How does it work. Is it like a fixed rule or is it supported by stats/numbers in game. Most importantly does it take fewer spells if it is upgraded ?
1 Answer
Someone else already did the math (its kind of complicated) here
Earthquake spells do damage based on percentage of current health, spell level, and number dropped. Consecutive earthquake spells do less damage to buildings. Earthquake spells deal bonus damage to walls (increasing damage).
Regardless of the level, 4 Earthquake Spells will take out any level wall. And no less than that will break any walls. Must use exactly 4 of any level Earthquake Spells to remove walls. Four level 1 Earthquake Spells are able remove level 11 walls, same as level 4 walls.
The math is explained in Reply number 8 here.
4