An introduction to Schumann resonance as a family of extremely low frequency electromagnetic resonances in the Earth-ionosphere cavity, together with the measurement limits that matter when interpreting live charts.
What Schumann resonances actually are
Schumann resonances are global electromagnetic resonances of the natural cavity formed by Earths surface and the lower ionosphere. They are excited mainly by lightning. The first mode is usually observed near 7.8 Hz and higher peaks occur above it, but exact frequency, width and amplitude vary with propagation conditions, local time and the global distribution of thunderstorms.
Frequency, amplitude, Q and the spectrogram
Frequency tells you where a spectral peak is located. Amplitude describes the magnitude of a calibrated signal. Linewidth describes the width of the resonance and Q relates the center frequency to that width. Spectrogram color without calibration can represent relative intensity but is not automatically a measurement in pT or pT/sqrtHz. These quantities are physically different and must not be used interchangeably.
What can and cannot be inferred
Spectral changes can contain information about lightning, Earth-ionosphere cavity conditions and the quality of a local measurement. By themselves they do not establish effects on health, mood, consciousness or a specific personal experience. GeoLira separates physical measurements, derived analysis and authored indices, and the external Near Live source is not presented as a complete calibrated measurement of all F1-F4 modes.