The problem of direction of arrival (DoA) estimation of seismic plane waves impinging on an array of sensors is considered from a new deterministic perspective using tensor decomposition techniques. In addition to temporal and spatial sampling, further information is taken into account, based on the different propagation speed of body waves (P and S) through solid media. Performances are evalua...

In the classic microseismic band of 5-20 s seismic noise consists mainly of fundamental mode Rayleigh and Love waves; however, at shorter periods seismic noise also contains a significant amount of body wave energy and higher-mode surface waves. In this study we perform a global survey of Earth’s short period seismic noise field with the goal of quantifying the relative contributions of these p...

We consider a class of inverse problems in which the forward model is the solution operator to linear ODEs or PDEs. This class admits several dimensionality-reduction techniques based on data averaging or sampling, which are especially useful for large-scale problems. We survey these approaches and their connection to stochastic optimization. The data-averaging approach is only viable, however,...

Remote detection and characterization of fractured reservoirs is facilitated in this project by developing a revolutionary software system. The Model-Automated Geo-Informatics (MAGI) software integrates basin modeling, seismic data, synthetic seismic wave propagation and well data via information theory. The result is a seismic inversion cast in terms of fracture and other reservoir characteris...

Comparison of seismic velocities in mantle minerals, under mantle conditions, with seismic data is a first step toward constraining mantle chemistry. The calculation, however, is uncertain due to lack of data on certain physical properties. "Global" systematics have not proved very useful in estimating these properties, particularly for the shear parameters. A new approach to elasticity estimat...

Seismic interferometry allows one to create a virtual source inside a medium, assuming a receiver is present at the position of the virtual source. We discuss a method that creates a virtual source inside a medium from reflection data measured at the surface, without needing a receiver inside the medium and, hence, going beyond seismic interferometry. In addition to the reflection data, an esti...

It is a conceptually simple process to compute differences between two 3D seismic monitoring surveys. However, interpretation of seismic differences in terms of reservoir changes during production assumes repeatability of the surveys. As a result, the naive application of this methodology can lead to erroneous results. Ross et al. (1996, 1997) discussed many of the problems associated with diff...

Stacks of global seismic data reveal the time and distance dependence of high-frequency (1-hertz) precursors to the seismic phase PKKP. Synthetic seismogram modeling shows that scattering from random small-scale topography at the PKKP core-mantle–boundary reflection point generates precursory arrivals similar to those seen in the data. Models with a root mean square core-mantle–boundary topogra...

[1] We report measurements of long-period P wave polarization (Ppol) in Australia and Tahiti made by combining modeling of the polarization deviation and harmonic analysis. The analysis of the deviation of the horizontal polarization of the P wave as a function of event back azimuth may be used to obtain information about (1) sensor misorientation, (2) dipping discontinuities, (3) seismic aniso...