> Mining probably also plays a decent role.

In the Johannesburg area in South Africa, gold mining has produced up to half of all gold ever extracted in the world, with mines reaching depths of 4000m.

This has resulted in frequent seismic events, in the 2.0 to 3.0 range on the Richter scale, occurring on a daily or weekly basis, more occasionally reaching 5.0. This started around 1906 and still continues today. See:

https://www.sciencedirect.com/science/article/pii/S167477551...