Saul:
Knowledge (geography) would probably be of more use in learning volcanic/topographic information of that nature, but the Nat 20 lets you see that the surrounding area appears seismically 'stable' with no indication of geologically recent earthquakes or eruptions. Of course, that could just mean they're due.
The water is hot enough to be uncomfortable on unprotected skin, but merely reddens it, rather than causing a more serious burn, when you're careful not to keep the skin submerged more than a few seconds.
The woods are remarkably still, though whether as a matter of course or due to your fight with the Displacer Beast is hard to say. No fish or other life of any sort are readily apparent in the water. The worked staircase is visible to all of you as Milo carefully gathers the water into Makala's waterskin. It includes a stone and wood cover against the weather, which someone takes the time to tend to and keep in good repair. There appears to be an iron helmet or cap of some sort on the ground in front of the stairs.
