Earth, Planets and Space

Table 2 Summary of the physical parameters for viscoelastic flow

From: Frictional and structural controls of seismic super-cycles at the Japan trench

Oceanic asthenosphere
Background strain rate	\({\dot{\varepsilon }}^0_{22}\)	\(-10^{-14}\) \(\hbox {s}^{-1}\)
Basal mantle temperature	\(T_0\)	1380 \(^\circ\)C
Pre-factor	A	90 \(\hbox {MPa}^{-n} \hbox {s}^{-1}\) (ppm H/Si)\(^{-r}\)
Power law stress exponent	n	3.5
Activation energy	E	510 kJ/mol
Activation volume	\(\Omega\)	13 \(\hbox {cm}^3\)/mol
Water content	\(C_\text {OH}\)	1000 ppm H/Si
Water content exponent	r	1.2
Thermal age	a	120 Myr

Mantle wedge
Background strain rate	\({\dot{\varepsilon }}^0_{22}\)	\(-10^{-14}\) \(\hbox {s}^{-1}\)
Basal mantle temperature	T	1380 \(^\circ\)C
Pre-factor below arc	A	90 \(\hbox {MPa}^{-n}\hbox {s}^{-1}\) (ppm H/Si)\(^{-r}\)
Pre-factor offshore	A	27 \(\hbox {MPa}^{-n}\hbox {s}^{-1}\) (ppm H/Si)\(^{-r}\)
Power law stress exponent	n	3.5
Activation energy below arc	E	490 kJ/mol
Activation energy offshore	E	510 kJ/mol
Activation volume	\(\Omega\)	11 \(\hbox {cm}^3\)/mol
Water content below arc	\(C_\text {OH}\)	4000 ppm H/Si
Water content offshore	\(C_\text {OH}\)	1000 ppm H/Si
Water content exponent	r	1.2
Thermal age	a	53 Myr

The thermal model is based on a cooling half-space with a thermal age a and a basal temperature \(T_0\), where the top of the slab is the reference depth, to account for advection. The mantle wedge is cooled as a function of proximity to the down-going slab, following the perturbation \(\Delta T\,e^{-z/z_0}\), where \(\Delta T=-900^\circ\)C, z is the distance to the slab, and \(z_0=25\,\)km

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