[gphistogram] Exporting curve data in terms of phase velocity

[seguuu91]

Dear Marc,

I have a question regarding 'gphistogram.'

When using 'add curve' in gphistogram, is it possible to get the values (i.e., mean and standard deviation) in terms of phase velocity instead of slowness, especially when using the Gaussian mixture curve?

As an alternative, I tried to use a *.max file in which the slowness values are converted to phase velocity.
However, it seems that gphistogram is unable to read this file.


Thanks,
YJ Jeon

[admin]

Slowness or velocity on a log scale are equivalent (it just reverts the axis). You can compute the statistics in slowness and convert them to velocity without loosing anything. For historical reasons, everything is done in slowness internally. Hence, I can see no reason to modify the input .max file.

If the values of the mean curve are for instance

Code: Select all

...
10 0.0020 1.025
11 0.0021 1.024
...

At 10 Hz, the velocity inside one standard deviation is between 487 m/s and 512 m/s.
This file can be easily translated to

Code: Select all

...
10 500.00 1.025
11 476.19 1.024
...

The standard deviation remains unchanged between the two files. If you want to translate the error to a standard deviation computed on a linear scale in velocity, it would be approximately 2.5% of 500 m/s=12.5 m/s