A new hybrid Coulomb/statistical model for forecasting aftershock rates

Sandy Steacy, Matt Gerstenberger, Charles Williams, David Rhoades, Annemarie Christophersen

    Research output: Contribution to journalArticlepeer-review

    41 Citations (Scopus)


    Forecasting the spatial and temporal distribution of aftershocks is of great importance to earthquake scientists, civil protection authorities and the general public as these events cause disproportionate damage and consternation relative to their size. At present, there are two main approaches to such forecasts—purely statistical methods based on observations of the initial portions of aftershock sequences and a physics-based approach based on Coulomb stress changes caused by the main shock. Here we develop a new method which combines the spatial constraints from the Coulomb model with the statistical power of the STEP (short-term earthquake probability) approach. We test this pseudo prospectively and retrospectively on the Canterbury sequence against the STEP model and a Coulomb rate–state method, using data from the first 10 d following each main event to forecast the rate of M ≥ 4 events in the following 100 d. We find that in retrospective tests the new model outperforms STEP for two events in the sequence but this is not the case for pseudo-prospective tests. Further, the Coulomb rate–state approach never performs better than STEP. Our results suggest that incorporating the physical constraints from Coulomb stress changes can increase the forecasting power of statistical models and clearly show the importance of good data quality if prospective forecasts are to be implemented in practice.
    Original languageEnglish
    Pages (from-to)1-6
    JournalGeophysical Journal International
    Publication statusPublished (in print/issue) - 11 Nov 2013


    • Earthquake interaction
    • forecasting
    • and prediction
    • probabilistic forecasting
    • statistical seismology


    Dive into the research topics of 'A new hybrid Coulomb/statistical model for forecasting aftershock rates'. Together they form a unique fingerprint.

    Cite this