Near a borehole, stress concentration effects may cause a complex spatial variation of elastic anisotropy. Stress-induced sonic anisotropy results when moduli and velocities are stress dependent and the state of stress is nonhydrostatic. For such cases, the appropriate material model is that of an elastic orthorhombic medium with material axes aligned with the principal axes of stress. We simul...

[1] We present a multiple step procedure for joint modeling of surface wave group velocity dispersion curves and teleseismic receiver functions for lithospheric velocity structure. The method relies on an initial grid search for a simple crustal structure, followed by a formal iterative inversion, an additional grid search for shear wave velocity in the mantle, and finally, forward modeling of ...

A sudden decrease in water depth, called a negative surge or expansion wave, is characterised by a gentle change in free-surface elevation. Some geophysical applications include the ebb tide flow in macro-tidal estuaries, the rundown of swash waters and the retreating waters after maximum tsunami runup in a river channel. The upstream propagation of expansion waves against an initially steady f...

We constrain seismic properties of the inner core using various body wave observations. In the epicentral distance range of 10−70 o , our high quality measurements of the amplitude ratio of PKiKP and PcP provide a new estimate of the density contrast (0.6-0.9 g/cm 3) at the Inner Core Boundary (ICB). This estimate is compatible with a recent reevaluation of normal mode data, and thus reconciles...

We report on observations of shear Alfvén waves radiated from a source of small transverse size, and the subsequent radial confinement of wave magnetic field energy within a cylindrical plasma. The radius of confinement lies between the kinetic regime of the bulk plasma and the inertial regime at the plasma edge; this radius is found to be a function of wave frequency. Numerical calculations us...

Wormlike micelles are long wormy cylindrical aggregates of surfactants, self-assembled within a solvent, which entangle and continuously break and reform at thermal equilibrium. Rheological characterization and flow visualization experiments with micellar solutions show that under steady state shearing flow the deformation field may not remain homogeneous but instead spatially localize, resulti...

AIM OF THE STUDY Since there have been only few works reporting the diagnosis of kidneys using Acoustic Radiation Force Impulse technique and those works do not provide consistent results of shear wave velocity measurements in renal tissue, we have decided to use kidney phantoms with known properties to examine the reliability of the method itself in a controlled setup similar to kidneys examin...

A new shear wave velocity model offshore Southern California is presented that images plate boundary deformation including both thickening and thinning of the crustal and mantle lithosphere at the westernmost edge of the North American continent. The Asthenospheric and Lithospheric Broadband Architecture from the California Offshore Region Experiment (ALBACORE) ocean bottom seismometer array, t...

[1] We present DR2012, a global SV-wave tomographic model of the upper mantle. We use an extension of the automated waveform inversion approach of Debayle (1999) which improves our mapping of the transition zone with extraction of fundamental and higher-mode information. The new approach is fully automated and has been successfully used to match approximately 375,000 Rayleigh waveforms. For eac...

Isotropic earth models are unable to provide uniform fits to the gross Earth normal mode data set or, in many cases, to regional Loveand Rayleigh-wave data. Anisotropic inversion provides a good fit to the data and indicates that the upper 200 km of the mantle is anisotropic. The nature and magnitude of the required anisotropy, moreover, is similar to that found in body wave studies and in stud...