Focal mechanism estimation by classification
  A classification technique for identifying focal mechanism type and fault plane orientation based on the polarity of P-wave "first motion" data is derived. A support vector machine is used to classify the polarity data in the space of spherical harmonic functions. The classification is non-parametric in the sense that there is no requirement to make a priori assumptions source mechanism. A metric of similarity potentially able to distinguish shear versus tensile dislocation without requiring estimation of the fault plane orientation is a natural consequence of this procedure. Going further, correlation functions between template source mechanism is derived, gives an estimate of fault plane orientation assuming a particular source mechanism. 
Ben G. Lasscock, Brendon J. Hall and Michael E. Glinsky
physics.geo-ph