Slab2, a comprehensive subduction zone geometry model

Hayes, Gavin P.; Moore, Ginevra L.; Portner, D. E.; Hearne, Michael; Flamme, Hanna; Furtney, M.; Smoczyk, Gregory M.

doi:10.1126/science.aat4723

Cited by 995 publications

(1,348 citation statements)

References 39 publications

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“…For example, in the central Sunda arc values of H change by more than 100 km, over horizontal separations of less than 150 km (Pacey et al, ). We have shown that Mariana is another example of this variation, since H for active arc volcanoes, determined from the SLAB2 model (Hayes et al, ), ranges from 110 to 180 km across the arc. This entire range is apparent over short distances in the south, from Tracey to Esmerelda, where there can be no change in slab descent speed (Figures and S1).…”

Section: Discussionmentioning

confidence: 76%

Upper Plate Stress Controls the Distribution of Mariana Arc Volcanoes

2020

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We present a spatial analysis of volcano distribution and morphology in the young, intraoceanic Mariana Arc. Both the quality of fit to idealized models and the divergence from those ideals indicate that Mariana Arc volcanoes are arranged into five great circle segments, rather than a single small circle or multiple small circles. The alignment of magmatic centers suggests that magma transport is controlled by the stress regime in the deep crust and/or lithospheric mantle of the Philippine Sea Plate, into which the arc is emplaced, and that arc‐normal tension is the dominant process operating in the deep lithosphere along the whole arc. Volcano morphologies indicate that the stress regime in the shallow crust varies between arc‐normal tension and compression, which also implies that the stress field can vary with depth in the arc lithosphere. We show that this horizontal and vertical stress partitioning can be related to the changing dip of the subducting plate and the breadth of the zone where it is coupled with the overriding plate. The variation in stress regime is consistent with both the distribution of seismicity in the Philippine Sea Plate and with the structural fabrics of the nonvolcanic part of the plate margin to the south. Our analysis suggests that the upper plate exerts the principal control on the distribution of volcanoes in the Mariana Arc. Where tension in the deeper parts of arc lithosphere is sufficiently concentrated, then a distinct volcanic front is produced.

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Section: Discussionmentioning

confidence: 76%

Upper Plate Stress Controls the Distribution of Mariana Arc Volcanoes

2020

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“…In addition to the Moho, we also consider two crustal discontinuities modified from the CRUST1.0 model (Laske et al, ) and finally constructed a three‐layer crustal model (Figures S3 and S4). To date, several models for the geometry of the subducting Pacific slab beneath Alaska have been proposed (e.g., Gou, Zhao, et al, ; Hayes et al, ; Jadamec & Billen, ; J. Li et al, ; Zhao et al, ), but these slab models are different from each other, especially in the fore‐arc area of south‐central Alaska. In this study, we adopt the slab model produced by J. Li et al () in the starting model for the tomographic inversion, which was inferred from the Wadati‐Benioff zone seismicity located precisely using the double‐difference earthquake location method (Waldhauser & Ellsworth, ).…”

Section: Methodsmentioning

confidence: 99%

Structural Heterogeneity in Source Zones of the 2018 Anchorage Intraslab Earthquake and the 1964 Alaska Megathrust Earthquake

Gou

Zhao

Huang

et al. 2020

Geochem Geophys Geosyst

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Structural heterogeneities in subduction zones can affect slip behaviors of the megathrust faults and the generation of intraslab earthquakes. In this work we study the 3‐D seismic structures (Vp, Vs, and Poisson's ratio) in and around the source zones of the 2018 Anchorage intraslab earthquake (Mw 7.1) and the 1964 Alaska megathrust earthquake (Mw 9.2). The Anchorage earthquake occurred in an anomalous zone within the subducting Yakutat/Pacific plate with a higher Poisson's ratio than the normal slab. Above the source zone, the overriding North American plate shows a low Vs and a high Poisson's ratio. These features indicate that strong dehydration occurs in the source zone and released fluids ascend into the overlying crust. Two areas with long‐term slow slip events in the Upper and Lower Cook Inlet predominantly exhibit a high Poisson's ratio in the lowermost portion of the crust and the cold nose of the mantle wedge, whereas a low Poisson's ratio zone is revealed between them, suggesting that their segmentation is possibly related to localized slab‐releasing fluids. In the Prince William Sound, the rupture of the 1964 Great Alaska earthquake initiated beneath a high‐V and high Poisson's ratio zone of the overlying crust and the large slips occurred beneath a low‐Vs and high Poisson's ratio zone, suggesting that lateral heterogeneities of the overriding plate may have played an important role in the nucleation and rupture processes of the Great Alaska earthquake.

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“…Geomorphological observations indicate spatially variable roughness of subducting seafloor at different subduction margins (Kopp, 2013; Lallemand et al, 2018; Ryan et al, 2009). Field and laboratory observations have also documented variations in other parameters, including plate convergence rate (DeMets et al, 2010), slab dip angle (Hayes et al, 2018), and subduction décollement strength (Ikari, 2019; Ikari & Kopf, 2017). Detailed regional studies suggest that some of these subduction zone parameters can even vary substantially over short distances along strike at a single margin, possibly leading to contrasting forearc features including megathrust locking state and slip behavior, wedge morphology and faulting style, and sediment consolidation state (e.g., [Sumatra] Dean et al, 2010; [Cascadia] Han et al, 2017; [Alaska] Li et al, 2018; [Hikurangi] Wallace et al, 2009).…”

Section: Methodsmentioning

confidence: 99%

Coupled Evolution of Deformation, Pore Fluid Pressure, and Fluid Flow in Shallow Subduction Forearcs

2020

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Deformation and fluid flow in subduction zone forearcs are dynamically coupled, but our quantitative understanding of their coupling is incomplete. In this work, we investigate the hydrological and mechanical coupling in shallow forearcs, using a Lagrangian‐Eulerian finite element model that incorporates constitutive and transport properties of sediments and faults constrained by laboratory and field measurements. Wide‐ranging observations show that sediment thickness and composition, plate convergence rate, basement strength and roughness, and subducting slab dip angle vary between subduction zones. We therefore systematically study their effects on forearc stress and pore fluid pressure states, consolidation and dewatering patterns, and margin morphology. Our models, with the incorporation of a simple description of permeability enhancement along fault damage zones, yield a range of fault permeability (10−13–10−17 m2) consistent with previous estimates and describe the important role of upper plate splay faults in causing heterogeneous dewatering and consolidation patterns and in modulating effective normal stress on the plate interface. Spatial variations in tectonic loading and sediment consolidation can also be caused by subducting basement roughness such as a horst‐and‐graben structure. For typically observed relief and spacing, our models predict locally enhanced porosity reduction by up to 50% at the downdip edge of the horsts and anomalously high sediment porosity above the geometrical highs. At the margin scale, our results demonstrate that sediment permeability and thickness are dominant controls on fluid overpressure, sediment compaction, and megathrust strength. Rough and frictionally strong megathrusts produce similar effects in driving high wedge tapers.

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Slab2, a comprehensive subduction zone geometry model

Cited by 995 publications

References 39 publications

Upper Plate Stress Controls the Distribution of Mariana Arc Volcanoes

Upper Plate Stress Controls the Distribution of Mariana Arc Volcanoes

Structural Heterogeneity in Source Zones of the 2018 Anchorage Intraslab Earthquake and the 1964 Alaska Megathrust Earthquake

Coupled Evolution of Deformation, Pore Fluid Pressure, and Fluid Flow in Shallow Subduction Forearcs

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