Curves

The Earth is almost impossible to understand with simple algebra.  Most of the universe defies simple substitution and modeling.  Once the reality gets to be too much, it all turns into estimation and general models that are at once so infuriatingly complex that no one can understand them, and so outrageously scientific looking that people buy exactly what they say.

Most natural cycles follow a magnitude frequency curve.  This is a curve where data points are used to plot on a logarithmic scale the probability of magnitudes.  Every stream has a flood magnitude-frequency curve.  Every seismic area has an earthquake mag-freq curve.  Every time you decide to punch someone, every one of your muscle fibers responds somewhere inside the plot of the mag-freq curve.

The problem with the idea of these curves is that they give a common enough sounding phrase enormously complex ramifications.  Take for instance a hundred-year flood.  If you live and die along a river, especially a batshit frenetic river like the Colorado, you have heard the phrase.  Hundred year flood, fifty year flood, five year flood, these are the terms you pick up and use over the Sunday morning coffee at the Raintree Diner.  And usually every one uses it wrong.

A hundred-year flood has a .01 probability of occurring every year.  That means that a hundred year flood is not something to count on.  And given that water metering along the Colorado has not been reliably practiced for more than one hundred years, the front-side error is fairly high.

Which means:

It means nothing.

“So, geologist, when is the next hundred year flood coming?”

The subtext to the question is, “What magic can science perform for us today?”

While you can predict intervals, you cannot predict frequency.  When you first meet someone and their eyes shoot some sort of loin shaking laser beam into your soul, you have no idea what the magnitude of this natural occurrence will be, you only know that the water is rising.

When you live in California, you feel the wrenching away of the Pacific plate from North America and when you catch the first rumble and the first sound of breaking glass reaches you, you say silently to yourself, “Is this the big one?”

There is no way to know.  The Richter scale has been more or less abandoned.  The actual magnitude of earthquakes adopted the handy and impressive sounding log scale.  A magnitude 9.0 will knock a city on its ass.  But a mag 7 won’t do too much in a city like Tokyo that is engineered to take the occasional shake.

When you meet that person, and after the rumbling ramps two or three times, you begin to wonder more loudly inside the seismology department of your head if this is the big one.  The one that surpasses your preparations.

But the magnitude-frequency is only telling you it will happen.  Never what any of it means.