The three virtues

Don’t forget the three virtues of a Geophysicist, namely:
True Love, True Friendship, True Amplitudes. ~ M. Tygel

This happens to be my favorite quote about geophysics.
A fellow writer asked me, what this quote was all about. So I began to elaborate on this.
The part about “True Love” appears to be the easiest to me. Having met the woman who is more than I ever dared to dream of, puts me in the position to say this true love gives me strength and support I need to move mountains. (What a lovely idiom for a geoscientist, right?!)
Now I hear some say “friends come and go”, but you should have your couple of friends that can count on you just like you can always count on them.
Those are the two ingredients that keep the geophysicist from going crazy when he’s entangled in some fancy dimension of Fourier- or Hilbertransforms. (Or maybe just missed the conversion from feet to meters?)?Now this part probably made my friends reading this quite happy, but didn’t solve the real puzzlement about the amplitudes.

Let’s see.
I work in seismics and I just happen to know the quote is from a fellow geophysicist in seismics. What we do in seismics is sending acoustic waves into the ground. Those waves waves get reflected at inconsistencies in the subsurface. So they get back to the surface and that’s where we set out our recorders to pick up an image of the earth we stand on.

There’s something wonderful about waves.

They are characterized by very distinct featuresProperties of waves, such as the wavelength, polarization and amplitude. Now I’ll try not to make this too physical. When you hear sound, its pitch is determined by its frequency. The higher your frequency goes, the higher the pitch goes. However, if you want to figure out if this sound will burst your eardrums you should rather have a look at the amplitude. This will tell you how loud your sound is.
You might ask yourself why this is so interesting for us geophysicists. I mean, a reflector is a reflector right? So when there is something in the ground that will reflect your acoustic wave, you don’t need to care about it’s intensity. Well, first of all you can get a good estimate, how strong of a reflector you have in the underground. When there is a strong inconsistency in the ground, this will be shown by the amplitude of the reflected wave.Quantitative Seismic Interpretation – Stanford University But this isn’t all! The amplitudes of a seismic trace can be used as an indicator for carbohydrates in the underground. When a reservoir is filled with a fluid, this changes the behavior of our wave. The influence of the fluid on the wave increases by the time the wave travels through. Now it’s basic geometry to see that waves arriving with steeper angles have a shorter stay in the fluid filled sediments.

This results in slight changes of the amplitude with increasing angles. For all of this you need the true amplitudes. Therefore, we call any process that works on seismic data and leaves the amplitudes intact “amplitude preserving” or “True Amplitude”.

Now you know about the three virtues of a geophysicist. And coincidentally, why I use the shorturl amplt.de.
What are your favorite geoscientific quotes?