The seismic cycle at subduction thrusts: 1. Insights from laboratory models

Abstract

[1] Subduction megathrust earthquakes occur at the interface between the subducting and overriding plates. These hazardous phenomena are only partially understood because of the absence of direct observations, the restriction of the instrumental seismic record to the past century, and the limited resolution/completeness of historical to geological archives. To overcome these restrictions, modeling has become a key-tool to study megathrust earthquakes. We present a novel model to investigate the seismic cycle at subduction thrusts using complementary analog (paper 1) and numerical (paper 2) approaches. Here we introduce a simple scaled gelatin-on-sandpaper setup including realistic tectonic loading, spontaneous rupture nucleation, and viscoelastic response of the lithosphere. Particle image velocimetry allows to derive model deformation and earthquake source parameters. Analog earthquakes are characterized by "quasi-periodic" recurrence. Consistent with elastic theory, the interseismic stage shows rearward motion, subsidence in the outer wedge and uplift of the "coastal area" as a response of locked plate interface at shallow depth. The coseismic stage exhibits order of magnitude higher velocities and reversal of the interseismic deformation pattern in the seaward direction, subsidence of the coastal area, and uplift in the outer wedge. Like natural earthquakes, analog earthquakes generally nucleate in the deeper portion of the rupture area and preferentially propagate upward in a crack-like fashion. Scaled rupture width-slip proportionality and seismic moment-duration scaling verifies dynamic similarities with earthquakes. Experimental repeatability is statistically verified. Comparing analog results with natural observations, we conclude that this technique is suitable for investigating the parameter space influencing the subduction interplate seismic cycle.

On the efficient and reliable numerical solution of rate-and-state friction problems

“…We validate our algorithm through a comparison of 2-D simulations of a laboratory-scale subduction zone setting with experimental results, similar to Corbi et al (2013. The experimental results are obtained through analogue modelling (Rosenau et al 2009(Rosenau et al , 2010.…”

Analogue earthquakes and seismic cycles: experimental modelling across timescales

“…These models can only be applied conceptually to nature. instability, statistics Seismotectonic scale models (elasto-viscoplastic solids and fluids with similarity to prototype) Megathrust Gelatine Corbi et al (2013) Van Dinther et al (2013a, b), Herrendörfer et al (2015), Kaneko et al (2010) Rupture dynamics, seismic cycle Megathrust Rubber/granular /silicone Rosenau et al ( , 2010, Oncken (2009) Pipping et al (2016), Kaneko et al (2010) Seismotectonic evolution, seismic cycle, statistics, tsunami genesis Megathrust…”

“…Viscoelastic models feature the following characteristics that make them useful in the investigation of different aspects of the seismic cycle: Figure 4. Examples of seismotectonic scale models: (a) viscoelastic gelatine wedge set-up used by Corbi et al (2013) to study subduction megathrust earthquakes (modified from there); (b) elastoplastic granular wedge set-up used in this study to simulate subduction megathrust seismotectonic evolution, which is developed from a similar set-up used by Rosenau et al ( , 2010, and the resulting earthquake deformation pattern (side view, modified after ; (c) layered elastic-viscoelastic foam rubber-silicone wedge set-up used by Dominguez et al (2015) to study subduction megathrust earthquakes and the resulting earthquake deformation pattern (top view; left: displacement; right: pseudo-InSAR fringe pattern); (d) layered elastic-viscoelastic foam rubber-silicone strike-slip set-up used by Caniven et al (2015) and the resulting earthquake deformation pattern (top view; left: displacement; right: pseudo-InSAR fringe pattern) (modified from Caniven et al, 2015).…”

“…The analogue models of Corbi et al (2013) have been tested against numerical models using the finite-element technique (van Dinther et al 2013a, b). An extensive benchmark has been carried out analysing a set of parameters that are characteristic of both the inter-seismic and coseismic stages (i.e.…”

“…Viscoelastic seismotectonic scale models (e.g. Corbi et al, 2013;Fig. 4a) were used to study rupture dynamics and elastic coseismic deformation of the forearc wedge.…”