The thermal structure of subduction zones constrained by seismic imaging: Implications for slab dehydration and wedge flow

Abers, G. A.; Keken, Peter E. van; Kneller, E. A.; Ferris, A.; Stachnik, J. C.

doi:10.1016/j.epsl.2005.11.055

Cited by 224 publications

(175 citation statements)

References 38 publications

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“…2; Kita et al, 2006Kita et al, , 2010a, with a marked reduction in number and deepening of the earthquakes with respect to the top of the crust at greater depth. A similar pattern, and correlation with low seismic velocities in the crust, is seen in the central Alaska subduction zone (Abers et al, 2006). Thermalpetrological modeling following van Keken et al (2011) strongly suggests that earthquakes in a particular cross section below northern Tohoku are limited by the blueschist-tohydrous-eclogite phase boundary (Fig.…”

Section: Introductionmentioning

confidence: 64%

Thermal structure and intermediate-depth seismicity in the Tohoku-Hokkaido subduction zones

2012

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Abstract. The cause of intermediate-depth (> 40 km) seismicity in subduction zones is not well understood. The viability of proposed mechanisms, which include dehydration embrittlement, shear instabilities and the presence of fluids in general, depends significantly on local conditions, including pressure, temperature and composition. The wellinstrumented and well-studied subduction zone below Northern Japan (Tohoku and Hokkaido) provides an excellent testing ground to study the conditions under which intermediatedepth seismicity occurs. This study combines new finite element models that predict the dynamics and thermal structure of the Japan subduction system with a high-precision hypocenter data base. The upper plane of seismicity is principally contained in the crustal portion of the subducting slab and appears to thin and deepen within the crust at depths > 80 km. The disappearance of seismicity overlaps in most of the region with the predicted phase change of blueschist to hydrous eclogite, which forms a major dehydration front in the crust. The correlation between the thermally predicted blueschist-out boundary and the disappearance of seismicity breaks down in the transition from the northern Japan to Kurile arc below western Hokkaido. Adjusted models that take into account the seismically imaged modified upper mantle structure in this region fail to adequately recover the correlation that is seen below Tohoku and eastern Hokkaido. We conclude that the thermal structure below Western Hokkaido is significantly affected by timedependent, 3-D dynamics of the slab. This study generally supports the role of fluids in the generation of intermediatedepth seismicity.

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Section: Introductionmentioning

confidence: 64%

Thermal structure and intermediate-depth seismicity in the Tohoku-Hokkaido subduction zones

2012

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“…Meshes with variable grid resolution are used with a typical maximum element size of 10 km and a resolution down to 100 m in the boundary layers. The methodology used here is the same as that used in Van Keken et al (2002), Van Keken (2003 and Abers et al (2006).…”

Section: Contributing Codesmentioning

confidence: 99%

“…This thermomechanical approach should yield a reasonable prediction of the temperatures in the slab, which then can be linked to the metamorphic processes leading to slab dehydration, arc volcanism and seismogenesis. High accuracy of the thermal models is needed since thermodynamic, field-based and experimental predictions of the relevant metamorphic phase changes predict relatively narrow pressure-temperature ranges for the key phase changes (Schmidt and Poli, 1998;Connolly and Kerrick, 2002;Hacker et al, 2003;Forneris and Holloway, 2004;Abers et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

A community benchmark for subduction zone modeling

Keken

Currie

King

et al. 2008

Physics of the Earth and Planetary Interiors

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199

144

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“…At pressures sufficiently great for eclogite to form, temperatures in the interiors of old 416 subducted slabs, such as those beneath the Izu-Bonin or Tonga-Kermadec subduction zones, can be 417 as low as 400 °C (Peacock and Wang 1999;Abers et al 2006;Syracuse et al 2010). Indeed, 418 thermal modeling of the Nicaragua-Costa Rica subduction zone shows that, even at pressures in 419 excess of 6 GPa, temperatures at the center of a subducting slab may be <600 °C (Peacock et al 420 2005).…”

Section: Effect Of Cation Disorder 283mentioning

confidence: 99%

The effect of cation order on the elasticity of omphacite from atomistic calculations

Skelton

Walker

2015

Phys Chem Minerals

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9Omphacite, a clinopyroxene mineral with two distinct crystallographic sites, M1 and M2, and 10 composition intermediate between diopside and jadeite, is abundant throughout the Earth's upper 11 mantle, and is the dominant mineral in subducted oceanic crust. Unlike the end-members, 12 omphacite exists in two distinct phases, a P2/n ordered phase at low temperature and a high-13 temperature C2/c disordered phase. The crystal structure and full elastic constants tensor of ordered 14 P2/n omphacite have been calculated to 15 GPa using plane-wave density functional theory. Our 15 results show that several of the elastic constants, notably C 11 , C 12 , and C 13 deviate from linear-16 mixing between diopside and jadeite. The anisotropy of omphacite decreases with increasing 17 pressure and, at 10 GPa, is lower than that of either diopside or jadeite. The effect of cation disorder 18 is investigated through force-field calculations of the elastic constants of Special Quasirandom 19 2 Structures supercells with simulated disorder over the M2 sites only, and over both cation sites. 20These show that cation order influences the elasticity, with some components displaying particular 21 sensitivity to order on a specific cation site. C 11 , C 12 , and C 66 are sensitive to disorder on M1, while 22 C 22 is softened substantially by disorder on M2, but insensitive to disorder on M1. This shows that 23 the elasticity of omphacite is sensitive to the degree of disorder, and hence the temperature. We 24 expect these results to be relevant to other minerals with order-disorder phase transitions, implying 25 that care must be taken when considering the effects of composition on seismic anisotropy. 26

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The thermal structure of subduction zones constrained by seismic imaging: Implications for slab dehydration and wedge flow

Cited by 224 publications

References 38 publications

Thermal structure and intermediate-depth seismicity in the Tohoku-Hokkaido subduction zones

Thermal structure and intermediate-depth seismicity in the Tohoku-Hokkaido subduction zones

A community benchmark for subduction zone modeling

The effect of cation order on the elasticity of omphacite from atomistic calculations

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