Trader consensus on Polymarket reflects a 90.5% implied probability for no magnitude 9.0+ earthquake before 2027, driven by the extreme rarity of such megathrust events, which require full-margin rupture along major subduction zones like Cascadia or Nankai amid accumulated strain over decades. USGS global monitoring shows no precursory seismic swarms, slow-slip events, or strain anomalies signaling an imminent great quake in the roughly eight months remaining, consistent with historical frequency of one to three M9+ globally per century—none since the 2011 Tohoku 9.1. Recent April 2026 M7.4 off northern Japan highlights ongoing subduction activity but falls far short of M9 thresholds. Realistic challenges include a surprise Cascadia full rupture (10-15% odds over 50 years per USGS), though short-term models show negligible risk; continuous seismic data updates from USGS could shift sentiment if anomalies emerge.