natural magnetic field of the earth is dipolar with a strength of 0.5 Gauss or 50 micro Tesla (µT). Although we do not actually feel this magnetic field, it influences the daily lives of humankind and nature in a decided way. We know for example that very many animals are dependent on the earth's magnetic field for their sense of direction (bees, termites, ants, beetles, migratory birds, storks, sharks, skate, turtles, whales etc).
The Schumann Resonance's are quasi-standing electromagnetic waves that exist in the Earth's 'electromagnetic' cavity (the space between the surface of the Earth and the Ionosphere). Like waves on a string, they are not present all the time, but have to be 'excited' to be observed. They are not caused by anything internal to the Earth, its crust or its core. They seem to be related to electrical activity in the atmosphere, particularly during times of intense lightning activity.
Its proposed that it is not merely a phenomenon caused by lightning in the atmosphere, but a very important electromagnetic standing wave, acting as background frequency and influencing biological oscillators within the mammalian brain.
During his research Dr Ludwig came across the ancient Chinese teachings which state that Man needs two environmental signals: the YANG (masculine) signal from above and the YIN (feminine) signal from below. This description fits the relatively strong signal of the Schumann wave surrounding our planet being YANG and the weaker geomagnetic waves coming from below, from within the planet, being the YIN signal
Schumann (YANG) wave simulation without the geomagnetic (YIN) signal caused serious health problems. On the other hand, the absence of Schumann waves creates a similar situation. Professor R.Wever from the Max Planck Institute for Behavioral Physiology in Erling-Andechs, built an underground bunker which completely screened out magnetic fields. Student volunteers lived there for four weeks in this hermetically sealed environment. Professor Wever noted that the student's circadian rhythms diverged and that they suffered emotional distress and migraine headaches.
The rest of the article.....http://altered-states.net/index2.php?/emf/schumann.htm