Can Sun trigger earthquakes? Scientists uncover how solar cycles and heat fluctuations add to seismic risks

Earthquakes have long been considered unpredictable, but new research suggests solar activity may play a role in triggering seismic events. Scientists at the University of Tsukuba in Japan have identified a link between sunspot cycles and earthquake occurrences, offering fresh insights into how fluctuations in the sun’s energy impact the Earth’s crust.

The sun follows an 11-year cycle, marked by shifts in sunspots, solar flares, and its magnetic field. During its most active phase — known as the solar maximum — solar radiation intensifies, affecting Earth’s atmosphere and climate. Now, scientists believe these changes may also make the planet’s surface more susceptible to seismic activity.  

Solar-driven temperature shifts alter rock properties and underground water movement, potentially making the Earth’s crust more prone to fractures. In regions where tectonic stress is already high, these fluctuations could provide the final push needed to trigger an earthquake.  

The link between solar activity and earthquakes first emerged in a 2022 study by Matheus Henrique Junqueira Saldanha and Yoshito Hirata at the University of Tsukuba. Their research found a correlation between sunspot activity and earthquake frequency, though the underlying mechanism remained unclear.  

To investigate further, the researchers developed a computational model combining historical sunspot data, surface temperature records, and earthquake statistics. Their findings revealed that rising surface temperatures, driven by solar radiation, increased the likelihood of shallow earthquakes in the upper crust.

Earth’s crust is highly sensitive to temperature and pressure changes. Increased solar activity heats the surface, causing rocks to expand, contract, and weaken over time, making them more prone to fracturing. Additionally, variations in rainfall and snowmelt — also influenced by solar cycles — can redistribute pressure along fault lines, subtly increasing seismic risk. While tectonic forces remain the primary driver of earthquakes, researchers suggest that external factors like solar heat may serve as additional triggers.  

Forecasting earthquakes remains one of the biggest challenges in geophysics. While scientists can estimate where earthquakes are likely to occur, pinpointing when they will strike is far more complex due to the sheer number of variables involved. By integrating solar activity and temperature fluctuations into existing prediction models, researchers hope to refine earthquake forecasts. Since shallow earthquakes appear most affected by these changes, this approach could be particularly useful for regions prone to surface-level seismic activity.  

However, scientists caution that this is just one piece of a much larger puzzle. While tectonic forces drive earthquakes, external influences like solar radiation may offer additional clues to improve prediction models. The study underscores the intricate relationship between the Earth and the sun, revealing how even subtle shifts in solar radiation can impact geological processes. Though further research is needed, these findings open a new frontier in earthquake science—one that incorporates space weather and solar physics into seismology.