The 7.0 Mw Charleston earthquake strikes southeastern South Carolina

Background. Charleston lies on Charleston Harbor, an inlet of the Atlantic Ocean formed by the confluence of the Ashley, Cooper, and Wando rivers. In modern times it is the most populous city in South Carolina and home to the Port of Charleston, one of the busiest in the United States. Prior to 1886, very little to no historical earthquake activity had occurred in this region, which sits on the Charleston seismic zone, an unusual characteristic for any seismic area.

Event Details. The earthquake struck about 9:50 p.m. local time on August 31, 1886. Scientists classify it as an intraplate earthquake with an estimated moment magnitude of 6.9–7.3 and a maximum Mercalli intensity of X (Extreme). It is recognized as one of the most powerful and damaging earthquakes to hit the East Coast of the United States.

Impact and Aftermath. The earthquake caused 60 deaths and $5–6 million in damage to 2,000 buildings in the Southeastern United States. Structural damage was reported several hundred miles from Charleston, including in central Alabama, central Ohio, eastern Kentucky, southern Virginia, and western West Virginia. Cities such as Savannah, Augusta, and Columbia also suffered damage.

Aftershocks. Following the main shock, significant aftershock activity occurred. Reports indicate 300 smaller aftershocks within the first 30 years following the earthquake in 1886, with a total count of 435. The earthquake and its aftershocks caused damage to buildings in cities such as Savannah, Augusta, and Columbia.