Western U.S. Volcanism due to Intruding Oceanic Mantle Driven by - - PowerPoint PPT Presentation

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Sep 01, 2023 376 likes •589 views

Western U.S. Volcanism due to Intruding Oceanic Mantle Driven by Ancient Farallon Slabs Project PI : Lijun Liu, Univ. of IL at Urbana-Champaign Presenter : Quan Zhou NCSA team : Ryan Mokos, Bill Gropp, Darren Adams, Yifeng Cui June 5 Blue

SLIDE 1

Western U.S. Volcanism due to Intruding Oceanic Mantle Driven by Ancient Farallon Slabs

Project PI: Lijun Liu, Univ. of IL at Urbana-Champaign Presenter: Quan Zhou NCSA team: Ryan Mokos, Bill Gropp, Darren Adams, Yifeng Cui June 5 Blue Waters Symposium

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1000 km Yellowstone

What are the processes forming these volcanoes?

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Process I: Subduction

http://www.bgs.ac.uk/discoveringgeology/hazards/volcanoes

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Process II: Mantle plume

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Earth Tomography

https://geology45.blogspot.com/2016/12/describe-how- seismic-waves-are-used-to.html

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Observations in mantle

Seismic Tomography

(Obresbki et al. 2010)

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Earth mantle simulation

Governing Equations

Assume the mantle is an incompressible fluid, which satisfies the Boussinesq approximation

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Method

Data can be assimilated: (Schmandt & Lin 2014) Plate motion and sea-floor age Tomography

Data assimilation mantle convection simulation

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Different data assimilation methods Method Summary Data assimilated Forward /Sequential Simple Backward Inverse(SBI) Adjoint /Variational Hybrid (foward+adjoint) Solving the governing equations forward in time, updating the model when observational constraints are available (imposing plate motion, and updating oceanic lithosphere temperature based on sea-floor age) Solving the governing equations backward in time, either neglecting thermal diffusion or using normal diffusion. Starting with a first guess of the initial condition, normally generated from the SBI. And then a forward integration predicts the present-day mantle structure, whose difference from the observed structure is integrated back to the initial time using the adjoint solver, correcting the initial condition. First, obtaining a rough estimate of the initial condition through SBI. Second, applying the sequential method to forward predict the present-day mantle structure. Third, introducing the adjoint method to further refine the initial condition and subsequent mantle evolution. Plate Motion Sea-floor age Plate motion Tomography Plate motion Tomography Plate motion Sea-floor age Tomography

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Why Blue Waters

CitcomS

has a very good scalability, up to ~10,000 CPUs

n Blue Waters.
Blue

Waters is compatible with the softwares we use, including CitcomS, DrexS and FSTRACK

Larger capacity leads to larger

allocation and shorter waiting time.

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Modeled vs. observed present mantle structure based on the hybrid convection model

Modeling Observation

(Schmandt & Lin 2014)

(Zhou et al. 2018)

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20 Ma 18 Ma 16 Ma 14 Ma 12 Ma 10 Ma 8 Ma 6 Ma 4 Ma 2 Ma 0 Ma

Subduction and Mantle Flow

120°
110

100°

km 660 km

(Zhou et al. 2018)

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Plume Evolution 3D View

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18 Ma 16 Ma 14 Ma 12 Ma 10 Ma 8 Ma 6 Ma 4 Ma 2 Ma 0 Ma

Implication on Intra-plate volcanism

(Zhou et al. 2018)

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(Zhou et al. 2018)

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Conclusions

The sinking ancient Farallon slab drives the hot anomalies below the oceanic lithosphere to intrude into the western U.S. The propagation of oceanic hot anomalies below the western U.S. induces the intra-plate volcanisms

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Driving force: Ancient Farallon Slab

(Zhou et al. 2018)

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Driving force: Ancient Farallon Slab

(Zhou et al. 2018)

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(Zhou et al. 2018)

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Why Blue Waters

CitcomS has a very good

scalability, up to ~10,000 CPUs

n Blue Waters.
Blue Waters is compatible

with the softwares we use, including CitcomS, DrexS and FSTRACK

Larger capacity leads to larger