MathSoft, Inc. - Data Analysis Products Division
In 1811-1812 three huge (8.0+) earthquakes occured near New Madrid, Missouri. The devastation that would be caused by such large quakes today would be immense, more so than in comparable California quakes, for reasons of geology and complacency. We estimate seismic deformation using stream elevation data from topographic maps. Streams have a natural profile, whose gradient depends on the underlying soil and rock and the flow in the stream, and react to perturbations by adjusting their channels to restore the natural profile. Deviations from the natural gradient may indicate recent deformation. We use penalized regression splines to estimate the natural profile and the deformation surface. The technique is relatively cheap, and may apply to other intracontinental areas such as in India. This is joint work with Dorothy Merritts, a geomorphologist.