Major volcano eruption (VEI ≥6) in 2026?

This event tracks whether 2026 will see a rare, high-magnitude volcanic eruption, with two prediction markets framing the question at different thresholds. Polymarket asks specifically whether a natural eruption reaching a Volcanic Explosivity Index of 6 or higher will occur before year-end, resolving via the Smithsonian Institution's Global Volcanism Program. Kalshi lists a related but lower-bar market keyed to VEI-4 eruptions counted by the same source, with tiered outcomes covering at least one, two, or three qualifying events. On Polymarket, "No" for a VEI ≥6 eruption is the overwhelming favourite at 94.7%, with "Yes" priced at just 5.3%, consistent with how infrequently such large eruptions occur. Kalshi's VEI-4 ladder is far more competitive: "At least 1" sits at 54.0%, "At least 2" at 37.0%, and "At least 3" drops to 10.0%, reflecting a steep decline in implied likelihood as the required count rises. Because Polymarket and Kalshi are resolving different questions (VEI ≥6 versus VEI-4 counts), there is no direct cross-platform spread on any shared outcome. The takeaway: markets treat a VEI ≥6 event as highly unlikely in 2026, while a single VEI-4 eruption is close to a coin flip on Kalshi.