This prediction market asks how many volcanic eruptions with a Volcanic Explosivity Index (VEI) of 4 or higher will occur in 2026. VEI is a logarithmic scale used to measure the explosivity of volcanic eruptions, ranging from 0 (non-explosive) to 8 (mega-colossal). A VEI 4 eruption is considered 'cataclysmic,' ejecting at least 0.1 cubic kilometers of tephra, with column heights exceeding 10 kilometers. Examples include the 2010 Eyjafjallajökull eruption in Iceland, which disrupted air travel across Europe, and the 2011 eruption of Grímsvötn. VEI 5 eruptions are 'paroxysmal,' like the 1980 Mount St. Helens event, while VEI 6 includes the 1991 Pinatubo eruption, which cooled global temperatures by about 0.5°C for a year. The market resolves based on data from the Smithsonian Institution's Global Volcanism Program (GVP), which maintains a comprehensive database of Holocene volcanoes and their eruptions, assigning VEI values where possible. The GVP's annual summaries, typically updated in early January, provide the official count for the prior year. The question is of interest not only to volcanologists but also to economists, insurers, and policymakers, as large eruptions can have significant regional and global impacts, including aviation disruption, agricultural damage, and short-term climate effects. The market also taps into broader discussions about whether volcanic activity is increasing, with some studies suggesting that the apparent uptick in recorded eruptions is due to better monitoring and reporting rather than a real increase. The resolution period is January 1 to December 31, 2026, Eastern Time, and the market will use the GVP's cumulative figures for VEI 4, 5, and 6, as specified on their FAQ page 'Eruptions Avg 2000-2024 (N/T).' This is a niche but data-driven market, attracting forecasters who follow geological and atmospheric science.

Historical Context

The Volcanic Explosivity Index was introduced in 1982 by Chris Newhall of the USGS and Stephen Self of the University of Hawaii to provide a comparative measure of eruption size. It is a base-10 logarithmic scale, so a VEI 5 eruption is 10 times more explosive than a VEI 4. Since the index's inception, the GVP has cataloged eruptions back to the Holocene (about 12,000 years ago), but VEI assignments for older events are often uncertain. For the modern era, from 1950 onward, the record is more complete due to improved monitoring and communication. According to GVP data, the average number of VEI 4+ eruptions per year since 2000 is about 6.6, but this varies widely: 2002 had 11, while 2005 had only 3. The most recent VEI 5 eruption was in 2022, when the Hunga Tonga-Hunga Ha'apai volcano in Tonga erupted with a VEI 5 (some estimates suggest VEI 6), causing a global tsunamigenic wave and injecting a record amount of water vapor into the stratosphere. The year 2023 saw no VEI 5 or higher, but there were several VEI 4 events, including eruptions at Shiveluch in Russia and Nilgufu in Tonga. The GVP's 'Eruptions Avg 2000-2024 (N/T)' page shows that the average number of VEI 4 eruptions per year is 5.6, VEI 5 is 0.8, and VEI 6 is 0.1. This historical baseline is what the market will compare against. Notably, the 1990s had a cluster of large eruptions, including Pinatubo (1991, VEI 6) and Mount Hudson (1991, VEI 5), but the 2000s were relatively quiet, with no VEI 6. The 2010s saw the Eyjafjallajökull VEI 4 and the 2011 Grímsvötn VEI 4, but no larger events until 2022. This variability is driven by plate tectonics and magma supply, not by climate change, though some research suggests that glacial retreat might affect volcanic activity in some regions.