Information from seismic noise

Authors

Richard L. Weaver (Department of Theoretical and Applied Mechanics, University of Illinois, Urbana, IL, USA)

Published in

Science

Publication date

11 March 2005

Abstract

It is commonly supposed that noise obscures, but does not contain, useful information. Intuition suggests that multiple scattering of waves garbles them into illegibility. Yet insights arising out of a branch of physics called “mesoscopic physics” are challenging this assumption. Theory shows that, regardless of scattering, linear waves preserve a residual coherence. This coherence leads to behaviors that confound intuition, such as Anderson localization in which a multiply scattered wave field is confined to a finite volume and unable to diffuse. Correlation of seismic noise is a new and intriguing tool with numerous possible applications. Examples include oil exploration without explosives or thumper trucks, seismic wave profiling and deep Earth tomography from arbitrary positions without waiting for an earthquake, and the extraordinary pleasure of using and interpreting a wealth of data that were previously considered worthless.