A method is provided for processing microseismic data whereby the relative probability of an earthquake source model type, or combination of source model types, is estimated by: performing forward modelling source parameter estimation on the microseismic data, the estimation being constrained to one or more selected source model types; calculating the likelihoods of the microseismic data for given source model types by forward-modelling synthetic data from a sampled source parameter probability distribution derived from the estimation for each given source model type, and comparing the synthetic data against the microseismic data; marginalizing the calculated data likelihoods over prior probabilities for the model parameters for the given source model types to give respective likelihoods for the given source model types; and using Bayesian inference to convert the source model type likelihoods and the prior probabilities to posterior probabilities for the source model types.