Let's assume a small (and smooth) vertical deformation of the seabed. If done quickly, I can consider it a vertical force generating an acoustic wave in the water, where every particle of water returns to its original position. That is provided the deformation is small enough to use infinitesimal strain theory. However, if done slowly, I imagine a flow where water is simply flowing off the deformation, even if any one 'water particle' is flowing only a small (horizontal) distance. And back in when the deformation retracts. Which parameter controls it's a flow or an acoustic deformation?
The seabed is made of very soft mud, in case that makes a difference. I see an earthquake wave on a vertical geophone, but barely on a hydrophone.