3D and 4D imaging using a non-destructive ambient noise seismic interferometry

In recent years there has been increasing interest in the study of so-called ambient noise seismic interferometry. This method is used to extract meaningful information from long recordings (hours to days) of ambient seismic noise. This meaningful information is extracted in the form of wavefields propagating between those receiver positions at which the noise was recorded, i.e., as if a source had been placed at one of those locations - a so-called “virtual source”. The method has found most success in global/regional seismology where low-frequency (sub-1 Hz) fundamental mode surface waves are extracted by cross-correlating months of ambient noise recorded on two or more receiver stations. Whereas the most successful applications of the method have been in recovering surface waves propagating between receiver locations, other successful applications have seen the recovery of body waves. Another very appealing aspect of the ambient noise interferometry is the possibility to use it for time-lapse or continuous un-invasive monitoring of the subsurface properties.