I am watching the news about Turkey conducting seismographic surveys in the Eastern Mediterranean and from day 1 I have been wandering if a "listener" can record the sound produced by the survey vessel using a hydrophone array and, knowing the position of the sound source, be able to produce meaningful results? Furthermore, could the origin of the sound be worked out as well as the mapping data?

From what I understand, these vessels drag an array of hydraulic "hammers" that produce a loud sound and an array of hydrophones to record how the sound waves are reflected/absorbed from the surrounding environment. My best guess is that the sound emitted has a rich spectrum so that we can observe the level of attenuation on each frequency band (bin) in order to distinguish different materials, as well as the timing of the reflections to map the environment in 3D by measuring the delay and triangulating.

Does the location of the listener matter in the quality of the analysis? If so, to what degree?

I know that the speed of sound is a lot faster in water than it is in air wouldn't this make the area where the survey is audible from larger? And does distance from source matter more, or the amount of surrounding noise?

  • $\begingroup$ Some afterthoughts on this. Maybe we could imagine how well we can understand the shape and materials of a room when somebody else in the room is clapping their hands (impulse response). If we are close to the other person, then we get similar first reflections - those that help us calculate the distance from reflecting surfaces. But if we are quite far away, and especially if there are obstacles between the source and our position, then we only have reflections, diffraction and no real time reference for the original sound. $\endgroup$ Oct 23 '20 at 15:26
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    $\begingroup$ been a while but seem to remember that this is regularily done, and one of the main reason we can glean the composition of the core. As for sound in a room and the even harder light, we can do this. $\endgroup$
    – joojaa
    Nov 4 '20 at 15:10
  • $\begingroup$ Are you asking if seismic oil exploration is real ? Or if seismic sea floor topography is real ? $\endgroup$ Nov 4 '20 at 15:24
  • $\begingroup$ Neither. I am asking if the sound reflections can be recorded by a 3rd party and processed to produce a valid map of the seabed and the materials under it. $\endgroup$ Nov 4 '20 at 16:30

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