Above, a brick House at 157 Tradd Street that was wrecked by the Charleston earthquake of August 31, 1886. – United States Geological Service
by William “Doc” Halliday
When I think of earthquakes, I naturally think of California because of the San Andreas Fault. Foremost in my mind is the San Francisco earthquake in April of 1906 rated 7.8 Magnitude. I also think of the Alaskan earthquake that occurred in March of 1964 and is rated at 9.2 Magnitude. That is the largest earthquake recorded in the United States. Third on my list is the series of earthquakes that hit New Madrid, Missouri in 1811 and 1812. Tectonic earthquakes can occur anywhere there is adequate stored elastic strain energy to drive fracture transmission along a fault plane. I have even experienced earthquakes in New England of all places.
In most regions east of the Rocky Mountains, the best guide to earthquake hazards is the earthquakes themselves. An earthquake on the east coast can be felt over an area that is ten times greater than a similar Magnitude earthquake on the west coast. There had been virtually no historical earthquake activity in the Charleston area prior to 1886. This is unusual for a seismic area.
One hundred and thirty years ago today, on August 31, 1886, a 7.3 Magnitude earthquake occurred in the Charleston, South Carolina area. It was so severe that outside of the immediate area, there was speculation that the Florida peninsula had broken away from the North American continent. It was rated with a Mercalli intensity of “X” for extreme.
South Carolina actually experiences an average of 10-15 earthquakes each year below a 3 Magnitude.
It started with a hardly noticeable tremor at 9:51 p.m. on this evening of August 31. Over the next 40 seconds or so, the tremor became stronger and stronger until it was a roar like a freight train passing next to you in a tunnel. At the same time the ground shook so harshly that it seemed that nothing would be left standing. In fact, very few buildings in the city escaped damage and many were completely destroyed. At least 14,000 homes had their chimneys destroyed. A succession of wide fissures opened parallel to the Ashley River. When the bank slid into the river, several large trees were uprooted and also slid into the river.
Eight minutes later, the first and strongest of seven aftershocks within 24 hours was felt. The initial earthquake was felt in 30 states and the province of Ontario, Canada. The total area affected by the event was almost 2 million square miles. This included Boston, Massachusetts; New York City; Milwaukee, Wisconsin; Chicago, Illinois; New Orleans, Louisiana; Bermuda; and Havana, Cuba. When it was over, at least 60 and perhaps over 100 people were dead and an estimated $23 million in damages had been sustained by at least 2,000 buildings in Charleston.
Damage to railroad tracks about three and a half miles northwest of Charleston, included lateral and vertical displacement of tracks, formation of S-shaped curves and longitudinal movement. At least one locomotive was derailed. There were about 50 miles of severely damaged railroad track and over 500 square miles of extensive cratering and fissuring. Structural damage was reported in central Alabama, central Ohio, eastern Kentucky, southern Virginia, and western West Virginia. Prolonged effects were observed at distances exceeding 600 miles. Tybee Island, Georgia, a barrier island, received major damage.
In Summerville, a small town with a population of about 2,000, many houses settled in an inclined position or were shifted as much as 2 inches. The town is about 15 miles northwest of Charleston. Chimneys constructed separate from houses frequently had the part above the roofline thrown to the ground. Many chimneys were crumpled at their bases, allowing the whole chimney to sink down through the floors of the house. Experts have determined that the predominant motion was vertical because of the absence of overturning in piered structures, and the nature of the damage to chimneys. The Old White Meeting House in that town, which was built about 1700, was completely destroyed.
After the earthquake, many people who were now homeless camped in the public city park square in Charleston. South Carolina actually experiences an average of 10-15 earthquakes each year below a 3 Magnitude. Most of these occur along the central coastline in the Charleston area.
William “Doc” Halliday is a writer and historian. He can be contacted at firstname.lastname@example.org