Resolution criteria

This market resolves to YES if Mount Aso (also known as Asosan) in Kumamoto Prefecture, Japan, undergoes an officially confirmed volcanic eruption at any point from January 1, 2026, through December 31, 2026, at 23:59 UTC. If no volcanic eruption occurs during this timeframe, the market resolves to NO.

An "eruption" is defined as an event where volcanic material (such as ash, lava, or pyroclastic flows) is actively ejected from the volcano, going beyond typical fumarolic steam emissions or passive outgassing. An increase in the volcanic alert level (such as to Level 3 or higher) by authorities without an actual eruptive event will not qualify the market for a YES resolution.

The primary sources of truth for resolving this market will be:

• Japan Meteorological Agency (JMA) Volcanic Warnings and Information: jma.go.jp

• Smithsonian Institution Global Volcanism Program report for Asosan: volcano.si.edu

Background

Mount Aso is one of Japan's most active and largest volcanoes. Its last confirmed eruption occurred in October 2021.

On August 14, 2026, the Japan Meteorological Agency (JMA) raised the volcanic alert level for Mount Aso from Level 2 to Level 3 (Do not approach the volcano/Entry restriction). The decision followed a sharp increase in the amplitude of volcanic tremors beginning on August 12, 2026, and a dramatic rise in sulfur dioxide gas emissions, which exceeded 2,000 tons per day. The JMA warned of an elevated risk of an eruption capable of ejecting large volcanic blocks and generating pyroclastic flows within a 2-kilometer radius of the Nakadake First Crater, though no eruption has actively begun as of mid-August 2026.