What is a hot spring and what do they suggest about the local volcanic system?
That it is active.
Hot springs are pools of water heated by underground sources. These sources are made of magma under the Earths crust. Hot springs are found in places like Iceland, Yellowstone, and in areas that surround the Pacific Ocean and places that are famous for having volcanic activity. So a hot spring would suggest that there is a hot spot nearby and there is active geologic and volcanic activity.