Seismic velocity discontinuities are commonly found within the upper 100 km of the mantle lithosphere, with great variability in their depth, lateral extent, and the polarity of velocity jump. Among the more commonly observed is the ‘80 km’ or Hales discontinuity, identified in a variety of tectonic environments, and sometimes associated with seismic anisotropy. Teleseismic receiver functions f...

Analysis of internal structures of the Brooks Range ophiolite at the three largest and well-exposed klippen reveals a NE-SW structural grain that may parallel the original axis of magmatism of a slow spreading marginal ocean basin. Sub-parallel directions of lattice·fabrics in olivine of mantle peridotite and shape fabrics in pyroxene and plagioclase of layered gabbro indicate that asthenospher...

Introduction. Ps and Sp images of sub-moho negative arrivals beneath the intermountain region of western U.S. are made using dense (2-40 km station spacing) arrays shown to the left that recorded for 1-2 years: the CREST, RISTRA, SIEDCAR, LODORE, LARAMIE, BILLINGS array data combined with Transportable Array data. The nominal Sp interpretational zoo includes an LAB arrival thought to manifest t...

Abstract The Moho – defined as the boundary that separates Earth’s crust from underlying upper mantle at depths of about 5 to 7 km beneath oceans and 30 40 below continents has been difficult pin down with observations. Different methods have yield a variety results, suggesting this simple definition may be misleading. Here, we present high-resolution deep penetrating seismic reflection data im...

An average shear-wave velocity structure has been estimated for the path between the Kamchatka Isthmus and Petropavlovsk-Kamchatski. It is obtained from the Monte Carlo inversion of the Rayleigh and Love wave group velocity dispersion curves measured using broad-band seismograms of events in Northern Kamchatka recorded by the IRIS station PET in Petropavlovsk-Kamchatski. The Moho interface was ...

The oceanic crust, covering two-thirds of the Earth's surface, is formed along mid-oceanic ridges by crystallization at shallow levels melts depth partial melting mantle peridotite. Yet, process melt transport to ridge axis remains poorly understood. Ophiolites, which provide a window into uppermost mantle, contain dunite bodies often interpreted as relics flow conduits, pyroxene dissolution du...

Apersistent seismic gap is hypothesized in the Pollino area (southern Italy), at the boundary between the Apennines and the Calabrian arc. Presently, seismic swarms are active in the gap area, creating concerns for possible future large earthquakes. In this study, we model the deep Earth structure across the Pollino range to give new insights on the kinematics and tectonics of this enigmatic ar...

We determine the three-dimensional shear wave velocity structure of the crust and upper mantle in China using Green’’s functions obtained from seismic ambient noise cross-correlation. The data we use are from the China National Seismic Network, global and regional networks and PASSCAL stations in the region. We first acquire cross-correlation seismograms between all possible station pairs. We t...

[1] In complex tectonics regions, seismological, geophysical, and geodynamic modeling require accurate definition of the Moho geometry. Various active and passive seismic experiments performed in the central Mediterranean region revealed local information on the Moho depth, in some cases used to produce interpolated maps. In this paper, we present a new and original map of the 3‐D Moho geometry...

Teleseismic receiver-functions and Rayleigh-wave dispersion curves are jointly inverted for quantifying S-wave velocity profiles beneath the active volcanic zone off Mayotte. We show that lithosphere in east-northeast quadrant is composed of four main layers, interpreted as edifice, crust with underplating, lithospheric mantle, asthenosphere, latter two presenting a low-velocity zone. The depth...