Sea level rises at Nuku'alofa as tsunami current passes [1]
Saturday, March 12, 2011 - 11:07. Updated on Monday, September 9, 2013 - 18:40.
STRONG currents and a swelling of the sea level was observed along the Nuku'alofa foreshore at 8:15 am this morning, over an hour after NOAA recorded a sea level rise of 0.37m or 1.2 feet at Nuku'alofa at 17:51GMT (6:51am local time).
Matangi Tonga editor, Pesi Fonua, who was swimming at 8:15 at the Yellow Pier on the Nuku'alofa foreshore, said that he noticed a rise in the level of the water on the seaward side of the reef.
"The current was flowing differently and you could feel it in the water. We noticed that the water along the reef was higher but the foreshore level by the Dateline Hotel was lower than usual.
"I thought the tsunami was finished because we knew it had passed Ha'apai earlier, but when I noticed the change in the current I swam back to the Yellow Pier," he said.
"We have to understand the tsunami it is different from a wave that you can see. It felt like a current flowing, which is different from a wave rolling. The current is powered. We were lucky that this was the tail end of it for Nuku'alofa."
He said another Friendly Islands Triathlon (FIT) athlete 'Alo Fe'iloakitau, who was on the Yellow Pier, also observed the tsunami effect, swelling the level of the water, and they cancelled Saturday morning's triathlon training.
South Pacific
Meanwhile, the latest Tsunami Bulletin Number 19, from the Pacific Tsunami Warning Centre, NOAA, following the earthquake in Japan reported measurements of tsunami wave activity for the Central and South Pacific Islands countries, with Nuku Hiva in the Marquesas experiencing a 1.48m (4.8ft) level. The measurements are as follows:
Issued at 2239Z 11 MAR 2011
GAUGE LOCATION LAT LON TIME AMPL PER
------------------- ----- ------ ----- --------------- -----
RIKITEA PF 23.1S 135.0W 2014Z 0.21M / 0.7FT 30MIN
RANGIROA PF 14.9S 147.7W 1822Z 0.29M / 0.9FT 08MIN
LOTTIN PT NZ 37.6S 178.2E 1839Z 0.23M / 0.7FT 20MIN
NORTH CAPE NZ 34.4S 173.0E 1846Z 0.23M / 0.8FT 32MIN
PAPEETE TAHITI 17.5S 149.6W 1822Z 0.39M / 1.3FT 26MIN
HONIARA SB 9.4S 160.0E 1436Z 0.26M / 0.8FT 50MIN
NUKU HIVA MARQUESAS 8.9S 140.1W 1824Z 1.48M / 4.8FT 14MIN
NUKUALOFA TO 21.1S 175.2W 1751Z 0.37M / 1.2FT 30MIN
RAROTONGA CK 21.2S 159.8W 1813Z 0.29M / 1.0FT 08MIN
FISHING ROCK RAOUL 29.3S 177.9W 1733Z 0.09M / 0.3FT 20MIN
VANUATU 17.8S 168.3E 1542Z 0.69M / 2.3FT 22MIN
LUGANVILLE VU 15.5S 167.2E 1537Z 0.54M / 1.8FT 54MIN
LAUTOKA FJ 17.6S 177.4E 1545Z 0.33M / 1.1FT 76MIN
LOMBRUM MANUS IS PG 2.0S 147.4E 1529Z 1.04M / 3.4FT 62MIN
PAGO PAGO AS 14.3S 170.7W 1556Z 0.34M / 1.1FT 16MIN
MANUS PG 2.0S 147.4E 1425Z 0.93M / 3.1FT 34MIN
KANTON KI 2.8S 171.7W 1425Z 0.05M / 0.2FT 10MIN
CHRISTMAS KI 2.0N 157.5W 1447Z 0.56M / 1.9FT 52MIN
BETIO TARAWA KI 1.4N 172.9E 1225Z 0.21M / 0.7FT 24MIN
NAURU 0.5S 166.9E 1156Z 0.20M / 0.7FT 24MIN
LAT - LATITUDE (N-NORTH, S-SOUTH)
LON - LONGITUDE (E-EAST, W-WEST)
TIME - TIME OF THE MEASUREMENT (Z IS UTC IS GREENWICH TIME)
AMPL - TSUNAMI AMPLITUDE MEASURED RELATIVE TO NORMAL SEA LEVEL.
IT IS ...NOT... CREST-TO-TROUGH WAVE HEIGHT. VALUES ARE GIVEN IN BOTH METERS(M) AND FEET(FT). PER - PERIOD OF TIME IN MINUTES(MIN) FROM ONE WAVE TO THE NEXT.
EVALUATION
SEA LEVEL READINGS CONFIRM THAT A TSUNAMI HAS BEEN GENERATED WHICH COULD CAUSE WIDESPREAD DAMAGE. AUTHORITIES SHOULD TAKE APPROPRIATE ACTION IN RESPONSE TO THIS THREAT. THIS CENTER WILL CONTINUE TO MONITOR SEA LEVEL DATA TO DETERMINE THE EXTENT AND SEVERITY OF THE THREAT.
A TSUNAMI IS A SERIES OF WAVES AND THE FIRST WAVE MAY NOT BE THE LARGEST. TSUNAMI WAVE HEIGHTS CANNOT BE PREDICTED AND CAN VARY SIGNIFICANTLY ALONG A COAST DUE TO LOCAL EFFECTS. THE TIME FROM ONE TSUNAMI WAVE TO THE NEXT CAN BE FIVE MINUTES TO AN HOUR, AND THE THREAT CAN CONTINUE FOR MANY HOURS AS MULTIPLE WAVES ARRIVE.
FOR ALL AREAS - WHEN NO MAJOR WAVES ARE OBSERVED FOR TWO HOURS AFTER THE ESTIMATED TIME OF ARRIVAL OR DAMAGING WAVES HAVE NOT OCCURRED FOR AT LEAST TWO HOURS THEN LOCAL AUTHORITIES CAN ASSUME THE THREAT IS PASSED. DANGER TO BOATS AND COASTAL STRUCTURES CAN CONTINUE FOR SEVERAL HOURS DUE TO RAPID CURRENTS. AS LOCAL CONDITIONS CAN CAUSE A WIDE VARIATION IN TSUNAMI WAVE ACTION THE ALL CLEAR DETERMINATION MUST BE MADE BY LOCAL AUTHORITIES.
BULLETINS WILL BE ISSUED HOURLY OR SOONER IF CONDITIONS WARRANT.
THE TSUNAMI WARNING WILL REMAIN IN EFFECT UNTIL FURTHER NOTICE.