1st scan is Thor using a waterfall.2nd and 3rd scans shows the Asgardians throwing every known ballistic in their arsenal.4th and 5th scans shows Thor hurling a Planetoid.The 6th scan shows the Asgardians using a freeze gun.All attacks proved futile on bringing down Surtur.From Thor#177
Surtur is much underrated i believe in the comics. In norse and Germanic lore, Surtur destroys everything in his wrath, is so massive the rainbow bridge crumbles under his weight, his power is so great that at the end up of Ragnarok he destroys himself because his power is uncontrollable. In essence he is greater than any GOD or entity that ever existed in the 9 or 10 realms.
Surtur is also a craftsman.He created weapons that were actually capable of matching Thor's hammer Mjolnir.The very collision of these weapons against Mjolnir was shown catastrophic.From Thor Vol 2 #80