Oklahoma Geological Survey annual earthquake maps 1977-2001
Magnitude symbols appear on a base map at the top. Below the magnitude symbols the page may be scrolled downward for annual earthquake maps from 1977 to 2001 followed by a cumulative map
The earthquake map is a Lambert Conformal Conical projection, with standard
parallels of 34.5N and 36.5N. It is centered at 35.5N and 98.62W. This is similar, but not identical, to a geometric projection of Oklahoma onto a cone which
cuts through Oklahoma on two latitudes, 34.5N, and 36.5N
The map is plotted with the awesome freeware package named "Generic Mapping Tools" written by Paul Wessel and Walter H. S. Smith. The maps are further processed with freeware "ImageMagick" by John Cristy, Bob Friesenhahn and others. Ken Luza of the Oklahoma Geological Survey produced the 5530 point Oklahoma County Boundary file.