—We present a method to detect social events in a set of pictures from an image hosting service (Flickr). This method relies on the analysis of user-generated tags, by using statistical models trained on both a small set of manually annotated data and a large data set collected from the Internet. Social event modeling relies on multi-span topic model based on LDA (Latent Dirichlet Allocation). Experiments are conducted in the experimental setup of MediaEval'2011 evaluation campaign. The proposed system outperforms significantly the best system of this benchmark, reaching a F-measure score of about 71%.