Zone Observatory Big Geodynamics Related Science Questions Magali Billen Department of Earth amp Planetary Sciences UC Davis Collaborators amp Students Ana Negredo Moreno Juan RodriguezGonzalez PD Katrina Arredondo GS John ID: 357997
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Slide1
Subduction Zone Observatory
Big
Geodynamics
-Related Science Questions
Magali Billen
Department of Earth & Planetary Sciences
UC Davis
Collaborators & Students: Ana
Negredo
-Moreno, Juan Rodriguez-Gonzalez (PD), Katrina Arredondo (GS), John
Naliboff
(PD),
Taras
Gerya
,
Manuelle
FaccendaSlide2
Big
Geodynamics
Science Questions
From the Bottom Up:
What do we know (or not know) about plate boundary shear zone coupling?What is the role of the overriding plate?How does Internal deformation of the slab occur (faulting plastic flow)?How does the slab couple to the mantle wedge/asthenosphere?What are the mechanisms & controls on intermediate & deep seismicity?What controls slab interaction with the transition zone?When do slabs make it to the CMB?Slide3
Key Issues for
SZO
From the Bottom Up:
What do we know (or not know) about plate
boundary shear zone coupling?What is the role of the overriding plate?How does Internal deformation of the slab occur (faulting plastic flow)?How does the slab coupling to the asthenosphere?What are the mechanisms & controls on intermediate & deep seismicity?What controls slab
interaction with the transition zone?
When do slabs make it to the CMB?Slide4
Asthenosphere
& Mantle
Wedge
What is the role of non-linear rheology?
How can we better use numerical models to constrain mantle flow & dynamics?Need more seismic observations beneath the oceanic side of subducting plates are needed?Miller & Becker,
Nature 2012
Faccenda
&
Capitanio
,
G
3
, 2013 Slide5
Asthenosphere &
Mantle
Wedge
Moving beyond the corner flow…
Affect of melt buoyancy and hydration on flowNeed higher resolution seismic data & EM imaging of all kinds and modeling that includes melt & fluidsGerya & Yuen, EPSL 2003
McGary
et al., Nature 2014 Slide6
Affect
of
the
Overriding Plate
Overriding plate motion Trench retreat/advanceThickness variations can affect slab shape and dipModifies flow in the mantle wedgeBetter constraints on present and past structure are needed to interpret slab evolutionVary overriding plate structure in numerical models **
Rodriguez-Gonzalez,
EPSL 2014
Taramon
et al.,
submittedSlide7
Affect
on
the
Overriding Plate
Stress state & volcanism depends on how slab & overriding plate interactCompression versus extensionTransfer of stresses inboard of the plate boundarye.g., Andes, Aleutians…Depends on existing structure and the nature of the plate boundary shear zone.Collect more data on surface deformation and changes in timePredict and compare overriding plate deformation in numerical models **
Jadamec
et al., EPSL 2013Slide8
Plate Boundary Shear Zone
In dynamical models, this is a low viscosity shear zone or channel.
No strong, independent constraints on value of effective viscosity
Chosen to get “realistic” rates given rest of model design.
Important for all other aspects of subduction dynamics and surface deformation.Arredondo & Billen AGU 2014
Naliboff
et al., AGU 2014Slide9
Plate Boundary Shear Zone
Physically related to short time-scale
seismogenic
properties.
Need to devote attention to the properties that link the behavior across time-scales: fluids, mineralogy, grain size, rheology, …?Audet & Burgman, Nature 2014Slide10
Geodynamics & Other Topics in SZO
Hazards
Faulting & Deformation
Volcanism
The plate boundary shear zoneDeformation of the subducting plateAffect of/on the overriding plateAsthenosphere/mantle wedge rheology
Geodynamics
Other Topics in SZOSlide11
Conclusions & Suggestions
Recent models illustrate
potential deeper insights
More, higher resolution
seismic/E-M imaging data & other seismic constraints are neededMore realistic, higher resolution geodynamical models are also needed.Focus on bridging time-scales of physics from long term tectonics to the earthquake hazards.
Li et al., JGR 2014
Liu &
Stegman
, Nature 2012