[3] Scientists have classified it as an intraplate earthquake, and said that it had an estimated moment magnitude of 6.9–7.3 and a maximum Mercalli intensity of X (Extreme).

[3] The shock was felt as far away as Boston, Massachusetts, to the north; Chicago, Illinois, and Milwaukee, Wisconsin, to the northwest; New Orleans, Louisiana, to the west; and across water to Cuba to the south, and Bermuda to the east.

The tremor was now a rude, rapid quiver, that agitated the whole lofty, strong-walled building as though it were being shaken--shaken by the hand of an immeasurable power, with intent to tear its joints asunder and scatter its stones and bricks abroad, as a tree casts its over-ripened fruit before the breath of the gale.Sand boils were common throughout the affected area due to soil liquefaction.

It is thought that such ancient faults remain active from forces exerted on them by present-day motions of the North American plate.

Roger Bilham and Susan Hough studied historical mapping projects published between 1884 and 1919 and discovered a 1 m (3 ft 3 in) uplift at Summerville along the South Carolina Railroad.

Photographic evidence of the South Carolina Railroad southeast of Summerville also showed a right-lateral offset of 4.5 ± 0.3 m (14.76 ± 0.98 ft) on the track.

Direct observation of the earthquake's effects also reported the rail bed being "forced to the right", supporting the identification of this offset.

[9] The Old White Meeting House near Summerville, Dorchester County, South Carolina was reduced to ruins.

[14] The initial shock in Charleston lasted for about 45 seconds and was extremely destructive, leaving nearly all of the 8,000 city structures with either interior damage or broken windows.

The earthquake and its aftershocks caused damage to buildings in cities such as Savannah and Augusta, Georgia, as well as Columbia, South Carolina, more than 100 miles from Charleston.

The quake was even felt in cities as far as Boston and Chicago, where plaster fell from ceilings in upper floors of some buildings.