Earthquake Prediction Markets vs. USGS: How Kalshi’s Daily Quake Markets Settle

By Arthur Angelo, PredictionScout Research · Updated Oct 15, 2026, 7:59 AM ET

Key findings

• Median miss 0.41 magnitude. The day’s biggest quake came in above the market median 13 times and below it 13 times over 26 days. Threshold contracts went the way the market leaned 184 of 236 times (78%).
• The forecast barely moves. Before the day starts, the market’s median sat between M5.6 and M5.9 on every scored day, while the day’s actual biggest quake ranged from M4.8 to M7.7. Earthquakes cannot be predicted day to day, so the market prices the typical daily maximum; most of its accuracy comes from contracts that settle once a quake happens during the day.
• Magnitudes get revised. On 13 of 44 days, the largest magnitude in today’s USGS catalog differs from the value Kalshi recorded at settlement. Kalshi settles on the magnitude USGS reports at the time, and markets are not reopened.
• Sep 11, 2026: settled range vs. today’s catalog. Kalshi recorded M6.6; USGS now lists the day’s largest at M6.5 (121 km NNE of Teluknaga, Indonesia). The “6.6 or higher” contract settled YES.
• Sep 18, 2026: settled range vs. today’s catalog. Kalshi recorded M5.5; USGS now lists the day’s largest at M5.3 (Kermadec Islands region). The “5.4 or higher” contract settled YES.
• Sep 21, 2026: settled range vs. today’s catalog. Kalshi recorded M5.5; USGS now lists the day’s largest at M5.3 (101 km SSW of Sarangani, Philippines). The “5.4 or higher” contract settled YES.
• Sep 27, 2026: settled range vs. today’s catalog. Kalshi recorded no qualifying quake; USGS now lists the day’s largest at M5.3 (Balleny Islands region). The “5.2 or higher” contract settled NO.
• Sep 29, 2026: settled range vs. today’s catalog. Kalshi recorded M5.6; USGS now lists the day’s largest at M5.5 (southern Mid-Atlantic Ridge). The “5.6 or higher” contract settled YES.
• Biggest day in the sample: Oct 9, 2026, M7.7 (12 km WSW of Pitaloza Arriba, Panama). The market median before the day began was M5.7.

Day by day

“Kalshi recorded” is the highest expiration value Kalshi published for the day’s contracts. “Settled range” is bounded by the highest strike that settled YES and the lowest that settled NO.

Download the data

Daily earthquake markets vs USGS (CSV)

One row per settled market period. Per-contract price histories are not included. Free to reuse under CC BY 4.0 with a link back to this page.

Methodology

• Markets. Kalshi’s KXBIGGESTQUAKE series: daily ladders of “biggest earthquake worldwide will be X or higher” contracts for a UTC day, settled on the magnitude USGS reports. Prices are hourly bid/ask midpoints (or last trade) at 23:59 UTC the day before; the implied median is where the chance of “X or higher” crosses 50%.
• Official data. The USGS FDSN event service: the largest magnitude (any magnitude type) between 00:00 and 23:59:59 UTC, re-queried every run, so revisions show up here.
• Limits. Daily markets started in September 2026, so the sample is weeks, not years; magnitudes are revised for days or weeks after a quake; USGS magnitude types differ by quake size. Nothing here is investment advice. Last run: Oct 15, 2026, 7:59 AM ET.

Data sources: prices and volumes come from the public APIs of Kalshi and Polymarket, with earthquake data from the USGS. All trademarks belong to their owners. PredictionScout is independent and not affiliated with any exchange. Nothing here is investment, betting, or legal advice.

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