Abstract Visco‐elastic‐plastic modeling approaches for long‐term tectonic deformation assume that co‐seismic fault displacement can be integrated over 1000s–10,000s years (tens of earthquake cycles) with the appropriate failure law, and that short‐timescale fluctuations in the stress field due to individual earthquakes have no effect on long‐term behavior. Models of the earthquake rupture process generally assume that the tectonic (long‐range) stress field or kinematic boundary conditions are steady over the course of multiple earthquake cycles. This study is aimed to fill the gap between long‐term and short‐term deformations by modeling earthquake cycles with the rate‐and‐state frictional (RSF) relationship in Navier‐Stokes equations. We reproduce benchmarks at the earthquake timescale to demonstrate the effectiveness of our approach. We then discuss how these high‐resolution models degrade if the time‐step cannot capture the rupture process accurately and, from this, infer when it is important to consider coupling of the two timescales and the level of accuracy required. To build upon these benchmarks, we undertake a generic study of a thrust fault in the crust with a prescribed geometry. It is found that lower crustal rheology affects the periodic time of characteristic earthquake cycles and the inter‐seismic, free‐surface deformation rate. In particular, the relaxation of the surface of a cratonic region (with a relatively strong lower crust) has a characteristic double‐peaked uplift profile that persists for thousands of years after a major slip event. This pattern might be diagnostic of active faults in cratonic regions.
The Underworld team would like to congratulate Bénédicte Cenki-Tok and co-authors at the University of Sydney and the University of Montpellier on their recent publication, B. Cenki-Tok, P.F. Rey, D. Arcay;
à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Visco-elastic-plastic modelling approaches for long-term tectonic deformation assume that co-seismic fault displacement can be integrated over 1,000s-10,000s years (tens of earthquake cycles) with the appropriate failure law, and that short-timescale fluctuations in the stress field due to individual earthquakes have no effect on long-term behavior. Models of the earthquake rupture process generally assume that the tectonic (long-range) stress field or kinematic boundary conditions are steady over the course of multiple earthquake cycles. In this study, we develop a numerical framework that embeds earthquake rupture dynamics into a long-term tectonic deformation model by adding inertial terms and using highly adaptive time-stepping that can capture deformation at plate-motion rates as well as individual earthquakes. We reproduce benchmarks at the earthquake timescale to demonstrate the effectiveness of our approach. We then discuss how these high-resolution models degrade if the time-step cannot capture the rupture process accurately and, from this, infer when it is important to consider coupling of the two timescales and the level of accuracy required. To build upon these benchmarks, we undertake a generic study of a thrust fault in the crust with a prescribed geometry. We find that lower crustal rheology affects the periodic time of characteristic earthquake cycles and the inter-seismic, free-surface deformation rate. In particular, the relaxation of the surface of a cratonic region (with a relatively strong lower crust) has a characteristic double-peaked uplift profile that persists for thousands of years after a major slip event. This pattern might be diagnostic of active faults in cratonic regions.
To date <em>weak scaling </em>tests have been run on two of the largest computers in Australia: <strong>Gadi</strong> (NCI) and <strong>Magnus </strong>(Pawsey). Here we present the results of those tests and discuss: <strong>Gadi: Weak scaling - SolDB3D Q1</strong>Gadi - v2.11-prerelease: Weak scaling of SolDB3D (linear elements) to ~10k procs <strong>Gadi: Weak scaling - SolDB3D Q2</strong>Gadi - v2.11-prerelease: Weak scaling of SolDB3D
Abstract Long‐lived high to ultra‐high temperature (HT‐UHT) granulitic terranes formed throughout Earth's history. Yet, the detailed processes involved in their formation remain unresolved and notably the sequence of appearance and duration of migmatisation and granulites conditions in the orogenic cycle. These processes can be evaluated by analytical and numerical models. First, solving the steady‐state heat equation allows underlining the interdependency of the parameters controlling the crustal geotherm at thermal equilibrium. Second, performing two‐dimensional thermo‐mechanical experiments of an orogenic cycle, from shortening to gravitational collapse, allows to consider non‐steady‐state geotherms and understand how deformation velocity may affect the relative timing of migmatite and granulite formation. These numerical experiments with elevated radiogenic heat production and slow shortening rates allow the formation of large volumes of prograde migmatites and granulites going through the sillimanite field as observed in many HT‐UHT terranes. Finally, the interplay between these parameters can explain the difference in predicted pressure‐temperature‐time paths that can be compared with the natural rock archive.
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