828 



EXPLORATION GEOPHYSICS 



record. A mechanical drive is provided to adjust the time-delay sequence 

 for directions spaced, for example, 4° apart, so that the operation of the 

 machine is automatic. Figure 511 shows a composite record for the sequence 

 of 19 discreet directions, each trace representing one direction. The east- 

 west and north-south components are shown in the upper and lower halves 

 of the figure, respectively. The actual angle of wave arrival for each 

 reflection is indicated by the maximum amplitude trace. By analysis of 

 such indicated reflections, a section map may be produced. 



71 ME A ^ I' 



Fig. 511. — Typical record in a complex territory. For simplicity of illustration, the correspond- 

 ing components of one wave group are outlined in a rectangle. Traces of maximum amplitude are 

 marked with dots in each of the two component groups. (Courtesy of Richer Laboratories.) 



Geo vision. — As an outgrowth of the experience gained with the 

 advantages attainable from a memory-type record, Frank Rieber con- 

 ceived a new approach to the problem of geophysical interpretation 

 and devised methods which may yield an increased perception coupled 

 with a greater speed of analysis. In this proposed method the principles 

 of radar and television are to be utilized in conjunction with some of the 

 accepted techniques of reflection seismography. The name "Geovision" has 

 been applied to this proposed system for exploring geological formations 

 and presenting the results of this exploration on a fluorescent screen where 

 they may be inspected directly and interpreted. 



Broad-band signals derived from conventional geophones are amplified 

 in a manner not unlike that of conventional reflection seismograph equip- 

 ment, but with filter characteristics attempting to preserve the signal 

 identity while suppressing the undesirable frequency components. After 

 passing through a corrective network, this signal energy is used to vary the 

 filament temperature of small incandescent lamps illuminating well-defined 

 slits. A series of these slits, corresponding to the number of geophone 

 channels, is then focused on the surface of a photo-sensitive material. 



