Scientists tested the Pacific Ocean's tsunami-warning system Tuesday, sending alarms about imaginary earthquakes to more than 30 countries at risk for another disaster like the one that swept the Indian Ocean in 2004.

The warning system has been in place since 1965, but Tuesday's exercise was its first extensive test since the Asian tsunami that left at least 216,000 people dead or missing, sparking international calls for improvement.

At the start of the test, a beeping sound filled the Pacific Tsunami Warning Center in Ewa Beach, signaling a mock magnitude 9.2 earthquake off the coast of Chile. Within 10 minutes, warnings clearly labeled as part of the exercise went out from the Hawaii facility, as well as the Alaska Tsunami Warning Center near Anchorage.

It was the first of nine bulletins issued throughout the day, warning of a fictitious wave that grew to as big as 30 feet. Tsunamis generally travel at the speed of a commercial jet, but the center increased the speed four times, for the drill to finish in six hours.

The noticeable difference between the exercise and a real event was that the phones were silent. Normally, as soon as warnings are issued, the center is flooded with calls from governments and media, while scientists try to answer questions and monitor seismic activity.

Governments were to report back on how efficiently they received the warnings, which are relayed through nearly a dozen circuits, including weather services, e-mails and faxes.

The Hawaii center called some of the nations individually to verify they received the alerts. The bulletins were also sent to many other countries that were not participating.

Some evacuations were planned during the drill in American Samoa, Thailand, Malaysia and the Philippines. But most participating countries were expected to conduct only mock responses.

Charles McCreery, director of the Hawaii-based center, said the exercise was a success even before it started because it attracted interest from so many nations. "That's something we have never seen before," McCreery said.

Prior to the Asian disaster, worldwide interest in tsunami warnings had waned in the four decades since the last major catastrophe.

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

The Indian Ocean tsunami in December 2004 prompted improvements in the Pacific warning system. Other countries, including Indonesia and nations in the Caribbean, are now spending millions of dollars to establish their own warning centers modeled after the Hawaii facility.

Several hours before the start of the drill, a real 7.4-magnitude earthquake rocked New Zealand, and a 6.8-magnitude quake later hit western Indonesia. No damage or injuries were reported.

Scientists in Hawaii went ahead with the drill because no tsunami warning had to be issued for either quake.

Tsunami center spokesman Brian Yanagi said the center detects earthquakes every day, but not all of them cause tsunamis.

"It's not like a hurricane where you can see what's going on through satellite," he said. "This is a very different animal."