The San Andreas Fault is a transform plate boundary, so the 2 sides are scraping past each other and locking for decades in certain areas. The Maria are smoother and therefore safer to land on. The oldest and the original lunar crust is in the Highlands.
Crustal plates separate at divergent plate boundaries.
The shape of Earth's magnetic field - the field lines come to the surface at the 2 poles. The lunar chronology is the lifestory of the Moon , describing how the highlands and maria formed, etc. The crust is twice as thick on the far side , so the near side crust cracked more easily.