Alaska Earthquake and Tsunami, I — Pararas-Carayannis 
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1. Two main tsunami-generating areas can 
be distinguished : one along the continental 
shelf bordering the Gulf of Alaska; the other 
in Prince William Sound. 
2. The main generating area in the Gulf of 
Alaska roughly corresponds to the geographic 
distribution of the major aftershocks. 
3. The energy of the tsunamis generated in 
Prince William Sound was expended inside the 
Sound; not much energy escaped this closed 
region. 
4. The long period of the waves generated 
in the Gulf of Alaska is related to the long 
seiche period of the shallow shelf. 
5. The preferential radiation of energy to- 
ward the southeast is attributed to the orienta- 
tion of the tectonic displacements along the 
continental shelf of the Gulf of Alaska. 
6. The waves arriving at Cape Yakataga had 
their origin in the shallow coastal area near the 
Bering Glacier, whereas the waves arriving at 
Yakatat traveled through the deeper waters. 
7. In Prince William Sound two major tsu- 
namis were distinguished: one had its origin 
near the west coast of Montague Island, the 
other originated in the Port of Valdez. 
8. Two types of tsunami-generating mecha- 
nisms were associated with the Alaska earth- 
quake: (a) waves generated directly by tectonic 
movements of the sea floor, and (b) waves 
generated indirectly from landslides, mudflows, 
and slumping of alluvial deposits. 
9. In Prince William Sound both generation 
mechanisms were evident, while in the generat- 
ing area along the Gulf of Alaska, the generated 
tsunami was the direct result of tectonic move- 
ments. 
ACKNOWLEDGMENTS 
The work on which this paper is based was 
supported in part by the National Science Foun- 
dation under the United States-Japan program 
for cooperative research in the Pacific, through 
grant No. GF-153, and in part by the Office 
