Observations of seismic anisotropy can offer relatively direct constraints on patterns of mantle deformation, but most studies have focused on the upper mantle. While much of the lower mantle is thought to be isotropic, several recent studies have found evidence for anisotropy in the transition zone and uppermost lower mantle (the mid-mantle), particularly in the vicinity of subducting slabs. H...

Mapping sparse well data into 3D volumes is a challenging problem. Specifically, as seismic velocity model buildings (VMB) requires 3D velocity and anisotropy volumes, and as most anisotropy estimates are calibrated to borehole data, generating 3D anisotropic models relies heavily on extrapolating sparse well data. This spatial extrapolation problem is ill posed and many subjective decisions ar...

This paper proposes a method for quantitative integration of seismic (elastic) anisotropy attributes with reservoir performance data as an aid in characterization of systems of natural fractures in hydrocarbon reservoirs. This method is demonstrated through application to history matching of reservoir performance using synthetic test cases. Discrete Feature Network (DFN) modeling (Dershowitz et...

S U M M A R Y We present a significant addition to the data set of traveltimes of seismic PKP waves that sample the Earth’s lowermost mantle and core along the Earth’s rotation axis. Recorded at permanent Global Seismic Network (GSN) and temporary SSCUA deployment broadband seismographic stations in Antarctica, the new data improve the previously poor and biased coverage that underlies the seis...

Estimation of the fast polarization direction of shear seismic waves that deviate from horizontal axis is a valuable approach to investigate the characteristics of the lower crust and uppermost mantle structures. The lattice preferred orientation of crystals, which is generally parallel to the downward or upward flow of the mantle or crust, is an important reason for the occurrence of fast axis...

We discuss the use of reverse time migration (RTM) with dense seismic networks for the detection and location of sources of atmospheric infrasound. Seismometers measure the response of the Earth's surface to infrasound through acoustic-to-seismic coupling. RTM has recently been applied to data from the USArray network to create a catalogue of infrasonic sources in the western US. Specifically, ...

[1] Shear wave splitting is a robust tool to infer the direction and strength of seismic anisotropy in the lithosphere and underlying asthenosphere. Previous shear wave splitting studies in the Afar Depression and adjacent areas concluded that either Precambrian sutures or vertical magmatic dikes are mostly responsible for the observed anisotropy. Here we report results of a systematic analysis...

The observed seismic anisotropy of the southern African mantle from both shear-wave splitting and surface wave observations provides important constraints on modes of mantle deformation beneath this ancient continent. We find that the mantle anisotropy beneath southern Africa is dominated by deformational events in Archean times occurring within the lithosphere, rather than present-day processe...