Are major earthquakes more common on full moon days?
No difference
There is no difference you could use for everyday disaster preparedness. Be prepared regardless of the moon.
- Average (whole period)
- 0.32 per day
- Full moon days (±24h)
- 0.31 per day
- New moon days (±24h)
- 0.32 per day
- Verdict for days with today's moon phase (age 25.7)
- No difference
- Data
- 1973–2026, USGS global catalog, 6,334 events after aftershock removal
Today's numbers
M6+ earthquakes in the last 7 days: 7 (average since 1973: 2.7 per week)
Latest M6+ earthquakes and the moon age at each
- June 10, 2026M6.0Auckland Islands, New Zealand regionMoon age 24.2 days
- June 8, 2026M6.1102 km WNW of Mantua, CubaMoon age 22.9 days
- June 8, 2026M6.520 km WSW of Balangonan, PhilippinesMoon age 22.2 days
- June 7, 2026M6.06 km SSW of Pangyan, PhilippinesMoon age 22.2 days
- June 7, 2026M6.016 km WSW of Balangonan, PhilippinesMoon age 22.2 days
They strike regardless of moon phase — living evidence for the verdict above. Updated daily.
Act II: If not the moon, what does?
Came looking for a difference? Here is a real one.
×12
In the 30 days after an M6+ earthquake, the same source region produces M6+ quakes at roughly 12× the normal rate (aftershocks and swarms).
About 15% of M6+ earthquakes are follow-ups — within 30 days and close to a preceding quake of equal or greater magnitude.
Watching the 30 days after a big quake is, by the data, far more rational than watching the moon.
How this verdict is computed
Every day we pull magnitude 6.0+ earthquakes since 1973 from the USGS global earthquake catalog. We deliberately ignore smaller quakes: detection networks have improved over the decades and vary by region, so small-magnitude counts are dominated by observation bias rather than actual seismicity.
Large earthquakes are followed by swarms of aftershocks. Counting them naively would let a single mainshock that happens to land near a full moon pile hundreds of events onto the "full moon" side. We therefore apply a simple declustering rule: events that occur close to a larger earlier event (same source region, within 30 days, smaller magnitude) are removed as aftershocks.
For each remaining earthquake we compute the time difference (in UTC) between the event and the nearest full moon instant. Events within ±24 hours of the full moon instant are compared against the count you would expect if earthquakes ignored the moon entirely. The same calculation is done for new moons. Whether the difference is statistically meaningful is evaluated internally and translated into the one-word verdict at the top of this page. See the methodology for the exact criteria.
Is the moon really irrelevant to earthquakes?
Whether tidal forces can trigger earthquakes is actually a serious research topic (tidal triggering). The gravitational pull of the moon and sun does exert a tiny stress on the crust, and some studies have reported small statistical correlations under specific conditions (shallow thrust faults where tidal stress aligns with fault motion, for example).
The effects in those studies are extremely small — nothing that would justify "full moon days are dangerous." Our verdict answers a narrower question: are major earthquakes visibly more frequent on calendar full moon days? It does not contradict tidal research.
Sources
- USGS Earthquake Catalog — earthquake event data (public domain)
- Moon phase instants computed in-house from Jean Meeus, "Astronomical Algorithms" (UTC)
Last updated: June 11, 2026 13:31 UTC (rebuilt daily)