Linking the Nazca plate rigid motions to the megathrust earthquakes occurring along the Chilean subduction zone

It is typically assumed that the relative plate motions are not affected by temporal stress changes occurring during the seismic cycle, which comprises a phase of slow buildup of stress (interseismic phase) followed by a phase of sudden release of stress accompanied by rapid fault slip (coseismic phase). However, small- to medium-sized tectonic plates experience a reduced viscous resistance at their base, making the torques necessary to change their motions comparable to those generated by large earthquakes.

Here we explore whether the motions of medium-size tectonic plates experience temporal variations associated with earthquake-cycle stresses. In particular, we focus on the kinematics of the Nazca plate (NZ) in relation to the most recent M_w>8 megathrust earthquakes occurring across the Chilean trench (e.g., 2010 Maule and 2015 Illapel earthquakes). We utilise available GNSS time series to explore links between the recent (i.e., past two decades) plate kinematics and the seismic cycle of megathrust earthquakes occurring along the Chilean subduction zone. Our approach differs from classical studies on the earthquake-cycle induced deformation of the plate boundary region in that it focuses on the potential impact of large earthquakes onto rigid whole-plate kinematics.