ELF Electromagnetic Waves and Ionospheric Physics Seminar


                                      March 25, 2026





Anirban Guha (Tripura Univ.)    "Q-burst geolocation and characterization using the HeartMath six-station ELF network"


Abstract:

This study presents a comprehensive analysis of Q-bursts-powerful, extremely low frequency (ELF) transients associated with intense lightning strokes- using data from the HeartMath Institute's six-station ELF magnetometer network. Over 489 days (April 2017- June 2024), the network recorded millions of events, which were detected using a scanning-window algorithm with dynamic thresholds. Source locations were determined through a combination of triangulation and trilateration, incorporating a propagation velocity factor to account for variability in the Earth-ionosphere waveguide. Initial localization using a constant velocity factor of 0.80c yielded a 46% match with strokes from the World Wide Lightning Location Network (WWLLN) and a mean distance error of 550 km. A refined two-dimensional propagation model, incorporating path illumination and azimuth, improved the match rate to 67% and reduced the mean error to 417 km.

From the oriented magnetic field signals, the source current moment was reconstructed, enabling estimates of charge moment and continuing current. Results reveal distinct global distributions for positive and negative Q-bursts, with positive events dominating mid-latitude regions and exhibiting stronger continuing currents. Regional polarity varies, with Africa showing ~47% positive events, the Americas ~43%, and the Maritime Continent ~54%. Diurnal patterns generally follow thunderstorm activity, though a notable morning peak remains unexplained. The study also identifies intriguing temporal dynamics, including pre-event quiescence and post-event increases in ordinary lightning, suggesting complex storm-scale processes. Future work will focus on implementing a segmented path model to further refine propagation corrections and explore the physical mechanisms underlying observed phenomena.



Contact: Contact_ELFseminar(at)oa.uj.edu.pl