ИСТИНА

According to the data of deepwater DONET observatories, the relationship between ocean-bottom pressure variations and acceleration of ocean-bottom motions during the 2011 Tohoku earthquake was investigated. The method of cross-spectral analysis confirmed the existence of a linear relationship between the pressure variations and the vertical acceleration component in the “forced oscillation” frequency range. The connection is manifested as a close to unity value of magnitude-squared coherence at practically zero phase lags. It is shown that the slight deviations from this rule observed for some stations are related to the contribution to pressure variations of horizontal seismic motions of nearby underwater slopes. This work was supported by the Russian Foundation for Basic Research, projects 16-55-50018, 16-05-00053.