Tsunamis can be created by the fast displacement of water
when the sea floor lifts and/or falls due to crustal movements that accompany
very large earthquakes. The shallow nature of the sea floor off the coast of Alaska could raise the
destructive potential of a tsunami wave in the Pacific.
Earthquake behavior is difficult to forecast in this region
which is a transition zone between two of the world's most active plate
boundary faults; the Fair-weather fault, and the Aleutian subduction zone. In
1899 and 1979, large earthquakes occurred in the region but did not trigger a
Tsunami because the rupturing was restricted beneath the land instead of the
sea floor.
Prof Ron Bruhn from the University of Utah said: "If
the larger earthquake that is suggested by our work hits the region, the size
of the potential tsunami could be significantly larger than in 1964 since a
multi-rupture quake would displace the shallow continental shelf of the Yakutat
microplate."
"In the case of a multi-rupture event, the energy
imparted to the tsunami will be better but spread out over a longer strike
distance. But for the small communities at the tsunami source in Alaska, the longer length will have more of an effect on
areas farther from the source such as southeastern Alaska,
British Columbia, and the US west coast from Washington
to California."
