简介:We introduce and test an experimental approach to simulate elastoplastic megathrust
earthquake cycles using an analogue model and apply it to study the seismotectonic
evolution of subduction zones. The quasi-two-dimens简介:We introduce and test an experimental approach to simulate elastoplastic megathrust
earthquake cycles using an analogue model and apply it to study the seismotectonic
evolution of subduction zones. The quasi-two-dimensional analogue model features
rate- and state-dependent elastic-frictional plastic and viscoelastic material properties and
is scaled for gravity, inertia, elasticity, friction, and viscosity. The experiments are
monitored with a high-resolution strain analysis tool based on digital image correlation
(particle imaging velocimetry, PIV), providing deformation time series comparable to
seismologic, geodetic, and geologic observations. In order to separate elastic and
nonelastic effects inherent the experimental deformation patterns, we integrate elastic
dislocation modeling (EDM) into a hybrid approach: we use the analogue earthquake slip
and interseismic locking distribution as EDM dislocation input and forward model the
coseismic and interseismic elastic response. The residual, which remains when the EDM
prediction is subtracted from the experimental deformation pattern, highlights the
accumulation of permanent deformation in the model. The setup generates analogue
earthquake sequences with realistic source mechanisms and elastic forearc response and
recurrence patterns and reproduces principal earthquake scaling relations. By applying
the model to an accretionary-type plate margin, we demonstrate how strain localization at
the rupture peripheries may lead to a seismotectonically segmented forearc, including a
tectonically stable shelf and coastal high (<20% plate convergence accommodated by
internal shortening) overlying the area of large megathrust earthquake slip. Fifty to 75% of
plate convergence is accommodated by internal shortening in the slope region where
earthquake slip tapers out toward the trench. The inner forearc region remains undeformed
and represents a basin.详细>