Scan: Will there be exactly 0 confirmed VEI 4 or higher volcanic eruptions worldwide in 2026?

date	predicted	market price	confidence
2026-08-29	42%	46%	48%
2026-08-08	40%	52%	38%

1. Planner Fable 5.1 · Fermi decomposition + tool plan

Tools chosen: polymarket_direct polymarket_related kalshi_related article_search claude_news gdelt_news wikipedia code_execution

Sub-questions (Fermi decomposition)

Has any volcanic eruption in 2026 to date been reported or preliminarily assigned VEI 4 or higher by GVP, USGS, or national observatories (e.g., large Plinian eruptions with ash columns >20 km or significant SO2 loads)?
What fraction of years from 2000-2024 show zero VEI 4+ eruptions in the GVP 'Eruptions by year' table, and what is the mean annual count of VEI 4+ eruptions?
How quickly does GVP assign VEI ratings to recent eruptions — for prior years (e.g., 2023, 2024, 2025), how many VEI 4+ eruptions were listed on the GVP page within ~3 months after year-end versus later?
Are there currently elevated-alert volcanoes (e.g., Campi Flegrei, Iwo Jima/Ioto, Taal, Ruang, Lewotobi, Krakatau, Ulawun, Semeru) showing precursory unrest that raises the probability of a large explosive eruption in the remainder of 2026?
What do the sibling Polymarket markets in this event (exactly 1, exactly 2, 3+, etc.) imply about the distribution, and does the sum of prices reveal mispricing?
Does Polymarket's definition of 'confirmed' align with GVP's VEI listing, and could a borderline VEI 3/4 eruption (e.g., a '4?' rating) cause ambiguity?

Planner reasoning

This is a base-rate question with a strong data-lag wrinkle: GVP's yearly VEI tallies often lag, so 'exactly 0 confirmed VEI 4+' as of March 31, 2027 depends both on whether a large eruption actually occurs in 2026 and on how quickly GVP assigns VEI ratings. Historically roughly 1 VEI 4+ eruption occurs per year on average (2000-2024), but several individual years show zero confirmed VEI 4+ in the GVP table. The current market price plus any already-observed 2026 eruptions are the key anchors.

2. Research Parallel tool calls

tool	status	time	items	summary
polymarket_direct	OK	0.5s	1	## This Market's Polymarket Data Will there be exactly 0 confirmed VEI 4 or higher volcanic eruptions worldwide in 2026? - Current price (probability): 78.50% - 7-day price change: +31.00% - 30-day price change: +22.50% - Total volume: $499,626 (USD notional) - Price range: 42.00% - 78.50% - Da
polymarket_related	OK	2.2s	0	Scanned 100 active Polymarket markets, kept 0 matches. keyword 'volcano': 0 markets \| keyword 'VEI': 0 markets \| keyword 'eruption': 0 markets
kalshi_related	OK	2.1s	1	1 related markets / summaries. keyword 'volcano': ok \| keyword 'eruption': no matches \| keyword 'VEI': no matches
article_search	OK	0.4s	18	Fetched 18 unique articles across 3 queries (lookback=120d). 'large volcanic eruption 2026 VEI 4': 10 articles \| 'Plinian eruption ash column 2026 volcano': 10 articles \| 'Smithsonian Global Volcanism Program eruption 2026 explosivity index': 10 articles
claude_news	OK	31.3s	15	Based on research gathered: - GVP data page for 2026 (through 31 March 2026 update) shows there were 47 confirmed eruptions at some point during 2026 from 47 different volcanoes; 6 of those were new eruptions that started during the year — but this page does not indicate any VEI 4+ ratings fo
gdelt_news	OK	192.7s	20	GDELT: 20 articles across 3 queries (lookback=90d). 'volcano eruption ash column stratosphere 2026': 10 hits \| 'volcanic eruption VEI 4': error GDELT rate-limited after retries (429) \| 'major volcanic eruption evacuation 2026': 10 hits
wikipedia	OK	0.2s	3	Fetched 3 Wikipedia entries (1 missing pages).
code_execution	OK	21.1s	0	## Key Findings - Base rate (2000–2024, n=25 years): 8/25 years had exactly 0 VEI 4+ eruptions → empirical frequency = 32.0%. Mean annual rate λ = 0.92 eruptions/year (empirical distribution: 32% zero, 48% one, 16% two, 4% three — reasonably close to a Poisson shape). - **Full-year Poisson

