These are homebrew rules relating to The Age of Civilization
On a roll of 8 on The Great Disaster, or if you feel like it, you can use one of these disasters.
- Fault Line: Occurs on a d8 roll of 2 or 3 on the Great Disaster table (instead of Earthquake). The Earth shakes and splits, one part of the tectonic plate rubbing up against the other. Determine two random start points - one at the top of the page and one at the bottom. Draw a line between the two. Move one side of this line one finger either up or down (determine randomly). On the surface, weathering causes the resultant jagged extrusion to become rounded - the eroded rock in this area is easy to dig and gives easier access to deeper mineral layers now moved a finger up. Any mining settlements start there. (Peter Cobcroft at BoardGameGeek)
- Sinkhole Lake: At a random point at the top of the map, draw a lake about two thumbrints in size. Select a direction at random and generate an underground river from this point towards that side of the map. (Dyson Logos)