Where are you getting this idea the Juubi can't cause some magma to rise when he can quite literally ravage the entire surface of the planet
We've seen the Juubi actually going all out and the best Bijuu Dama was fired in near ocean whose shockwave reached the alliance. That's it. Also the Tenpenchii feat which is just country level at best.
The previous panel (I know which panel you mean) are based on hearsay, that's what that character knew about the Juubi (Idk if Kakashi explained this one or not).
Plus, "world ending" statements are usually taken with a grain of salt. After all, WB's power was also said to destroy the world and his earthquakes reached several islands when he shifted the tectonic plates.
Again, that's a reason why I said Juubi's Bijuu Dama might come close to that.
Juubi Obito "The nunoboko was used by the sage of six Paths to reshape the planet after the Juubis rage of destruction".
This sword was destroyed by pre PU Naruto and Sasuke including all key characters...
Plus, Hagoromo fought Kaguya. The Juubi is so much weaker than Kaguya.
Also how many days did Juubi need to destroy the planet's surface? Sure, he can keep spamming Bijuu Damas for all day but that's not how we gauge AP feats.