• journal_title：Bulletin of the Seismological Society of America
• Contributor：P. C. Leary ; Y.-G. Li ; D. V. Manov
• Publisher：Seismological Society of America
• Date：1990-
• Format：text/html
• Language：en
• journal_abbrev：Bulletin of the Seismological Society of America
• issn：0037-1106
• volume：80
• issue：3
• firstpage：717
• section：Articles

A microprocessor-based orientable three-component seismic sonde has been built and tested. The sonde is designed to share a single four-conductor logging cable with similar sondes via standard processor networking. Each sonde microprocessor receives serial communications from a wellhead computer, instructing it to measure the tilt and magnetic orientation of the sonde, accurately control a motor-driven pinning arm, collect, stack and store three-component gain-ranged seismic data at rates up to 3.6 kHz (1.2 kHz/channel), and transmit three-component full waveform seismic data uphole at 9600 baud using standard RS-232 components. The on-board tiltmeter permits the orientation of the sonde to be deduced if a borehole interval has a known oriented tilt vector. The sonde clamping mechanism is sufficiently strong to sustain cable tension in excess of 2250 N (500 lbf). A principal use of the sonde has been to acquire seismograms that resolve crystalline rock fracture-induced S-wave velocity anisotropy to ∼5 msec (Δt/t ∼ 3 to 5 per cent).