Tools chosen: kalshi_direct kalshi_related polymarket_related wikipedia claude_news gdelt_news code_execution

Sub-questions (Fermi decomposition)

Planner reasoning

This is an ultra-long-horizon geological tail-risk question; the dominant consideration is the base rate of VEI-8 (or however Kalshi defines 'supervolcano') eruptions, which is on the order of once per 15,000–100,000 years, implying a ~0.03–0.2% chance over 25 years. The main sources of upward deviation are Kalshi's resolution definition (if it counts VEI-7 or 'supervolcano system' activity like Campi Flegrei/Taupō unrest) and the market's structural price floor/illiquidity. So I anchor on the Kalshi price, pin down the definition, and compute Poisson base rates.

# Current state The market resolves YES only if an actual eruption occurs (Kalshi rules give no explicit VEI-8 threshold, but the true geologic definition of "supervolcano" = VEI-8). No VEI-8 eruption has occurred since Toba (~74,000 years ago) or Taupō/Oruanui (~25,600 years ago). All major supervolcano systems remain far from eruptive conditions; the market is currently priced at 24% YES, far above any credible base-rate estimate. # Timeline of key events - ~74,000 years ago: Toba (Indonesia) VEI-8 eruption — last unambiguous supervolcano-scale event (confirmed, geologic record). - ~25,600 years ago: Taupō Oruanui eruption, VEI-8 — most recent VEI-8 eruption on Earth (confirmed, Wikipedia/geologic record). - 2004-2009: Yellowstone experienced measurable uplift from magma injection (confirmed, USGS/Wikipedia). - 2022: Taupō alert level briefly raised; since returned to background (confirmed, GeoNet/volcano.si.edu). - 2025-01 to 2026-03: Campi Flegrei uplift accelerates to ~163.5cm cumulative (~25.5cm since Jan 2025) (confirmed, protezionecivile.gov.it). - 2026-05-20/21: Livescience/sott.net report "major eruption could be on the way" at Campi Flegrei; M4.4 quake hits region (reported — speculative headline framing). - 2026-07-31: M4.7 earthquake near Naples, strongest in ~40 years for the region; 26 injured, buildings collapse (confirmed, multiple outlets). - 2026-08-03/08-05: Families evacuated, hundreds displaced near Campi Flegrei following quake (confirmed, ansa.it). - As of Aug 2026: Campi Flegrei at yellow alert (unrest, not eruption-imminent); Yellowstone at GREEN/Normal; Taupō quiet; Long Valley routine monitoring (confirmed, USGS/volcanolive/GVP). # Event Will a supervolcano (VEI-8-class eruption) occur anywhere on Earth before Jan 1, 2050? # Outcomes to forecast Yes / No # Kalshi market anchor Current YES price: **24.00%** (kalshi_direct). 7-day change: +5%; 30-day change: -6%. Price range over 73 days: 16.80%–32.90%. Average daily volume: only 62 contracts — thin, illiquid market. No related Kalshi sub-buckets exist beyond this single ticker; Polymarket has no matching market. # Sub-question answers 1. **Current price/trend?** — 24.00% YES, recently up 5% over 7 days (likely tracking Campi Flegrei news), but down 6% over 30 days; volume is thin (~62 contracts/day) (kalshi_direct). 2. **How does Kalshi define "supervolcano eruption"?** — No explicit VEI-8 threshold or caldera list specified in public rules; traders note genuine ambiguity, and resolution is expected via major news outlet reporting (NYT/AP/Reuters) rather than a strict scientific definition (claude_news/octagonai.co). 3. **Historical VEI-8 frequency and Poisson probability to 2050?** — VEI-8 recurrence is estimated at 1-in-15,000 to 1-in-100,000+ years, implying a fair-value probability of only 0.02%–0.16% over the ~24 remaining years (code_execution). USGS separately estimates annual probability of a Yellowstone-scale supereruption at ~1-in-730,000 (~0.00014%) (claude_news). 4. **Current unrest at major calderas?** — Campi Flegrei is the standout: yellow alert, ongoing bradyseism, M4.7 quake (Jul 2026) causing injuries/evacuations, but officials maintain eruption is not imminent. Yellowstone (Normal/Green, magma only 5-15% molten), Taupō (quiet), Long Valley (routine monitoring) show no elevated risk (claude_news, multiple sources). 5. **Do other venues price this consistently?** — No Polymarket market exists; no other Kalshi sub-buckets to cross-check. Implied recurrence interval consistent with the 24% Kalshi price would need to be ~150-300 years for VEI-8 — inconsistent with any credible geologic base rate, suggesting market mispricing or resolution-ambiguity premium (code_execution). # Key facts (high-confidence, factual) 1. [Wikipedia] Supervolcano = VEI-8 eruption, >1,000 km³ deposits; last such eruption was Taupō ~25,600 years ago. 2. [USGS/claude_news] Yellowstone alert level: Normal/Green; magma chamber only 5-15% molten, not eruptible. 3. [protezionecivile.gov.it] Campi Flegrei uplift reached ~163.5cm by March 2026, with acceleration since 2025. 4. [ansa.it/multiple] M4.7 earthquake struck Naples region July 31, 2026 — strongest in 40 years, causing injuries and evacuations. 5. [code_execution] Fair-value probability for VEI-8 eruption by 2050 under realistic base rates: ~0.02%-0.16%. # Cross-market signals - Kalshi related: only this single ticker exists; no sub-bucket/date markets for arbitrage. - Polymarket: no matching markets found. - Sportsbook implied: none applicable. # Analyst opinions and speculation - Octagonai.co/covers.com note the ~20-24% market price is vastly inflated relative to USGS's ~0.00014% annual Yellowstone estimate, implying either sentiment-driven mispricing, illiquidity, or trader expectation that "supervolcano" will be loosely interpreted (e.g., Campi Flegrei VEI-7 event reported as "supervolcano eruption" by media). - Livescience/sott.net (May 2026) ran speculative "major eruption could be on the way" headlines re: Campi Flegrei — these are journalistic framing, not scientific consensus; protezionecivile and volcano observatories explicitly state eruption is not imminent. # Directional lean per outcome - **Yes**: Supported by elevated Campi Flegrei unrest/seismicity (though Campi Flegrei's largest known eruptions are VEI-7, not VEI-8) and by market's recent 7-day uptick; opposed by base-rate geology (VEI-8 recurrence measured in tens of thousands of years) and all monitoring agencies denying imminent eruption. - **No**: Overwhelmingly supported by VEI-8 base rates (0.02-0.16% fair value), current Normal/Green status at Yellowstone, and no historical VEI-8 event in living record; only real uncertainty is whether Kalshi loosely resolves YES on a lesser (VEI-7) "supervolcano-labeled" eruption like a Campi Flegrei event, given rules ambiguity. # Gaps / unknowns - No official Kalshi resolution source clarifies VEI-8 vs. looser "supervolcano" media framing — this ambiguity is the single biggest swing factor. - Unclear how a Campi Flegrei eruption (historically VEI-7 max) would be treated for resolution. - No polling of Kalshi rules committee statements found. # Calibration anchors - Kalshi current YES price: 24.00% (anchor). - Geologic base rate: last true VEI-8 was ~25,600 years ago (Taupō); implied annual probability ~0.0001%-0.007%. - USGS Yellowstone-specific estimate: ~1-in-730,000 per year (~0.00014%).

