Sonic Waveform Data
Science operator: Texas A&M University
Hole: U1467E
Expedition: 359
Location: Maldives (Central Equatorial N Indian Ocean)
Latitude: 4° 51.0362' N
Longitude: 73°17.0197' E
Logging date: November 5-6, 2015
Sea floor depth (driller's): 498.4 m DRF
Sea floor depth (logger's): 499.5 m WRF (MSS/HRLA/APS/HLDS/EDTC-B/HNGS main run)
Total penetration: 1212.4 m DRF (712.9 m DSF)
Total core recovered: dedicated logging hole, no core recovered
Oldest sediment recovered: see Hole U1467C
Lithology: see Hole U1467C
ACOUSTIC TOOL USED: DSI (Dipole Sonic Imager)
Recording mode: Monopole P&S, Upper and Lower Dipole, and Stoneley mode (all passes).
Remarks about the recording: none.
MONOPOLE P&S 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.
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
Number of rows: 3840 (downlog)
Number of rows: 3531 (pass 1)
Number of rows: 3735 (pass 2)
The following files have been loaded:
DSI from FMS/DSI/GPIT/EDTC-B/HNGS (Downlog, drill pipe at 95.5 m WSF)
359-U1467E_ldip_d.bin: 94.5-679.5 m WSF
359-U1467E_mono_d.bin: 94.5-679.5 m WSF
359-U1467E_st_d.bin: 94.5-679.5m WSF
359-U1467E_udip_d.bin: 94.5-679.5m WSF
DSI from FMS/DSI/GPIT/EDTC-B/HNGS (Pass 1, recorded open hole)
359-U1467E_ldip_d.bin: 141.5-679.5 m WSF
359-U1467E_mono_d.bin: 141.5-679.5 m WSF
359-U1467E_st_d.bin: 141.5-679.5 m WSF
359-U1467E_udip_d.bin: 141.5-679.5m WSF
DSI from FMS/DSI/GPIT/EDTC-B.HNGS (Pass 2, drill pipe at 95.5 m WSF)
359-U1467E_ldip_p2.bin: 94.5-663.5 m WSF
359-U1467E_mono_p2.bin: 94.5-663.5 m WSF
359-U1467E_st_p2.bin: 94.5-663.5 m WSF
359-U1467E_udip_p2.bin: 94.5-663.5 m WSF
The sonic waveform files are depth-shifted to the seafloor ( -499.5 m) but they are not depth-matched to the reference run (MSS/APS/HLDS/HRLA/EDTC/HNGS main pass). 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 359.