What is happening now at the San Andreas fault zone?

Answer 1

The Earth's crust comprises many pieces called tectonic plates. These structures are in continual motion. They float on top of the layer known as the asthenosphere which is an extremely hot, ductile rock layer, and collide with one another in a perpetual conflict. Heavier oceanic plates generally sink beneath lighter continental plates if they collide head on, causing the continental plates to rise up forming mountains, while the oceanic plates sink beneath, exposing them to enormous heat and pressure that results in their remelting and becoming new mantle or sometimes forming new rock types. These collisions of plates are not always head on. Sometimes the plates slide parallel to one another, as is the case with the San Andreas fault region. Also, sometimes the plates separate from on another causing a linear crack to form, exposing the molten mantle to conditions allowing it to solidify, creating the formation of "new" tectonic plates.