Stefano Carlino descends underground, into a deep pit occupied by what looks like a heavy-duty fire hydrant: a wellhead. Below, unseen, a narrow hole continues about half a kilometre into the Earth's crust. Carlino, a vulcanologist with Italy's National Institute of Geophysics and Vulcanology (INGV), shows me fiberoptic cables flowing down to instruments inside the borehole that measure temperature, seismic activity, and stress. He also points out where tubes emerge from the hole, letting carbon dioxide escape to relieve pressure, and the large, black valve that could be used to close off the borehole in case of emergency.
Scientists plan to drill into a supervolcano in Italy
