The subduction of dense oceanic crust into the mantle plays an essential role in driving plate tectonics. However, the details of how new subduction zones form are poorly understood. In this model a section of buoyant oceanic crust arrives at a subduction trench and blocks it, causing the already-subducted slab to break off, and halting subduction. Then subduction starts in the opposite direction. The model shows not just a reversal, but how a new subduction can start, which is a matter of much

This video, adapted from a Pacific Tsunami Warning Center animation, shows every recorded earthquake, in sequence, from January of 1980 to March of 2020 in California and surrounding states. Most earthquakes in the world, including those in the United States, are “interplate” earthquakes that occur at plate tectonic boundaries where large sections of the earth’s crust either grind past each other, pull apart, or slam together. With the exception of the Pacific Coast of Southern California, the c