<p>See page 2 here for example: <a href="https://pangea.stanford.edu/courses/gp262/Notes/8.SeismicVelocity.pdf" rel="nofollow noreferrer">https://pangea.stanford.edu/courses/gp262/Notes/8.SeismicVelocity.pdf</a> . </p>

<p>What you refer to as Cp (as far as I can gather from your linked paper), is in the geophysics world generally referred to as the P-wave velocity (P stands for the primary/pressure/compressional wave; separating it from the S-wave which is the slower secondary/shear/transverse wave mode). It kind of depends on the specific mineralogy, compaction, depth, ... to determine exactly what the velocity is for any given rock. Note that the range of velocities is not particularly great (all values lie within one order of magnitude for typical rocks), so if your method is not particularly dependent on getting the P-wave velocity exactly right, you shouldn't have too much of a problem taking some average value for your rock! If, on the other hand, it is very sensitive to this value, you'll have to make an accurate measurement on your sample (which is not a trivial thing to do at all!).</p>

CC BY-SA 4.0
2019-06-15T12:10:22.717Z
2019-06-15T12:10:22.717Z
Erik
<p>In Cunningham's paper, <a href="https://miningandblasting.files.wordpress.com/2009/09/the-kuz-ram-fragmentation-model-e28093-20-years-on.pdf" rel="nofollow noreferrer"><em>"The Kuz-Ram fragmentation model - 20 years on"</em></a>, he makes mention of <em>compressional stress wave velocity</em>, <strong>C<sub>p</sub></strong>. He only comments that the <strong>C<sub>p</sub></strong> of granite = 5.2 km/s. I using a relation that includes <strong>C<sub>p</sub></strong> but the rock type is not granite. A search on Google for the exact mention of compressional stress wave velocity lists only 3 results all of which are either the same paper or refer to Cunningham's paper.</p>

<ul>
<li>Is there a table where I can check the <strong>C<sub>p</sub></strong> for the rock type? </li>
<li>Is there a relation that I can use to derive the value of <strong>C<sub>p</sub></strong> based on other known values of the rock</li>
</ul>

<p>Any of the above is acceptable. Thanks in advance.</p>

CC BY-SA 4.0
2019-06-13T18:34:11.630Z
Is Cp the same as P-wave velocity? If so, you can use the Voigt-Reuss-Hill averaging scheme to calculate average bulk and shear moduli based on the mineralogy of the rock. You could also get an average density based on the mineralogy as well.
g.z.
<rocks>
How to calculate or find the compressional stress wave velocity, Cp for a rock
Charitoo
# How to calculate or find the compressional stress wave velocity, Cp for a rock

(Asked by: username_0 on 2019-06-13)

In Cunningham's paper, [*"The Kuz-Ram fragmentation model - 20 years on"*](https://miningandblasting.files.wordpress.com/2009/09/the-kuz-ram-fragmentation-model-e28093-20-years-on.pdf), he makes mention of *compressional stress wave velocity*, **Cp**. He only comments that the **Cp** of granite = 5.2 km/s. I using a relation that includes **Cp** but the rock type is not granite. A search on Google for the exact mention of compressional stress wave velocity lists only 3 results all of which are either the same paper or refer to Cunningham's paper.

* Is there a table where I can check the **Cp** for the rock type?
* Is there a relation that I can use to derive the value of **Cp** based on other known values of the rock

Any of the above is acceptable. Thanks in advance.

**Tags:** rocks

> **Comments:**
> **username_1**: Is Cp the same as P-wave velocity? If so, you can use the Voigt-Reuss-Hill averaging scheme to calculate average bulk and shear moduli based on the mineralogy of the rock. You could also get an average density based on the mineralogy as well.  

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## 1 answers

### Answer by username_2 on 2019-06-15. Score: 1

See page 2 here for example: <https://pangea.stanford.edu/courses/gp262/Notes/8.SeismicVelocity.pdf> .

What you refer to as Cp (as far as I can gather from your linked paper), is in the geophysics world generally referred to as the P-wave velocity (P stands for the primary/pressure/compressional wave; separating it from the S-wave which is the slower secondary/shear/transverse wave mode). It kind of depends on the specific mineralogy, compaction, depth, ... to determine exactly what the velocity is for any given rock. Note that the range of velocities is not particularly great (all values lie within one order of magnitude for typical rocks), so if your method is not particularly dependent on getting the P-wave velocity exactly right, you shouldn't have too much of a problem taking some average value for your rock! If, on the other hand, it is very sensitive to this value, you'll have to make an accurate measurement on your sample (which is not a trivial thing to do at all!).


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