Seismic data imaging system

DETAILED DESCRIPTION Seismic exploration uses information in an attempt to determine the character of the ground without actually drilling into the ground.
Many seismic exploration systems are based on launching acoustic probe waves with a vibratory element and measuring reflected probe waves from underground layers with an array of detectors distributed on ground surface.
An example of such technique is illustrated with reference to FIG.
1.
An acoustic probe wave or seismic wave is initiated at a point on the surface of the ground shown as shock point 100.
The acoustic wave essentially emanates from a point at the source point 100.
The wavefront would approach a spherical shape and travel outward in all directions if the underground is a homogeneous medium.
Various geological formations exist and interact with the acoustic wave.
In particular, the acoustic wave is reflected from various layers in the ground.
Detection of the spatial and temporal characteristics of the reflections from these underground formations forms the basis for seismography.
The acoustic probe wave can be generated by a blast of dynamite.
Alternatively, the probe ware may be generated by using a mechanized vibrator which vibrates the ground at certain frequencies.
The vibrator can be controlled by a central control unit (e.
g.
a computer), for example, to produce a swept frequency signal for improved signal-to-noise ratios.
A plurality of sensors are spatially distributed on or near the ground surface to measure the reflections of the acoustic wave from the layers.
Well-known sensors, such as geophones, are normally used to detect the reflected seismic waves.
Geophones are miniature force sensors operable to convert vibrations into electrical signals.
Geophones are spread over the surface or near the surface of the ground in an array to determine magnitudes of vibrations caused by the reflected acoustic waves.
Hundreds or thousands of geophones can be used in an array.
A single, or groups of geophones (e.
g.
, geophone station), are attached by cables to a central processing element which receives the geophone data and processes it to extract various information about the structure of the earth from these seismic reflection paths