scholarly journals Fast asthenosphere motion in high‐resolution global mantle flow models

2015 ◽  
Vol 42 (18) ◽  
pp. 7429-7435 ◽  
Author(s):  
Jens Weismüller ◽  
Björn Gmeiner ◽  
Siavash Ghelichkhan ◽  
Markus Huber ◽  
Lorenz John ◽  
...  
Keyword(s):  
High Resolution ◽  
Mantle Flow ◽  
Flow Models

Similarities between the Madeira and Canary Hotspots Revealed by Seismic Anisotropy from Teleseismic and Local Shear-Wave Splitting with the SIGHT Project

2021 ◽  
Author(s):  
David Schlaphorst ◽  
Graça Silveira ◽  
João Mata ◽  
Frank Krüger ◽  
Torsten Dahm ◽  
...  
Keyword(s):  
Shear Wave ◽  
Canary Islands ◽  
Delay Time ◽  
Seismic Anisotropy ◽  
Vertical Component ◽  
Mantle Flow ◽  
Crust And Upper Mantle ◽  
Length Scales ◽  
Flow Models ◽  
Using Data

<p>The Madeira and Canary archipelagos, located in the eastern North Atlantic, are two of many examples of hotspot surface expressions, but a better understanding of the crust and upper mantle structure beneath these regions is needed to investigate their structure in more detail. With the study of seismic anisotropy, it is possible to assess the rheology and structure of asthenosphere and lithosphere that can reflect a combination of mantle and crustal contributions.</p><p>Here, as part of the SIGHT project (SeIsmic and Geochemical constraints on the Madeira HoTspot), we present the first detailed study of seismic anisotropy beneath both archipelagos, using data collected from over 60 local three-component seismic land stations. Basing our observations on both teleseismic SKS and local S splitting, we are able to distinguish between multiple layers of anisotropy. We observe significant changes in delay time and fast shear-wave orientation patterns on short length-scales on the order of tens of kilometres beneath the western Canary Islands and Madeira Island. In contrast, the eastern Canary Islands and Porto Santo the pattern is much more uniform. The detected delay time increase and more complex orientation patterns beneath the western Canary Islands and Madeira can be attributed to mantle flow disturbed and diverted on small-length scales by a strong vertical component. This is a clear indication of the existence of a plume at each of those archipelagos, nowadays exerting a strong influence on the western and younger islands. We therefore conclude that a plume-like feature beneath Madeira exists in a similar way to the Canary Island hotspot and that regional mantle flow models for the region should be reassessed.</p><p>This is a contribution to project SIGHT (Ref. PTDC/CTA-GEF/30264/2017). The authors would like to acknowledge the financial support FCT through project UIDB/50019/2020 – IDL.</p>

Dynamic surface topography: A new interpretation based upon mantle flow models derived from seismic tomography

1993 ◽  
Vol 20 (3) ◽  
pp. 225-228 ◽  
Author(s):  
A. M. Forte ◽  
W. R. Peltier ◽  
A. M. Dziewonski ◽  
R. L. Woodward
Keyword(s):  
Surface Topography ◽  
Seismic Tomography ◽  
Mantle Flow ◽  
Dynamic Surface ◽  
Flow Models ◽  
New Interpretation

scholarly journals Reproducing past subduction and mantle flow using high-resolution global convection models

2018 ◽  
Vol 2 (3) ◽  
pp. 189-207 ◽  
Author(s):  
JiaShun Hu ◽  
◽  
LiJun Liu ◽  
Quan Zhou
Keyword(s):  
High Resolution ◽  
Mantle Flow

High-resolution constraints on LAB structure at the Blanco transform

2020 ◽  
Author(s):  
William Hawley ◽  
James Gaherty
Keyword(s):  
High Resolution ◽  
Azimuthal Anisotropy ◽  
Plate Motion ◽  
Pacific Basin ◽  
Mantle Flow ◽  
Detailed Knowledge ◽  
Plate Boundaries ◽  
Seismic Structure ◽  
The Pacific ◽  
Juan De Fuca

<p>Detailed knowledge of the seismic structure, fabric, and dynamics that surround the oceanic LAB continue to be refined through offshore seismic studies. Previous high-resolution studies in the Pacific basin far from plate boundaries show asthenospheric fabric that aligns neither with the lithospheric fabric (the paleo-spreading direction) nor with absolute plate motion, but rather in between. Here we present preliminary results from the Blanco Transform and Cascadia Initiative experiments, investigating the structure of the Juan de Fuca and Pacific plates on either side of the Blanco Transform. We measure ambient-noise and teleseismic Rayleigh-wave phase velocities, and solve for the period-dependent azimuthal anisotropy on either side of the transform. We will contextualize and interpret the fabrics based on mantle flow inferred from these previous Pacific basin studies. </p>

scholarly journals High-resolution central-upwind scheme for second-order macroscopic traffic flow models

