Small tsunami exposes glitches
A quake in Tonga tests the Oahu-based warning network
Yesterday's earthquake and tsunami near Tonga exposed flaws in the tsunami warning system for the Pacific and Hawaii but did not result in any injuries or major property damage.
A magnitude-7.9 earthquake centered 34 miles below sea level about 95 miles south of the island of Neiafu, Tonga, occurred at 5:26 a.m. Hawaii time.
About 16 minutes later, the Pacific Tsunami Warning Center in Ewa Beach issued a warning for Fiji and New Zealand.
But the initial warning was not issued for Tonga, Samoa and the small island nation of Wallis-Futuna because of a computer software mistake, said Gerard Fryer, acting director for the tsunami center. A power failure in Tonga's emergency operating center and meteorological offices also kept them from getting any information from the center.
A watch was issued for Hawaii and other areas of the Pacific, except for Alaska, the U.S. West Coast and British Columbia.
Hawaii's Department of Education closed 14 schools in inundation zones on the advice of state Civil Defense, although the threat ended before school started. About 8,000 students were affected.
Tsunami experts locally said the tsunami also shows the need to redraw inundation zone maps for the south shores of all Hawaiian islands.
Current maps are based on tsunamis coming from the north and east of Hawaii, not from the west or the south, which is where yesterday's earthquake occurred.
Daniel Walker, a tsunami adviser for the Oahu Civil Defense Agency, said there are no computer models for an earthquake from Tonga, which could have been used by Civil Defense officials to determine if schools on Oahu's North Shore needed to be closed.
The tsunami generated by the earthquake was only about a foot tall in Pago Pago, Samoa, and the warning was downgraded to a watch and an advisory for Hawaii, Fryer said.
An 8-inch wave measured from trough to crest but with a height of about 4 inches above sea level was recorded in Hilo at about 11:30 a.m., Fryer said.
The tsunami occurred just a week after the tsunami warning center began 24-hour operations and two weeks before an international tsunami drill.
Fryer described the earthquake as "the perfect event" because no lives were lost and it exposed flaws in the warning system that can now be corrected.
"We learned a tremendous amount," he said.
Scientists at the tsunami warning center were "too eager" to get information out and issued the warning before the computer system that sends warnings out had finished calculating arrival times for the tsunami, he said.
So Tonga, Samoa and Wallis-Futuna did not receive the initial warning, although enough information was sent by the center to figure out that a tsunami could arrive, Fryer said.
Tonga's problem was magnified because of a two-hour power failure, so officials only got an alert that the warning was canceled.
"We fouled up in a couple of ways, which is not going to happen again," Fryer said.
Alerts are sent out by e-mail, fax, a meteorological information system and by phone. But Fryer said the center does not have enough staff to call all of the nations in the Pacific.
Staff also was tied up answering more than 100 calls from the news media, he said.
Fryer said one of the things they learned was that the center needs dedicated phone lines to communicate with the Alaska warning center and with the National Oceanic and Atmospheric Administration headquarters on the mainland.
He said the center might also look into whether to include the media in their warning lists and if the language of the warnings should be changed to make them more understandable.
Ray Lovell, a spokesman for the state Civil Defense, said the agency would likely review their tsunami response but that they were satisfied with how things turned out.
Greg Knudsen, a spokesman for the Department of Education, said by the time the tsunami watch had been downgraded to an advisory at 6:34 a.m., it was too late to reverse course and not close the schools.
"We had to make the decision quickly," Knudsen said.
"Once the word had gone out, once the buses were told not to head out and pick up kids, then it was awfully difficult to reinstate," he said.
"Given the Southeast Asian tsunami experience and the timing, the decision was made on the side of caution on behalf of the safety of the students," Knudsen said. "We're very fortunate that the conditions changed so that there was no threat to Hawaii."
The Associated Press and Star-Bulletin reporter Susan Essoyan contributed to this report.