Earthquake dataset, downloaded by Bill Menke, April 7, 2015

I downloaded earthquake data from the US Geological Survey's
database http://earthquake.usgs.gov/earthquakes/search/ on
April 7, 2015.  I set the search parameters as follows:
    magnitde range: 5 - 10
    depth range: 0 - 50 km
    date range: 01/01/2000 - 12/31/2010
    order by time
The orininal output file is called eartqhuakes.csv
I stipped out a list of magnitues into the file
    earthquake_magnitudes.txt

I also looked up the Gutenberg-Richter magnitude-energy relation,
which is:
   log10(E in ergs) = 1.5 MW + 11.8
(note 1 erg = 10^-7 joules)