From Dark and Darker Wiki
Info is pulled from game files. Thanks for pointing this out. Sometimes the data in files doesn't reflect in-game logic perfectly and additional checks have to be put in.
For Earthquake the damage applied is 60, but it's likely hitting the player twice, instantly. Similar to how Cleric's Earthquake used to be bugged and hit for twice as much as intended. Whether the double damage is intended or not we can't tell. We will change the Ghost King value under this assumption so it's less suspect.
If anyone is willing to test this on a high HP character in Normals, it'd be greatly appreciated; I know from personal experience that the Normal GK Earthquake can be tanked past some health threshold.