LARGE APERTURE SEISMIC ARRAY FINAL SPECIFICATIONS REPORT.
Final rept., 1 Oct 64-30 Jun 65,
TEXAS INSTRUMENTS INC DALLAS
Pagination or Media Count:
This report describes the installation of Angela and Hysham subarrays of the Large Aperture Seismic Array LASA. Each subarray consists of 24 peripheral instruments located on six radials. At each location within the subarrays a borehole was drilled approximately 200 ft deep, cased and cemented. A Hall-Sears HS-10 seismometer was then lowered into each borehole. Data from the seismometers are amplified at the wellhead of each borehole and transmitted to a central gathering point by buried cable. Lightning protectors were installed. Data from the two subarrays was used in carrying out two studies. First, the subarray systems were evaluated from an engineering viewpoint in order to determine those elements and characteristics which would affect the desired performance of the array. Second, characteristics of the seismic information field signal and noise were determined within a single subarray and between the two subarrays. Summarizing the results from the engineering study, the system noise with the seismometer replaced by its equivalent resistance is about 30 to 35 db below the ambient seismic noise at 1.0 cps. This is an improvement of 8 to 12 db of separation over previous array systems at CPO, UBO and BMO. Author
- Seismic Detection and Detectors