This animation shows how waves of energy from the Tohoku-Oki earthquake and tsunami of March 11, 2011, pierced through into Earth's upper atmosphere in the vicinity of Japan, disturbing the density of electrons in the ionosphere. These disturbances were monitored by tracking GPS signals between satellites and ground receivers.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 220.127.116.11.0