I'd say like 60% confidence. I also have no knowledge on the subject, but it's what makes sense. Developing mechanisms to recognize different types of sounds is a lot more difficult than just moving towards sounds in general.

Burrowing animals would create vibrations, but it wouldn't be constant unless it's near a nest of some kind. Even if that did happen, there wouldn't be any harm. If we consider the results with just burrowing towards vibration in general and burrowing towards a recognized water sound, the outcomes are about the same with one mechanism being significantly easier to evolve.