Preliminary test of the EEPAS long term earthquake forecast model in Australia

Paul Somerville, Jeffrey Fisher, David Rhoades, Mark Leonard

Research output: Chapter in Book/Report/Conference proceedingOther chapter contribution


EEPAS is a long term earthquake forecasting procedure (Every Earthquake a Precursor According to Scale) developed by Evison and Rhoades. To date, the EEPAS procedure has been successfully tested in the tectonically active regions of New Zealand, Japan and California, but has not been tested in tectonically stable regions like Australia. We have made a preliminary test of the EEPAS procedure in Australia, beginning our analysis by applying it in a retrospective fitting mode to four regions of Australia, identified by Leonard (2005), that have relatively high levels of seismic activity and catalogue completeness. These include Southeast Australia, South Australia, Southwest Australia, and Northwest Australia. It appears from our preliminary analysis that the EEPAS procedure is applicable to the tectonically stable region of Australia. In Southeastern Australia, the data are sufficiently complete above M2.0 to use M2.0 as a minimum magnitude, with a target set of M>4.25 for the time period of 1975 – 2003. The optimal EEPAS parameters are similar to those obtained in tectonically active regions, except for a high value of 0.5 for the failure rate. The information gain per earthquake of EEPAS over a simpler model (PPE, i.e. Proximity to Past Earthquakes) is 0.64 for SE Australia, which is roughly the same as in other applications, but we note that this only a retrospective fitting exercise. We have tested the procedure in a prospective mode to the 1989 Newcastle earthquake. EEPAS did not indicate a large likelihood gain before the Newcastle earthquake, but the magnitude 5.3 Ellalong earthquake of 1994, together with the magnitude 5.5 Newcastle earthquake of 1989, give rise to increased probability of a larger earthquake in this region.
Original languageEnglish
Title of host publicationEarthquake engineering in Australia
Subtitle of host publicationconference : 2006 : proceedings of a conference held by the Australian Earthquake Engineering Society : Canberra, ACT : 24-26 November 2006
EditorsKevin McCue, Sonja Lenz
Place of PublicationJamison, A.C.T.
PublisherAustralian Earthquake Engineering Society
Number of pages6
ISBN (Print)0646469215
Publication statusPublished - 2006
EventAustralian Earthquake Engineering Society Conference - Canberra
Duration: 24 Nov 200626 Nov 2006


ConferenceAustralian Earthquake Engineering Society Conference


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