Delimitation of Near-fields boundaries (Final Report)

Abstract

We examine possibilities to delineate the boundaries between near-field and far-field radiation of seismic waves. Near-field (NF), intermediate-field (IF) and far-field (FF) terms represent different properties of the seismic wave-field: the near-source motions are sensitive to the spatio-temporal details of the rupture process, while far-field terms tend to carry the overall signature of the rupture. Due to the longer propagation path of far-field waves through complex Earth structure, their waveform properties also depend more strongly on media properties (scattering; intrinsic attenuation), than it is the case for the NF-wavefield.