[1] Recordings in western Tibet of Rayleigh and Love waves at periods less than 70 s from aftershocks of the 2008 Sichuan earthquake cannot be matched by an isotropic velocity model beneath Tibet. These intermediate‐period Rayleigh and Love waves require marked radial anisotropy in the middle crust of Tibet, with the vertically polarized S‐ waves propagating more slowly than S‐waves with horizo...

Chemical weathering, as well as physical erosion, changes the composition and shapes the surface of the continental crust. However, the amount of continental material that has been lost over Earth's history due to chemical weathering is poorly constrained. Using a mass balance model for lithium inputs and outputs from the continental crust, we find that the mass of continental crust that has be...

Intermediate-period Rayleigh and Love waves propagating across Tibet indicate marked radial anisotropy within the middle-to-lower crust, consistent with a thinning of the middle crust by about 30%. The anisotropy is largest in the western part of the plateau, where moment tensors of earthquakes indicate active crustal thinning. The preferred orientation of mica crystals resulting from the crust...

I have enjoyed reading several items on the rare-earth elements in Physics Today over past few years. David Kramer’s most recent piece focused topic (February 2021, page 20) was about neodymium-based magnets, but readers might be interested to learn of another class magnets based samarium. Among their applications are traveling wave tubes (TWTs), which form backbone world’s entire space communi...

The conditions in the protoplanetary disc are determinant for various planet formation mechanisms. We present a framework which combines self-consistent structures with calculations of growth rates planetary embryos via pebble accretion, order to study Super-Earths. first perform 2D hydrodynamical simulations inner discs, considering grain size distribution multiple chemical species and their c...

First-order (transform) and second-order ridge-axis discontinuities create a fundamental segmentation of the lithosphere along mid-ocean ridges, and in slow spreading crust they commonly are associated with exposure of subvolcanic rust and upper mantle. We analyzed available morphological, gravity, and rock sample data from the Atlantic Ocean to determine whether consistent structural patems oc...