How many large volcano eruptions (VEI ≥4) in 2026?

Resolution Criteria

This market will resolve according to the number of natural volcanic eruptions with a Volcanic Explosivity Index (VEI) of 4 or higher between January 1 and December 31, 2026, 11:59 PM ET. The primary resolution source will be the Smithsonian Institution Global Volcanism Program (GVP: https://volcano.si.edu/), specifically the cumulative figures for 2026 for VEI 4, VEI 5, and VEI 6 released on the page currently titled "Eruptions Avg 2000-2024 (N/T)" (https://volcano.si.edu/faq/index.cfm?question=eruptionsbyyear) as of March 31, 2027, 12 PM ET. Any prior updates will not be considered finalized. If this dataset has not been updated to include all relevant events by March 31, 2027, or if the Smithsonian GVP becomes permanently unavailable, this market may resolve based on a consensus of credible scientific sources, including the U.S. Geological Survey (USGS), national or regional volcanic observatories, or credible reporting of a scientific consensus. Note: Smithsonian Institution Global Volcanism Program databases, which include eruptions that reached the relevant threshold prior to this market’s timeframe (e.g., https://volcano.si.edu/faq/index.cfm?question=eruptionsbyyear&checkyear=2025), will not be considered.

This prediction market asks how many large volcanic eruptions (VEI 4 or higher) will be recorded globally in 2026, resolving against the Smithsonian Institution Global Volcanism Program's cumulative data published by 31 March 2027. Volume is heavily concentrated on the lower end of the outcome range, with zero eruptions the heaviest-backed single outcome, followed at a considerable distance by exactly one eruption.

Market structure

The market offers six discrete outcomes: 0, 1, 2, 3, 4, and 5 or more VEI ≥4 eruptions in calendar year 2026. Volume is heavily concentrated toward the low end, with the zero and one outcomes together accounting for the overwhelming majority of positions. Outcomes of two or more are sparsely backed. Resolution uses the Smithsonian GVP's published 2026 cumulative figures as of 31 March 2027, with USGS and regional observatories as fallback sources.

Background

The Volcanic Explosivity Index is a logarithmic scale used to characterise the size of volcanic eruptions, with VEI 4 representing a large eruption capable of injecting significant material into the stratosphere and affecting regional climate and air travel. Historical data from the Smithsonian GVP shows that eruptions at VEI 4 or above are relatively infrequent on an annual basis: the modern record since 2000 suggests years with zero officially confirmed events at this threshold are common, and years with multiple such eruptions are comparatively rare. Notable recent examples include the 2022 Hunga Tonga–Hunga Ha'apai eruption, which reached VEI 5 or 6, and the 2014 Ontake eruption in Japan. The GVP database is considered the authoritative global catalogue, though confirmation and classification of eruptions can take months or years, which is why resolution is set to March 2027 rather than January 2027.

Key factors

Several structural factors shape how this market resolves. First, the GVP classification process involves post-event analysis and peer review, meaning eruptions occurring late in 2026 may not receive confirmed VEI ratings until well into 2027; the March 2027 resolution deadline accounts for this lag but does not eliminate it entirely. Second, the distinction between a VEI 3 and VEI 4 eruption can be marginal and subject to revision, so borderline events carry classification uncertainty. Third, the geographic distribution of active volcanoes — particularly in the Pacific Ring of Fire, Indonesia, Central America, and Iceland — means that regional seismic cycles and magmatic recharge rates influence base probabilities, though these are difficult to predict on annual timescales. Fourth, the market excludes eruptions that began before 1 January 2026, which introduces a definitional question for long-duration eruptions spanning year boundaries. Fifth, if the GVP database is unavailable or incomplete by the resolution deadline, the fallback to USGS and observatory consensus introduces a degree of source ambiguity that could affect close outcome calls.

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