2020 ◽  
Vol 31 (07) ◽  
pp. 2050097
Author(s):  
Jianzhong Chen ◽  
Ronghui Liu ◽  
Yanmei Hu
Keyword(s):  
High Resolution ◽  
Traffic Flow ◽  
Approximation Method ◽  
Numerical Approximation ◽  
Second Order ◽  
Upwind Scheme ◽  
Flow Models ◽  
Macroscopic Traffic Flow ◽  
Traffic Flow Models ◽  
Macroscopic Traffic Flow Models

Traffic flow models are important tools for traffic management applications such as traffic incident detection and traffic control. In this paper, we propose a novel numerical approximation method for second-order macroscopic traffic flow models. The method is based on the semi-discrete central-upwind numerical flux and high-order reconstructions for spatial discretizations. We then apply the designed high-resolution schemes to three representative types of second-order traffic flow models and perform a variety of numerical experiments to validate the proposed methods. The simulation results illustrate the effectiveness, simplicity and universality of the central-upwind scheme as numerical approximation method for macroscopic traffic flow models.

High-Resolution Compositional Reservoir Simulation with Dynamic Coarsening and Local Timestepping for Unstructured Grids

SPE Journal ◽  
2021 ◽  
pp. 1-17
Author(s):  
Ø. S. Klemetsdal ◽  
O. Møyner ◽  
A. Moncorgé ◽  
H. M. Nilsen ◽  
K-. A. Lie
Keyword(s):  
High Resolution ◽  
Reservoir Simulation ◽  
Unstructured Grids ◽  
Computational Time ◽  
Flow Equations ◽  
Flow Models ◽  
Fluid Physics ◽  
Computational Overhead ◽  
Complex Fluid ◽  
Quantities Of Interest

Summary Numerical smearing is oftentimes a challenge in reservoir simulation, particularly for complex tertiary recovery strategies. We present a new high-resolution method that uses dynamic coarsening of a fine underlying grid in combination with local timestepping to provide resolution in time and space. The method can be applied to stratigraphic and general unstructured grids, is efficient, introduces minimal computational overhead, and is applicable to flow models seen in practical reservoir engineering. Technically, the method is based on three concepts: Sequential splitting of the flow equations into a pressure equation and a system of transport equations Dynamic coarsening in which we temporarily coarsen the grid locally by aggregating cells into coarse blocks according to cell-wise indicators on the basis of residuals (gradients and other measures of spatial and temporal changes can also be used) Asynchronous local timestepping that traverses cells/coarse blocks in the direction of flow We assess the applicability of the method through a set of representative cases, ranging from conceptual to realistic, with complex fluid physics and reservoir geology, and demonstrate that the method can be used to reduce computational time and still retain high resolution in spatial/temporal zones and quantities of interest.

Mantle convection beneath East Asia under global mantle convection spherical framework

2020 ◽  
Author(s):  
Qunfan Zheng ◽  
Huai Zhang
Keyword(s):  
Tibetan Plateau ◽  
East Asia ◽  
Upper Mantle ◽  
Mantle Convection ◽  
Mantle Flow ◽  
The Tibetan Plateau ◽  
Mantle Structure ◽  
Lithospheric Deformation ◽  
Mantle Dynamics ◽  
Flow Models

<p>East Asia is a tectonically active area on earth and has a complicated lithospheric deformation due to the western Indo-Asian continental collision and the eastern oceanic subduction mainly from Pacific plate. Till now, mantle dynamics beneath this area is not well understood due to its complex mantle structure, especially in the framework of global spherical mantle convection. Hence, a series of numerical models are conducted in this study to reveal the key controlling parameters in shaping the present-day observed mantle structure beneath East Asia under 3-D global mantle flow models. Global mantle flow models with coarse mesh are firstly applied to give a rough constraint on global mantle convection. The detailed description of upper mantle dynamics of East Asia is left with regional refined mesh. A power-law rheology and absolute plate field are applied subsequently to get a better constraint on the related regional mantle rheological structure and surficial boundary conditions. Thus, the refined and reasonable velocity and stress distributions of upper mantle beneath East Asia at different depths are retrieved based on our 3-D global mantle flow simulations. The derived large shallow mantle flow beneath the Tibetan Plateau causes significant lithospheric shear drag and dynamic topography that result in prominent tectonic evolution of this area. And the Indo–Asian collision may have induced mantle flow beneath the Indian plate and the different velocity structures between the asthenosphere and lithosphere indicate the shear drag of asthenospheric mantle. That may explain the reason that Indo–Asian collision has occurred for 50 Ma, and this collision can still continue to accelerate uplift in the Tibetan plateau. Finally, we also consider the possible implementations of 3-D numerical simulations combined with global lithosphere and deep mantle dynamics so as to discuss the relevant influences.</p>

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