© Unsplash/CC0 Public Domain
Kyoto, Japan -- Researchers at Kyoto University have proposed a new physical model that
explores how disturbances in the ionosphere may exert electrostatic forces within the Earth's crust and potentially contribute to the initiation of large earthquakes under specific conditions.The study does not aim to predict earthquakes but rather presents a theoretical mechanism describing how ionospheric charge variations -- caused by intense solar activity such as solar flares -- could interact with pre-existing fragile structures in the Earth's crust and influence fracture processes.
In the proposed model, fractured zones within the Earth's crust are assumed to contain high-temperature, high-pressure water, potentially in a supercritical state. These zones behave electrically like capacitors and are capacitively coupled with both the ground surface and the lower ionosphere, forming a large-scale electrostatic system.
When strong solar activity increases electron density in the ionosphere, a negatively charged layer can form in the lower ionosphere. Through capacitive coupling, this space charge may induce strong electric fields inside nanometer-scale voids within fractured crustal regions. The resulting electrostatic pressure could reach magnitudes comparable to tidal or gravitational stresses known to affect fault stability.
Quantitative estimates in the study suggest that ionospheric disturbances associated with large solar flares -- corresponding to increases in total electron content of several tens of TEC units -- could generate electrostatic pressures on the order of several megapascals within crustal voids.
