ENGAGE
Tsunami - Seismic Sea Waves
Tsunami have been around as long as Earth has had earthquakes and oceans. While we have some geologic record of tsunamis, our brief human history has a limited record of these cataclysmic events.
After exploring resources in the preceding two sections about earthquakes and volcanoes, it's not surprising that Alaska also has quite a history of tsunamis. Some of the most dramatic Alaska Tsunami stories are the result of the seismically active Fairweather fault that runs hundreds of miles along the coast of southeast Alaska--right through the head of Lituya Bay south of Yakutat on the Gulf of Alaska.
Tlinget oral tradition tells of one such earthquake and resultant tsunami in 1853 or 1854 that devastated a village in Lituya Bay. According to the story, most of the men had left their village in Lituya Bay to hunt and returned later to find only one young girl and her dog who were spared because she had been on high ground picking berries.
Another tsunami visited the same bay in 1936, wiping out the garden and shed of the Bay's sole inhabitant, Jim Huscroft, who lived in the center of the bay on Cenotaph Island.
But the most dramatic story in Lituya Bay tsunami history occurred late in the evening of July 9, 1958. Fishermen in their boats anchored in the sheltered waters of Lituya Bay for the night awoke to the terrible shaking and groaning of the earth.
The surrounding mountains shed a huge volume of land and ice into the waters at the head of the bay creating a displacement wave tsunami that initially swept more than 1700 feet up the side of the opposing mountain, clearing it of everything down to bedrock. Some fishermen lived to tell the story....
EXPLORE
Check out this BBC Nature video, MegaTsunami on YouTube.
While you're there, you're bound to find more amazing video resources about tsunamis, like these two tsunamisimulations.
BBC Nature video, MegaTsunami Lituya Bay simulation
Lituya-pro.mov
EXPLAIN
- How was the 1958 Lituya Bay tsunami different from most seismic sea waves?
EXTEND
- What stories do you know of landscape changing forces that shaped the culture of a place ?
EVALUATE
- Describe the value of YouTube as an educational tool.
ENGAGE
Goo
gle Earth - TsunamiOne valuable and interesting aspect of the perspective that Google Earth gives us is the opportunity to better understand the scale of geologic forces. In Google Earth, or on any map, you can see the network of fjords, straits and inlets that make up the Alexander Archipelago of Southeast Alaska.
While you may already know that these fjords are the result of glacial erosion over eons, did you know these passages incidentally also mark the network of underlying faults that resulted from the formation of this geologically complex region?
EXPLORE
- Find Lituya Bay and locate the glacial valley that runs perpendicular through the head of the bay. This is the enormous and active Fairweather Fault.
- Try exploring the features of the region by rotating and tilting the image to provide a 3D perspective.
- Locate the swash zone left behind by the enormous tsunami of 1958. (It looks like a pale green bathtub ring around the inside of the bay.)
EXPLAIN
- What is the relationship between the Fairweather Fault and recurring tsunami in Lituya Bay?
- Why does the tsunami swash zone appear a different color?
EXTEND
- How does the system of faults along the Gulf of Alaska coast indicate the action of plate tectonics?
- Comment on the value or utility of geo-info rich digital resources, alongside the value of culturally rich stories.
ENGAGE
TD Resources - Tsunami
No story of Alaska tsunamis is complete without a look at the terrible waves that swept over Alaska towns and villages in the wake of the 1964 magnitude 9.2 Good Friday earthquake. Take a look at the TD resource, Alaska Tsunami.
EXPLORE SOME MORE...
Alaska Tsunami Helpful Hint: For more information about tsunamis, try these links to great NOVA resources:Wave of the Future and Wave that Shook the World.
EXPLAIN
- Besides tectonic plate displacement, what are other causes of tsunamis?
- Why are tsunami inevitable along the gulf coast of Alaska?
EXTEND
- Include Google Earth screen shots or other information and links that you found useful in portraying tsunami in Alaska.
EVALUATE
- How do these resources impact your, or your students learning?
