Why earthquakes keep shaking Richmond
Four earthquakes have hit Central Virginia this year, including two that shook the Richmond area in recent weeks.
Why it matters: Richmond isn't cursed; there's a geological reason for our seismic activity.
The big picture: Though most earthquakes happen along geologic faults, in Virginia they happen within seismic zones.
All of Virginia's earthquakes have happened in three seismic zones, according to the Virginia Department of Energy, which oversees geological surveys.
They are the Eastern Tennessee Seismic Zone along the Tennessee border in Southwest Virginia, the Giles County Seismic Zone in the New River Valley, and the one Richmonders feel, the Central Virginia Seismic Zone.
Zoom in: Along the East Coast, earthquakes are caused by the compression of hard rocks running deep underground, AP reports.
That's different from West Coast quakes, which are caused by two sections of the Earth rubbing together.
Because East Coast rock is (apparently) harder than West Coast rock, and our quakes happen deeper underground, they tend to occur less frequently and are less severe, according to the U.S. Geological Survey.
It's also why they're felt across a greater distance.
Worth noting: Earthquakes aren't happening more often in Virginia, or anywhere, per USGS.
There are just better tools to measure them now and more ways for people to share widely that they felt them.
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