Ch. 4] GEOLOGY 75 



of scientific principles, but also an intimate acquaintance with the 

 implementation thereof. 



Geophysical methods require the collection of substantial amounts 

 of field data. For this purpose specially designed equipment is used, 

 operated by trained technicians and scientists. The task of gathering 

 field data with this equipment is, in itself, a special skill. Not only 

 is the quality of data better, but also the unit cost is lower when the 

 data are gathered by competent field units. In many areas of applied 

 geophysics competence is widespread, but, for the past ten years, there 

 has not been enough personnel to meet the demands. If geophysical 

 activities continue at the current rate, little improvement of this con- 

 dition can be expected. If more geophysicists are required, it is neces- 

 sary that more schools of geophysics be established. In addition to 

 their formal education, geophysicists also require a comprehensive 

 program of field training. Excepting the petroleum industry, no such 

 program of training is in effect. For these reasons many problems in 

 sedimentation which would benefit from the attention of experienced 

 geophysicists are now being neglected. 



The following discussion contains the principal topics covered by 

 the cited divisions of geophysics. These divisions exist mainly in the 

 published literature. For convenience of reference they are retained 

 herein. 



"PURE SCIENCE" GEOPHYSICS 



Seismology 



The subject of seismology includes earthquakes, their cause and 

 their effect; frequency and places of occurrence; the internal constitu- 

 tion of the earth; long-distance propagation of seismic waves; micro- 

 seisms, their origin and propagation, their correlation with meteor- 

 ology, and their use in storm forecasting. 



Applications to sedimentation. Seismology has many practical ap- 

 plications: the design of quakeproof structures; soil mechanics and 

 foundation problems; selection of sites for installations, buildings and 

 public works in consideration of the structural properties of the 

 ground; amplitudes of vibrations from natural and man-made sources; 

 soil tests and test equipment. 



Geology 



Sediments are one of the three fundamental rock types, and they 

 cover three-fourths of the surface of the land areas of the world. 

 Sedimentation comprises the following subjects: the fundamental laws 

 of sedimentation ; the work of water, wind, and ice in removing, trans- 



