Zusammenfassung
Classical seismological receiver functions are correlational or deconvolutional
combinations of vertical and horizontal component seismometer recordings
of earthquake waves that focus information on near-receiver subsurface
Earth structure and properties. We show that seismic interferometry
can be thought of as a generalisation of receiver functions analysis
to cases where recordings at pairs of receivers are considered simultaneously,
and where either the same or different component recordings are combined.
Further, seismic interferometry uses any of deconvolution, convolution
and cross-correlation, and energy from either impulsive or random
noise sources. We show both how receiver functions can logically
be extended to a new, convolutional form, and that the now little-used
correlational form of receiver functions contains more intuitive
information than previously realised. Seismic interferometry has
provided other extraordinary extensions to seismologists' arsenal.
Passive noise recordings can be converted into seismograms from virtual
(imagined) earthquakes that in turn can be used to image the real
Earth. Active sources (e.g., earthquakes or man-made sources) can
be redatumed into new, virtual sources elsewhere, or can be converted
into virtual sensors (seismometers) that record seismograms from
other real earthquakes, man-made sources or noise sources that occur
either in the future or in the past. And the ability to construct
virtual sources and sensors at desired times and locations (rather
than having to wait for earthquake sources that occur at uncontrollable
locations) promises more repeatable monitoring of changes in Earth
subsurface properties over time. Indeed, so-called coda wave interferometry
offers unprecedented accuracy in detecting such changes. Finally,
existing theoretical extensions to other regimes such as electromagnetic,
electrokinetic and diffusive energy propagation may lead to future
revolutions in other domains of science.
Nutzer