[1] Energy from seismic events traveling up a subduction zone is frequently associated with significant large-amplitude, high-frequency signals with sustained long coda. Such seismic waves guided by the subducted plate with high wave velocity and high Q can cause surprisingly large seismic intensity in the fore-arc area. In this study, we characterize the guiding behavior of the subducted Phili...

Receiver functions calculated from a ten-station subset of the Earthscope Transportable Array (TA) show a well-defined 45 km thick low-velocity layer atop the 410-km discontinuity (“410”) beneath the Tucson, Arizona, region. This observation is consistent with a previously detected layer of increased electrical conductivity in the same region, from which the existence a 5-30 km thick layer of p...

High-grade gneisses (amphibolite–granulite facies) of the Namche Barwa and Gyala Peri massifs, in the eastern Himalayan syntaxis, have been unroofed from metamorphic depths in the late Tertiary–Recent. Rapid exhumation (2–5 mm year) has resulted in a pronounced shallow conductive thermal anomaly beneath the massifs and the intervening Tsangpo gorge. The position of the 300 !C isotherm has been ...

[1] We investigate the lithospheric and upper mantle shear wave velocity structure and the depth-dependence of anisotropy along the Red Sea and beneath the Arabian Peninsula using receiver function constraints and phase velocities of surface waves traversing two transects of stations from the Saudi Arabian National Digital Seismic Network. Frequency-dependent phase delays of fundamental-mode Lo...

The receiver function (RF) technique is a well-established method to investigate the crustal and upper mantle structures based on three-component seismograms of teleseismic events. In the present study, we propose a modified automatic procedure to determine the back azimuth and polarization angles of a teleseismic event based on the RF technique. The method is tested for the recording of 3 perm...

Oceanic lithosphere provides an ideal location to decipher the nature of the lithosphere-asthenosphere system which is vital to our understanding of plate tectonics. It is well established that oceanic lithosphere cools, thickens, and subsides as it ages according to the conductive cooling models. Yet this simple realization fails to explain various observations. For example, old oceanic lithos...

We determined the variations in seismic structure beneath southern California by using a tomographic method of inversion on teleseismic P delays recorded with the Southern California Array. The algorithm employed was a modified form of an Algebraic Reconstruction Technique (ART) used in medical X-ray imaging. Deconvolution with an empirically estimated point spread function was also used to hel...

We determined the variations in seismic structure beneath southern California by using a tomographic method of inversion on teleseismic P delays recorded with the Southern California Array. The algorithm employed was a modified form of an Algebraic Reconstruction Technique (ART) used in medical X-ray imaging. Deconvolution with an empirically estimated point spread function was also used to hel...

[1] We present numerical models of mantle convection incorporating changes in viscosity and thermal conductivity at depth. Increasing the viscosity and/or thermal conductivity by a factor of 5 at depths below 2000 km increases the size and stability of thermal upwellings. Decreasing the thermal conductivity beneath 2000 km, in contrast, has comparatively little effect on thermal upwellings. Inc...

The Carpathian–Pannonian system of Eastern and Central Europe represents a unique opportunity to study the interaction between surface tectonic processes involving convergence, extension and convective overturn in the upper mantle. Here, we present high-resolution images of upper mantle structure beneath the region from P-wave finite-frequency teleseismic tomography to help constrain such geody...