|Late medieval woodcut representing destruction in Basel|
On the evening of 18 October 1386, an earthquake took place whose force is estimated at 6.0-7.1.* It was one of the largest of the approximately 10,000 earthquakes detected in Switzerland in the last 800 years. Based on the accounts, a rumble occurred about 8:00pm, with the major quake striking at 10:00pm.
Although it is impossible to determine now what the epicenter was, Basel suffered the greatest destruction (possible by virtue of being the largest set of structures affected by the earthquake). Basel was completely destroyed, as were any churches, castles, and towers within a 30-kilometer radius. Further damage was done to town buildings due to the fire caused by torches and candles being knocked over. Tremors were felt as far away as Zurich and the Île-de-France (272 miles away!). No building in Basel survived, according to reports.
Considering the size of the earthquake, and the timing, you would expect casualties in the thousands. While estimates vary, an estimate by a modern risk management firm is 300 deaths in Basel.
*On the Moment Scale, which has replaced the Richter Scale.