The largest earthquakes occur at subduction zones, where one plate descends beneath another into the underlying mantle, at a convergence plate boundary. Some subduction zones seem to host more large earthquakes than others (Fig. 1), potentially reflecting the influence of large-scale geodynamic processes, which vary from one subduction zone to the next. The plate interface stress state influences whether earthquakes quickly arrest or grow to large magnitudes, but it is unclear how it varies between regions. Our research, involving collaboration between Cardiff University, Université de Montpellier and the Australian National University, explores how shear stress at the plate interface is likely to vary between subduction zones and which dynamics influence it at the whole-margin and million-year scales.
This is a companion discussion topic for the original entry at https://www.geo-down-under.org.au/a-tight-squeeze-between-tectonic-plates/