What does the "investiture of stone" spell's earthquake do?

Question

I feel a little bit like I'm asking a noob question since I found nothing on the internet even talking about it, but here it is :

When you cast the spell "investiture of stone", you can use you action to make a "small earthquake" in a 15 feet radius around you.

What is the effect of this "small earthquake"? Does it just make people fall? Does it make the terrain difficult? Should we use the "earthquake" spell's description and apply its effect just 15 feet around you?

Answer 1

The spell description of investiture of stone says:

You can use your action to create a small earthquake on the ground in a 15-foot radius centered on you. Other creatures on that ground must succeed on a Dexterity saving throw or be knocked prone.

It's possible you missed it because, in the Elemental Evil Player's Companion, the paragraph continues over the page.