AR = cavity aspect ratio a = speed of sound b = cavity half-width ~ C = dynamic compressibility c = phase speed cp = specific heat at constant pressure f = frequency H = cavity depth k = wave number m = propagation constant P = pressure Pr = Prandtl number R = reflection coefficient p = acoustic pressure pi = initial pulse amplitude Re = acoustic Reynolds number s = cavity spacing T = temperatu...

We develop a new one-way wave prestack depth migration method called Fourier integration (FI) method which uses the exact extrapolation operator and the exact velocity model without any approximations or assumptions. The work is performed on a CUDA (Compute Unified Device Architecture) based Graphic Processing Unit (GPU). Compared to the traditional one way wave method, the GPU version FI metho...

An accurate depth-velocity model is the key for obtaining good quality and reliable depth images in areas of complex geology. In such areas, velocity-model definition should use methods that describe the complexity of wavefield propagation, such as focusing and defocusing, multiple arrivals, and frequency-dependent velocity sensitivity. Wave-equation tomography in the image space has the abilit...

OBJECTIVES Arterial stiffness and wave reflection parameters assessed from both invasive and non-invasive pressure and flow readings are used as surrogates for ventricular and vascular load. They have been reported to predict adverse cardiovascular events, but clinical assessment is laborious and may limit widespread use. This study aims to investigate measures of arterial stiffness and central...

Introduction: Large scale reductions in compressional velocity caused by impact-induced damage is an important but largely unstudied feature of impact craters [1]. Damage depth beneath impact craters can be used to extract information about the impact cratering process. A new non-destructive method is developed to study the damage structure beneath impact craters in the laboratory. Experimental...

Marine seismic data from the Blake Outer Ridge offshore Florida show strong “bottom simulating reflections” (BSR) associated with methane hydrate occurence in deep marine sediments. We use a detailed amplitude versus offset (AVO) analysis of these data to explore the validity of models which might explain the origin of the bottom simulating reflector. After careful preprocessing steps, we deter...

In a recent global scale seismic study, the correlation between S wave velocity under ridge axes and spreading rate was pointed out. The correlation is strong for depths to about 70 km, but it diminishes below this depth. We present the correlation plots at four depths, 38, 66, 90, and 110 km, for which correlation is strong at 38 and 66 km but is weak at 90 km and is almost nonexistent at 110 ...

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...