3. Evidence Brief Sonnet 5 · 6273 chars

# Current state As of the latest available GVP database update cited in research (through 31 Mar 2026), the Smithsonian GVP has confirmed **zero VEI 4+ eruptions for 2026 to date**. Several large explosive events later in the year (Fuego, Anak Krakatau, Sinabung) have occurred but have **not yet been assigned a confirmed VEI rating** — GVP updates lag months behind real-time events, and final resolution depends on the cumulative GVP page as of March 31, 2027. # Timeline of key events - 2026-01-01 to 2026-03-31: GVP database updated through this period; **no VEI 4+ eruption confirmed** for 2026 (confirmed, GVP). - 2026-05-23: M6.0 earthquake near Kilauea, Hawaii; USGS forecasts next Kilauea eruptive episode for 5/24-5/27 (confirmed, USGS/CNBC). - 2026-06-28: Semeru and Lewotobi Laki-laki (Indonesia) erupt repeatedly same day (reported, GDELT). - 2026-07-01 to 07-16: Taal (Philippines) ash plume ~4,000 ft; separate Philippine volcano eruption noted, scientists monitoring closely (reported). - 2026-07-05 to 08-17: Etna (Italy) sustained eruptive/ash-emission phase; ash to 15,000 ft; American tourist killed nearby (reported). - 2026-08-04: Fuego (Guatemala) major eruption; second-highest national alert, evacuations, officials warn volcano "moving toward a more explosive phase" (confirmed widely reported, no VEI assigned yet). - 2026-08-24 to 08-30: Anak Krakatau erupts six times in one morning; Lewotobi ash plume ~2.5 km (reported). - 2026-09-02/03: Mount Sinabung eruption, 615 evacuated (reported). - 2026-09-04/05: Anak Krakatau high-level eruption, ash column to ~15 km (50,000 ft) — largest plume in dataset (reported, VEI unassigned). # Event Will GVP confirm exactly 0 VEI 4+ volcanic eruptions worldwide for calendar year 2026 (resolved via GVP data as of March 31, 2027)? # Outcomes to forecast Yes (0 confirmed VEI 4+) / No (1+ confirmed) # Kalshi market anchor No kalshi_direct price was returned for this ticker in research. Best available anchor is the sibling **Polymarket market on the identical question**: current YES (0 eruptions) price **78.5%**, up sharply from a 90-day low of 42% (+31% in 7 days, +22.5% in 30 days), $499,626 volume. This suggests markets have moved decisively toward "no VEI4+ yet confirmed" as 2026 progresses without a confirmed rating, despite several large candidate eruptions. # Sub-question answers 1. **Any 2026 eruption reported/prelim VEI4+?** No formal VEI4+ confirmation yet. Candidates awaiting rating: Fuego (Aug), Anak Krakatau (Sept, ash to 15km), Sinabung (Sept). [claude_news] 2. **2000-2024 base rate:** 8/25 years (32%) had zero VEI4+ eruptions; mean annual count ≈0.92; Poisson model gives ~40% baseline P(0) for a full year. [code_execution] 3. **GVP assignment lag:** Database updates occur ~quarterly (e.g., Sep, Nov, Dec, Mar); VEI ratings for a given year's eruptions are often not finalized until many months later, sometimes past year-end. [claude_news] 4. **Elevated-alert volcanoes:** Fuego (2nd-highest alert, escalating), Anak Krakatau (repeated high ash eruptions), Sinabung (evacuations), Lewotobi/Semeru (frequent activity), Sakurajima (alert 3/5, intensified since Aug), Kilauea (episodic eruptions forecast). None confirmed to have crossed VEI4 threshold yet. [gdelt/claude_news] 5. **Sibling Polymarket distribution:** A separate "exactly 3" bucket market exists; a VEI≥6 market prices only 8% Yes (low tail risk). One claude_news snippet cites older/possibly stale pricing (~41-47%) inconsistent with the 78.5% polymarket_direct figure — likely reflects a different/earlier market snapshot; treat with caution. 6. **"Confirmed" vs GVP ambiguity:** Research flags that GVP sometimes uses provisional "4?" ratings and long confirmation lags, creating dispute risk near the resolution deadline, but no specific 2026 borderline case identified yet. # Key facts (high-confidence, factual) 1. [GVP] No VEI4+ confirmed for 2026 through the most recent cited database update. 2. [code_execution] 32% of 2000-2024 years had zero VEI4+ eruptions; mean ~0.92/year. 3. [CBS/BBC/AlJazeera] Fuego (Guatemala) erupted violently Aug 4, 2026, prompting evacuations. 4. [Watchers.news/Tempo] Anak Krakatau had a high-ash eruption (~15km) Sept 4-5, 2026. 5. [Polymarket] Direct market price for "exactly 0" = 78.5%, up steeply over 30 days. # Cross-market signals - Kalshi related: "Supervolcano erupt before 2050" priced 27.9% (different timeframe/threshold, not directly comparable). - Polymarket (same question): 78.5% Yes, strong upward momentum. - Polymarket (VEI≥6 in 2026): 8% Yes — low tail risk, supports no mega-eruption. - No sportsbook data applicable. # Analyst opinions and speculation - claude_news synthesis argues "exactly 0" is "plausible but not highly likely," estimating true probability in 40-65% range given base rates and unrated H2 2026 eruptions — notably more bearish on Yes than the 78.5% market price. - Code_execution model: full-year P(0) baseline ~40%, but adjusting for reporting lag and ~3 months remaining in 2026 pushes P(0) toward 60-80%. # Directional lean per outcome - **Yes (0 confirmed):** Supported by market momentum (78.5%, rising), no formal VEI4+ rating yet, historical GVP lag often delays/dilutes confirmations, only 32% base-rate years, but recent momentum suggests confidence building through H2 2026. - **No (1+ confirmed):** Supported by multiple significant unrated eruptions (Fuego, Anak Krakatau, Sinabung) with real potential to be later rated VEI4+, base rate mean ~0.92/year (>50% chance of at least one historically), and resolution won't finalize until March 2027 giving time for upgrades. # Gaps / unknowns - No direct Kalshi price for this ticker was retrieved. - No official VEI has been assigned to Fuego, Anak Krakatau, or Sinabung 2026 events in sourced research. - Discrepancy between polymarket_direct (78.5%) and claude_news-cited "41%" figure unresolved — likely different/stale market. - Unknown how GVP will resolve provisional/ambiguous VEI ratings near March 2027 deadline. # Calibration anchors - Polymarket YES (proxy anchor): 78.5%, sharply up from 42% low. - Historical base rate: 32% empirical zero-years; ~40% Poisson-modeled. - Reporting-lag-adjusted model estimate: 40-65% (later-year favors higher).

