the pacific plate was moving in the northwesterly direction while the emperor seamounts were forming.
the pacific plate was moving in the northwesterly direction while the emperor seamounts were forming.
in what direction was the pacific plate moving while the emperor seamounts were forming?
northwesterly direction
in 1963, geologist john tuzo wilson hypothesized the origins of the hawaiian–emperor seamount chain, explaining that they were created by a hotspot of volcanic activity that was essentially stationary as the pacific tectonic plate drifted in a northwesterly direction, leaving a trail of increasingly eroded volcanic islands and seamounts in its wake. an otherwise inexplicable kink in the chain marks a shift in the movement of the pacific plate some 47 million years ago, from a northward to a more northwesterly direction, and the kink has been presented in geology texts as an example of how a tectonic plate can shift direction comparatively suddenly. a look at the usgs map on the origin of the hawaiian islands clearly shows this "spearpoint".
hawaiian–emperor seamount chain
the volcano formed 23 million years ago during tectonic subduction of the oceanic juan de fuca plate beneath the continental north american plate, a process often associated with volcanic eruptions near the plate boundaries. subsequent complex geophysical mechanisms caused a segment of the juan de fuca plate to fuse to the eastern edge of the adjoining pacific plate, ending subduction and initiating horizontal shear movement between the plates, with the pacific plate moving northwesterly and the north american plate moving in the opposite southeast direction. this transform movement began approximately 20 million years ago and the resultant shear lineation is the san andreas fault zone. the neenach volcano was situated directly over the primary san andreas fault, causing it to be split in two once the transform fault movement began. the average relative motion along the fault is about 1.5 cm per year, equivalent to six inches per decade. over the course of this movement, the two halves of the volcano drifted about 195 miles (314 kilometers) apart and eroded down into the minor rock formations visible today.
neenach volcano