City and Borough of Juneau
155 S. Seward Street
Juneau, Alaska 99801
tel. 907-586-5240
fax 907-586-5385
http://www.juneau.org

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Juneau Police Department

Questions Posted to "Ask a Dispatcher"


Q. Does Juneau have a tsunami evacuation route/ shelters, if so where can you find it?


Dear Juneau Resident,

I passed this question on to CBJ's Emergency Programs Manager and here is his answer.

Juneau is located in the interior of S.E. Alaska's Inside Passage. When I visited the Alaska Tsunami Warning Center in Palmer Alaska last year they told me that Juneau was not at high risk for Tsunami's.

Tsunami danger has to do with a couple of things. Earthquake danger varies from region to region.

There are 2 primary kinds of earthquakes.

The first is a Slip Fault where the two earth plates grind across one another sideways. The second is a Strike Fault where two earth plates directly impact one another. Slip faults create smaller earthquakes and do not have as high a risk of catastrophic earthquakes. Strike faults build up more pressure and when they release they create larger earthquakes and also the way the plates release during these events is what causes the Tsunami.

The second primary factor for tsunami danger is where the earthquake happens in relation to your location.

For tsunami's generated from locations such as Chile and Japan, by the time it gets to the Alaska coastline it is much less of a concern. Then, by the time it gets through all the islands and channels it has dispersed and slowed enough that we are not at high risk here in Juneau. An earthquake generated off of the Alaska coast would create a greater concern. The spot this earthquake originates would determine how greatly we could be affected. If the quake is north or south of your location it creates a smaller wave than if it was perpendicular to your location. So a strike fault perfectly perpendicular to, and nearby our location would be the greatest concern.

In SE Alaska the way the plates move does not form a strike fault. We are on a slip fault. The main part of the state, especially the Cordova, Valdez, the Kenai Penninsula and down the Aleutian's, are on a strike fault which is a much greater concern.

According to the Alaska Tsunami Warning Center Juneau does not have to be greatly concerned with Tsunami events do to the fact that we will not see as large of earthquakes in SE Alaska. Even the "largest" possible quake generated tsunami off of our slip fault (which causes less wave) would still have all the channels and islands to slow and disperse this wave and current event.

Do to this fact Juneau does not have Tsunami Evacuation Zones or predetermined Tsunami Evacuation Routes.



Juneau does have many disaster shelters and they remain ready for times of crisis.

Although according to the Alaska Tsunami Warning Center Juneau is not in an area of great risk that is not to say we are ignoring the situation entirely. I am currently revising the Juneau Emergency Operations Plan. In this revision one of the new additions will be an Evacuation Annex. It is currently in draft form. This annex has 2 facets. First, how to evacuate locally to areas of safety and secondly, how to evacuate the greater portion of the population out of town do to some catastrophic event.

The primary Tsunami concern for Juneau comes in the form of a mass wasting event or landslide into the channel somewhere very nearby. This has the ability to generate a Tsunami that could affect our population. The likelihood remains very low for this type of an event. Should this type of an event occur we would probably not even know it was happening until it hit.

Juneau is the only place in the State of Alaska with a functional Emergency Communications Committee. All the key players in alert/ notification sit on this committee. In the event of an emergency the National Weather Service, JPD, CCFR, Coast Guard or the City Managers Office all have the ability to immediately notify the public via TV, Radio, VHF Radio, and NOAA Weather Radio should notification of an evacuation be necessary.

At this time that message would be quite simply, “Please Seek Higher Ground”... and we would fill in whatever other key information was needed such as shelter locations.

Currently when I hear of earthquakes and tsunamis generated from afar I immediately think about how Juneau can support those who would be affected such as Sitka and Craig. We alert and notify the hospitals and fire department so their teams go on standby. We watch the news to see the affects of this event, then determine our course of action after seeing the magnitude of its destruction.

Interesting side note, September 11/12, 2011 Sitka will host the first ever SE AK Tsunami Workshop. They will be releasing new models to allow us to better understand what magnitude of earthquake, at what location, are needed to effect individual locations in S.E. AK.

Thank you,

Tom Mattice



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