4. Forecasters Fable 5.1 + GPT-5.6 Sol · in parallel

claude-fable-5-1

45% conf

Yes	70%
No	30%

The best anchor is the identical Polymarket question at 78.5% Yes, and GVP has confirmed zero VEI 4+ eruptions for 2026 through its latest update, with no candidate event formally rated. However, the base rate (only ~32% of 2000-2024 years had zero VEI 4+, mean ~0.92/yr) implies roughly a 20-25% chance of a new VEI 4+ in the remaining ~3.5 months alone, and several large unrated 2026 events (Anak Krakatau's ~15 km plume, Fuego's escalating explosive phase, Sinabung) carry real upgrade risk before the March 2027 GVP resolution snapshot. GVP's confirmation lag and tendency toward provisional ratings modestly favor Yes, but not enough to fully justify the market's recent sharp run-up, so I shade below the anchor to ~70%.

gpt-5.6-sol

57% conf

Yes	70%
No	30%

The best market anchor is the identical Polymarket question at 78.5% Yes, reflecting that no VEI 4+ eruption has yet been formally confirmed. The historical zero-eruption rate of 32–40% is less favorable, but reaching September without a confirmed qualifying event and GVP's substantial assignment lags raise the conditional probability of zero for 2026. Fuego, Sinabung, and especially Anak Krakatau's roughly 15 km plume remain credible candidates for a later VEI 4 rating, so I discount Yes below the market anchor. The low 8% price for any VEI 6+ event limits the extreme tail but does not materially eliminate VEI 4 risk.

