Three Key Facts About the Yellowstone Caldera

1. Colossal Scale: The caldera spans ~55 × 35 miles (89 × 56 km), covering much of Yellowstone National Park. Its last supereruption (Lava Creek, 631 ka) ejected 1,000 km³ (VEI 8)—creating the current caldera.
2. Active Magmatic System: A shallow magma reservoir (5–15 km depth, ~50% melt) feeds >10,000 hydrothermal features (geysers, hot springs, fumaroles) and drives measurable ground deformation (cm/yr uplift/subsidence).
3. Supervolcano Status: Classified as a "supervolcano" (eruption volume >1,000 km³). Next such event would be globally catastrophic (volcanic winter, agriculture collapse). Annual probability ~0.00014% (1 in 700,000); monitored 24/7 by YVO (USGS).

Note: "Supereruption" ≠ imminent. Most activity is hydrothermal/ seismic. The system is closely watched—science, not speculation.