Sonic Waveform Data
Science operator: Texas A&M University
Hole: U1473A
Expedition: 360
Location: SW Indian Ridge (SW Indian Ocean)
Latitude: 32° 42.3622' S
Longitude: 57° 16.688' E
Logging date: January 23-24, 2016
Sea floor depth (driller's): 721 m DRF
Sea floor depth (logger's): 721 m WRF (FMS/DSI/GPIT/EDTC/HNGS Pass 3)
Total penetration: 1510.2 m DRF (789.2 m DSF)
Total core recovered: 469.15 m (63.2 % of cored section)
Oldest sediment recovered: N/A
Lithology: Olivine gabbro
Acoustic tool used: DSI (Dipole Sonic Imager)
Recording mode: Monopole, Upper and Lower Dipole and Stoneley (downlog); Monopole, Stoneley and Cross-Dipole (pass 1, 2, 3).
Remarks about the recording: none.
MONOPOLE MODE: measures compressional and hard-rock shear slowness. The monopole transmitter is excited by a high-frequency pulse, which reproduces conditions similar to previous sonic tools.
UPPER DIPOLE MODE: measures shear wave slowness using firings of the upper dipole transmitter.
LOWER DIPOLE MODE: measures shear wave slowness using firings of the lower dipole transmitter.
CROSS-DIPOLE MODE: uses alternate firings of upper and lower dipole transmitter, thus allowing acquisition of orthogonally polarized data for anisotropy studies.
STONELEY MODE: measures low-frequency Stoneley wave slowness. The monopole transmitter, driven by a low-frequency pulse, generates the Stoneley wave.
Acoustic data are recorded in DLIS format. Each of the eight waveforms generally consists of 512 samples, each recorded every 10 (monopole P&S) and 40 microsec (dipolemodes), at depth intervals of 15.24 cm (6 inches).The original data in DLIS format is first loaded on a Sun system using GeoFrame software. The packed waveform data files are run through a GeoFrame module that applies a gain correction and then converted into ASCII and finally binary format.
Number of columns: 4097 (other than cross-dipole mode)
Number of columns: 1025 (cross-dipole mode)
Number of rows: 4942 (downlog - all modes)
Number of rows: 4568 (pass 1 - all modes)
Number of rows: 1418 (pass 2 - all modes)
Number of rows: 4942 (pass 3 - all modes))
The following files have been created:
DSI from FMS/DSI/GPIT/EDTC-B/HNGS (Downlog, drill pipe at ~30 m WSF)
360-U1473A_ldip_d.bin: 30-783 m WSF
360-U1473A_mono_d.bin: 30-783 m WSF
360-U1473A_st_d.bin: 30-783m WSF
360-U1473A_udip_d.bin: 30-783 m WSF
DSI from FMS/DSI/GPIT/EDTC-B/HNGS (Pass 1, recorded open hole)
360-U1473A_cd_ldip_crossline_p1.bin: 89-785 m WSF
360-U1473A_cd_ldip_inline_p1.bin: 89-785m WSF
360-U1473A_cd_udip_crossline_p1.bin: 89-785 m WSF
360-U1473A_cd_udip_inline_p1.bin: 89-785m WSF
360-U1473A_mono_p1.bin: 89-785m WSF
360-U1473A_st_p1.bin: 89-785m WSF
DSI from FMS/DSI/GPIT/EDTC-B.HNGS (Pass 2, recorded open hole)
360-U1473A_cd_ldip_crossline_p2.bin: 569-785 m WSF
360-U1473A_cd_ldip_inline_p2.bin: 569-785 m WSF
360-U1473A_cd_udip_crossline_p1.bin: 569-785 m WSF
360-U1473A_cd_udip_inline_p2.bin: 569-785 m WSF
360-U1473A_mono_p2.bin: 569-785m WSF
360-U1473A_st_p2.bin: 569-785 m WSF
DSI from FMS/DSI/GPIT/EDTC-B/HNGS(Pass 3, drill pipe at ~30 m WSF)
360-U1473A_d_ldip_crossline_p3.bin: 30-783 m WSF
360-U1473A_cd_ldip_inline_p3.bin: 30-783 m WSF
360-U1473A_cd_udip_crossline_p3.bin: 30-783 m WSF
360-U1473A_cd_udip_inline_p3.bin: 30-783m WSF
360-U1473A_mono_p3.bin: 30-783m WSF
360-U1473A_st_p3.bin: 30-783 m WSF
The sonic waveform files are depth-shifted to the seafloor ( m) but they are not depth-matched to the reference run. Please refer to the 'depth_matches' folder in the hole index page for the depth-matching values and to the "DEPTH SHIFT" section in the standard processing notes for further information.
Additional information about the drilling and logging operations can be found in the Operations and Downhole Measurements sections of the expedition report, Proceedings of the International Ocean Discovery Program, Expedition 360.