New study shows the Sun and Moon's pull may trigger San Andreas earthquakes

Sun And Moon's Pull Can Trigger San Andreas Earthquakes

Earthquakes can be caused by the sun and moon's gravitational forces, finds new research.

The recently published paper, led by the U.S. Geological Survey, focuses on the 800-mile-long San Andreas fault in southern California.

After assessing more than 80,000 tremors in the area between 2008 and 2015, the team determined that they occurred more actively during periods when the tides were becoming stronger.

While tides exhibit 12 and 24-hour cycles, there is also a longer one involving the alignment of the sun and moon to Earth which lasts 14 days (fortnightly cycle); this is the span the team used.

According to a study summary, "deep, small earthquakes on the San Andreas Fault are most likely to occur during the waxing fortnightly tide—not when the tidal amplitude is highest, as might be expected, but when the tidal amplitude most exceeds its previous value."

Just as gravitational pulls impact ocean currents, they can also shift the Earth's plates.

The hope is that this research can help to better predict earthquakes in the future, notes Gizmodo.

Active fault lines/zones in the United States:

Active fault lines/zones in the United States -- earthquakes
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Active fault lines/zones in the United States -- earthquakes

The Alaska-Aleutian Megathrust is located across 3,600 kilometers between Kamchatka, Russia to the Gulf of Alaska.

(Photo by Daniel A. Leifheit via Getty Images)

The Cascadia Megathrust stretches along the coasts of Washington and Oregon up into Canada

(Photo via Encyclopaedia Britannica/UIG via Getty Images)

The Eastern Tennessee Seismic Zone runs from Alabama to Virginia and is responsible for four earthquakes in the past century. 

(Photo by Harrison Shull via Getty Images)

The Elsinore Fault Zone lies along the Santa Ana Mountains in Southern California

(Photo handout via NASA)

The Hayward Fault Zone runs along San Francisco Bay for 119 miles.

(Photo by Dave and Les Jacobs via Getty Images)

The Humboldt Fault (red) and the Midcontinent Rift System (green) are both located in Kansas and Nebraska. 

(Photo via Public Domain)

The Laguna Salada Fault runs from the US to Mexico and caused the 2010 Mexicali quake.

(Photo credit should read Daniel CONEJO/AFP/Getty Images)

The Moab Fault is located in Utah.

(By Andrew Wilson (Own work) [CC BY-SA 4.0], via Wikimedia Commons)

The New Madrid Fault Zone is located in Missouri.

(Photo via Public Domain)

The San Andreas Fault System runs along 1,300 kilometers in California. 


USA-EARTHQUAKE HISTORIC - Map of California visualizing earthquake activity over the past 25 years. Includes fault lines

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