TY  - JOUR
T1  - Mechanism of ionospheric descent prior to intense earthquakes by electrostatic coupling with an electrically charged fractured layer
A1  - Mizuno, Akira
A1  - Kao, Minghui
A1  - Umeno, Ken
Y1  - 2025///
KW  - 2024 Noto earthquake
KW  - supercritical water
KW  - electric field
KW  - ionospheric descent
KW  - ionogram
JF  - International Journal of Plasma Environmental Science and Technology
VL  - 19
IS  - 1
SP  - e01010
EP  - e01010
DO  - https://doi.org/10.34343/ijpest.2025.19.e01010
UR  - http://ijpest.com/Contents/19/1/e01010.html
N2  - Ionospheric descent has been observed prior to intense earthquakes. Changes in the velocity of Medium-Scale Traveling Ionospheric Disturbances (MSTID) have also been reported, leading to various discussions about the electromagnetic coupling between the Earth's crust and the ionosphere. We previously reported that during pre-seismic fracturing of the crust, water penetrates the fractured layer in a high-temperature, high-pressure supercritical state. Due to sudden pressure changes during penetration, nanoparticles can be generated from ions dissolved in the supercritical water. Additionally, due to the low conductivity and high temperature of the supercritical water, electron emission from nanoparticles can occur, resulting in their positive charging. When the fractured layer becomes charged, the Earth's surface potential changes, affecting the electric field strength between the Earth's surface and the lower ionosphere. By assuming that the charged fractured layer attracts the ionosphere, we estimated the time constant of ionospheric descent, finding that the calculated value closely matches the observed descent time constant. This suggests that electrostatic capacitive coupling between the charged fractured layer and the ionosphere may be responsible for the ionospheric anomalies observed before intense earthquakes.
ER  -