Trader consensus on Polymarket prices zero large volcano eruptions (Volcanic Explosivity Index, or VEI, ≥4) at 57.5% implied probability for 2026, driven by the absence of any such events through mid-May despite 47 confirmed smaller eruptions worldwide, as tracked by the Smithsonian Global Volcanism Program. This reflects the historical baseline of roughly one to two VEI≥4 events per year—defined by ejecting at least 0.1 cubic kilometers of dense rock equivalent—with no evidence of increasing frequency over the past century per USGS and GVP data. Current unrest at over 40 volcanoes remains predominantly effusive or low-intensity, lacking precursors like rapid seismicity or significant deformation signaling explosive escalation. Weekly GVP reports and USGS monitoring will provide key updates through year-end, when final tallies resolve the market.