Schumann resonances · Observatoire des phénomènes naturels

Explanatory page, no live data. No open, calibrated stream exists: the stations (Tomsk, Nagycenk in Hungary, Hylaty in Poland, California) publish images or share their measurements on request. The Observatory therefore presents the values established in the literature, without a “real-time” curve.

Typical spectrum of the extremely-low-frequency magnetic field (diagram)

Sum of Lorentzian peaks at the frequencies and quality factors typical of the literature (Price, 2016), height decreasing with the mode: an illustration, not a measurement. A real spectrum is dominated by local noise (the 50 Hz mains and its harmonics) and needs hours of averaging.

Frequencies of the first five modes

Mode	Ideal cavity	Observed (typical)	Ratio	Q
n = 1	10.6 Hz	7.8 Hz	0.74	4.0
n = 2	18.3 Hz	14.3 Hz	0.78	4.5
n = 3	25.9 Hz	20.8 Hz	0.80	5.0
n = 4	33.5 Hz	27.3 Hz	0.82	5.5
n = 5	41.0 Hz	33.8 Hz	0.82	6.0

Ideal cavity between two perfectly conducting spheres: f = c / (2πR) √(n(n + 1)), with R = 6,371 km (Schumann, 1952). The frequencies measured since 1960 (Balser and Wagner) are about 20 % lower, because the ionosphere conducts poorly and absorbs part of the energy; this also broadens the peaks (quality factor Q of 4 to 6).

What really makes them vary

About 50 lightning flashes a second strike the Earth; each sends extremely-low-frequency waves that circle the globe in a seventh of a second and sustain the resonances.

The intensity follows global thunderstorm activity: it peaks around 14 h UTC (African storms), 20 h UTC (the Americas) and 8 h UTC (South-East Asia). The frequencies move by a few tenths of a hertz with the time of day, the seasons and the solar cycle, as the height and conductivity of the ionosphere change; El Niño, which shifts the storms, and solar flares also leave their mark.

The “Schumann spikes” of social media

The images shared as a “Schumann resonance at 40 Hz” usually come from the spectrograms of the Tomsk station: their white patches are saturations of the colour scale caused by nearby storms, interference or outages, not a change in the Earth’s frequency. The fundamental has stayed near 7.8 Hz since it has been measured.

No link between these resonances and health, mood or “consciousness” has been established by controlled studies.

Method and sources

Ideal frequencies computed with Schumann’s formula (1952); observed frequencies and quality factors: typical values from the review by Price (2016), after the measurements since Balser and Wagner (1960). The spectrum is built for illustration from these values.

Reading these data

Measuring the resonances needs very sensitive induction magnetometers far from any power line, and hours of integration: hence so few stations, and raw data not streamed continuously. If an open, calibrated stream appears, the Observatory will add it.

SOURCES OF THIS PAGE

Schumann (1952): Schumann, W. O. (1952). Über die strahlungslosen Eigenschwingungen einer leitenden Kugel, die von einer Luftschicht und einer Ionosphärenhülle umgeben ist. Zeitschrift für Naturforschung A, 7(2), 149–154. · doi:10.1515/zna-1952-0202
Licence : Published literature; cited
Balser et al. (1960): Balser, M., & Wagner, C. A. (1960). Observations of Earth–ionosphere cavity resonances. Nature, 188, 638–641. · doi:10.1038/188638a0
Licence : Published literature; cited
Price (2016): Price, C. (2016). ELF electromagnetic waves from lightning: the Schumann resonances. Atmosphere, 7(9), 116. · doi:10.3390/atmos7090116
Licence : Published literature; cited

Schumann resonances The Earth rings at 7.8 Hz, struck by lightning

Typical spectrum of the extremely-low-frequency magnetic field (diagram)

Frequencies of the first five modes

What really makes them vary

The “Schumann spikes” of social media