SEISMIC METHODS 911 



mobile station toward or away from the fixed station is indicated by the 

 change in heterodyne frequency due to the well-known Doppler effect. 

 The Raydist system permits only one user at a time, but improvements now 

 appear possible whereby about 12 units may be used jointly, by allocating 

 a different carrier frequency to each mobile unit, and filtering out the 

 undesirable heterodyned signals. With the Raydist system operational accu- 

 racies of ± 25 feet may be obtained at ranges of 50 miles. 



RESPONSIBILITY IN EXPLORATION 



The primary thinking initiating any exploration program should be 

 geological. The technical execution of the program rests primarily with 

 the geophysicist. As the work progresses and the field data become avail- 

 able, interpretation must be based upon the best geological and geophysical 

 probabilities. Here close teamwork between the geophysicist and the 

 geologist is required. In many instances there has not been proper inte- 

 gration of the geological and the geophysical effort. A full exchange of 

 information and ideas between the geologist and the geophysicist is essential 

 for the most successful work. Although this section deals primarily with 

 seismic prospecting, the same direction, cooperation, and integration are 

 necessary in any geophysical program employing any technique. The funda- 

 mental problem is the interpretation of the geophysical observations in 

 terms of economic geology. 



The purpose of the exploration program is the discovery of new re- 

 serves, and one of the essentials in exploration is the skillful employment 

 of technical personnel and capital. The more intelligently these resources 

 of technology and capital are used, the more assurance there can be of 

 success. 



We often hear of dry holes drilled on seismic prospects which did not 

 check with the initial interpretation. These are usually termed "busts" and 

 the blame is placed on the geophysicist, where it should rest if he failed to 

 gather the field data properly and to reduce it to the correct physical para- 

 meters. However in most instances the actual responsibility belongs to the 

 geologist who fails to make a critical analysis of all the geological factors 

 which may affect the interpretation as it proceeds from the physical para- 

 meters to the probable subsurface geology.* Many dry holes could be 

 avoided if the geologist assumed his full responsibility in the exploration 

 program. The history of exploration is replete with cases where dry holes 

 furnished the basis for discoveries by another operator who took advantage 

 of the error made by his less alert competitor. 



To further the success of any exploration program, there is a general 

 procedure which may be followed. It may logically be divided into five 



* For discussion of such factors, the reader is referred to the excellent volumeon 

 case histories prepared under the able chairmanship of Henry C. Cortes : "Geophysical 

 Case Histories," Society of Exploration Geophysicists, Vol. 1, 1948 



