Final answer:
Present-day plate motions, measured using GPS and VLBI, indicate that tectonic plates move at about 4 to 5 centimeters per year, and this movement is associated with stress build-up and subsequent earthquakes along fault zones.
Step-by-step explanation:
Measurements of present-day plate motions reveal that tectonic plates move at rates comparable to the speed at which human nails grow, typically around 4 to 5 centimeters per year. Geoscientists employ sophisticated techniques, such as GPS (Global Positioning Satellites) and VLBI (Very-Long Baseline Interferometry), to monitor and calculate these motions.
This detailed surveillance facilitates an understanding of the dynamics of Earth's crust, specifically the relative rates of motion between different plates. Notably, along fault zones like the San Andreas Fault, the plates do not move smoothly; rather, they build up stress over time and eventually release it through earthquakes. Furthermore, information provided by the US Geological Survey allows us to observe earthquakes and their relation to tectonic plate boundaries.