Does the spell Erupting Earth disrupt the surface it's cast on?

Question

The spell erupting earth says, in part:

A fountain of churned earth and stone erupts in a 20-foot cube centered on that point.

Does this mean about 20 cubic feet of material from the ground is churned up and disrupted? Or is the fountain comprised of newly created or summoned material?

RAW, the spell only deals damage to creatures and makes the terrain difficult. My player is wanting to use the spell to damage stone and dislodge a deposit of ore, arguing that the word 'erupting' means it should deal damage to the terrain as well.

If it churns up material from the ground, I can see this working; however, if the material is created by the spell, then that would explain why it doesn't explicitly damage objects/terrain.

What is the correct or intended interpretation of this aspect of the erupting earth spell?

Answer 1

RAW - the spell only damages creatures and creates difficult terrain

In 5e, spells do only what they say they do. In this case, as you say, the spell does damage only to creatures and then makes the area difficult terrain. If the spell was intended to deal damage to objects and terrain it would say so explicitly. In this case "erupting" is just descriptive of the way the dirt and rocks act, but not of any mechanical effects to the surrounding area.

The surface is covered in dirt and rocks, but the spell doesn't say from where

However, the spell never actually says if the churned earth and stone is from the surrounding area at all. As this is a magic spell, it can easily be that these are magically created dirt and rocks. After all, not all "ground" necessarily involves places with dirt and rocks together. The fact that the spell works the same regardless of where you cast it (as long as it is "ground") says that this is probably magically created debris.

Since this is an unclear area of the rules, it is up to the DM to decide how to handle them.

As DM you can tweak the effects to allow creative uses

As a DM you have the latitude to interpret spells to work in different ways than strictly RAW. For example, if this is an area in which ore was prevalent I would probably allow some of that ore to surface as part of the "fountain of churned earth and stone". This is a fun and thematic use of a spell in my opinion, and if you don't have to follow strict RAW then it seems fine to allow it.

Regarding damaging objects with the spell, it makes a bit less sense to me and I am not sure I would allow it. The damage in this case comes from the falling debris not from the "eruption". And I would be careful with ruling to expand the things a spell can affect without careful consideration of other ways it might be used once ruled. There are other spells (eg shatter) that are specifically designed to shatter inorganic objects so I feel like changing this spell to allow that would basically be giving two spells in one. That being said, if you are fine with these objections you can still allow it and see what happens.

Answer 2

These are all valid points. I would like to contribute to this spell analysis with some detailed analytics. The player is limited by what the spell says, is the golden rule. So with that in mind...

1. Erupting Earth is a "Transmutation" school and there for it alters what is already in existence. Transmutation alters a creature, object, or environment.
2. Churn: defined as "agitate", so I would say yes, the ground is disrupted and loosens the materials of earth and stone in the area
3. Per wall of stone AC 15 and 30 HP per inch thick in a 10ft x 10ft, and since the spell produces damage to those in the area, I would say every 30 damage is 1 inch of stone that erupts, which may not be nearly enough to dislodge ore embedded in the ground. Repeated use the spell and slots to continue tally damage may be enough over time to basically mine it out, but again, DM's interpretation and house rules.
4. Since damage to the stone and earth is automatic, as a DM, I would put in a thought of AC 15 is pointless, but depending on the environment, say in a magical place or holy ground, this could be a save of the grounds for half damage and rule an all or nothing. If the spell does not deal 30 damage then it is not enough to dislodge the ore by 1 inch, only rubble of stones, pebbles, and flakes erupted.
5. Per point 4, I would also as a DM rule that the spell still affects as normal, but for the topic of mining or pulling loose something from the ground that is not really meant to be, I would make it into its' own storyline. A couple of nights performing the task with some wandering monsters, and potentially an NPC who is also out for the ore for what ever the reason. A creative use of the spell, needs creative story line, and this is a 3rd level spell slot. Players may not be too keen on spending that much time and magic attempting a very slim chance of success.

Answer 3

I would say that it would also have to depend what the objects in question are made of. If, for example, lets say that the player wishes to use this spell to effect a earthen wall or rampart, I would rule that they could, if they used an additional spell slot / use the spell as a ritual (adding 10 minutes to the casting) / increase the value of the material components / ect. Reguardless, I would work with the player to come up with a solution. At the very least, they would have to research the altered version of the spell.