Abstract. Strong constraints can be placed on the origin of heterogeneity of seismic wave velocities and density if the observed ratios of various parameters are compared with mineral physics predictions. They include the shear to compressional wave velocity heterogeneity ratio, Rs/p --• log Vs /• log Vp, the bulk sound to shear wave velocity heterogeneity ratio, R•/s --6 log V• /6 log Vs, and the density to velocity heterogeneity ratio, R,,,,p --6 log p /6 log V,,p.

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We report a scalable approach to synthesize a large-area (up to 4 mm) thin black phosphorus (BP) film on a flexible substrate. We first deposited a red phosphorus (RP) thin-film on a flexible polyester substrate, followed by its conversion to BP in a highpressure multi-anvil cell at room temperature. Raman spectroscopy and transmission electron microscopy measurements confirmed the formation of a nano-crystalline BP thin-film with a thickness of around 40 nm. Optical characterization indicates a bandgap of around 0.28 eV in the converted BP, similar to the bandgap measured in exfoliated thin-films. Thin-film BP transistors exhibit a field-effect mobility of around 0.5 cm 2 /Vs, which can probably be further enhanced by the optimization of the conversion process at elevated temperatures. Our work opens the avenue for the future demonstration of largescale, high quality thin-film black phosphorus.

Abstract. Shear experiments on olivine-basalt aggregates provide compelling evidence that the dynamic distribution of melt is controlled by the magnitude and orientation of the differential stress. Our results suggest that deformed, partially molten upper mantle rocks will have highly anisotropic physical properties including seismic wave velocities and melt permeability. In addition, our results provide a basis for interpreting geophysical observations, such as shearwave splitting and for modeling melt migration processes beneath mid-ocean ridges, specifically focused flow of melt toward the ridge axis.