PLAN TODAY. STAY ALERT. STAY ALIVE
An Earthquake Resource Compiled by the S.C. Emergency Management Division
Earthquakes in South Carolina
August 31, 1886
Preparing for an Earthquake
Home Hazard Hunt
And More . . .
An earthquake is the violent shaking of the earth caused by a sudden movement of rock
beneath its surface.
Although earthquakes can occur anywhere on earth, the majority of earthquakes worldwide
occur at plate boundaries. These earthquakes are known as interplate earthquakes. In
contrast, South Carolina is located within the interior of the North American plate, far from any
plate boundary. Earthquakes occuring within a plate are intraplate earthquakes. Little is
known as to why intraplate earthquakes occur. The most widely accepted model is that
several geologically old fault systems of varying orientation within the subsurface are being
reactivated while being subjected to stress. This stress buildup may be due to the Plate
Tectonic Theory. For hundreds of millions of years, the forces of continental drift have resha-
ped the Earth. Continental drift is based on the concept that the continents bumped into, and
slid over and under each other and at some later time broke apart. Today, most people accept
the theory that the Earth's crust is on the move.
South Carolina’s Fault System:
Most of South Carolina’s earthquakes occur in the Coastal Plain where the
underlying rocks are very faulted or broken from the break-up of the plates. These
cracks in the deep rocks mean that this area of the plate is weak. If pressure is
exerted on the edge of the plate, some of these faults/breaks will allow the rocks to
move. Faults in South Carolina have been mapped and estimated. Fault rupture is
not the only cause of earthquakes. Small earthquakes may also occur near dams
from water pressure and near the Appalachian Mountains.