scholarly journals Role of faults, nonlinear rheology, and viscosity structure in generating plates from instantaneous mantle flow models

1998 ◽  
Vol 103 (B7) ◽  
pp. 15255-15268 ◽  
Author(s):  
Shijie Zhong ◽  
Michael Gurnis ◽  
Louis Moresi
Keyword(s):  
Mantle Flow ◽  
Nonlinear Rheology ◽  
Flow Models

scholarly journals Effects of basal drag on subduction dynamics from 2D numerical models

2020 ◽  
Author(s):  
Lior Suchoy ◽  
Saskia Goes ◽  
Benjamin Maunder ◽  
Fanny Garel ◽  
Rhodri Davies
Keyword(s):  
Numerical Models ◽  
Force Balance ◽  
Plate Motion ◽  
Mantle Flow ◽  
Plate Motions ◽  
Flow Models ◽  
Plate Size ◽  
Modelling Studies ◽  
Subduction System

Abstract. Subducting slabs are an important driver of plate motions, yet the force balance governing subduction dynamics remains incompletely understood. Basal drag has been proposed to be a minor contributor to subduction forcing, because of the lack of correlation between plate size and velocity in observed and reconstructed plate motions. Furthermore, in single subduction system models, low basal drag, associated with a low ratio of asthenospheric to lithospheric viscosity, leads to subduction behaviour most consistent with the observation that trench migration velocities are generally low compared to convergence velocities. By contrast, analytical calculations and global mantle flow models indicate basal drag can be substantial. In this study, we revisit this problem by examining the drag at the base of the lithosphere, for a single subduction system, in 2D models with a free trench and composite non-linear rheology. We compare the behaviour of short and long plates for a range of asthenospheric and lithospheric rheologies. We reproduce results from previous modelling studies, including low ratios of trench over plate motions. However, we also find that any combination of asthenosphere and lithosphere viscosity that produces Earth-like subduction behaviour leads to a correlation of velocities with plate size, due to the role of basal drag. By examining Cenozoic plate motion reconstructions, we find that slab age and plate size are positively correlated: higher slab pull for older plates tends to be offset by higher basal drag below these larger plates. This, in part, explains the lack of plate velocity-size correlation in observations, despite the important role of basal drag in the subduction force-balance.

scholarly journals Effects of basal drag on subduction dynamics from 2D numerical models

Solid Earth ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 79-93
Author(s):  
Lior Suchoy ◽  
Saskia Goes ◽  
Benjamin Maunder ◽  
Fanny Garel ◽  
Rhodri Davies
Keyword(s):  
Numerical Models ◽  
Force Balance ◽  
Plate Motion ◽  
Mantle Flow ◽  
Plate Motions ◽  
Flow Models ◽  
Plate Size ◽  
Modelling Studies ◽  
Subduction System

Abstract. Subducting slabs are an important driver of plate motions, yet the relative importance of different forces in governing subduction motions and styles remains incompletely understood. Basal drag has been proposed to be a minor contributor to subduction forcing because of the lack of correlation between plate size and velocity in observed and reconstructed plate motions. Furthermore, in single subduction system models, low basal drag leads to subduction behaviour most consistent with the observation that trench migration velocities are generally low compared to convergence velocities. By contrast, analytical calculations and global mantle flow models indicate basal drag can be substantial. In this study, we revisit this problem by examining the drag at the base of the lithosphere, for a single subduction system, in 2D models with a free trench and composite non-linear rheology. We compare the behaviour of short and long plates for a range of asthenospheric and lithospheric rheologies. We reproduce results from previous modelling studies, including low ratios of trench over plate motions. However, we also find that any combination of asthenosphere and lithosphere viscosity that produces Earth-like subduction behaviour leads to a correlation of velocities with plate size, due to the role of basal drag. By examining Cenozoic plate motion reconstructions, we find that slab age and plate size are positively correlated: higher slab pull for older plates tends to be offset by higher basal drag below these larger plates. This, in part, explains the lack of plate velocity–size correlation in observations, despite the important role of basal drag in the subduction force balance.

THE ROLE OF DEEP MANTLE FLOW IN SHAPING THE HAWAIIAN-EMPEROR BEND

2017 ◽  
Author(s):  
Simon Williams ◽  
◽  
Rakib Hassan ◽  
Dietmar Müller ◽  
Michael Gurnis ◽  
...  
Keyword(s):  
Mantle Flow ◽  
Deep Mantle

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 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

scholarly journals Role of mantle flow in Nubia-Somalia plate divergence

2015 ◽  
Vol 42 (2) ◽  
pp. 290-296 ◽  
Author(s):  
D. S. Stamps ◽  
G. Iaffaldano ◽  
E. Calais
Keyword(s):  
Mantle Flow

scholarly journals Spatial Spillover Effects of Agricultural Transport Costs in Peru

2021 ◽  
Author(s):  
Pedro Herrera-Catalán ◽  
Coro Chasco ◽  
Máximo Torero
Keyword(s):  
Spatial Configuration ◽  
Spillover Effects ◽  
Equilibrium Analysis ◽  
New Economic Geography ◽  
Spatial Equilibrium ◽  
Transport Costs ◽  
Economic Activities ◽  
Flow Models ◽  
Spatial Spillovers

The role of agricultural transport costs in core-periphery structures has habitually been ignored in New Economic Geography (NEG) models. This is due to the convention of treating the agricultural good as the numéraire, thus implying that agricultural transportation costs are assumed to be zero in these models. For more than three decades, this has been the standard setting in spatial equilibrium analysis. The paper examines the effects of agricultural transport costs on the spatial organisation of regional structures in Peru. In doing so, the Krugman’s formulation of iceberg transport costs is modified to introduce the agricultural transport costs into the dynamic of the NEG models. We use exploratory spatial flow data analysis methods and non-spatial and spatial origin-destination flow models to explore how the regional spatial structure change when real transportation data for agricultural goods is included into the iceberg transport costs formulation. We show that agricultural transport costs generate flows that are systematically associated with flows to or from nearby regions generating thus the emergence of spatial spillovers across Peruvian regions. The results of the paper support the contention that NEG models have overshadowed the role of agricultural transport costs in determining the spatial configuration of economic activities.

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