The message after Hawaii’s tsunami scare: Be prepared (because this will happen again)

HONOLULU (HawaiiNewsNow) - A tsunami scare early Tuesday is a good reminder of the importance of being prepared, officials said.

A Tsunami Watch for Hawaii was canceled early Tuesday after officials determined a large quake off Alaska posed no threat of damaging waves.

But Hawaii spent a tense hour under the watch, which was triggered by a 7.9-magnitude quake off Alaska.

Chip McCreery, director of the Pacific Tsunami Warning Center, said Hawaii is "very lucky" destructive waves weren't generated by the quake.

Tsunami are generated after an earthquake causes the sea floor to move up and down.

But in this case, the sea floor moved sideways and didn't disturb the sea much.

The episode also illustrates that Hawaii wouldn't have much time to prepare for a tsunami generated by an Alaska temblor.

It would take about four to five hours for waves from a quake off Alaska to impact Hawaii.

For earthquakes off South America, Hawaii has about 15 hours.

"Actually, Alaska and the Aleutian islands are the most dangerous area," McCreery said. "They can produce the biggest tsunamis in Hawaii because they're closer to Hawaii."

He added that the tsunami scare is a reminder that it's always a good idea to be prepared for disasters.

"We know that in the future we will get hit by destructive tsunamis, so everyone who lives here should keep that in mind, know where the evacuation zone is, have a family plan for what you're going to do, what your family's going to do, and that way you can be safe when a tsunami occurs."

TSUNAMI PREP RESOURCES

Tsunami Evacuation Zones Emergency kit supply list

McCreery said the Pacific Tsunami Warning Center generally has a threshold of three hours before impact time to make a decision, and during that time, the center coordinates with the Hawaii Emergency Management Agency so that officials can get the word out to the police and fire departments.

The Hawaii Emergency Management Agency, which has already been under scrutiny for the length of time it took to alert the public and news media about a false missile alert last week, contacted Hawaii News Now at around 12:35 a.m. and offered to assist in news coverage.

But it sent out its first tweet regarding the tsunami watch nearly seven hours later — at around 7:30 a.m. A follow-up tweet about the cancellation was sent about 15 minutes later.

The U.S. Geological Survey said the quake happened southeast of Kodiak Island at about about 11:32 p.m. Hawaii time at a depth of 12 miles.

It had an initial magnitude of 8.2 but was later downgraded.

A Tsunami Watch was also issued for much of the U.S. West Coast, while parts of Alaska were under a Tsunami Warning. All watches and the warning have been canceled.

At around the same time, the Alaska earthquake happened, a 3.7-magnitude earthquake struck north of Hawaii Island and east of Maui. No tsunami alerts were issued for that one.

This story will be updated.

Copyright 2018 Hawaii News Now. All rights reserved.