This zone sits in the middle of the North American plate, and covers about 3000 square miles around the . A may also be a hint that it sits on a seismically active area, as the Appalachian Mountains pass right through it, and the Virginia Seismic Zone could link to various other nearby faults. In fact, , "the released energy traveled 'along the grain' of the Appalachian Mountains to the northeast and southwest." In other words, a seismic chain reaction.

Depth could have played a key factor in the Virginia quake's coverage. The Central Virginia Seismic Zone is hard to find on seismic activity maps because the quakes within the zone usually happen very deep underground--so by the time the seismic waves reach the surface, they're hardly noticeable unless you have a seismograph. However, the Virginia quake was only 3.7 miles below the surface--quite shallow for an earthquake.

So, due to the shallow depth of the quake's epicenter, which happened in the Virginia Seismic Zone, which is connected to other faults, the quake's seismic energy was able to travel at a stronger force over a wider distance than a similar-sized quake in, say, California.

The Ground Matters