Accession Number:

AD0419653

Title:

FULL-FIELD SEISMIC MODELLING,

Descriptive Note:

Corporate Author:

AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS

Personal Author(s):

Report Date:

1963-06-01

Pagination or Media Count:

14.0

Abstract:

Many of the problems of seismology are too com plicated for an analytical approach to be feasi ble. Model procedures are indicated but the methods are not sufficiently developed to permit their use in a wide variety of the important problems of seismology. The most frequently used modelling technique utilizes small electromechani cal transducers to view the wave as a function of time at a fixed position. In contrast this re port discusses a method of viewing and photo graphing the entire field of the wave simultane ously at all positions. Time dependence is ob tained by sequential photography. Excitation of the model is produced by striking it repetitively with a small metal pin operated by the cam fol lower on a 14-inch flywheel rotating at 30 cps. The mode are transparent, permitting visuali zation and quantitative representation of the wave through the photoelastic effect. The waves appear to stand still or to propagate through the use of stroboscopic illumination and a contin uously variable phase relationship between strik ing and flashing, controllable by the observer. Simultaneous full-field viewing of models up to 16 inches in diameter is possible. Isochromatic and isoclinic photographs of propagating waves in a 12-inch-square model are shown. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE