AUTHOR=Recchiuti D. , D’Angelo G. , Papini E. , Diego P. , Cicone A. , Parmentier A. , Ubertini P. , Battiston R. , Piersanti M. 

TITLE=Detection of electromagnetic anomalies over seismic regions during two strong (MW > 5) earthquakes

JOURNAL=Frontiers in Earth Science

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/earth-science/articles/10.3389/feart.2023.1152343

DOI=10.3389/feart.2023.1152343

ISSN=2296-6463

ABSTRACT=Ionospheric disturbances (such as electromagnetic emissions) in connection to strong
earthquakes have been reported in literature since over two decades. However, to be reliable, the
identification of such disturbances would require a robust definition of the ionospheric background
in absence of seismic activity and any other possible external input (e. g. solar activity).
In this work, we present a new technique to evaluate the electromagnetic (EM) ionospheric
background over seismic regions. We performed a multiscale statistical analysis of the ionospheric
environmental background, using almost the entire CSES-01 (China Seismo-Electromagnetic
Satellite) electric and magnetic field dataset (2019-2021).
The result is a map of the averaged relative energy in a 6° x 6° latitude-longitude cell centered
over the earthquake epicenter (EE), representing the ionospheric background. Only EM signal
which statistically differs from the background should be considered as a potential event to be
investigated.
Finally, we present the results obtained for two strong earthquakes, the August 14, 2021 Haitian
earthquake (7.2 MW ) and the September 27, 2021 Cretan (Greece) earthquake (6.0 MW ). For
the first event a signal emerging from the background, characterized by a peculiar frequency ≃
250 Hz has been identified. In the second event, the strong geomagnetic activity did not allow
identifying any distinguishable signal from the background.