Statistical study of ELF/VLF emissions recorded by a low‐altitude satellite during seismic events

This paper presents a statistical study of low‐altitude satellite data linked to seismic events. Data of the satellite AUREOL 3 are considered during 24‐hour windows around the time of 325 earthquakes with M s > 5. Amplitudes at the output of different frequency filters in the ELF/VLF range, connected to electric or magnetic components, were stored in a file. This file is organized as functions of three parameters: Δ t , the difference between the time of the earthquake and the time of the satellite data; ΔLong, the difference between the longitude of the earthquake and the longitude of the satellite; and ΔInv.Lat, the difference between the invariant latitude of the earthquake and the invariant latitude of the satellite. When all data are averaged over time, the amplitude is maximum in the interval ΔLong < 10° regardless of ΔInv.Lat. This indicates that, due to propagation, waves related to seismic processes can be observed all along the magnetic meridian passing over the epicenter of an earthquake. However, as the AUREOL 3 data were not continuously recorded, thus providing a limited number of events, it was impossible to carry out a complete statistical study.