MORE INFORMATION.
THIS MESSAGE IS FOR INFORMATION ONLY. THERE IS NO TSUNAMI WARNING
OR WATCH IN EFFECT.
AN EARTHQUAKE HAS OCCURRED WITH THESE PRELIMINARY PARAMETERS
ORIGIN TIME - 1459Z 23 DEC 2004
COORDINATES - 50.1 SOUTH 161.1 EAST
LOCATION - NORTH OF MACQUARIE ISLAND
MAGNITUDE - 7.9
THIS EARTHQUAKE IS LOCATED OUTSIDE THE PACIFIC. NO TSUNAMI THREAT
EXISTS TO COASTLINES IN THE PACIFIC.
HOWEVER - THIS EARTHQUAKE HAS THE POTENTIAL TO GENERATE A WIDELY
DESTRUCTIVE TSUNAMI IN THE SEA NEAR THE EARTHQUAKE. AUTHORITIES
IN THAT REGION SHOULD BE AWARE OF THIS POSSIBILITY.
THIS WILL BE THE ONLY BULLETIN ISSUED FOR THIS EVENT UNLESS
ADDITIONAL INFORMATION BECOMES AVAILABLE.
THE WEST COAST/ALASKA TSUNAMI WARNING CENTER WILL ISSUE BULLETINS
FOR ALASKA - BRITISH COLUMBIA - WASHINGTON - OREGON - CALIFORNIA.