Constraining Earth's nonlinear mantle viscosity using plate-boundary resolving global inversions

Hu, Jiashun1; Rudi, Johann2; Gurnis, Michael3; Stadler, Georg4

2024-07-09

10.1073/pnas.2318706121

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   影响因子和分区

0027-8424

1091-6490

Variable viscosity in Earth's mantle exerts a fundamental control on mantle convection and plate tectonics, yet rigorously constraining the underlying parameters has remained a challenge. Inverse methods have not been sufficiently robust to handle the severe viscosity gradients and nonlinearities (arising from dislocation creep and plastic failure) while simultaneously resolving the megathrust and bending slabs globally. Using global plate motions as constraints, we overcome these challenges by combining a scalable nonlinear Stokes solver that resolves the key tectonic features with an adjoint-based Bayesian approach. Assuming plate cooling, variations in the thickness of continental lithosphere, slabs, and broad scale lower mantle structure as well as a constant grain size through the bulk of the upper mantle, a good fit to global plate motions is found with a nonlinear upper mantle stress exponent of 2.43 +/- 0.25 (mean +/- SD). A relatively low yield stress of 151 +/- 19 MPa is required for slabs to bend during subduction and transmit a slab pull that generates asymmetrical subduction. The recovered longterm strength of megathrusts (plate interfaces) varies between different subduction zones, with South America having a larger strength and Vanuatu and Central America having lower values with important implications for the stresses driving megathrust earthquakes.

mantle rheology plate motion adjoint inversion stress exponent activation energy

SCI

英语

第一 ; 通讯

National Key R&D Program of China[2023YFF0806300] ; National Natural Science Foundation of China[92155307] ; NSF["TG-EAR160027","TG-DPP130002"]

Science & Technology - Other Topics

Multidisciplinary Sciences

WOS:001272127500001

NATL ACAD SCIENCES

BIOLOGY & BIOCHEMISTRY ; CLINICAL MEDICINE ; MULTIDISCIPLINARY ; PLANT & ANIMAL SCIENCE ; ENVIRONMENT/ECOLOGY ; SOCIAL SCIENCES, GENERAL ; MICROBIOLOGY ; ECONOMICS BUSINESS ; IMMUNOLOGY ; MATERIALS SCIENCE ; MATHEMATICS ; SPACE SCIENCE ; MOLECULAR BIOLOGY & GENETICS ; PHARMACOLOGY & TOXICOLOGY ; CHEMISTRY ; PSYCHIATRY/PSYCHOLOGY ; NEUROSCIENCE & BEHAVIOR ; PHYSICS ; GEOSCIENCES ; AGRICULTURAL SCIENCES ; ENGINEERING

Web of Science

1.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen 518055, Peoples R China
2.Virginia Tech, Dept Math, Blacksburg, VA 24061 USA
3.CALTECH, Div Geol & Planetary Sci, Seismol Lab, Pasadena, CA 91125 USA
4.NYU, Courant Inst Math Sci, New York, NY 10012 USA

Hu, Jiashun,Rudi, Johann,Gurnis, Michael,et al. Constraining Earth's nonlinear mantle viscosity using plate-boundary resolving global inversions[J]. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,2024,121(28).

Hu, Jiashun,Rudi, Johann,Gurnis, Michael,&Stadler, Georg.(2024).Constraining Earth's nonlinear mantle viscosity using plate-boundary resolving global inversions.PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA,121(28).

Hu, Jiashun,et al."Constraining Earth's nonlinear mantle viscosity using plate-boundary resolving global inversions".PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 121.28(2024).