Why does the United States have such varying risks of seismic activity?

A) Some areas are near plate boundaries, while others are not.
B) Some regions in the continental interior have active fault systems.
C) Volcanic activity can cause seismic risk in some areas.
D) These are all reasons the United States has varying risks of seismic activity.

Plate Boundaries

The edges where two or more of Earth's tectonic plates meet, often associated with seismic and volcanic activities.

Fault Systems

Networks of fractures in the Earth's crust along which displacement has occurred, important in understanding the movement of Earth's tectonic plates.

Volcanic Activity

Refers to the eruption of magma from beneath the Earth's crust, forming igneous rocks and often creating mountains or craters.