In recent years, we had seen several studies, one Japanese study in particular, which looked at the relationship between strong earthquakes and the activity of the Sun as it enters its minimum phase. This study concluded that it appeared that the number of strong earthquakes globally increased during solar minima.

An additional more recent and specific study also piqued our interest--a paper published in 2015 in the Journal “Concepts in Global Tectonics” by John Casey and Dong Choi -- which looked specifically at earthquakes in the New Madrid Seismic Zone in the United States, and deep solar minima. This region, located in the interior of the United States, stretches southwest from New Madrid, Missouri and encompasses parts of the states of Illinois, Indiana, Missouri, Arkansas, Kentucky, Tennessee, and Mississippi. Quakes in continental interiors typically have high fatality rates.

This region had 4 major 8.0+ magnitude earthquakes from December 1811-February 1812, during the Dalton Minimum (which included the “Year Without a Summer” of 1816), as well as during other periods of intense seismic activity during solar grand minima.

According to Casey and Choi, the past four strong periods of earthquake activity in this zone have all occurred during periods of very low solar activity-- during the Sporer (1450), Maunder (1699), Dalton (1811-12), and Centennial (1895) Grand Minima.