Statistical models for temporal variations of seismicity parameters to forecast seismicity rates in Japan

This paper introduces a model to forecast the rate of earthquakes for a specified period and area. The model explicitly predicts the number of earthquakes and b-value of the Gutenberg-Richter distribution for the period of interest with an autoregressive process. The model also incorporates a time dependency adjustment for higher magnitude ranges, assuming that as time passes since the last large earthquake within the area, the probability of another larger earthquake increases. These predictions are overlaid on a spatial density map obtained with a multivariate normal mixture model of the historical earthquakes that have occurred in the area. This forecast model differs from currently proposed models by its density estimation and its assumption of temporal changes. The model has been submitted to the Earthquake Forecasting Testing Experiment for Japan.