University of Bergen
Dept. of Earth Science
Allé gt. 41, N-5007 Bergen, NORWAY
Tel: (+47) 5558 3600 Fax: (+47) 5558 3660
http://www2.geo.uib.no/

Last update: Aug. 8, 2004 by OM
Arctic Ocean 2001 Geophysical Surveys
Lomonosov Ridge - Eurasia Basin

Postscript August 2004:

On August 8, 2004, the Arctic Coring Expedition (ACEX) started in Tromsø, Norway. Two icebreakers and a drill ship are then heading for the Lomonosov Ridge, where they will attempt to retrieve a 500 meter core sample that will reveal climate history during the last 50 mill. years. Data from the "Arctic Ocean Geophysical Surveys" in 2001 aided in the drill site selection process.  Links:

Contents

Photo Album

  1. Overview
  2. Contact information
  3. Time schedule
  4. Instrument- and compressor container
  5. List of equipment
  6. Instrumentation diagrams
  7. Seismic survey parameters
  8. Impact on marine life
  9. MV "ODEN" information
  10. SWEDARCTIC 2001
  11. Lomonosov Ridge: Background information

1. Overview

The Institute of Solid Earth Physics, (now, 2004, Dept. of Earth Science) at the University of Bergen (UiB) is planning two geophysical surveys in the Arctic Ocean in 2001, using the swedish icebreaker MV ODEN:

  1. Lomonosov Ridge Survey - five days of site survey in support of Ocean Drilling Program (ODP) proposal #533 for scientific drilling on the ridge. This survey is a joint undertaking with Dr. Bernard Coakley, University of New Orleans. Funding for five days of ODEN's ship time is applied for from the US National Science Foundation.

  2. Eurasia Basin Survey north of Svalbard - 10 to 14 days of seismic reflection measurements. The Eurasia Basin survey is supported by the Norwegian Petroleum Directorate, and will be conducted back-to-back to the Swedish 2001 polar expedition with ODEN from Longyearbyen, Svalbard.

The Lomonosov Ridge extends from northern Greenland to Central Siberia and separates the two nearly equal basins of the Arctic Ocean - the Eurasia and the Amerasia. It measures  about 1700 km in length.

Map showing ODEN's cruise is from http://www.polar.se/english/expeditions/ao2001/map.html. Click to enlarge.

Fig. 2. ODEN's cruise plan (from www.polar.se). Click to enlarge.



2. Contact information

Responsibility Name
IFJ Project leader Prof. Yngve Kristoffersen
IFJ instrumentation / docs / web Ole Meyer
IFJ guns/winch/logistics Helge Johnsen


3. Time Schedule

Leg designations are made with reference to "Arctic Ocean 2001: Route and stationplan" issued by NN (check). Detailed time schedule also in this document.

    = IFJ Leg A
  = IFJ Leg B

Date / Period

Days

Activity
5 June - 15 June 9 IFJ Instrumentation configuration and test.
18 June - 20 June 3 Packing / shipping IFJ equipment (to Gothenburg)
26 June 1 ODEN Departure Stockholm
29 June 1 ODEN Embarking Gothenburg
Rotation 1B: 15 July 1 Helicopter lift from Longyearbyen, Svalbard
Leg 2: 16 July - 24 July 9 Transit to Lomonosov
Leg 3: 25 July - 29 July 5 Seismic survey
Lomonosov 87.4N 142E
Leg 4 & 5: 30 July - 28 August 30 Makarov basin, ice drift
End of expedition (a): 29 August 1 Embarking Longyearbyen, Svalbard
Leg 6: 29 August - 12 September 15 10 to 14 days of seismic reflection measurements
End of expedition (b): 12 September 1 Longyearbyen, Svalbard


4. Instrument- and compressor container

  • Instrument container: No. 10A, 10' length, shared with CTD logging and -winch control.
  • Compressor container: No. 3C, 10' length.
  • Streamer winch to be placed adjacent to container #10A, on center line.
  • Click to see larger image.

Fig. 3. ODEN aft deck layout. Click to enlarge.

 

5. List of equipment

Click on main item descriptions for further details.

Color coding legend:

  • = not ok
  • = ready for testing / under test
  • = ok

Latest: Shipment left Bergen June 21.

Item Sub
item		 Description Web Qty Availability Ship no later then: Respons. Status
1   AIRGUNS AND GUN CONTROLLER            
  1.1 Sodera G-GUNS
250 cu. in.
150 cu. in.
3 ea
1 ea		 Delivery June 19 20 June yk, om
  1.2 Gun spares and accessories 1 set Delivery June 19 20 June yk, om
  1.3 Gun controller, Read 1   20 June yk, om
  1.4 Gun harness / signal cables     20 June yk, om, hj
  1.5 Signal cables, Fjord, 22m 10 ea   20 June hj
  1.6 Pressurized air cables     20 June  
2   COMPRESSOR UNIT            
  2.1 Compressor   1 ea   Early May yk, hb
  2.1 Compressor spare parts   1 set   Early May yk, hb  
3   STREAMER PARTS (25m GL)          
  3.1 Active sections   7 ea   27 April om, hj
  3.2 Stretch sections   2 ea   27 April om, hj
  3.3 Scrambler Adapter 25 m G.L   1 ea   27 April om, hj
  3.4 Scrambler Adapter 12.5 m G.L   1 ea     om, hj
  3.5 Lead-in   1 ea   27 April om, hj
  3.6 Deck cable   1 ea   27 April om, hj
  3.7 Tool box   1 ea     om, hj
                 
