Juan de Fuca Ridge and Plate Details

Juan de Fuca Ridge has been examined in detail because it is located close to the US West Coast. The alignment can be expressed with the formula:

(x – C_n)² + (y – 32)² = 35.34²

where x is latitude and y is longitude. Cn is a reference point on 32°N, -97.7.

This is the same formula as applies to the Reykjanes Ridge, except that the reference point there is -7.7.

Many maps describing the ridge can be found, and we can use one of them to compare with this formula. We do it graphically like this:

It is easy to detect the resemblance, and analysing the geophysical proberties becomes much like reading a book. The ridge of Juan de Fuca extends along a red division line (up-welling) for a distance resembling two polygons, marked by the convection rolls below.

The Gorda Ridge is of slightly different nature, because it is not found on a division line, but between them. It means that the area between the relevant divsion lines is being pulled by the main tectonic drift, resulting in the tension creating the ridge. Similar difference between features located directly above division lines (Reykjanes Ridge) and those occupying the areas above a single convection roll (East Volcanic Zone of Iceland) are aligned along the convection rolls system.

For a second look, this drawing, based on the same map as above, can be added:

There are many details to be noticed, even though this map is not nearly as accurate as could be provided. The Blanco Transform Fault extends between two points where division lines cross each other, because those are points of weakness in the deep tectonic framework. The Gorda Ridge bends at the border line between polygons, as the stress field changes there. The Cascadia Subduction Zone bends back and forth along a lower convection rolls division line. As most people have not yet learned about the convection rolls system, and its implications, it is good to check the present state of knowledge regarding Juan de Fuca plate and its development on the Wikipedia site: https://en.wikipedia.org/wiki/Juan_de_Fuca_Plate.