Seismic interferometry and ambient noise tomography: theoretical background and application in south India

Seismic interferometry can be used to extract useful information about Earth's subsurface from the ambient noise wave field. It is an important new tool for exploring seismically quiescent areas. The method involves extraction of empirical Green's function from the background ambient vibrations of the Earth, followed by computation of group or phase velocity and tomographic imaging. Here we provide a review of seismic interferometry and ambient noise tomography (ANT) and present an example of the method in south India.