  The continuous geomagnetic field survey holds an important potential in
future prevention of tsunami damages, and also, it could be used in tsunami
forecast. In this work, we were able to detected for the first time Rayleigh
and ionospheric acoustic gravity wave propagation in the Z-component of the
geomagnetic field due to the Japanese tsunami, 2011 prior to the tsunami
arrival. The geomagnetic measurements were obtained in the epicentral near and
far-field. Also, these waves were detected within minutes to few hours of the
tsunami arrival. For these reasons, these results are very encouraging, and
confirmed that the geomagnetic field monitoring could play an important role in
the tsunami warning systems, and also, it could provide additional information
in the induced ionospheric wave propagation models due to tsunamis.
