Global correlations between maximum magnitudes of subduction zone interface thrust earthquakes and physical parameters of subduction zones

•Correlating 24 subduction parameters and maximum earthquakes at subduction zones.•Correlations for 24 parameters are low (|R|=0.00–0.51), irrespective of dataset.•Epicenters of giant earthquakes only occur at compressive/neutral overriding plates.•Giant earthquakes might be triggered at normal stress asperities on interface.•Giant earthquakes require gentle thrust dip, slow trench motion and flat interface. The maximum earthquake magnitude recorded for subduction zone plate boundaries varies considerably on Earth, with some subduction zone segments producing giant subduction zone thrust earthquakes (e.g. Chile, Alaska, Sumatra–Andaman, Japan) and others producing relatively small earthquakes (e.g. Mariana, Scotia). Here we show how such variability might depend on various subduction zone parameters. We present 24 physical parameters that characterize these subduction zones in terms of their geometry, kinematics, geology and dynamics. We have investigated correlations between these parameters and the maximum recorded moment magnitude (MW) for subduction zone segments in the period 1900–June 2012. The investigations were done for one dataset using a geological subduction zone segmentation (44 segments) and for two datasets (rupture zone dataset and epicenter dataset) using a 200km segmentation (241 segments). All linear correlations for the rupture zone dataset and the epicenter dataset (|R|=0.00–0.30) and for the geological dataset (|R|=0.02–0.51) are negligible-low, indicating that even for the highest correlation the best-fit regression line can only explain 26% of the variance. A comparative investigation of the observed ranges of the physical parameters for subduction segments with MW>8.5 and the observed ranges for all subduction segments gives more useful insight into the spatial distribution of giant subduction thrust earthquakes. For segments with MW>8.5 distinct (narrow) ranges are observed for several parameters, most notably the trench-normal overriding plate deformation rate (vOPD⊥, i.e. the relative velocity between forearc and stable far-field backarc), trench-normal absolute trench rollback velocity (vT⊥), subduction partitioning ratio (vSP⊥/vS⊥, the fraction of the subduction velocity that is accommodated by subducting plate motion), subduction thrust dip angle (δST), subduction thrust curvature (CST), and trench curvature angle (αT). The results indicate that MW>8.5 subduction earthquakes occur for rapidly shortening to slowly extending ov