Computers in Seismic Tomography

Seismic Tomography

The inversion of seismic travel-time data for radially varying media was initially investigated by Herglotz, Wiechert, and Bateman (the HWB method) in the early part of the 20th century [1]. Tomographic inversions for laterally varying media began in seismology starting in the 1970's. This included early work by Aki, Christoffersson, and Husebye who developed an inversion technique for estimati...

Diffraction and seismic tomography

Diffraction tomography is formulated in such a way that the data ( t ravel t ime4r waveform perturbations) are related to the medium perturbations through the sum of two terms. The first term is the ray integral of ordinary tomography and involves only phase perturbations. The additional diffraction term involves both phase and amplitude perturbations. The diffraction term is linear in the grad...

Seismic Traveltime Tomography 1

Travel Time Inversion in Seismic Tomography

The word tomography finds its origins in the two Greek words tomos, meaning section, and graphy, which translates as drawing. There are many different types of tomography used in many sciences such as medicine, biology, materials science and geology. The basic idea of tomography in all of its uses is to obtain a cross-section of an object which will then be used to infer various facts regarding...

Full waveform seismic inversion using a distributed system of computers

The aim of seismic waveform inversion is to estimate the elastic properties of the Earth’s subsurface layers from recordings of seismic waveform data. This is usually accomplished by using constrained optimization often based on very simplistic assumptions. Full waveform inversion uses a more accurate wave propagation model but is extremely difficult to use for routine analysis and interpretati...