Features

Image: courtesy gerard fryer

Tsunami Tag

Better communications would improve public safety, a scientist says.

In two years, Hawaii has had three tsunami evacuations, but wave heights fell short of predictions. Five hours into the most recent warning, on Oct. 27, no waves higher than 2.5 feet had arrived. So the evacuation probably hadn’t been necessary, staff geophysicist Gerard Fryer, Ph.D., told television reporters outside the NOAA Pacific Tsunami Warning Center in ‘Ewa Beach. The Weekly followed up with Dr. Fryer by phone.


Dr. Gerard Fryer

What was the highest tsunami this time?

At Kahului, 80 centimeters (about 24 inches) above normal sea level.

What were the highest Oahu has had?

In the 1946 Aleutian earthquake, a 10-foot tsunami hit Haleiwa. ‘Aina Haina got a five-foot-plus wave that swept far inland. A couple hung onto palm trees, and survived.

We appreciated your candor that night.

My candor was perhaps not well-advised. I was volunteering more information than I should have, [and] I’ve had my knuckles rapped for being too open.

Even though you were stating the obvious?

Yes. Our job is to issue a warning if we think it’s necessary and then turn it over to Civil Defense. They follow evacuation procedures and it’s not up to us to second-guess [things] once they’re underway.

Why was the warning not called until 7:15 p.m. Saturday, two hours after the quake?

We realize that our thresholds for measuring different warning products need to be modified. This earthquake [7.7 on the Richter scale ] was a little bit smaller than the normal threshold, and there was no instrument to measure a tsunami at that island [Haida Guai, off the coast of British Columbia]. But it produced a tsunami pointed right at Hawaii. It had to be at least an advisory. What we don’t want to have happen is what happened this time: People didn’t have enough time.

How can things be improved?

[By] provid[ing] more information. We would like to publish maps about what a tsunami is going to be like, for every event. Right now we have the advisory, which means you don’t have to evacuate but should stay off the beach. A warning means evacuate from zones. We would like to be more specific: Would it be just along the beach, or would there be major flooding? With sea level rise, major inundation is expected in the next hundred years. Are we actually being conservative enough? We have to sit down with the counties and the state and figure out how we’re going to provide information to the public.

What about equipment?

[I]t would be nice to see the tsunami again between where it’s generated and before it hits us. We do have pretty darn good gauges in those places (the Aleutians, Chile) from where a big tsunami is likely to come.

Can you explain why all shores are vulnerable?

A tsunami may first reach the North Shore, but it lifts sea level all around the islands. Its energy turns toward shallow waters and can be trapped there and go around the island. Some places, like Haleiwa and Waialua, pick up the shape of the tsunami and amplify it. Where you have a low open valley, anything going by is going to cause significant run-up. At Hawaii Kai or Hanauma Bay, you don’t expect very large waves, but you do expect them to last a very long time.

Is it true there are no signs on Oahu? If so, why not?

Most places, such as Hilo, have signs that say you are entering or leaving a tsunami evacuation zone, but there are no signs on Oahu. [Maybe in the past] the hotel industry didn’t want to scare people, but now they’re in favor of information. In New Zealand, where I’m from, you have a blue line painted on the road. We need that on Oahu.