Triple Junction

A triple junction is the point where the boundaries of three tectonic plates meet, with each of the three boundaries being a ridge, a trench, or a transform fault. Triple junctions are classified by which combination of these three boundary types converges at the point, such as fault-fault-trench or ridge-ridge-ridge, and of the ten geometrically possible combinations only a few remain stable through geological time; the concept was first formally defined in a 1969 paper and has since been extended to any point where three plates meet, not only where boundaries are diverging.