Fig. 5

Anomaly detection for the group at 33.10°N, 132.20°E (Fig. 4b). a Difference between the log-likelihood of the model with a single change point and that of the reference model with no change points. b Difference between the log-likelihood of the double change-point model and that of the reference model with no change points. The circle shows the location of the best combination of the two change points. c Histogram of inter-event times. The gray bars are the original times. The blue and orange bars correspond to the two distributions for the best double change-point model. The fitted distributions are also shown. d Comparison of the transformed times and event numbers. The dotted line shows the relationship between the event number and the original event time normalized to the event number. The black dashed and blue lines are the comparisons of the original and double change-point models, respectively. The orange lines show the change points