EVALUATION OF SEISMIC INSTRUMENTS AND BASIC RESEARCH ON SEISMIC WAVE PROPAGATION.
Final rept. 1 Sep 61-31 May 66.
WESTON OBSERVATORY MASS
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A measuring program, using dynamic photoviscoelastic methods, was conducted with the aim of determining the complete rheo-optical characterization of HYSOL a urethane rubber compound AD-616 391. A data analysis center, capable of sophisticated analysis of seismic data was assembled. A preliminary investigation of the time and space-stationary statistical characteristics of seismic noise was made. Three complete seismic instrumentation packages for use in seismic field studies were constructed. Some features of the seismicity and the crustal structure of New England were investigated. Early stages of the brittle shear fracture process were studied in modeled arrays of cracks. Seismic pulses were emitted during each early crack-growth stage, and appreciable increases of applied stress above preceding crack-growth stress were required for further crack growth before crack coalescence could be attained. These results possibly explain some of the microseismic and foreshock activity observed in earthquake phenomena. Author
- Geology, Geochemistry and Mineralogy