Final rept. 16 Jul 1964-28 Feb 1967
GEOTECH GARLAND TX
Pagination or Media Count:
A deep-hole array of six short-period seismometers was tested at the test site near Grapevine, Texas GV-TX. After a brief period of successful operation, half the array was moved to the site near Apache, Okalahoma AP-OK, and the other half was moved to the site near Franklin, West Virginia FN-WV. Various techniques were employed to process the output of these arrays. The deep-hole test site GV-TX was maintained for testing applications requiring the use of a deep hole, including testing the triaxial seismometer and testing to determine if a useful long-period response could be obtained from the Model 11167 deep-hole seismometer. The results indicated it would require a complex and unstable system to provide a long period response. During the 29-month duration of this program, measurements were made in deep holes in West Virginia, Texas, Utah, Oklahoma, and Pennsylvania. Additionally, an off-shore measurement program was undertaken. The information from wells and surface arrays was used to study short-period 6.0-0.3 sec period noise and signals. An attempt was made to show that higher mode Rayleigh waves and body waves are present in the noise by comparing theoretical curves with experimental results. It was shown that surface waves generally predominate at the longer periods while body waves appear at the shorter periods at quiet sites. Not all data could be interpreted to define the wave types present. The short-period signals were analyzed both visually and digitally. Signal amplitudes at the surface were shown to be at least twice as large as at depth.