4   STREAMER WINCH PARTS            
  4.1 Winch 1 ea   Early May yk
  4.2 Winch spare parts   1 set   Early May yk
  4.2 Slip ring box 1 set   Early May yk
                 
5   EQUALIZER AND CHARGE AMPLIFIER            
  5.1 56 ch, Fjord Instruments 1 ea     om
6   STREAMER RECORDING SYSTEM            
  6.1 Main: Geometrics ES-2401 (IFJ) 1 ea     om
  6.2 Spare parts Geometrics ES-2401   1 ea     om
  6.3 Backup: ABEM (NGU) part B (?)   1 ea     om  
  6.4 Offline data storage/processing system 1 ea     om
                 
7   SONOBUOYS, RADIO RECEIVER            
  7.1 Sonobuoys, Sparton SSQ-57A   48 ea   20 June yk
  7.2 Sonobouy radio receiver
ICOM IC-R8500		 1 ea     om
  7.4 Yagi antenna   1 ea     om
8   SONOBUOY RECORDING SYSTEM            
  8.1 LinAcq PC recording  1      om
  8.2 Back-up PC       om
                 
8   SEISMOGRAPHS            
  8.1 GBV recorders w/ 10MByte disks 7 ea     ca
  8.2 Advanced Telemetry Systems: Transmitters to locate GBV recorders   5 ea     yk
                 
9   SYNC UNIT
Interface between navigation - source - recording		            
  9.1 GPS Garmin mod.: GPS 35-HVS 2 ea     om
  9.2 Lap-top PC   -     om
  9.3 Software -     om
  9.4 12 Vdc power supply   2     om
  9.5 Trigger interface box
In: TTL high pulse
Out: 3 ea opto-coupled contact closures		   1     eg
10   BACKUP MEDIA            
  10.1 Exabyte tape   20 ea     om
  10.2 CD-ROM W   10 ea     om
  10.3 Diskette   10 ea     om
11   UPS: Pulsar EL 7   1     om

 


6. Instrumentation diagrams

Fig. 2 shows the instrumentation block diagram for Leg 6, the Eurasia Basin survey. The instrumentation for leg 3 is identical, except that the icefloe seismograph equipment will not be used.

Fig. 4. Instrumentation block diagram, Eurasia Survey.


7. Seismic survey parameters

Abbreviations:

  • TBD = To Be Determined

Streamer parameters:

Parameter Lomonosov Ridge ops Eurasia Basin ops Notes
Active section type HSSG, 100 m HSSG, 100 m  
Group length [m] 12.5 25  
Total length active sections [m] At least 300
(i.e. 3 sections)		 500
(i.e. 5 sections)		  
No of recording channels 24 20  
Sample interval [ms] 2 2  
Recording duration [ms] TBD TBD Mask off water column, if possible
Shooting interval [s] (20) (20)  
Shooting on distance or time TBD TBD  
Vessel speed [kt] 2 (??) 2  
Water depth, approx [m] 1500 3800  
Target zone ?? 3 s TWT below ocean floor  

Sonobuoy recording parameters:

Parameter Lomonosov Ridge ops Eurasia Basin ops Notes
Sample interval [ms] 4 4  
Recording duration [s] 16 16  
No of recording channels 1 1  

 

8. Impact on marine life

Articles in "The Leading Edge", August 2000 issue, special section: Effects of air guns on marine mammals. The following documents are stored on IFJ web server:

Pressure outputs from Sodera airguns, ref.: G. GUN, The Recoilless Air gun, Sodera. Page numbers are with reference to this document.

Volume
[cu. in.]		 Pressure
[bar-meter]

Conditions
150 3.7 (zero to peak) Air pressure = 2000 psi
Gun depth = 5.0 m
Unfiltered
Ref. p. 9
2 * 150 = 300 4.6 (zero to peak)
8.2 (peak to peak)		 Air pressure = 2000 psi
Gun depth = 5.0 m
Filtered 0-256 Hz, 72db/octave
Ref. p. 11
3* 150 = 450 6.6 (zero to peak)
12.3 (peak to peak)		 Air pressure = 2000 psi
Gun depth = 5.0 m
Filtered 0-256 Hz, 72 dB/octave
Ref. p. 12


9. Icebreaker "ODEN": Vessel information

Take a look at her. She can't claim elegance but other qualities - power and strength in particular - surely shines through. She made a name for herself by being the first non-nuclear icebreaker to reach the North pole, in 1991.


10. SWEDARCTIC 2001

SWEDARCTIC 2001 will be carried out during June-August to the high Arctic with the icebreaker Oden. Some 50 researchers will participate and the principal research projects will be in atmospheric chemistry and biogeochemistry. Research in oceanography, remote analysis, and marine zoology are also included, as well as a seismic program.


11. Lomonosov Ridge: Background information

University of Bergen
Institute of Solid Earth Physics
Allé gt. 41, N-5007 Bergen, NORWAY
Tel: (+47) 5558 3420 Fax: (+47) 5558 9669
Email: Yngve.Kristoffersen@ifjf.uib.no