How weak is the subduction zone interface?

Duarte, João C.; Schellart, Wouter P.; Cruden, Alexander

doi:10.1002/2014gl062876

Cited by 62 publications

(54 citation statements)

References 64 publications

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“…These values of shear stress are consistent with those reported in other subduction zones (e.g. Lamb, 2006;Von Herzen et al, 2001;Duarte et al, 2015). This suggests that neither the large sediment thickness of the Makran, which has been proposed to lubricate the plate interface through sediment underplating (e.g.…”

Section: Megathrust Shear Stresssupporting

confidence: 89%

Megathrust and accretionary wedge properties and behaviour in the Makran subduction zone

Penney¹,

Tavakoli²,

Saadat³

et al. 2017

Geophysical Journal International

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We study the Makran subduction zone, along the southern coasts of Iran and Pakistan, to gain insights into the kinematics and dynamics of accretionary prism deformation. By combining techniques from seismology, geodesy and geomorphology, we are able to put constraints on the shape of the subduction interface and the style of strain across the prism. We also address the long-standing tectonic problem of how the right-lateral shear taken up by strike-slip faulting in the Sistan Suture Zone in eastern Iran is accommodated at the zone's southern end. We find that the subduction interface in the western Makran may be locked, accumulating elastic strain, and move in megathrust earthquakes. Such earthquakes, and associated tsunamis, present a significant hazard to populations around the Arabian Sea.

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Section: Megathrust Shear Stresssupporting

confidence: 89%

Megathrust and accretionary wedge properties and behaviour in the Makran subduction zone

Penney¹,

Tavakoli²,

Saadat³

et al. 2017

Geophysical Journal International

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“…Although, some workers have argued that shear heating would be localized along the particular fault plane or shear zone and the addition of fluids to a serpentinites would produce talc, which would substantially reduce the coefficient of friction and therefore limit the degree of heating (e.g., Dengo & Logan, ; Goswami & Barbot, ). The observation that the highest temperatures are recorded in the highest strained amphibolites closest (0–5 m) to the Tsiknias Thrust and the peak metamorphic assemblages (in the S 2b fabrics) are syntectonic with respect to top‐to‐SW shearing is consistent with the shear heating hypothesis (Wada et al, ; Duarte et al, ; Edwards et al, ; Rice, ; Tarling et al, ). Furthermore, it is demonstrated that dissipative heating is required to explain the measured heat flow discrepancies in many active steady‐state subduction zones (England, ), particularly if the mantle wedge had cooled over a long time period.…”

Section: Discussionsupporting

confidence: 73%

The Age, Origin, and Emplacement of the Tsiknias Ophiolite, Tinos, Greece

et al. 2020

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The Tsiknias Ophiolite, exposed at the highest structural levels of Tinos, Greece, represents a thrust sheet of Tethyan oceanic crust and upper mantle emplaced onto the Attic‐Cycladic Massif. We present new field observations and a new geological map of Tinos, integrated with petrology, THERMOCALC phase diagram modeling, U–Pb geochronology and whole rock geochemistry, resulting in a tectonothermal model that describes the formation and emplacement of the Tsiknias Ophiolite and newly identified underlying metamorphic sole. The ophiolite comprises a succession of partially dismembered and structurally repeated ultramafic and gabbroic rocks that represent the Moho Transition Zone. A plagiogranite dated by U‐Pb zircon at 161.9 ± 2.8 Ma, reveals that the Tsiknias Ophiolite formed in a suprasubduction zone setting, comparable to the “East‐Vardar Ophiolites,” and was intruded by gabbros at 144.4 ± 5.6 Ma. Strongly sheared metamorphic sole rocks show a condensed and inverted metamorphic gradient, from partially anatectic amphibolites at P‐T conditions of ~8.5 kbar 850–600 °C, downstructural section to greenschist‐facies oceanic metasediments over ~250 m. Leucosomes generated by partial melting of the uppermost sole amphibolite, yielded a U‐Pb zircon protolith age of ~190 Ma and a high‐grade metamorphic‐anatectic age of 74.0 ± 3.5 Ma associated with ophiolite emplacement. The Tsiknias Ophiolite was therefore obducted ~90 Myr after it formed during initiation of a NE dipping intraoceanic subduction zone to the northeast of the Cyclades that coincides with Africa's plate motion changing from transcurrent to convergent. Continued subduction resulted in high‐pressure metamorphism of the Cycladic continental margin ~25 Myr later.

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“…This results in an estimated shear stress along the plate interface of approximately 36 MPa. Although this is toward the upper end of estimates made for other subduction zones (e.g., Duarte et al, ; Holt et al, ; Lamb, ), it is not unreasonable in view of the limited constraints on real friction coefficients and on the thickness of lithosphere and crust. As the shear operates along the coupling surface, the horizontal and vertical stresses can be estimated as vector components of the mean value.…”

Section: Discussionmentioning

confidence: 87%

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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How weak is the subduction zone interface?

Cited by 62 publications

References 64 publications

Megathrust and accretionary wedge properties and behaviour in the Makran subduction zone

Megathrust and accretionary wedge properties and behaviour in the Makran subduction zone

The Age, Origin, and Emplacement of the Tsiknias Ophiolite, Tinos, Greece

Upper Plate Stress Controls the Distribution of Mariana Arc Volcanoes

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