Japanese scientists have discovered new significant correlations between solar activity and earthquakes, according to recent research.
Japan is one of several countries that has long struggled with devastating seismic disturbances. In recent years, investigating how the tides and electromagnetic effects created by the sun and moon impact Earth’s seismology has become a significant avenue of research.
Tools that help forecast how tectonic plates will move, strain, and release energy can be vital in ongoing efforts to predict when potentially deadly earthquakes will occur, as well as those used in planning for emergencies that include evacuating cities in a natural disaster.
Earthquake Disasters
Japan’s Tōhoku earthquake hit a 9.0 magnitude on the Richter scale, generating a tsunami responsible for the Fukushima nuclear disaster and the loss of 18,000 lives. With such threats looming over the country, the University of Tsukuba and the National Institute of Advanced Industrial Science and Technology in Japan began their collaboration to explore how solar heat affects Earth’s climate to drive seismic activity, building on 2022 research linking sunspots with Earth’s seismic systems.
The Brazilian computer scientist behind the 2022 work, PhD candidate Matheus Henrique Junqueira Saldanha, is the first author of the resulting paper.
“Solar heat drives atmospheric temperature changes, which in turn can affect things like rock properties and underground water movement,” Junqueira Saldanha said. “Such fluctuations can make rocks more brittle and prone to fracturing, for example — and changes in rainfall and snowmelt can alter the pressure on tectonic plate boundaries. While these factors may not be the main drivers of earthquakes, they could still be playing a role that can help to predict seismic activity.”
Modelling the Earthquake and Sun Connection
Computer models combined earthquake data, solar activity records, and Earth surface temperatures, which the researchers analyzed to identify any causation links. The team considered many ways the sun may be driving Earthquakes, such as affecting the geomagnetic field, emitting particles toward the Earth, impacting tidal forces, and more.
It was initially challenging to link solar activity to a specific process on Earth generating quakes. Yet, the team found significant results when they considered the effect of solar activity on Earth’s surface temperature.
In their research, the team noted that including Earth’s surface temperatures improved forecasting accuracy, particularly in shallow quakes. Variations in seismic activity across seasons showed the correlation between temperature and earthquake activity.
“That makes sense, since heat and water mostly affect the upper layers of the Earth’s crust,” said Junqueira Saldanha.
Improving Earthquake Prediction
Moving forward, the research provides concrete evidence that calculating the transfer of solar heat to the Earth through detailed Earth surface temperature models based on solar activity predictions can improve Earthquake prediction accuracy.
A delayed sunspot time series the researchers studied showed a strong correlation to earthquakes, allowing for the timescales of heat transfer and their effect on the Earth’s systems. The authors caution that much research remains, and their data only presents a piece of the puzzle. Although their earlier work found significant links between the tides and earthquakes, unrelated studies have identified cosmic ray events associated with earthquakes, suggesting a complex interplay between Earth and the Sun.
“It’s an exciting direction, and we hope our study sheds some light on the bigger picture of what triggers earthquakes,” said Junqueira Saldanha.
The paper “The Role of Solar Heat in Earthquake Activity” appeared in Chaos, an interdisciplinary journal of nonlinear science, on November 28, 2024.
Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.