Pointed Discussion

excellent in a valakut deck.

Skred is almost always better :(

Well, Skred is only better if you build your deck around it. The cost for that is so minimal though that it is in practice always worth it,

By build a deck around it you mean use snow mountains, or just snow lands and splash red. Skred is better

Cheaper than Seismic Strike, but not at instant-speed.

"By build a deck around it you mean use snow mountains, or just snow lands and splash red. Skred is better" --nope.avi

Well, there aren't any snow dual/shock lands, so it won't be as efficient if you splash any other colors.
Sacred Foundry for example will work with Spitting Earth, but not with Skred.
So you might end up dealing more damage with this sorcery.
But yeah, even then you might prefer paying one less for slightly less damage if it's still sufficient to kill the creature.
And in simply structured, monored decks, Skred and Snow-Covered Mountains is always what you'd want to play instead.

Also, Skred is an Instant, which in comparison to Seismic Strike makes it even cheaper.

Kumano, Master Yamabushi to Kumano's Pupils. It isn't a bad card, just a number of cards do what it does better.

Not bad for some effective removal that doesn't lose steam late game.