A direct recording ocean bottom seismometer |
| |
| Authors: | Rex V Johnson II Clive R B Lister Brian T R Lewis |
| |
| Institution: | (1) Dept. of Oceanography, University of Washington, 98195 Seattle, WA., U.S.A. |
| |
| Abstract: | We have designed a simple, cheap and reliable ocean-bottom seismometer. Signals from three-component geophones are recorded directly on magnetic tape running continuously at a speed of 1 mm s1. Time reference is derived from a temperature-compensated quartz crystal oscillator and encoded on a fourth channel as an amplitude modulation of a 20 Hz carrier. A bipolar square-root signal-compression scheme doubles the tape dynamic range to 80 db, and the available bandwidth is 2 to 100 Hz. Tape and batteries are capable of 500-hr operation, and the unique magnetic release comes close to being a fail-safe system. A heavy, high-drag concrete anchor shaped like a flower-pot provides easy launching, fast stable descent and good coupling to the ocean floor. We have had numerous successful field emplacements which have yielded good earthquake and shot-refraction data. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
