At http://phys.org/print414856601.html … we learn that several 'hundred' miles off the Pacific NW coast a small plate, the Juan de Fuca, is slowly sliding under the North American continent – even though it has several hundred miles to go. It depends of course where the continental plate boundary is situated but as mainstream geology is certain that the mountains along the Pacific coast of North America are caused by plate subduction the author of the piece has no choice but to assume that is happening with Juan de Fuca. The researchers have done some amazing research on this microplate, ostensibly because it has the potential to generate huge earthquakes and tsunami waves that could strike the big cities in the Pacific NW region. What we have is a number of volcanoes situated on Juan de Fuca and these are thought to produce new crust generated by lava seeping from below. These volcanoes lie more than a mile underneath the ocean surface – and scientists know very little about them. The new research is published in Science Advances (May 2017) and the full paper would make a good read. It has come out with a new theory on how tectonic plates are built as a result of using new measuring equipment that has shown seismic energy extends really very deep, at least to a depth of 200km beneath the surface of the ocean. It may go even deeper but they were limited by their equipment.
They hope to extend their research, in the coming years, right across the Pacific basin – which might reveal some interesting information. You can read the full thing online by going to www.advances.sciencemag.org/3/5/e1602829.full ..but you can't print it out. You can, however, save the web page on to your computer to read later.