The description of the spell Erupting Earth says:
Choose a point you can see on the ground within range.
Does the use of the word “ground” limit this spell to floors that would be considered an “exposed surface of the earth”? Or can it be cast on other kinds of surfaces?
Other possibilities include:
- An indoor room on an upper level or over a basement
- An outdoor deck or patio
- A raised platform like a stage or pulpit
- A roof
- A balcony
- The deck of a ship
Commenter Hobbamok found an excellent related question that may reduce this one to an unnecessary duplicate: What is “the ground”?
Yes, otherwise dozens of spells would not function as intended.
For example, look at Tenser’s Floating Disk, which states that it “floats 3 feet above the ground” It later says that it can move up or down stairs, which typically aren’t made of exposed earth.
Another example, if you look at the 2nd level spell Levitate, it ends with: “When the spell ends, the target floats gently to the ground if it is still aloft.” If the ‘ground’ meant only exposed earth, if you were above wood you simply crash when the spell ends.
For more examples look at Shapechange, Tsunami, Phantom Steed, Meteor Swarm and many other spells that would not function properly if ‘ground’ only meant exposed earth.