This paper considers forecasting the number of large aftershocks in a given interval of time following the 12 May 2008 Wenchuan earthquake (Mw 7.9). First, we investigate the Gutenberg–Richter frequency distribution as a potential forecasting technique. The parameters of the Gutenberg–Richter distribution are calculated using short periods of time. We then combine well-known models describing aftershock sequences, Omori–Utsu and the epidemic-type aftershock sequence (ETAS), with the Gutenberg–Richter forecast to create a consensus forecast of the expected number of aftershocks above a designated magnitude. The Omori–Utsu or ETAS parameters are calculated using all available data, and therefore combining the Gutenberg–Richter predictions with the Omori–Utsu or ETAS forecasts can be considered as creating a forecast ensemble that contains both short-term and long-term information about the aftershock sequence. The results are illustrated over a variety of interval lengths of 10 to 20 days. The results show that the forecasts created by the windowed Gutenberg–Richter model perform as well as the more common aftershock forecasting methods. The ensemble forecasts are also shown to produce reliable predictions and are more accurate when forecasting the number of aftershocks greater than or equal to M 5.

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