I made a starter for my IPA instead of just dumping the vial into the carboy. 1 cup DME and 4 cups water and then my White Labs California yeast. There is so much action going on in the carboy that it has blown into my airlock and has even bubbled atop the airlock lid. It smells wonderful, but is there a thing as too much yeast? I'm still a novice and have not had volcanic yeast like this before. Next time should I use 1/2 cup DME and 2 cups water?
That's definitely not too much yeast; there just isn't enough head space for the fermentation. It will slow down very soon (if it hasn't, already).
Just keep everything clean so you don't get any nasties coming in through the mess.