Seismic methods were used to locate an impermeable water barrier (density body), constructed in front of a homogenous earth-fill dam (Prätisbach) in Eastern Styria, Austria. This detention reservoir, built in 1985/86, was constructed of locally mined materials. Key to this structures functionality is its impermeable core located within the upstream toe of the dam and parallel to the dam axis. T...

A new approach to seismic migration formalizes the classical diffraction (or common-tangent) stack by relating it to linearized seismic inversion and the generalized Radon transform. This approach recasts migration as the problem of reconstructing the earth’s acoustic scattering potential from its integrals over isochron surfaces. The theory rests on a solution of the wave equation with the geo...

Oscillatory seismic signals arising from resonant vibrations of hydraulic fractures are observed in many geologic systems, including volcanoes, glaciers and ice sheets, and hydrocarbon and geothermal reservoirs. To better quantify the physical dimensions of fluid-filled cracks and properties of the fluids within them, we study wave motion along a thin hydraulic fracture waveguide. We present a ...

We derive an approximate equation combining the quality factor Q, the traveltime of a wave, and the variation of the instantaneous frequency (IF) at the envelope peaks of two successive seismic wavelets, along the wave propagating direction, based on the theory of one-way wave propagation in a 1D viscoelastic medium. We then propose a method (called the WEPIF method) to estimate Q by measuring ...

This paper describes new procedures for processing data acquired with 4C seismic sensors distributed as horizontal arrays on the seafloor and seismic sources positioned either at the sea surface or on the seafloor. Two types of images can be produced from 4C seismic data: a P-P image and a P-SV (converted-shear) image. For P-P imaging, the large elevation difference between deep-water seafloor ...