Pacific Volcanic Islands
I am trying to understand the formation of the volcanic
islands of the Pacific. I read somewhere that the islands begin moving
in a northwesterly direction after their formation. My question is: are
the islands themselves actually moving (and eroding) or is the sub-sea
volcanic action moving?
It depends on the islands. Some of the volcanic Pacific islands form near
plate boundaries, which of course move over geologic time. The Hawaiian
chain if islands, however, is mid-plate, and sits over a hot spot.
Currently, it appears that the hot spot is standing fixed and the Pacific
plate is sliding over it, so that new islands form as the old ones move away
from the lava source. However, there is some evidence that the hgot spot
was moving earlier in its history, hence the dogleg bend in the Hawaiian
chain. As far as I know, this question has not been settled definitively.
Richard E. Barrans Jr., Ph.D.
PG Research Foundation, Darien, Illinois
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Update: June 2012