Are earthquakes on Earth triggered by solar flares in space? New light on the old debate

Whether earthquakes could be intensified or triggered by solar activity like flares has been a mystery, but new research sheds some light.

Solar flares could geomagnetically "activate" certain faults and earthquake zones.
Solar flares could geomagnetically "activate" certain faults and earthquake zones.

The question of whether solar activity such as solar flares connect to the Earth’s seismic activity has been debated for over a century and a half. Many research publications have eluded to the potential influence of the Sun on the Earth’s seismic activity but no conclusion or common consensus has been reached. Many scientists have denied the possible connection between Sun activity and lithosphere processes that contribute to earthquakes.

Research results have been relatively ambiguous and uncertain, as the debated has continued. A recently published 2024 article in MDPI by Sorokin and Novikov states that the previous studies addressing this question avoided certain detail, and only took a statistic analysis of seismological and geophysical data to find a positive or negative correlation between the sun and Earth’s seismic signals.

“The physical mechanisms of solar–terrestrial relations that resulted in the possible triggering of EQs were not considered in detail, and their possible existence was only indicated phenomenologically when a statistically significant relationship has been found between solar activity and the response of the Earth’s seismicity,” the authors wrote in their recent publication.

“Such a simplified approach to the study of the solar–terrestrial relationships may provide false results and incorrect conclusions, and no practical recommendations may be proposed for seismic risk mitigation.”

In addition to doing a statistical analysis of the impact of the top 50 “X-class” solar flares from 1997 to 2024 on seismic activity across Earth, as well as earthquake preparation zones, a method of superposition showed that increases in seismicity was observed during the 10 days after a solar flare (in contrast to the following 10 days).

Earth-based observations along earthquake-prone areas

They observed from the case study of a magnitude 9.1 earthquake on the Sumatra-Andaman Islands on 26 December 2004 which showed a correlation. This was also the case with the Darfield earthquake in New Zealand from September 2010 where it seemed X-class solar flares triggered two strong aftershocks. This was along New Zealand's Port Hills fault – supposedly sensitive to external electromagnetic forces on an electrical conductive level.

New Zealand tilted rocks.
Earthquakes in New Zealand have shaped the country, leading to tilted beds and dramatic landscapes.

These possible “electromagnetic triggering impacts” on vulnerable faults (rock fractures) along the earthquake preparation zones studied on Earth could potentially aid the forecasting of earthquakes ahead of time. They suggest however that this should have use restricted to earthquake-prone areas with conductive crustal fault types.

In answer to the question, it would appear based on the study that solar flares do seem to correlate with some strong earthquake events, but only in specific parts of the world with particular types of faults.

Source of the science news:

Possible Interrelations of Space Weather and Seismic Activity: An Implication for Earthquake Forecast (2024). Geosciences. MDPI.