English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Extensional and shear-wave velocities and attenuations (Ve, Vs, Qe, and Qs) were measured using the resonant bar technique in the same frequency range as used in sonic logging (10-20 kHz). Laboratory measurements at a simulated in-situ effective stress of about 6.3 MPa were made on seven core samples from an interval 230 to 252 m below seafloor at Site 637. High-frequency (500-kHz) transmission experiments were also conducted on one sample to measure Vp and Qp under uniaxial compressive stresses up to 16.0 MPa. Ultrasonic velocity was 10.3% greater than resonant bar results, whereas predicted dispersion for a constant-Q model is about 6.6% over this frequency band. Errors were generally less than 10% in both experiments, and the large apparent dispersion was probably due to interfering geometric effects in small samples. Compressional-wave velocity and attenuation were also computed from sonic log (10-20-kHz) waveforms recorded over the same interval in this well. Vp and Qp were calculated by the arrival-time delay and the spectral ratio, respec­ tively, of compressional waveforms at 2.44and 3.05-m receiver spacings from the source. The pressure-compensated resonant bar measurements of \p are in good agreement with the sonic log. However, resonant bar measurements of Qp are generally greater than the log-derived values, primarily because extrinsic effects such as interferences and scattering from boundaries and radiation of shear energy away from the borehole cannot be separated from the apparent in-situ attenuation. Extrinsic losses and intrinsic attenuation in this strongly foliated serpentinite are both important, yielding large apparent attenuation of compressional energy in highly altered zones and breccias.

Acoustic Properties of Altered Peridotite at Site 637 from Laboratory and Sonic Waveform Data