<p>What you have probably seen in the movies, as used by the oil and gas industry is <a href="https://en.wikipedia.org/wiki/Reflection_seismology" rel="nofollow noreferrer">reflection seismology</a>. This is where you shoot off a sound source (explosives, airguns, etc) and track the reflections of the sound waves from the various rock layers below the surface.  </p>

<p>At a smaller scale, there is <a href="https://en.wikipedia.org/wiki/Ground-penetrating_radar" rel="nofollow noreferrer">Ground Penetrating Radar</a>, good for a few 10s of meters at best, which is higher resolution and good for detecting voids.</p>

CC BY-SA 3.0
2017-09-25T10:37:03.737Z
2017-09-25T10:37:03.737Z
Andrew Jon Dodds
<p>As Andrew Jon Dodds states in his answer, underground voids can be located using reflection seismology. The results of such surveys will given an indication the size and extend of underground voids. </p>

<p>Once a void has been located a more accurate layout of the underground void can be obtained by conducting a <a href="https://en.wikipedia.org/wiki/Cave_survey" rel="nofollow noreferrer">cave survey</a>. This requires people to enter caves/voids <a href="http://cavingintro.net/surveymap.html" rel="nofollow noreferrer">with measuring equipment and to draw a diagram of the cave</a>, similar to how former maritime navigators charted coast lines. </p>

CC BY-SA 3.0
2017-09-25T12:40:01.880Z
2017-09-25T12:40:01.880Z
Fred
<p>Mapping the bottom of the ocean is called seafloor mapping.  I was wondering what mapping underground is called, such as when locating caves and caverns.   </p>

<p>I have seen it in movies, and I'm interested to know what is it called so that I can start searching for more info about it.</p>

CC BY-SA 3.0
2017-09-27T10:23:37.743Z
Maybe related: https://earthscience.stackexchange.com/questions/9890/how-do-seismic-charges-help-to-investigate-the-subsurface
wienein
<mapping>
How to map (survey) the structure of crust
capHossein12DarthVader
# How to map (survey) the structure of crust

(Asked by: username_0 on 2017-09-25)

Mapping the bottom of the ocean is called seafloor mapping. I was wondering what mapping underground is called, such as when locating caves and caverns.

I have seen it in movies, and I'm interested to know what is it called so that I can start searching for more info about it.

**Tags:** mapping

> **Comments:**
> **username_1**: Maybe related: https://earthscience.stackexchange.com/questions/9890/how-do-seismic-charges-help-to-investigate-the-subsurface  

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## 2 answers

### Answer by username_2 on 2017-09-25. Score: 3

What you have probably seen in the movies, as used by the oil and gas industry is [reflection seismology](https://en.wikipedia.org/wiki/Reflection_seismology). This is where you shoot off a sound source (explosives, airguns, etc) and track the reflections of the sound waves from the various rock layers below the surface.

At a smaller scale, there is [Ground Penetrating Radar](https://en.wikipedia.org/wiki/Ground-penetrating_radar), good for a few 10s of meters at best, which is higher resolution and good for detecting voids.


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### Answer by username_3 on 2017-09-25. Score: 3

As username_2 Jon username_2 states in his answer, underground voids can be located using reflection seismology. The results of such surveys will given an indication the size and extend of underground voids.

Once a void has been located a more accurate layout of the underground void can be obtained by conducting a [cave survey](https://en.wikipedia.org/wiki/Cave_survey). This requires people to enter caves/voids [with measuring equipment and to draw a diagram of the cave](http://cavingintro.net/surveymap.html), similar to how former maritime navigators charted coast lines.


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