For many years some geologists and seismologists have believed the Kamchatka Peninsula sits on the same tectonic plate as the mainland United States, Canada and Mexico -- the North America plate that extends through Alaska across the Bering Strait and into Siberia.

The idea the Kamchatka Peninsula is part of the North America plate is perhaps a case of "tectonic imperialism" reinforced by a lack of evidence to the contrary, said Jody Bourgeois, a University of Washington professor and lead author of the study.

But research of earthquakes and tsunamis along the Bering Sea coastline, including a magnitude 7.7 earthquake in 1969, suggests Kamchatka sits atop a smaller plate called the Okhotsk block, which is being deformed in a sort of convergence zone of tectonic plates, Bourgeois and colleagues said.

"What we are finding cannot be explained by a model that places Kamchatka on the North America plate," said Bourgeois.

A paper documenting the study appears in the May edition of the journal Geology.