For centuries, people have speculated about the Moon’s influence on Earthly events. Could its gravitational pull affect human behavior? Could it influence the weather?
And more recently, could it trigger earthquakes?
While these ideas have often been dismissed as myths, new research suggests there might be some truth to at least one of them.
A study conducted by researchers at the University of Tokyo has found that large earthquakes are more likely to occur during a full or new Moon—the two lunar phases where tidal stresses on Earth are at their peak.
By analyzing seismic data from three separate databases—including global records as well as regional data from California and Japan—scientists have identified a significant correlation between tidal forces and major seismic activity.
How the Moon’s Gravity Influences Earthquakes
At certain points in the lunar cycle, the Sun, Moon, and Earth align, amplifying the gravitational pull exerted on our planet. .
This alignment creates strong tidal forces, which we typically associate with ocean tides.
But these forces don’t just affect water—they also exert pressure on Earth’s crust and its many fault lines.
The Tokyo researchers reconstructed the tidal stresses leading up to major earthquakes with magnitudes 5.5 or greater over the past two decades.
Their findings were eye-opening: nine of the 12 largest earthquakes in the study—including the devastating 2004 Sumatra earthquake (9.3), the 2010 Maule earthquake in Chile (8.8), and the 2011 Tohoku-oki quake in Japan (9.0)—occurred near a new or full Moon.
Small Quakes vs. Big Ones
For years, scientists have debated whether tidal forces could influence earthquakes.
Some studies had shown a connection between the Moon’s position and tiny tremors, but skeptics argued that these forces weren’t strong enough to impact large-scale seismic events.
However, this new study challenges that assumption.
While the researchers found no clear link between small earthquakes and tidal stresses, they did observe something even more intriguing: as tidal stresses increase, so does the proportion of large earthquakes relative to small ones.
This suggests that while the Moon may not be responsible for triggering small quakes outright, it could play a role in determining which minor tremors escalate into catastrophic seismic events.
Could a Full Moon Predict the Next Big Earthquake?
If major earthquakes tend to occur around new and full Moons, does that mean we could use the lunar cycle as an early warning system? Not so fast.
Although the study establishes a strong correlation between tidal forces and major earthquakes, correlation is not causation.
Earthquake activity is primarily driven by tectonic processes deep within the Earth’s crust, where massive plates grind against each other until the pressure reaches a breaking point.
As Nicholas van der Elst, a seismologist from the US Geological Survey, explains: “The tides just add a little—1 percent or less—additional push on top of that tectonic loading.
Even though it’s a small contribution, it could be just the amount of stress that is the ‘straw that breaks the camel’s back.’”
A Small But Crucial Factor
Ultimately, while the Moon’s gravitational pull does not cause earthquakes on its own, it appears to be one of many contributing factors that can influence their timing and severity.
The idea that the Moon could influence seismic activity is no longer just speculation—it’s a measurable phenomenon backed by scientific data.
However, until we fully understand the complex interplay of forces that govern earthquakes, the Moon’s role will remain a fascinating but incomplete piece of the puzzle.
What this research does make clear is that seismic forecasting is more complicated than we ever imagined, and we may need to look beyond just tectonic shifts to get the full picture.
So the next time you look up at a full Moon, consider this: somewhere deep beneath the Earth’s surface, a fault line might be feeling the pull.
But whether that pull leads to disaster? That’s still up to chance.
