Why are there no active volcanoes or notable earthquakes in south dakota?

Question

Why are there no active volcanoes or notable earthquakes in south dakota?

Answer 1

Earthquakes are due to stressed regions in the Earth’s crust resulting from movement among and within the plates. The states that have the smallest number of earthquakes include Florida and North Dakota, followed by Iowa and Wisconsin. These states are not near any plate boundaries or faults.

Volcanoes are associated with plate boundaries or hot spots.  North Dakota has no hot spots in the underlying mantle.

Answer 2

You're on the stable interior of the continent. The area is geologically dead.