Inversion of seismic data to Acoustic Impedance is usually seen as a specialist activity, so despite the publicised benefits, inverted data are only used in a minority of cases. To help overcome this obstacle we aimed to develop a new algorithm which would not necessarily be best in class, but would be quick and easy to use and increase the use of inversion products within BPA. This new techniq...

[1] Since it has already been demonstrated that point-topoint seismic propagation Green Functions can be extracted from seismic noise, it should be possible to image Earth structure using the ambient noise field. Seismic noise data from 148 broadband seismic stations in Southern California were used to extract the surface wave arrival-times between all station pairs in the network. The seismic ...

Subsurface rock properties are manifested in seismic records as variations in traveltimes, amplitudes, and waveforms. It is commonly acknowledged that traveltimes are sensitive to the long wavelength part of the velocity, whereas amplitudes are sensitive to the short wavelength part of the velocity. The inherent sensitivity of seismic velocity at different wavelengths suggests an approach that ...

While known to be an important aspect of geostatistical simulations and inverse problems, an a priori model covariance can be difficult to specify and implement, especially where that model covariance is both anisotropic and spatially varying. The popular Matérn covariance function is extended to handle such complications, and is implemented as a cascade of numerical solutions to partial differ...

[i] We show that ocean temperature profiles can be accurately recovered using only acoustic methods employed at the sea surface. Using a towed air gun array and a hydrophone streamer, thermohaline boundaries are ensonified at a suite of frequencies and angles, yielding travel time trajectories and reflectivities. These data are inverted via full waveform inversion to estimate sound speed and, s...

High-resolution tomographic images obtained from crosshole geophysical measurements have the potential to provide valuable information about the geostatistical properties of unsaturated-zone hydrologic-state variables such as moisture content. Under drained or quasi-steady-state conditions, the moisture content will reflect the variation of the physical properties of the subsurface, which deter...

Hybrid geostatistical models imitate a sequence of depositional events in time. By considering sedimentation processes, these algorithms produce highly realistic subsurface structures from a variety of environments. However, since depositional events are forward-modeled, they cannot be directly conditioned to data. Therefore, conditioning requires solving a possibly expensive inverse problem. I...

Worldwide interest in shale plays has rapidly increased in recently years, thanks to the combination of horizontal drilling and hydraulic fracturing. Shale formations act as both the source and the reservoir for the natural gas and usually exhibit anisotropic properties at larger scale. Geological and petropysical studies found that the right combination of thickness, TOC (total organic carbon)...

in exploration seismology, estimation of elastic parameters of rocks using seismic amplitudes is considered as inverse problems. nowadays, model-based and more generally optimization-based algorithms are of the most common methods of seismic inversion. these algorithms which are known as deterministic methods, are suffering from two main problems; first, vertical resolution of outputs is very l...

I present a parallel matrix-free framework for frequency-domain seismic modeling, imaging and inversion. The framework provides basic building blocks for designing and testing optimization-based formulations of both linear and non-linear seismic inverse problems. By overloading standard linear-algebra operations, such as matrixvector multiplications, standard optimization packages can be used t...