Researchers at Kyoto University have introduced a groundbreaking theoretical model suggesting that disturbances in the ionosphere particularly those triggered by intense solar activity may influence earthquake initiation under specific geological conditions.
The study does not claim to predict earthquakes. Instead, it proposes a physical mechanism through which variations in ionospheric charge, caused by phenomena such as solar flares, could exert electrostatic forces within fragile zones of the Earth’s crust and potentially contribute to fracture processes when faults are already near failure.
New Electrostatic Model of the Earth–Ionosphere System
According to the researchers, fractured regions within the Earth’s crust may contain high-temperature, high-pressure water, possibly in a supercritical state. These zones are theorized to behave electrically like capacitors. In this configuration, they are capacitively coupled with both the Earth’s surface and the lower ionosphere, forming a large-scale electrostatic system.
During periods of strong solar activity, electron density in the ionosphere increases significantly. This can create a negatively charged layer in the lower ionosphere. Through capacitive coupling, the resulting space charge may induce strong electric fields inside nanometer-scale voids within fractured crustal regions.
The researchers estimate that these induced electric fields could generate electrostatic pressures reaching several megapascals magnitudes comparable to tidal or gravitational stresses known to influence fault stability.
Space Weather and Seismic Activity
The study highlights that ionospheric anomalies including increased electron density, lowered ionospheric altitude, and abnormal propagation of medium-scale traveling ionospheric disturbances have repeatedly been observed prior to major earthquakes.
Traditionally, scientists have interpreted such anomalies as consequences of stress accumulation within the Earth’s crust. However, the new model introduces a complementary perspective: the interaction between the Earth’s crust and the ionosphere may be bidirectional.
In other words, while tectonic stress may disturb the ionosphere, ionospheric disturbances themselves could also exert feedback forces on the crust. This framework does not suggest direct causation but provides a possible physical link between space weather phenomena and seismic processes.
Observations from Recent Earthquakes
The researchers reference recent large earthquakes in Japan, including the 2024 Noto Peninsula earthquake, noting that intense solar flare activity occurred shortly before these seismic events. They stress that temporal coincidence does not prove a direct causal relationship. However, the timing is consistent with the proposed mechanism, in which ionospheric disturbances may act as a contributing factor when tectonic systems are already in a critical state.
Expanding the Understanding of Earthquake Mechanisms
By integrating plasma physics, atmospheric science, and geophysics, the proposed model broadens the conventional understanding of earthquakes as processes driven solely by internal Earth dynamics. The findings suggest that external factors particularly space weather could play a role under certain circumstances.
The researchers emphasize that further investigation is needed. Future studies will combine high-resolution ionospheric tomography based on Global Navigation Satellite System data with detailed space weather observations to determine when and how ionospheric disturbances might exert meaningful electrostatic influence on crustal structures.
While earthquake prediction remains beyond current scientific capability, the new model offers a fresh avenue for exploring how complex Earth space interactions may contribute to seismic activity, potentially improving long-term understanding of earthquake initiation and hazard assessment.