Accordingly, few of the area's earthquakes can be linked to known faults. As in most other regions east of the Rockies, the best guide to earthquake hazards is the earthquakes themselves. An estimated $23 million ($ million in ) in damage was caused by one of the great earthquakes in United States history in 1886. Charleston and nearby cities suffered most of the damage, although points as far as away were strongly shaken. Many of the 20 earthquakes of intensity V or greater (Mercalli intensity scale) that centered within South Carolina occurred near Charleston. A 1924 shock in the western part of the State was felt over . Several earthquakes outside the State borders were felt strongly in South Carolina. The August 31, 1886 Charleston earthquake was initially perceived in that city as a barely perceptible tremor, then a sound like a heavy body rolling along; the sound became a roar, all movable objects began to shake and rattle, and the tremor became a rude, rapid quiver. The first shock was at 9:51 p.m. and lasted 35 to 40 seconds. A strong aftershock occurred 8 minutes later. Six additional shocks followed during the next 24 hours. Few buildings escaped damage and many were totally destroyed. Chimneys of at least 14,000 houses were destroyed. The maximum intensity has been estimated at X. An estimated 60 persons were killed by falling buildings and many more were injured. Within a radius of , the cities of Columbia, South Carolina and Augusta and Savannah, Georgia, also experienced damage. The total area affected by this earthquake covered more than and included distant points such as New York City; Boston, Massachusetts; Milwaukee, Wisconsin; Havana, Cuba; and Bermuda. All or parts of 30 states and Ontario, Canada, felt the principal earthquake. Two strong aftershocks were reported on October 22, 1886, and another on November 5. The first of these was felt (intensity VI) in Charleston, at Atlanta and Augusta, Georgia, and at other towns. The second shock was intensity VII in Summerville. which received significant damage from the August 31 earthquake. Another tremor caused intensity VI effects on November 5 in Charleston and was felt over the same area as the previous aftershocks. The total felt area covered approximately . On January 23, 1903, houses were shaken strongly (intensity VI) in the area of the South Carolina - Georgia border near Savannah. Intensity IV - V effects were noted at Charleston, III - IV at Columbia, and III at Augusta, Georgia. A moderate shock affected Charleston, Augusta, and Savannah on April 19, 1907.