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Shear wave velocity and attenuation in ocean bottom sediments from acoustic log waveforms
Author(s) -
Toksöz M. Nafi,
Wilkens R. H.,
Cheng C. H.
Publication year - 1985
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl012i001p00037
Subject(s) - geology , rayleigh wave , seismology , borehole , attenuation , waveform , shear velocity , canyon , shear (geology) , seismogram , microseism , shear waves , acoustics , geophysics , surface wave , geomorphology , optics , meteorology , physics , geotechnical engineering , petrology , turbulence , quantum mechanics , voltage
In boreholes where formation shear wave velocity is lower than borehole fluid velocity neither refracted shear waves nor pseudo‐Rayleigh waves can propagate. When frequency response of the sonde does not extend to low frequencies (e.g. 2 kHz) Stoneley waves are not excited. In such cases refracted P and leaking PL modes become dominant phases on a full waveform acoustic log. The P wave velocity can be determined from the first arrivals. Then, using synthetic seismograms and a waveform matching technique, formation shear wave velocity and attenuation can be estimated. This method is demonstrated using data from DSDP Site 612 in the Baltimore Canyon Trough area of the Atlantic margin.