Nearest neighbor test for probability density function of each of the four geologic factors. Based on the tests a Gaussian kernelwith a smooth factor of 1750 mfits best for vents, a Gaussian kernel with a smooth factor of 250 mfits best for faults, a
Gaussian kernel with a smooth factor of 200 m fits best for fumaroles, a Cauchy kernel with a smooth factor of 250 m fits best for springs.