Where do most earthquakes occur?

• A. At tectonic plate boundaries
• B. In the center of tectonic plates
• C. In equatorial regions
• D. On the Moon

Answer: (A)

Most earthquakes happen where rocks are under stress and rupture, which is most common at places where tectonic plates meet and interact. The Earth's crust is broken into moving plates. At their boundaries, the plates push, pull, or slide past one another, creating friction and accumulating stress. When that stress becomes too great, rocks crack and snap, releasing energy as seismic waves that we feel as earthquakes.

At divergent boundaries, plates move apart and new crust forms, with faults that can slip. At convergent boundaries, plates collide and one may dive beneath another, building huge pressures—leading to both shallow and deep earthquakes. At transform boundaries, plates slide horizontally past each other, producing earthquakes along the faults they form. Because these interactions concentrate stress at boundaries, most earthquakes occur there.

Earthquakes do occur within the interiors of plates, but far less frequently. Regions without active plate interactions—like the Moon—don’t experience Earth-style earthquakes in the same way.