The base of the regular tectonic plates, at least when they’re “flat” on the surface, is about 200 kilometers. (124 miles), so the newly discovered ones are way beneath that. So what’s going on here?
It’s likely that these plates are ancient ones. They would have encountered another tectonic plate during their more shallow existence at a “subduction zone”. Being denser than the other, they would have sunk beneath their colossal opponent, broken off, and drifted down into the mantle.
The discovery of this new layer of plate tectonics solves a long-standing mystery.
On occasion, incredibly deep-seated earthquakes rock the countries sitting above these plates, but they appeared to be originating from way below any known tectonic plate. You need plates to get quakes, so this has baffling scientists for a while now.
However, this new research has shown that they are probably coming from this new layer of tectonic plates. They may be semi-detached from the primary plates these days, but these enormous slabs can still bend, buckle, and break – and cause quakes as they do so. Indeed, their ongoing destruction is so energetic that it’s causing powerful shockwaves to make it all the way to the surface.
The research has yet to be peer-reviewed, but it’s looking likely that, once again, Earth’s hellish depths have been holding back more secrets from us than we’d realized.