Gravitational Waves Masquerading as Schumann Resonances

Metallic conductors like the 4 km long steel tubes of the LIGO interferometer are naturals for the attraction of electromagnetic disturbances. Back in 1893 FitzGerald noticed that the upper atmosphere was a good conductor of electricity. With a depth of 100 km, the cavity formed from what is now known as the ionosphere and the earth facilitates the establishment of very long wavelength electrodynamic oscillations having a period of roughly 0.1 sec. The electromagnetic waves are excited by lightning discharges and have a (discrete) spectrum ranging from 3 to 60 Hz--right smack in the frequency range of the detected initial frequencies of gravitational waves, Part of the electromagnetic disturbance exponentially penetrates through the metal walls, generating currents. The magnetic field is circular around the tube, and Poynting's vector shows that the energy flow is directed inward appearing as Joule heat. This is what Poynting argued. However, Heavside showed that there is a flux of energy directed along the tube, and this could generate a detectable phase shift in the mirrors. Since the mirrors weigh in at some 40kg, it would take some time to get them moving which could be attributed to a rise in frequency. Once the electromagnetic disturbance has passed, the mirrors return to a state of rest thereby mimicking the three phases of inspiralling, chirping, and ringdown that has been attributed to gravitational waves. And because the cavity consists of the earth and the ionosphere, it would explain the near coincidence of the two interferometers in Washington and Louisiana responding to the same electromagnetic perpeturbation. Moreover, it predicts that the "initial" frequencies of the gravitational waves should be at the extremely low frequencies of 14.3, 20.8, 27.3 and 33.8 Hz. If such electromagnetic disturbances are not gravitational waves, how has LIGO excluded such possibilities?