Like :) this took about 2 mins, the command is: (in a repeat command block):

execute at @e[type=minecraft:creeper] run summon minecraft:creeper ~ ~ ~ {ExplosionRadius:50,Fuse:0}

put a Redstone block next to it, all the creepers in your world will explode, and make huge craters!

if you spawn them it will also work :)

WARNING: do not use this command in a world with domobspawnning true! it WILL crash!