David Carter:Keith is right. I think he is also right in that the reduction of the sea level due to atmospheric pressure increases precisely cancels out this increase when calculating the pressure on the sea bed. The effect of atmospheric pressure changes on the sea bed is not just miniscule, it is zero.
What I said was:1)Therefore high pressure and low pressure systems modify the hydrostatic head of a column of seawater.
2)Low pressure can generate intense storms containing abundant energy leading to exaggerated tides,surges and wave action.
3)All these activities generate seismic noise.

Perfectly true as far as it goes. Now whether the atmospheric changes cancel out these hydrostatic changes instantaneously or if there is a time lag I have no idea and really is a non issue because in the deep ocean a change in hydrostatic head of 7psi would be negligible and although over dogger bank it may or may not have an impact it is the storm effects that are of significance. Increased wave action, increased tidal action, storm surges. Also some of these effects are accentuated by wind and direction, and the geometry of enclosed areas (N. Sea, Severn Estuary) There are numerous links on the web that support this. It is the storm that is significant, not the changes in atmospheric pressure.