"E" is for Earthquakes. Earthquakes (seismic events) have had an impact on South Carolina for thousands of years. The state’s earthquakes have been tectonic; that is, they have resulted from intraplate displacements on the North American plate and not from interplate movements. They generally have caused little serious damage. Exceptions have been the massive Charleston earthquake of 1886 and the Union County earthquake of 1913. Earthquakes in South Carolina historically have been unpredictable and quite varied in nature. According to seismologists, South Carolina is one of the most seismically active states east of the Mississippi River. All except several of the state’s northeastern counties have been the source of earthquakes at one time or another. Since the first earthquakes were recorded in 1698, South Carolina has witnessed nearly 200 earthquakes classified as major by seismologists.