Analogue earthquakes and seismic cycles: experimental modelling across timescales

Abstract

Abstract. Earth deformation is a multi-scale process ranging from seconds (seismic deformation) to millions of years (tectonic deformation). Bridging short-and long-term deformation and developing seismotectonic models has been a challenge in experimental tectonics for more than a century. Since the formulation of Reid's elastic rebound theory 100 years ago, laboratory mechanical models combining frictional and elastic elements have been used to study the dynamics of earthquakes. In the last decade, with the advent of high-resolution monitoring techniques and new rock analogue materials, laboratory earthquake experiments have evolved from simple spring-slider models to scaled analogue models. This evolution was accomplished by advances in seismology and geodesy along with relatively frequent occurrences of large earthquakes in the past decade. This coincidence has significantly increased the quality and quantity of relevant observations in nature and triggered a new understanding of earthquake dynamics. We review here the developments in analogue earthquake modelling with a focus on those seismotectonic scale models that are directly comparable to observational data on short to long timescales. We lay out the basics of analogue modelling, namely scaling, materials and monitoring, as applied in seismotectonic modelling. An overview of applications highlights the contributions of analogue earthquake models in bridging timescales of observations including earthquake statistics, rupture dynamics, ground motion, and seismic-cycle deformation up to seismotectonic evolution.

Control of asperities size and spacing on seismic behavior of subduction megathrusts

“…Basins are hypothetically a geologic indicator of asperities [Mogi, 1969;Nishenko and McCann, 1979;Wells et al, 2003;Fuller et al, 2006;Rosenau et al, 2017;Saillard et al, 2017], while high slip deficit rate zones highlight coupled locked areas of the megathrust where stress builds up during the monitoring period (i.e., the last 6 years in the case of Nankai).…”

“…Therefore, seismic waves are unlikely to be excited and dynamic effects not present. We adopted the "seismotectonic scale models" approach to develop our models, taking therefore into account geometric, kinematic, and dynamic similarity criteria [e.g., Hubbert, 1937;Rosenau et al, 2017]. An important consequence of such scaling is the introduction of a dyadic time-scaling factor that allows slowing down the earthquake rupture process and speeding up the interseismic stress buildup phase, keeping dynamic similarity in both stages Rosenau et al, 2017].…”

“…We adopted the "seismotectonic scale models" approach to develop our models, taking therefore into account geometric, kinematic, and dynamic similarity criteria [e.g., Hubbert, 1937;Rosenau et al, 2017]. An important consequence of such scaling is the introduction of a dyadic time-scaling factor that allows slowing down the earthquake rupture process and speeding up the interseismic stress buildup phase, keeping dynamic similarity in both stages Rosenau et al, 2017]. Despite the unavoidable experimental oversimplifications, the main advantages of analog models are: (a) the physically self-consistent behavior, which allows spontaneously nucleating analog earthquakes as a result of stress build-up and plates interface strength; (b) the capability of reproducing tens of seismic cycles in a convenient experimental time; and (c) the 3-D nature of the setup, which is mandatory for studying the synchronization process.…”

Smart Speed Imaging in Digital Image Correlation: Application to Seismotectonic Scale Modeling

“…Although the recurrence behavior of earthquakes on a single fault is quasiperiodic, under the assumption of constant loading rates and frictional parameters, it is not possible to predict the onset of seismic slip (Ben-Zion et al, 2003). Therefore, numerical simulations and physical experiments have been designed to model fault slip and the seismic cycle (Rosenau et al, 2017). Because of the multiscale nature of fault slip, many numerical simulations are limited to either short (e.g., rupture models) (Heinecke et al, 2014) or long timescales (e.g., geodynamic models) (Dinther et al, 2013).…”

“…Only few numerical techniques allow the combination of short term and long term processes, and frequently the parametrization and implementation of the non-linear, multiscale interactions between the long and short timescales remains difficult (Avouac, 2015). Seismotectonic analog experiments allow to address the multiscale nature of slip on a laboratory scale and may provide additional insight into the deformation over multiple seismic cycles (Rosenau et al, 2017). Even though the analog experiments are strong simplifications of a seismogenic fault system, they inherently show stick-slip dynamics without the need of a complex integration scheme (Caruso et al, 2007;Marković and Gros, 2014).…”