The intensity map below shows the highest likely earthquake intensity by county based on the most adverse geologic conditions.
This map shows earthquake intensities, by county, based on the Modified Mercalli Intensity Scale. The intensities shown on this map are the highest likely under the most adverse geologic conditions that would be produced by a combination of the August 31, 1886, Charleston, S.C., earthquake and the January 1, 1913, Union County, S.C., earthquake. The Rossi-Forel Scale initially used to describe the January 1, 1913, Union County, S.C., earthquake is considered comparable to the Modified Mercalli Intensity Scale for the purpose of developing this map.
Intensity is a numerical index describing the effects of an earthquake on the surface of the Earth, on man, and on structures built by man. The intensities shown on the map below are the highest likely under the most adverse geologic conditions. There will actually be a range of intensities within any small area such as a town or county, with the highest intensity generally occurring at only a few sites. Earthquakes represented on the map occurred during August 31, 1886, Charleston, SC., earthquake and January 1, 1913, Union County, SC., earthquake.