A type of seismic receiver most often used in marine seismic exploration.
As the name suggests, are for deployment in the water column. Naturally, there is a lot of non-seismic motion in water, so measuring displacement will not do. Instead, hydrophones contain two piezoelectric components, which generates a current when deformed by pressure. Because there are two elements, single-directional pressure pulses can be discriminated from true seismic pressure waves.
Hydrophones are usually towed in streamers behind a boat.
They have a similar response band to geophones.
- Geophysical stamps 3: Geophone — blog post