Study on the CSES Electric Field VLF Electromagnetic Pulse Sequences Triggered by Volcanic Eruptions

Volcanic eruptions, as a natural phenomenon, can generate electric field disturbances that may interfere with the ionosphere, potentially impacting communication systems and electronic devices. This paper conducts identification and classification analyses of the electromagnetic pulse (EMP) disturbances in the very low frequency (VLF) electric field data observed by the China Seismo-Electromagnetic Satellite (CSES) and finds that volcanic eruption events can trigger EMP sequences. This paper first applies Fourier transform to the VLF electric field waveform data to convert it into 4 s spectrograms. Then, a series of operations such as grayscale conversion, edge feature enhancement, and binarization are performed on the spectrograms. Subsequently, a K-means clustering algorithm is applied to the binarized results to identify EMP events on the spectrograms. Finally, a classification analysis is performed on the identified results, revealing that multiple volcanic eruption events generate EMP sequences. The results of this paper not only provide new insights into the impact of volcanic eruptions on the electromagnetic environment but also have significant implications for enhancing the anti-interference capability of communication systems and optimizing electromagnetic environment monitoring technologies.