In August of 1886, Charleston was struck by a massive earthquake. The Richter scale had not been invented at that time, but geologists estimate it was a seven or more. The earthquake was so severe, some residents were convinced that Florida has broken off from the mainland. About 75% of Charleston's grand homes were damaged.
Afterwards, homes already old in 1886 remained standing, but were in poor condition. Some that could be salvaged were repaired using long iron rods for reinforcement. These rods were run through the walls of the buildings and anchored with bolts. They can still be seen on many of the buildings. No one knows if these earthquake bolts will be effective if another earthquake occurs. One guide speculated that they would do more harm than good, since there would be no 'give' to the houses.
I had never heard of using earthquake bolts before, and I have been in many places that have experienced earthquakes. Perhaps some enterprising fellow had some iron he needed to sell, and came up with this brilliant idea.