Leveraging Legacy Broadband Magnetotelluric Data for Geoelectric Field Hazard Assessment in Southern Italy

The repository contains two types of electromagnetic data used in this study to investigate geomagnetic storm-time magnetic and geoelectric field variability in southern Italy: (i) two ASCII files (#1.txt and #2.txt) containing time series for two major geomagnetic storms that occurred in 2024, and (ii) two compressed archives (#3.zip and #4.zip) containing raw magnetotelluric (MT) time series acquired at the permanent GARG monitoring station on the Gargano Promontory, Italy.

#1 and #2 provide time series of the horizontal components of the magnetic field (in nanoteslas, nT) recorded at the Italian permanent geomagnetic observatory of Duronia (DUR), together with synchronous geoelectric field measurements (in millivolts per kilometer, mV/km) recorded at the GARG station. The time series have a temporal resolution of 1 s and cover two intense geomagnetic storms: the “Gannon” event of May 2024, included in #1, spanning 10 May 2024 to 13 May 2024, and a subsequent major storm in October 2024, included in #2, spanning 10 October 2024 to 13 October 2024.

#1 and #2 are structured with the following columns:

Bx: north–south magnetic field component (nT), recorded at DUR
By: east–west magnetic field component (nT), recorded at DUR
Ex: north–south electric field component (mV/km), recorded at GARG
Ey: east–west electric field component (mV/km), recorded at GARG

In addition, the repository includes two compressed archives, #3 and #4, containing raw MT time series acquired at the GARG station. These data are provided as examples of the raw MT recordings used in the processing workflow underlying the impedance tensor estimation presented in the study, and correspond to acquisitions collected at different original sampling rates. #3 contains MT time series acquired at 32 Hz from 21 May 2024 to 21 July 2024. #4 contains MT time series acquired at 512 Hz on 11 April 2024.

Each compressed archive includes a metadata/control file in .xml format and binary ATS files containing electric and magnetic field recordings for both the north–south and east–west components.