Identification and Analysis of Multi-Station Atmospheric Electric Field Anomalies before the Yangbi Ms 6.4 Earthquake on 21 May 2021

Abstract

This study reports the atmospheric electric field (AEF) anomalies associated with seismic-geological activity recorded by the monitoring network in the Sichuan–Yunnan region of China during the 15–30 days prior to the Yangbi earthquake in Yunnan Province, China, on 21 May 2021. Based on the real-time AEF data from continuous observation, this study summarized the characteristics of the anomalous interference of different meteorological factors on the AEF, compared the simultaneous meteorological data of the AEF anomalies, and ruled out the influence of precipitation, wind, fog, and other weather factors on the AEF anomalies in Yangbi County prior to the Yangbi Ms 6.4 earthquake. The AEF anomalies were identified and extracted from the two-month data from 1 April to 1 June, which were from multiple days, stations, and rupture zones near the 100 km radius from the epicenter of the Yangbi Ms 6.4 main earthquake. Using time series and wavelet transform analysis methods, the obvious common features of the anomalies were summarized, and the homology of the anomalies was verified. The main outcome of the investigation in this study will be used to distinguish and characterize the AEF anomalies associated with pre-seismic geologic activity of non-meteorological elements in the near future.

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

“…The previous workers [e.g., [30] [31] [32]] observed the anomalies in atmospheric electric field only on the order of a few hundred V/m. But, a recent extensive paper has been published based on the multi-station observation in China by Nie and Zhang (2023) [33], who have tried to extract the seismogenic atmospheric electric field changes associated with a particular EQ by eliminating climate-related perturbations. They have found that the anomalies appeared 15 -30 days before the EQ, electric field anomalies followed a consistent trend (with the electric field initially decreasing following sunny days before rising again, showcasing a decrease of 1 -3 kV/m, one order higher than the previous results), and the duration of anomaly fluctuations is concentrated to a range of 30 -60 minutes.…”