[1] We model broadband seismograms containing triplicated S, S, and S along with ScS to produce a pure path one-dimensional model extending from the crust to the core-mantle boundary beneath the East Pacific Rise. We simultaneously model all body wave shapes and amplitudes, thereby eliminating depth-velocity ambiguities. The data consist of western North American broadband recordings of East Pa...

Peter van Keken a, David A. Yuen b and Arie van den Berg a Received November 21, 1991, revision accepted June 17, 1992 Recent laboratory work has suggested that the rheology of the lower mantle may be Newtonian. We have studied the time-dependent dynamics of plumes interacting with a rheological interface separating an upper non-Newtonian mantle and a Newtonian lower mantle . Pulsating diapiric...

[1] In order to examine the potential of seismology to determine the interior structure and properties of Europa, it is essential to calculate seismic velocities and attenuation for the range of plausible interiors. We calculate a range of models for the physical structure of Europa, as constrained by the satellite’s composition, mass, and moment of inertia. We assume a water-ice shell, a pyrol...

Two dives of the DSV Shinkai 6500 in the Mariana Trough back-arc basin in the western Pacific sampled back-arc basin mantle exposures. Reports of peridotite exposures in back-arc basin setting are very limited and the lack of samples has hindered our understanding of this important aspect of lithospheric evolution. The Mariana Trough is a slow-spreading ridge, and ultramafic exposures with asso...

Sr, Nd and Pb isotope data for basalts from spreading axes and off-axis volcanoes near the Pacific–Antarctic risecrest, from Vacquier transform to just south of Udintsev transform, reveal an isotopically heterogeneous upper mantle. The Ž . isotopic composition of the mantle is represented by three end-members: 1 the ‘depleted’ source of the bulk of Pacific Ž . Ž . normal-type mid-ocean ridge ba...

Olivine is the most important phase in the Earth’s upper mantle, where the bulk rock composition varies on average from lherzolitic to harzburgitic, where the olivine fractions are normally >60 %. Olivine is of major importance for Earth’s mantle dynamics and the presence of grain boundaries in olivine and their type might partially be responsible for attenuation phenomena as well as thermal an...