Wireline Sonic Waveform Data


IODP logging contractor: USIO/LDEO

Hole: U1359D

Expedition: 318

Location: Wilkes Land Margin (Antarctic Ocean)

Latitude: 64° 54.2596' S

Longitude: 143° 57.5624 ' E

Logging date: February 22-23, 2010

Sea floor depth (driller's): 3023 m DRF

Sea floor depth (logger's): 3019.5 m WRF

Total penetration:  3625.2 m DRF (602.2 m DSF)

Total core recovered: 450 m ( 59.9 % of cored section)

Oldest sediment recovered: Middle Miocene

Lithology:  Diatomaceous silty claystones and finely-laminated claystones


TOOL USED: DSI (Dipole Sonic Imager)

Recording mode: Monopole P&S, Upper Dipole mode.

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.


Acoustic data are recorded in DLIS format. Each of the eight waveforms generally consists of 512 samples (256 in cross-dipole mode), each recorded every 10 (monopole P&S) and 40 microsec (all dipole and Stoneley modes), 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 then converted into ASCII and finally binary format.

Each line is composed of the entire waveform set recorded at each depth, preceded by the depth (multiplied by 10 to be stored as an integer). In the general case of 8 waveforms with 512 samples per waveform, this corresponds to 1 + 4x512 = 4097 columns. In this hole, the specifications of the files are:

Number of columns: 4097

Number of rows:  4107 (downlog)

Number of rows:  3298 (pass 1)

Number of rows:  3281 (pass 2)

Number of rows:  4056 (pass 3)


All values are stored as 'signed short integers' (= 16 bits signed).

Each file can be viewed directly as an image with Spyglass transform or NIH image on MAcs and PCs, or Fortner transform or Khoros on UNIX) - where it has to be opened as either 'raw' or 'binary matrix'. Any image or signal-processing package should also allow viewing it.


The following files have been loaded:

DSI from FMS/DSI/GPIT/HNGS (Downlog, drill pipe at 3122.5 m WRF)

318-U1359D_mono_d.bin: 3125.4-3627.9 m WRF

DSI from FMS/DSI/GPIT/HNGS (Pass 1, recorded open hole)

318-U1359D_mono_p1.bin: 3125.4-3627.9 m WRF

318-U1359D_udip_p1.bin: 3125.4-3627.9 m WRF


DSI from FMS/DSI/GPIT/HNGS (Pass 2, recorded open hole)

318-U1359D_mono_p1.bin: 3125.7-3625.6 m WRF

318-U1359D_udip_p1.bin: 3125.7-3625.6 m WRF


DSI from FMS/DSI/GPIT/HNGS (Pass 3, pipe at 3121 m WRF)

318-U1359D_mono_p3.bin: 3007.6-3625.6 m WRF

318-U1359D_udip_p3.bin: 3007.6-3625.6 m WRF

The sonic waveform files are not depth shifted to a reference run or to the seafloor. For depth shift to the sea floor, please refer to the DEPTH SHIFT section in the standard data processing documentation file.


NOTE: For users interested in reading and converting the data to a format more suitable for their own purpose, the fortran declaration used to open the file *.bin would be:


open (1, file = *.bin,access = 'direct', recl = 2*(1+nwav*nsamples))


where nwav is the number of waveforms (4 or 8) and nsamples the number of samples per waveforms (see above).

If the total number of depths where waveforms have been recorded is ndepth (for a 150 m interval with data every 15cm, ndepth would be 1000), a generic loop to read the data would be


do k = 1, ndepth


read(1, rec=k) iz, (data(i), i = 1, nwav*nsamples)





In such a case, the file dimensions will be ndepth rows by nwav*nsamples+1 columns


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 Integrated Drilling Program, Expedition        . For further questions about the logs, please contact:


Cristina Broglia

Phone: 845-365-8343

Fax: 845-365-3182

E-mail: chris@ldeo.columbia.edu


Tanzhuo Liu

Phone: 845-365-8630

Fax: 845-365-3182

E-mail: tanzhuo@ldeo.columbia.edu