MEMORANDUM FOR: Anchorage AMS Members and Affiliates

FROM:   Kristine Nelson, Anchorage Chapter President.

SUBJECT: Minutes, Anchorage AMS Chapter Meeting,
                    Mar. 19, 2008  

Call Meeting to Order: The meeting was called to order by Kristine Nelson, President, at 11:30 a.m. The meeting was held at the Twin Dragon Restaurant on 15th/Gambell

Treasurer’s Report: AMS ANC Chapter report is currently unavailable.

Old/New Business:
Elections for the coming year will be held at the next meeting.

National Science Fair
Laura Furgione volunteered to do the keynote address; Dave Vonderheide and Darrell
Randall volunteered to help judge; and Louise Fode volunteered to hand out AMS
Certificate and donated “prizes”.

Donations:
We can always use more prize donations.

Guest Speaker:
Bruce Turner – West Coast-Alaska Tsunami Warning Center
“Tsunami Awareness Week”
Bruce Turner is a geophysicist. He has worked in Hawaii at the Pacific Tsunami
Warning Center prior to coming to the Alaska-West Coast Tsunami Warning Center.
Over the coming summer, he will attempt to adapt to new duties…that of a retired
Federal employee!
Bruce first talked about the current Tsunami Warning Center structure. There are two
Tsunami Warning Centers in the U.S.. One is in Hawaii and the other in Alaska. The
West Coast/Alaska Tsunami Warning Center (WC/A TWC) was upgraded to a 24/7
operation following the devastating tsunami in Indonesia Dec. 26, 2004. The WC/A
TWC also acquired an increased area of responsibility which now consists of Canadian
coastal regions, Puerto Rico, the Virgin Islands, and the ocean coasts of all U.S. States,
except Hawaii. The Pacific Tsunami Warning Center, located in Hawaii, provides
warnings and monitoring for Hawaii, the rest of the Pacific Basin not covered by the
Alaskan Tsunami Warning Center, and countries participating in the Tsunami Warning
System in the Pacific, Indian Ocean, and Caribbean Sea.

WC/A TWC Operations area

The WC/A TWC has access to 400 tide gages and 35 Deep Ocean Tsunami Detectors
(DART). Deep Ocean Tsunami Detectors lie on the ocean floor and measure the water
column above them, while tide gages sit on the top of the water and subtract normal tide
fluctuations from tsunami waves. Initial warnings are based solely on seismic
information and are usually issued within 5 minutes. Follow-up messages or warnings
are produced following analysis of tide gage, DART, and other data and modeling
sources.
Following an earthquake, the Tsunami Warning Center analyzes the type of earthquake
for movement and size to determine whether a tsunami was generated. A lifting of the
earth upward along the seafloor with a strong enough earthquake magnitude, causes
tsunamis to be generated by displacing the water column upwards. The shock wave, then
propagates outward from the source point in 360 degrees. The coastline affected by those
tsunamis is determined by location of the earthquake and the wave propagation of the
tsunami as depicted by Tsunami Warning Center computer models.

Computer generated tsunamis model

Tsunami waves in open water appear quite small and amplify only when they approach
land. Tsunami waves can travel at speeds up to 500 mph over deep open waters and tend
to slow down in shallower coastline areas. Nonetheless, a tsunami can reach local
coastlines in a matter of minutes and distant ones within hours. Bruce showed us satellite
time-lapse composites of the wave action generated from the massive Indonesian
Earthquake and Tsunami which shows how every major ocean basin on the planet felt the
effects of this singular event within 24 hours after it occurred.
The importance of recognizing that a tsunami could occur is what Bruce says it most
important, especially for residents of coastal communities, of which Alaska has a great
many of. There are some locations along the Alaskan west and northern coast and the
waters around Anchorage where the sea floor is shallow mitigating the effects of
tsunamis. Coastal communities along the southern Alaskan coastline are highly exposed
and vulnerable to large earthquake generated tsunamis.
Prolonged and strong shaking is a sign to head for higher ground. In addition, if you are
on a beach and see water receding, head for high ground. Earthquakes in less tsunami
susceptible areas may still suffer a local tsunami generated by earthquake or volcano
produced landslides. During Augustine, the Tsunami Warning Center monitored
Augustine and collaborated with the Alaska Volcano Observatory regarding the potential
for an Augustine produced landslide tsunami. Bruce showed us pictures of Valdez
before a landslide produced tsunami in March 28th, 1964 as well the devastation
afterward. Even a small tsunami can cause millions of damage to boats moored to docks
in a harbor and to the harbor itself.

Valdez devastation following the landslide tsunami in 1964

Tsunamis travel so quickly that the best way to protect yourself is to understand that
rapidly receding water is the precursor to a tsunami. If you are in the local coastal
community that felt the strong earthquake, it is best to be cautious and move to higher
ground. In addition, oceanic earthquakes oftentimes produce a series of shockwaves
resulting in several tsunamis. Bruce emphasized that coastal communities vulnerable to
tsunamis should always expect more than one tsunami wave and to remain on higher
ground until the event is truly over.
Alaska is considered part of the Ring of Fire, an arc of volcanoes that stretch from the
Indonesian Islands north past Japan….into Russia’s Kamchatka Peninsula, entering US
Territory in Alaska’s Aleutian Arc. The Aleutians are strung out along an active
subduction zone where both seismic and volcanic activity are common.
The Warning system in place in Palmer, the West Coast-Alaska Tsunami Warning Center
can detect earthquakes anywhere in the world, with its computers integrated into a
worldwide monitoring system. The Center has even aided their Pacific TWC colleagues
in keep tabs on the Indian Ocean Basin following the devastating Dec. 26, 2004.
For more information, movies, and training materials, go to the WC/A TWC webpage at:
( http://wcatwc.arh.noaa.gov/ ).

Our next meeting will be 11 am May 16th, UAA Aviation Center, Room #243
The next speaker will be Nancy Schommer of the Federal Aviation Administration’s
Weather Camera Program