Tidal triggering of earthquakes

Tidal triggering of earthquakes is the idea that tidal forces may affect when earthquakes happen. This means that the gravitational pull of the sun and moon can influence the timing of earthquakes. When the sun and moon line up, creating the strongest tidal forces, they might push rocks that are already stressed to break and cause earthquakes.

Amplitude of the ocean tide at Golden Gate Bridge for five weeks in 1970. Brackets indicate seismic window periods as defined by Jim Berkland.

Scientists have studied this connection for over a century. They thought that more earthquakes might happen during times of strong tides, like during new and full moons. However, the results have been mixed. In most places, there isn’t a clear link between strong tides and more earthquakes. Some studies suggest that earthquakes might actually be more likely during low tides, especially for certain types of faults.

Even though the evidence isn’t strong for most earthquakes, scientists have found that very small tremors, especially near volcanoes, can be triggered by tidal forces. Volcanologists use these regular tidal movements to test their instruments for monitoring volcanoes. So, while tidal forces might not often trigger big earthquakes, they do play a role in some types of seismic activity.