Variations of Atmospheric ELF/VLF Radio Noise Due to Seismogenic Modifications in Tropospheric Conductivity  

作　　者：Masashi Hayakawa Alexander P. Nickolaenko Masashi Hayakawa;Alexander P. Nickolaenko(Hayakawa Institute of Seismo Electromagnetics, Co., Ltd. (Hi-SEM), UEC Alliance Center #521, Tokyo, Japan;The University of Electro-Communications (UEC), Advanced Wireless & Communications Research Center (AWCC), Chofu-shi, Tokyo;O.Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of the Ukraine, Kharkov, Ukraine)

机构地区：[1]Hayakawa Institute of Seismo Electromagnetics, Co., Ltd. (Hi-SEM), UEC Alliance Center #521, Tokyo, Japan [2]The University of Electro-Communications (UEC), Advanced Wireless & Communications Research Center (AWCC), Chofu-shi, Tokyo [3]O.Ya. Usikov Institute for Radiophysics and Electronics, National Academy of Sciences of the Ukraine, Kharkov, Ukraine

出　　处：《Open Journal of Earthquake Research》2024年第2期113-132,共20页地震研究（英文）

摘　　要：We suggest a possible explanation of the influence of pre-seismic activity on the registration rate of natural ELF(extremely low frequency)/VLF(very low frequency) pulses and the changes of their characteristics. The main idea is as follows. The distribution of the electric field around a thundercloud depends on the conductivity profile of the atmosphere. Quasi-static electric fields of a thundercloud decrease in those tropospheric regions where an increase of air conductivity is generated by pre-seismic activities due to emanation of radioactive gas and water into the lower atmosphere. The electric field becomes reduced in the lower troposphere, and the probability decreases of the cloud-to-ground (CG) strokes in such “contaminated” areas. Simultaneously, the electric field grows inside and above the thunderclouds, and hence, we anticipate a growth in the number of horizontal and tilted inter-cloud (or intra-cloud) (both termed as IC discharges) strokes. Spatial orientation of lightning strokes reduces vertical projection of their individual amplitudes, while the rate (median number strokes per a unit time) of discharges grows. We demonstrate that channel tilt of strokes modifies the spectral content of ELF/VLF radio noise and changes the rate of detected pulses during the earthquake preparation phase.We suggest a possible explanation of the influence of pre-seismic activity on the registration rate of natural ELF(extremely low frequency)/VLF(very low frequency) pulses and the changes of their characteristics. The main idea is as follows. The distribution of the electric field around a thundercloud depends on the conductivity profile of the atmosphere. Quasi-static electric fields of a thundercloud decrease in those tropospheric regions where an increase of air conductivity is generated by pre-seismic activities due to emanation of radioactive gas and water into the lower atmosphere. The electric field becomes reduced in the lower troposphere, and the probability decreases of the cloud-to-ground (CG) strokes in such “contaminated” areas. Simultaneously, the electric field grows inside and above the thunderclouds, and hence, we anticipate a growth in the number of horizontal and tilted inter-cloud (or intra-cloud) (both termed as IC discharges) strokes. Spatial orientation of lightning strokes reduces vertical projection of their individual amplitudes, while the rate (median number strokes per a unit time) of discharges grows. We demonstrate that channel tilt of strokes modifies the spectral content of ELF/VLF radio noise and changes the rate of detected pulses during the earthquake preparation phase.

关 键 词：ELF/VLF Radio Noise Earthquake Precursor Pre-Seismic Modification Conductivity Anomaly in the Lower Atmosphere Radioactive Radon Gases CG Lightning Discharges IC Discharges Cloud-to-Ionosphere Discharge 

分 类 号：P31[天文地球—固体地球物理学]