The horizontal motion of a water layer during the passage of tsunami waves based on data from a dense ocean-floor network of deepwater sea-level stations

A method for the retrieval the horizontal motion of a water layer during the passage of a tsunami wave is proposed based on the data from a dense network of sea-level deepwater stations. The method is applied for calculation of the horizontal velocity of the flow and displacement of water particles in the vicinity of the DONET/JAMSTEC observatories during the passage the 2011 Tohoku tsunami. It was found that the amplitude of the flow speed was  0.01 m/s, while the amplitude of the displacement exceeded 10 m.