We develop a model for the propagation of a fluid-filled crack in a porous medium. The problem is motivated by the mechanism whereby drainage networks may form in partially molten rock below the Earth‘s lithosphere. Other applications include the propagation of hydraulic fractures in jointed rocks and in oil drilling operations, and the formation of dessication cracks in soils. Motivated by the...

Abstract. Based on recent results of AlpArray, we propose a new model Alpine collision that involves subduction and detachment thick (∼ 180 km) European lithosphere. Our approach combines teleseismic P-wave tomography existing local earthquake (LET), allowing us to image the slabs their connections with overlying orogenic lithosphere at an unprecedented resolution. The images call into question...

Abstract The cratonic lithosphere–asthenosphere boundary is commonly invoked as the site of sheared peridotite and megacryst formation, a well-recognized petrological assemblage whose genetic relationships—if any—remain poorly understood. We have undertaken comprehensive petrology Sr–Nd–Hf–Ca isotope study xenoliths clinopyroxene megacrysts from c. 1150 Ma Premier kimberlite pipe on central Kaa...

Summary The lithosphere and asthenosphere are fundamental to plate tectonics many other earth processes. Vertical motions can be measured quickly accurately by the satellite Global Positioning System, GPS, methods. This paper describes a new analytic method for inferring elastic viscous properties of upper mantle from uplift rate history an area that has been subjected past surface load changes...

S U M M A R Y Azimuthal seismic anisotropy, the dependence of seismicwave speeds on propagation azimuth, is largely due to fabrics within the Earth’s crust and mantle, produced by deformation. It thus provides constraints on the distribution and evolution of deformation within the upper mantle. Here, we present a new global, azimuthally anisotropic model of the crust, upper mantle and transitio...

[1] Surface topography and associated gravity anomalies above a layer resembling continental lithosphere, whose mantle part is gravitationally unstable, depend strongly on the ratio of viscosities of the lower-density crustal part to that of the mantle part. For linear stability analysis, growth rates of Rayleigh-Taylor instabilities depend largely on the wave number, or wavelength, of the pert...

The sinking of lithosphere at subduction zones couples Earth’s exterior with its interior, spawns continental crust and powers a tectonic regime that is unique to our planet. In spite of its importance, it is unclear how subduction is initiated. Two general mechanisms are recognized: induced and spontaneous nucleation of subduction zones. Induced nucleation (INSZ) responds to continuing plate c...