### How to calculate Standard Deviation from Spectral Ratios

Posted:

**Wed Apr 09, 2014 2:53 pm**Hello all Geopsy users.

I'm trying to calculate the standard deviation (with seismic analysis code, sac from iris) from spectral ratios and compare with those calculated by Geopsy.

Do you know the formula that Geopsy uses?

or

Do you know some article that explain this?

Thanks a lot.

I'm trying to calculate the standard deviation (with seismic analysis code, sac from iris) from spectral ratios and compare with those calculated by Geopsy.

Do you know the formula that Geopsy uses?

or

Do you know some article that explain this?

Thanks a lot.