Lessons Learned: Tsunami danger is real for coastal Alaska
Can Anchorage get hit by a tsunami? The short answer is maybe.
While it's hard to generate a tsunami in the Pacific that moves up the Cook Inlet to impact Anchorage, local triggers such as landslides in the Inlet itself might be enough to trigger a dangerous wave. Until more research is done, the National Tsunami Warning Center in Palmer will continue to treat Anchorage like a coastal city when it comes to tsunami danger.
“Our really bad day in Alaska is an earthquake that is followed in lockstep by a tsunami,” said Mike West, the director of the Alaska Earthquake Center.
The Nov. 30 magnitude 7.1 earthquake in 2018 was a jolt that reminded many Alaksans of the true danger of seismic activity in the state. Of the many lessons learned from the quake, one that might have been lost is the true danger of tsunamis for coastal Alaska.
When the ground shook that day, the intensity met the criteria for the warning center to issue a tsunami warning. Over an hour later, when they were sure there was no tsunami threat, they cancelled that warning.
They say that just because that earthquake didn't trigger a tsunami, doesn’t mean a different one won’t in the future.
The warning center monitors the tsunami threat year-round at all hours of the day. At any given time there are two watchstanders on duty — there to solve the threat of a tsunami following a tsunami-triggering event. The warnings are their way of helping to save lives in the event of a tsunami.
With any major earthquake along a coast or in the ocean, the warning center follows protocol. They issue an alert ranging in severity from an information statement to a warning for possible inundation areas. Once a watch, advisory, or warning is issued they closely monitor the region for any waves and only when they are sure there is no threat of a tsunami — the alert is cancelled.
An interactive map from the Alaska Earthquake Center shows what areas are at risk of tsunami inundation and works on mobile devices as well.
In the event of significant shaking from a major earthquake, do not wait for a warning if you are in a coastal community. There is the possibility that the wave is generated locally or traveling faster than the warning can be issued. If you feel significant shaking, the time to seek higher ground or move inland is immediately.
When it comes to Anchorage, the threat is something that needs additional research. The warning center, in conjunction with the Alaska Earthquake Center, has put forward a proposal to have a comprehensive study done to determine the exact threat of a tsunami for Upper Cook Inlet.
Until that is done, it is best to air on the side of safety in the event of a tsunami warning.
Warning center director James Gridley says the most important thing for Alaskans to know is that the threat of a tsunami is very real for coastal Alaska. Knowing what to do in the event of one can save your life.
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