![]() This is backed up by evidence that the rupture of the 2001 Kunlun earthquake jumped more than 10 km across an extensional stepover. Numerical modelling has suggested that jumps of at least 8 km, or possibly more are feasible. For active strike-slip systems, earthquake ruptures may jump from one segment to another across the intervening stepover, if the offset is not too great. In the case of a dextral fault zone, a right-stepping offset is known as an extensional stepover as movement on the two segments leads to extensional deformation in the zone of offset, while a left-stepping offset is known as a compressional stepover. The areas between the ends of adjacent segments are known as stepovers. When strike-slip fault zones develop, they typically form as several separate fault segments that are offset from each other. Deformation styles Development of Riedel shears in a zone of dextral shear Flower structures developed along minor restraining and releasing bends on a dextral (right-lateral) strike-slip fault Stepovers Strike-slip tectonics is characteristic of several geological environments, including oceanic and continental transform faults, zones of oblique collision and the deforming foreland of zones of continental collision. Where the displacement along a zone of strike-slip deviates from parallelism with the zone itself, the style becomes either transpressional or transtensional depending on the sense of deviation. Areas of strike-slip tectonics are characterised by particular deformation styles including: stepovers, Riedel shears, flower structures and strike-slip duplexes. Where a zone of strike-slip tectonics forms the boundary between two tectonic plates, this is known as a transform or conservative plate boundary. Strike-slip tectonics or wrench tectonics is a type of tectonics that is dominated by lateral (horizontal) movements within the Earth's crust (and lithosphere). This transient process highlights the importance of addressing such solid-fluid coupling in studies aiming at constraining volcanic eruption triggers as well as seismic fault destabilization, and the means and pros of geothermal system development.Structure and processes associated with zones of lateral displacement in the Earth's crust We also show how a plasticity criterion as simple as the von Mises criterion already enhances fluid flow, locally. Pressure-driven fluid diffusion returns to stationary state between weeks to months after fault slip. We report a maximum fluid flux reaching 8 to 70 times the initial stationary flux. ![]() We investigate the spatial and temporal evolution of this fluid flow when varying fault permeability, shear modulus, fluid viscosity, and rock frictional strength. ![]() The appearance of negative and positive fluid pressure in these domains lead to a time-dependent focused fluid flow, which resembles the suction-pump mechanism proposed ca. The development of dilational and contractional domains in the fault' surroundings lead to mean stresses and volumetric strains that range between ☑ MPa and ☑0-4, respectively. Once this implementation is benchmarked, we assess the development of fluid flow due to a slipping vertical strike-slip left-lateral fault set at 5 km depth. We developed an original poro-elasto-plastic Finite Element Method (FEM) based on the FEniCS library, and in which the poro-elastic and the elasto-plastic constitutive equations are implicitly coupled. Here, we carry a preliminary modelling approach to be considered as a proof of concept, to show how within such a tectonic setting, a strike slip fault influences fluid flow out from a geothermal reservoir. The Planchon-Peteroa geothermal system of the South Andean Volcanic Zone (Chile), illustrates at tectonic crustal scale, how strike-slip faults appear closely involved in the localization of hydrothermal fluid flow. ![]() While faults can alter fluid flow in their surroundings, potentially acting as barriers or conduits for fluids, magmatic and hydrothermal fluids can also modify pore pressure and alter faults resistance to slip motion. While fluid-fault interactions in the upper crust have received a wealth of investigations using observational, experimental and modelling approaches, the multi-parametric processes at play are still poorly constrained. Geothermal systems are recognized as key energy resources as well as locations where hydrothermally enhanced chemical reactions can favour mineralizations of economic interest.
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