Ok sk i have lev 4 earthquake what now?

I still dont understand the power and placement of eq spells
Could someone please tell me the best use of and number off in war to take down lego walls in war?
It seems multiple lev 4 on the same wall shakes them a bit but thats all
How should i use them most effectively?

Use four earthquake spell (1 in cc) to destroy walls such that it make easy path to the core. And it is also useful in air attck by destroying an air defence using two lighting and one earthquake spell.