- VOLCANO
- Caldera's precursor
- It's dangerous when active
- Mars's Olympus Mons, for one
- Mount St. Helens, for one
- Occasional erupter
- Mauna Loa, e.g.
- It may be active
- Mount Rainier, e.g.
- Peru's El Misti, e.g.
- Cone site
- El Misti, e.g.
- Wilshire, in a '97 film
- Granite source
- Ultimate source of granite
- Island group to which Iwo Jima belongs.
- Lassen or Stromboli.
- Lassen of Asosan.
- What Popocatepetl is.
- Lassen, for example.
- Lassen or Hekla.
- Lassen, for one.
- Spitfire, so to speak
- Stromboli, e.g.
- See 69-Across
- One prone to blowing off steam
- Source of lava
- Active or "dormant" landform
- Spot for a blowout
- Pyroclastic flow source
- Mount Fuji, e.g.