5. Devil's Advocate Sonnet 5 · red-team critique

Both forecasts land on identical 0.700 despite claiming independent reasoning—this convergence looks like simple anchoring to the Polymarket 78.5% figure with an arbitrary "shade down" rather than genuinely independent modeling of the specific candidate eruptions.

Neither forecast quantitatively engages with the plume-height evidence: Anak Krakatau's ~15km (50,000ft) ash column on Sept 4-5 is in a range historically associated with VEI 4 (typically >10-25km plumes), yet this strong physical signal isn't translated into an explicit probability of upgrade—both just gesture at "credible candidate" without estimating P(Anak Krakatau rated VEI4+).

Neither decomposes the problem into its two distinct components: (a) P(one of the *already-occurred* unrated H2 2026 eruptions—Fuego, Anak Krakatau, Sinabung—eventually gets confirmed VEI4+) vs (b) P(a *new* eruption in the remaining Oct-Dec window crosses threshold). Conflating these obscures that most of the real uncertainty by September is about rating outcomes for known events, not new occurrences, and the base-rate Poisson framing (which is about full-year event counts) is a poor proxy for (a).

The brief explicitly flags a discrepancy between the 78.5% Polymarket price and a stale claude_news citation of ~41-47%—neither forecaster addresses whether this divergence undermines confidence in the market anchor itself (e.g., thin liquidity, snapshot timing), instead treating 78.5% as a solid, reliable reference point.

Neither forecast considers GVP's historical tendency to under-confirm VEI4 for many large explosive eruptions (i.e., what fraction of "major eruption with evacuations/high ash" events in the 2000-2024 base rate actually resolved at VEI4+ vs VEI3)—this reference-class detail would help calibrate whether Fuego/Sinabung-type events are more likely to resolve below threshold, which matters directly for the Yes case.

Both treat the 32% empirical zero-rate and ~40% Poisson estimate as the "unconditional" prior, but by September 2026 three-quarters of the year has already passed with zero confirmed VEI4+, which should sharply update the conditional probability upward (survival-analysis style)—this updating logic is asserted but not shown quantitatively, leaving unclear how much of the jump from ~40% base rate to ~70% final estimate is justified by time-elapsed vs. market anchoring alone.

6. Aggregator Fable 5.1 · final calibrated forecast

72% (51% confidence)

Yes: 72% No: 28%

Decomposing as the critique suggests: (a) the already-occurred H2 events (Fuego, Sinabung, Anak Krakatau's ~15 km plume) are the main risk, but historically these volcanoes' large paroxysms have mostly resolved at VEI 3 (Fuego 2018, Anak Krakatau 2018, most Sinabung episodes), since VEI depends on erupted volume rather than plume height alone, so P(one gets confirmed VEI 4+ by March 2027) is roughly 12-15%; (b) a new VEI 4+ in the remaining ~3.5 months at ~0.92/yr base rate gives ~20% occurrence, discounted for GVP confirmation lag before the March 2027 snapshot to ~13-15%. Combining gives P(Yes) ≈ 0.72-0.75, which sits just below the liquid Polymarket anchor of 78.5% (sharp recent rise, plausibly reflecting a GVP update that left the candidate events unrated) and slightly above both forecasters. The stale ~41-47% citation is most likely an earlier snapshot and does not undermine the current anchor. I settle at 0.72 Yes, shading modestly below market for residual upgrade and Q4 eruption risk.

Pipeline Timing

Total pipeline time: 343.1s

Per-tool research timings shown in the Research section above.