A magnitude 10.0 or greater earthquake has never been recorded in modern history. The strongest earthquake on record is the 1960 Great Chilean earthquake at magnitude 9.5. The Richter scale is logarithmic: each unit increase represents roughly 30 times more energy release. A 10.0 magnitude event would be extraordinarily catastrophic and would require unprecedented tectonic stress buildup. The market is pricing this at 5% probability through the end of 2026, reflecting consensus that such an event is extremely unlikely within the timeframe, though not impossible. Major earthquakes do occur—Japan experienced a 9.1 magnitude quake in 2011, and the 2004 Indian Ocean earthquake was 9.1—but 10.0+ events exist outside historical precedent. Resolution will be determined by seismic data from the USGS Earthquake Hazards Program and other authoritative monitoring networks. The low odds reflect the inherent stability of Earth's largest tectonic plates and the extreme energy requirements for such magnification.
Deep dive — what moves this market
The Richter magnitude scale, developed in 1935, quantifies the energy released by earthquakes on a logarithmic basis. Each whole number increase represents approximately 31 times more energy release. A magnitude 9.0 earthquake releases about 900 times the energy of an 8.0 event, and a 10.0 would be proportionally more energetic still. The largest recorded earthquake, the 1960 Great Chilean earthquake, registered 9.5 magnitude and killed approximately 1,600 people, triggering tsunamis across the Pacific. The 2011 Tohoku earthquake in Japan, at 9.1 magnitude, became the most powerful earthquake ever recorded in Japan and caused a massive tsunami that devastated coastal regions. These mega-thrust earthquakes occur at subduction zones where one tectonic plate slides beneath another, accumulating immense stress over centuries or millennia. For a 10.0 magnitude earthquake to occur, the stress accumulation and release mechanism would need to exceed anything observed in instrumental seismic history. Geologists monitor plate movement using GPS and other instruments, and current strain measurements on major subduction zones like the Cascadia Subduction Zone, the Nankai Trough, and the Japan Trench show elevated but not unprecedented stress levels. The Cascadia Subduction Zone, for instance, has a locked section that has not ruptured since 1700, creating potential for a very large earthquake, but most seismic models suggest a 9.0 to 9.2 magnitude as the upper bound for this zone, not a 10.0. What could push the market toward YES: discovery of new evidence of extreme long-term stress accumulation in an unmonitored subduction zone, a series of foreshocks indicating a mega-thrust rupture is imminent, or unforeseen physics in how tectonic energy dissipates. However, modern GPS networks and seismic monitoring cover Earth's major plate boundaries quite thoroughly, making a surprise 10.0+ event less likely than it would have been a century ago. What could push toward NO: ongoing instrumental data showing strain levels consistent with historical 8.5 to 9.5 magnitude events, continued absence of any 10.0+ magnitude events despite 150+ years of recording, and engineering models suggesting mechanical constraints of tectonic plates make energy release above 9.5 magnitude physically implausible. The current 5% odds reflect consensus that 10.0+ magnitude earthquakes are so far outside historical and theoretical precedent that traders assign them minimal probability, consistent with the scientific consensus that such an event is remote but not zero, especially given inherent uncertainty in long-term earthquake prediction.