1. Both forecasters heavily discount the Kalshi 24% anchor, but neither seriously entertains that thin volume (62 contracts/day, 73-day range 16.8%-32.9%) plus the explicit resolution ambiguity noted in the brief ("resolution is expected via major news outlet reporting... rather than a strict scientific definition") could justify a YES probability meaningfully closer to the market price than either 6% or 12% — the brief's own "Gaps/unknowns" section flags this as "the single biggest swing factor," yet both treat it as a minor adjustment rather than the dominant driver of the estimate. 2. Forecast 1's explicit calculation (45% loose-resolution chance × 15-20% chance of a media-labeled eruption by 2050 ≈ 9-12%) conflates two probabilities that should compound differently over a 24-year horizon — a 15-20% chance of *any* Campi Flegrei-type eruption by 2050 seems arbitrarily high given current yellow-alert/non-imminent status, but this figure is never cross-checked against historical base rates for Campi Flegrei's own eruption recurrence (its last eruption was 1538). 3. Neither forecaster addresses the inconsistency that Forecast 1 lands at 12% (near the market's lower historical range) while Forecast 2 lands at 6% (near the bottom of that range) — both claim to weight the same "resolution ambiguity" factor identically but produce a 2x spread, and neither explains why their point estimate should sit where it does within that wide plausible band rather than elsewhere. 4. Both forecasts almost entirely ignore other supervolcano systems with historical unrest potential mentioned only tangentially (Yellowstone 2004-2009 uplift episode, Taupō's 2022 alert) — while correctly noting these are currently quiet, a 24-year window is long enough that a second unrest episode at a different system (not just Campi Flegrei) could independently trigger the same "loose media resolution" pathway, which neither model incorporates as an additional probability mass. 5. The brief notes analysts suggesting the market price may reflect traders "betting that media would label any Campi Flegrei eruption a 'supervolcano eruption'" — but neither forecaster considers the scenario where Kalshi's actual rules committee, when forced to adjudicate, defaults to a strict VEI-8 scientific standard (given "supervolcano" has a specific geologic definition per Wikipedia) and resolves NO even amid loud media claims, which would push the ambiguity-driven premium toward zero rather than the 6-12% currently assigned. 6. Both forecasts anchor confidence at exactly 0.62, but given the huge disagreement in point estimates (6% vs 12%, a 2x difference) and the genuine unresolved rules ambiguity flagged by the brief itself, this shared confidence level seems arbitrary rather than derived from any explicit uncertainty quantification around the resolution-ambiguity parameter.

6% (62% confidence)

Yes: 6% No: 94%

A true VEI-8 supereruption carries a fair-value probability of only ~0.02%-0.16% over the remaining ~24 years, and every major caldera (Yellowstone Green/Normal with 5-15% melt, Taupō quiet, Long Valley routine) is at background; Campi Flegrei's unrest is real but its maximum historical eruptions are VEI-7, officials say eruption is not imminent, and its own eruption recurrence (last 1538) makes even a moderate event only ~10-15% likely by 2050. The 24% Kalshi anchor deserves heavy discounting: it is a 24-year-horizon contract with no interest paid on collateral, so buying NO at ~76¢ yields ~1%/yr — a structural disincentive that inflates YES on thin volume (62 contracts/day) independent of any real information. The critique's strongest point cuts both ways: resolution ambiguity is indeed the dominant YES pathway, but a rules committee forced to adjudicate 'supervolcano' would plausibly default to the standard geologic VEI-8 definition, so the loose-resolution premium should be modest (~30-40% loose × ~15% chance of any media-labeled 'supervolcano' eruption ≈ 5%), not the market's implied 24%. I therefore side with the lower forecast rather than splitting the difference, landing near 6% — leaving room for both cross-system unrest pathways and genuine rules looseness while refusing to treat an illiquid, carry-distorted long-dated price as informative.

Total pipeline time: 259.9s