The connection between earthquakes and Schumann resonance anomalies
Some researchers have reported unusual Schumann resonance signals in the days before large earthquakes. What those studies found, why they are not a forecast, and why a bright patch on the Tomsk chart is not an earthquake warning.
A few research groups have reported unusual Schumann resonance signals in the days before some large earthquakes, for example before the 1999 Chi-chi earthquake in Taiwan and the 2011 Tohoku earthquake in Japan. These are case studies analysed after the event. They are not a working forecast, and the US Geological Survey states that no scientist has ever predicted a major earthquake.
What the Schumann resonance is
The Schumann resonance is a set of natural radio frequencies, near 8, 14, 20, 26 and 32 Hz, that ring in the cavity between the ground and the ionosphere. Lightning keeps it going, with about 50 flashes every second around the world (Price 2016). Anything that changes the cavity, especially the ionosphere at its top, can change how the resonance looks at a given station. That is why researchers have asked whether the processes before an earthquake might leave a trace.
What the studies report
Chi-chi, Taiwan, 1999
A team led by Masashi Hayakawa examined a full year of data from Nakatsugawa, near Nagoya in Japan (Hayakawa et al. 2005). Around the Chi-chi earthquake of 21 September 1999 they found:
- an unusual increase in the strength of the fourth resonance mode, with its peak shifted by about 1 Hz, in one magnetic field component,
- anomalous signals from about one week to a few days before the main shock,
- a direction of arrival that pointed toward Taiwan.
A second earthquake in Taiwan on 2 November 1999, also above magnitude 6 but smaller, showed a similar but weaker and shorter anomaly. The authors proposed that a disturbance in the atmosphere above Taiwan scattered radio waves coming from thunderstorms in South America.
Tohoku, Japan, 2011
Researchers in China looked at two of their stations before the magnitude 9.0 Tohoku-Oki earthquake (Zhou et al. 2013). They found increased intensity in the first four modes in both magnetic components on 8 March 2011, three days before the main shock. Using a computer model, they linked it to a local change in atmospheric conductivity over the epicentre. They also noted that the pattern was different from the one seen in Japan before the Taiwan earthquakes.
Greece, about five years of data
A group running two stations at the northern and southern edges of Greece analysed almost five years of recordings (Tritakis et al. 2022). They concluded that particular Schumann resonance changes are useful for anticipating seismic activity, but only when combined with other observations.
Why this is not an earthquake forecast
- Case studies after the fact. Each study starts from a known earthquake and looks back for an anomaly. That is a legitimate first step. It does not tell you how often similar anomalies happen with no earthquake following.
- The patterns differ. The Taiwan anomaly was mainly in the fourth mode. The Tohoku anomaly appeared in the first four modes. The Greek group says the signal needs other observations to be useful. There is no single agreed signature.
- It is still an open problem. A 2016 review of Schumann resonance research lists “anomalous SR signals related to earthquakes” among the questions that remain open (Price 2016).
- Prediction has a strict meaning. The US Geological Survey says an earthquake prediction must give the date and time, the location and the magnitude, and that neither the USGS nor any other scientists have ever predicted a major earthquake (USGS).
Why a bright patch on the Tomsk chart is not a warning
The anomalies above were found with careful analysis of specific resonance modes and magnetic field components at particular stations. They are not something you can read off a public colour chart.
On the widely shared Tomsk chart, the station explains that white vertical stripes come from a local thunderstorm, black stripes mean missing data, and thin horizontal lines are man-made interference from nearby power lines and machinery (sos70.ru, in Russian). A white burst on that chart tells you about lightning near Tomsk in Siberia. It does not tell you that an earthquake is coming anywhere.
What to do instead
- For earthquake information, rely on official seismic agencies, such as the USGS or your national service. The USGS publishes probabilities for regions over years, not day-by-day predictions.
- For preparedness, follow your local civil protection guidance. It is useful whether or not any precursor exists.
- If you follow Schumann charts out of interest, read them next to the Kp index and the guide on how to read the current Schumann reading.
Frequently asked questions
Can the Schumann resonance predict earthquakes? No. Some studies report anomalies before specific large earthquakes, but there is no tested method that turns them into predictions of time, place and magnitude.
Did the Schumann resonance change before the 2011 Japan earthquake? One study of two Chinese stations reported increased intensity in the first four modes three days before the main shock (Zhou et al. 2013). That is one analysis, made after the event.
Is a Schumann “spike” a sign of an earthquake? Not on the evidence available. On the Tomsk chart, the station attributes white stripes to local thunderstorms.
How could an earthquake affect the resonance at all? The proposed idea in these papers is that processes before a large earthquake change the conductivity of the air or ionosphere above the fault zone, which then disturbs the radio waves passing through. This remains a hypothesis.
Sources
- Hayakawa, M., Ohta, K., Nickolaenko, A. P., Ando, Y. (2005). Anomalous effect in Schumann resonance phenomena observed in Japan, possibly associated with the Chi-chi earthquake in Taiwan. Annales Geophysicae 23, 1335 to 1346. doi:10.5194/angeo-23-1335-2005
- Zhou, H., Zhou, Z., Qiao, X., Yu, H. (2013). Anomalous phenomena in Schumann resonance band observed in China before the 2011 magnitude 9.0 Tohoku-Oki earthquake in Japan. Journal of Geophysical Research: Atmospheres 118. doi:10.1002/2013JD020269
- Tritakis, V. et al. (2022). How Effective and Prerequisite Are Electromagnetic Extremely Low Frequency (ELF) Recordings in the Schumann Resonances Band to Function as Seismic Activity Precursors. Atmosphere 13(2), 185. doi:10.3390/atmos13020185
- Price, C. (2016). ELF Electromagnetic Waves from Lightning: The Schumann Resonances. Atmosphere 7(9), 116. doi:10.3390/atmos7090116
- U.S. Geological Survey: Can you predict earthquakes?
- Space Observing System 70, Tomsk: ELF sonogram and how to read it (in Russian).