Seismic exploration involves the
generation, detection, analysis and interpretation of elastic waves in the
earth to study the sub-surface properties of the earth. A seismic section or
profile should represent accurately the configuration of the subsurface. But
due to topography and near-surface irregularities and other factors, this is
not so. One of the factors is the weathered zone, otherwise called the low
velocity layer (LVL) or weathered layer.
This portion of Earth affects and
is impacted by various human activities such as building, excavating, tunnelling,
storing or accidentally releasing hazardous materials. Moreover many of the
planet’s minerals, groundwater, and cultural resources are located in the
uppermost subsurface layers.This layer effectively slows down the propagation
of seismic waves through the earth and hence increases their travel times.
This can lead to erroneous depth
predictions of structures during final interpretation of seismic sections and
reflections may appear deeper than they actually are In seismic reflection
work, one
very important method in eliminating this problem is the application of static
corrections. But before static corrections can be determined and applied,
the LVL characteristics of velocity, thickness of the LVL and its elevation
must be known and thus incorporated into the processing programme of seismic
reflection data.
The aims of this research are,
therefore, to determine the LVL characteristics of thickness, weathering
velocities and the consolidated layer velocities in the Upper Flood Plain and
the Mangrove Swamp areas in the Niger Delta, and to make a comparison between
these characteristics in the two zones.
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