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1. Assessing plate reconstruction models using plate driving force consistency tests

   https://doi.org/10.1038/s41598-023-37117-w  

   Clennett, Edward J.; Holt, Adam F.; Tetley, Michael G.; Becker, Thorsten W.; Faccenna, Claudio (December 2023, Scientific Reports)

   Abstract Plate reconstruction models are constructed to fit constraints such as magnetic anomalies, fracture zones, paleomagnetic poles, geological observations and seismic tomography. However, these models do not consider the physical equations of plate driving forces when reconstructing plate motion. This can potentially result in geodynamically-implausible plate motions, which has implications for a range of work based on plate reconstruction models. We present a new algorithm that calculates time-dependent slab pull, ridge push (GPE force) and mantle drag resistance for any topologically closed reconstruction, and evaluates the residuals—or missing components—required for torques to balance given our assumed plate driving force relationships. In all analyzed models, residual torques for the present-day are three orders of magnitude smaller than the typical driving torques for oceanic plates, but can be of the same order of magnitude back in time—particularly from 90 to 50 Ma. Using the Pacific plate as an example, we show how our algorithm can be used to identify areas and times with high residual torques, where either plate reconstructions have a high degree of geodynamic implausibility or our understanding of the underlying geodynamic forces is incomplete. We suggest strategies for plate model improvements and also identify times when other forces such as active mantle flow were likely important contributors. Our algorithm is intended as a tool to help assess and improve plate reconstruction models based on a transparent and expandable set of a priori dynamic constraints. 

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2. Inner Forearc Stress State and Plate Coupling

   https://doi.org/10.1029/2024GC011812  

   Sharma, Viven; Wada, Ikuko; Rippke, Joe (January 2025, Geochemistry, Geophysics, Geosystems)

   Abstract The long‐term state of stress in the subduction forearc depends on the balance between margin‐normal compression due to the plate‐coupling force and the margin‐normal tension due to the gravitational force on the margin topography. In most subduction margins, the outer forearc is largely in margin‐normal compression due to the dominance of the plate‐coupling force. The inner forearc's state of stress varies within and among subduction zones, but what gives rise to this variation is unclear. We examine the state of stress in the forearc region of nine subduction zones by inverting focal mechanism solutions for shallow forearc crustal earthquakes for five zones and inferring the previous inversion results for the other four. The results indicate that the inner forearc stress state is characterized by margin‐normal horizontal deviatoric tension in parts of Nankai, Hikurangi, and southern Mexico. The vertical and margin‐normal horizontal stresses are similar in magnitudes in northern Cascadia as previously reported and are in a neutral stress state. The inner forearc stress state in the rest of the study regions is characterized by margin‐normal horizontal deviatoric compression. Tension in the inner forearc tends to occur where plate coupling is shallow. A larger width of the forearc also promotes inner‐forearc tension. However, regional tectonics may overshadow or accentuate the background stress state in the inner forearc, such as in Hikurangi. 

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3. Modelling architected plate using a non-local derivative-free shear deformable plate theory

   https://doi.org/10.1007/s11012-023-01677-y  

   Saxena, Mukul; Sarkar, Saikat; Reddy, J N (August 2023, Meccanica)

   The internal length scale relating to the cell size plays a crucial role in predicting the response of architected structures when subjected to external stimuli. A Volterra derivative-based approach for arriving at the non-local derivative-free continuum laws for architected structures is proposed. A mainstay of the work is the derivative-free directionality term, which recovers its classical counterpart in the infinitesimal limit. Using this approach, we derive the non-local integro-differential governing equations of a shear deformable plate. We also suggest a physical basis for the consideration of energy for nonaffine deformations and accurately estimate it by performing buckling analysis. This discards the requirement of the additional energy to be incorporated in an arbitrary manner for suppressing the unwanted spurious oscillations induced from zero energy modes. The numerical results demonstrate the efficacy of the proposed framework in precisely capturing the mechanical response of web-core shear deformable plate, thereby, manifesting the supremacy of the reduced model in shrinking the cost and computational time. To bolster our claim, various numerical models with different loading conditions have been analysed and compared against the three-dimensional FEM results. 

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4. Grain damage, phase mixing and plate-boundary formation

   https://doi.org/10.1016/j.jog.2017.05.002  

   Bercovici, David; Skemer, Philip (July 2017, Journal of Geodynamics)
5. ESTIMATION OF PLATE PARAMETERS FROM VERTICAL DISPLACEMENT DATA USING A FAMILY OF PLATE MODELS

   https://doi.org/10.58997/ejde.2023.15  

   WHITE, LUTHER; MALYSHEVA, TETYANA; KARLSTROM, LEIF (January 2023, Electronic journal of differential equations)

   We develop a method for estimation of parameters of an elastic plate resting on a Winkler-type elastic foundation solely from data on the vertical displacements of the plate. The method allows one to estimate components of the external body force density field, plate thickness, elastic foundation stiffness parameters, horizontal displacements of the plate, and stresses. The key idea of the method is that multiple plate models are used simultaneously, namely the proposed reduced three-dimensional (R3D) plate model, the Mindlin plate model, and the thin plate model. The three plate models form a hierarchy of elastic plate models based on assumptions imposed on stresses, with the R3D plate model being the most generalized model and the thin plate model being the most constrained one. The hierarchical relationship among the plate models allows one to incorporate prior information into the estimation technique. The applicability of the proposed estimation method is illustrated by a numerical example. 

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