I mean it sounds more powerful than Hyper Beam and you're only damaged and don't even get a recharge turn
This move does the same damage to yourself as it does to the user, so basically you're attacking yourself with this powerful move, as well as the foe. So this is a last-resort move. See? Nothing is overpowered if you have the correct side-effects.
Personally, I think Earthquake is overpowered. It does 100 damage, 100% accuracy, hits everyone on the opposing team, and is super-effective against 5 different types. The best thing about this move is that it has no side-effects, good or bad. That is why Earthquake is considered the best move ever - because it is powerful, reliable, and has no side-effects.
Hyperbeam and explosion seem really powerful at first glance, but their side-effects are just horrible, making them bad moves despite their overwhelming power.