'EWA BEACH — Had the tsunami drill conducted yesterday by the Pacific Tsunami Warning Center been real, Hilo Bay would have been under the threat of a wave more than 20 feet high.

While the Pacific-wide exercise was only a simulation, it allowed Hawai'i, along with more than 30 countries, to test communication and emergency response capabilities. This was the first time a Pacific-wide test has been conducted even though the warning system has been in place since the mid-1960s, officials said.

Two mock tsunami warnings were issued yesterday, the first at 9:04 a.m., after a hypothetical earthquake of 9.2 magnitude off the coast of Chile.

In the minutes after the initial "detection" of the quake, mock warning bulletins were sent to countries all over the Pacific Basin, allowing each individual state to test its ability to receive and respond to an actual warning. Another was issued at 4 p.m.

"In the past, 30 countries have conducted tsunami exercises individually in their own countries at certain times. But this is the first time we are getting over 30 countries involved simultaneously," said Brian Yanagi, deputy director of the International Tsunami Information Center.

The center, a U.N. organization, has an office here and often works in conjunction with the tsunami warning center.

Each participating country is expected to evaluate its performance during the drill, and a report on the exercise will be made to the U.N.'s Intergovernmental Oceanographic Commission in Paris in June.

Planning for the drill began after the 2004 Indian Ocean tsunami, which killed at least 216,000 people.

The Indian Ocean disaster raised concerns about preparedness and response, said Charles McCreery, director of the Pacific Tsunami Warning Center.

Yesterday's drill also followed reports that several South Pacific island nations were not alerted to possible generation of a tsunami by an earthquake near Tonga earlier this month. Tonga was one of the countries that missed out on a tsunami warning or tsunami watch because of a technical glitch.

However, Tonga did receive warning messages yesterday during the drill, said McCreery.

"When the Tonga earthquake occurred on May 3, there were some software problems and those problems have been corrected," Yanagi said.

Yesterday's drill went smoothly, with no major problems reported by late afternoon.

While most countries used the drill to test their communication abilities, it was also an opportunity for some to educate their citizens about tsunami warning signs.

At least four participating locales — Malaysia, the Philippines, Thailand and American Samoa — planned to use the drill as an opportunity to conduct test evacuations near coastal areas, Yanagi said.

McCreery said people living near the coast need to learn to immediately evacuate "when they feel a strong quake."

"This was a golden opportunity to try to bring that level of preparedness back up," McCreery said.

"We were really considering this to be the first of continuing series of tsunami exercises for the Pacific."

Before yesterday's drill, state Civil Defense officials said there would be minimal participation here in Hawai'i, consisting mostly of monitoring whether warning messages are received.

The first phase of the drill lasted nearly six hours. During that time, nine separate bulletins were sent out to participating countries and the tsunami center monitored whether the messages were received. Follow-up phone calls were made with most countries to confirm receipt of the mock warnings.

A second phase of the drill was conducted at 4 p.m. Hawai'i time and alerted countries of a possible tsunami affecting the Western Pacific and South China Sea as a result of a mock earthquake of 8.8 magnitude off the Philippines. That exercise was expected to last about two hours.

Tsunami centers in Alaska and Japan also participated in the drills yesterday.

The tsunami center in Alaska typically handles monitoring and warnings for the U.S. West Coast and parts of Central and South America, said McCreery.

Japan recently opened its Northwest Pacific Tsunami Advisory Center, which issues warnings for Asia and the Pacific, he said.

Reach Loren Moreno at lmoreno@honoluluadvertiser.com.