This is interesting.

https://www.postandcourier.com/columbia/news/columbia-area-rocked-by-scs-strongest-earthquake-in-8-years/article_7521722a-f54d-11ec-a360-1bdb818648b2.html

Shaw AFB is approx 20 mi SE of quake area. Based on my initial research the area has a bunch of old gold mines surrounding nearby.