Spaghetti Scenarios · Global risk
A gigantic volcano spews out more than a thousand cubic kilometers of ash, rock and gases. What reaches the upper atmosphere cools the planet for years —a volcanic winter— and ruins harvests worldwide. It has happened several times in Earth's history, tens or hundreds of thousands of years apart.
No large caldera shows signs of a super-eruption today, but some are moving and are being closely monitored.
Ground deformation
168.5 cm
is how much the ground rose in Pozzuoli (Campi Flegrei caldera, Italy) between November 2005 and August 2026. In Yellowstone, by contrast, there was almost no deformation in recent months.
▼ Still rising, ~1 cm per month since February 2026
Seismicity in calderas
4.7
magnitude: the strongest earthquake measured at Campi Flegrei since instruments have existed (July 31, 2026). Yellowstone remains at background levels: 77 earthquakes in September 2026, the largest a 3.4.
▼ From 315 earthquakes a year (2016) to 8,682 (2025) at Campi Flegrei
Gas emissions
~3,500 t/day
of carbon dioxide came out of the Solfatara-Pisciarelli area (Campi Flegrei) in 2023, as much as at active volcanoes that degas nonstop.
▼ ~3,200 t/day in 2020; a multi-year upward trend
Hydrothermal changes
+8 °C
is how much the average ground temperature rose at the Solfatara of Campi Flegrei between 2002 and 2025. In Yellowstone, a small explosion of boiling water threw mud and rocks 30 meters high on September 27, 2026.
▼ Sustained heating and pressurization of the system
How much the ground rose in Pozzuoli, at the center of the caldera, since the current phase of unrest began in November 2005. The uplift has accelerated since 2020.
December values for each year; 2026 = August. Rione Terra station.
Earthquakes recorded each year in the caldera. Almost all are small, but their number grew more than 25-fold in ten years.
On July 31, 2026 the strongest earthquake since instruments have existed struck: magnitude 4.7.