Utilising short-term and medium-term forecasting models for earthquake hazard estimation in the wake of the Canterbury earthquakes

David A. Rhoades, Matthew C. Gerstenberger, Annemarie Christophersen, & Maria Liukis

Published August 2013, SCEC Contribution #2046

Following the Canterbury earthquake sequence, a specially developed operational earthquake forecasting model is being used for decision-making on building standards and urban planning for the rebuilding of Christchurch city. This is a hybrid model, with contributions from two short-term, two medium-term and four long-term forecasting models. It estimates the earthquake occurrence in the Canterbury region for the next 50 years.

The models contributing to the hybrid model are individually very different, but are designed to capture different known features of earthquake occurrence. The short-term models describe the way in which aftershock rates typically decay following a large event. The medium-term models exploit the observation that small earthquakes often precede larger ones in the medium term. The long-term models describe the average rate at which main shocks or all earthquakes of magnitude 5 or greater are expected to occur in the long term. The weighting that each individual model received in the hybrid model was decided by eliciting the opinions of an international panel of experts.

We tested the individual and hybrid models over 26 years in the whole New Zealand region, starting in 1986 when there was a major improvement in the quality of the earthquake catalogue. We also estimated the best hybrid model that could be fitted to this part of the earthquake catalogue.

Citation
Rhoades, D. A., Gerstenberger, M. C., Christophersen, A., & Liukis, M. (2013, 8). Utilising short-term and medium-term forecasting models for earthquake hazard estimation in the wake of the Canterbury earthquakes. Presentation at GNS Science Consultancy Report 2013.