Articles | Volume 5, issue 2
Solid Earth, 5, 631–639, 2014
https://doi.org/10.5194/se-5-631-2014
Solid Earth, 5, 631–639, 2014
https://doi.org/10.5194/se-5-631-2014

Method article 04 Jul 2014

Method article | 04 Jul 2014

Modelling complex geological circular data with the projected normal distribution and mixtures of von Mises distributions

R. M. Lark1, D. Clifford2, and C. N. Waters1 R. M. Lark et al.
  • 1British Geological Survey, Keyworth, Nottingham, UK
  • 2CSIRO Computational Informatics, Ecoscience Precinct, G.P.O. Box 2583, Brisbane, Qld 4001, Australia

Abstract. Circular data are commonly encountered in the earth sciences and statistical descriptions and inferences about such data are necessary in structural geology. In this paper we compare two statistical distributions appropriate for complex circular data sets: the mixture of von Mises and the projected normal distribution. We show how the number of components in a mixture of von Mises distribution may be chosen, and how one may choose between the projected normal distribution and the mixture of von Mises for a particular data set. We illustrate these methods with a few structural geological data, showing how the fitted models can complement geological interpretation and permit statistical inference. One of our data sets suggests a special case of the projected normal distribution which we discuss briefly.