Scientists say a fault-line running across Alaska could cause tsunamis of the same magnitude as the Japanese disaster of March last year.

Attention has turned to the Alaskan-Aleutian subduction zone, a region where one of the earth's tectonic plate, carrying the Pacific Ocean, drops beneath the North American plate.

A particular section of the fault near the Semidi Islands has not ruptured since at least 1788, and measurements on this area - which lies four to five kilometres under water - reveal the pressure is accumulating rapidly.

If the Pacific Ocean plate slips, as happened in the geographically-similar Tohoku subduction zone off the coast of Japan, a tsunami could occur - and the deaths could happen as far away as Hawaii and California.

The last time a slip between the Alaskan plates occurred led to the Good Friday Earthquake, on March 27, 1964, which was the powerful earthquake in U.S. history - a 9.2 magnitude earthquake which led to 145 deaths.