IGCP Project 559
Crustal Architecture and Images
Updated: Nov 20, 2008
IGCP Project 559 - Seismic Images
Definition of a "Classic" Transect
The work of IGCP Project 474 is largely based on compiling and distributing "classic" deep seismic profiling transects from a number of tectonic terranes that have nfluenced global thinking on geological processes. The word "classic" is used in the context of IGCP 474 as being regarded as one of the best examples of its type in the world, a leading or ideal example.
To be classic, a transect should have made a major, global impact on geological thinking in terms of:
Material to be included in IGCP 474 TransectsDesirable information
The compilation for each transect should preferably have as a minimum the following mandatory information:
Other non-mandatory information can also be included, for example, images of the gravity and magnetic fields, modelled potential field data along cross sections, etc.
* Where alternative interpretations are available, these should be included, as well as a discussion of the significance of any areas of disagreement and steps that could be taken to address the disagreement, because these may become the focus of future research work.
Other seismic images
Seismic images of the Earth's interior have also been produced using "passive" seismic sources, namely, earthquakes. These investigations commonly produce three-dimensional "tomographic" wave-speed images of the Earth's crust and upper mantle for both P and S waves. These three-dimensional images can be "sliced" both vertically and horizontally to illustrate geological structures along transects or at a particular depth.
Seismic profiling using "active" seismic sources at very long offsets between the seismic source and the receiver array are commonly called "wide-angle" seismic profiles. Such profiles have been recorded for many years and have used explosive, vibroseis and marine airgun seismic sources. The seismic source to receiver offsets can vary from less than a kilometer for near-surface geological investigations to over a 1000 km for studies of the deep crust and upper mantle.
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