Leg 191 Borehole Seismological Observatory Photographs

Figure Captions

Figure 1. Photos 001, 002, 003. Preparation of the SAM-191 electronics. Silicone RTV rubber was put on screws that fixed electric parts on a frame to prevent loosening by vibration during installation procedures.

Figure 2. Photos 035, 036, 037, 038. The MEG-191 is a system that acquires signals from the OBH sensors and sends the converted digital data to the data recorder (SAM-191). After the condition of the system was checked, the electrical components were installed in an 8.5-in OD titanium pressure vessel.

Figure 3. Photos 085, 086, 087, 088, 089, 090, 091. A (085), C (087). The MEG-191 was put on the riser/hanger using the MEG frame. B (086). The MEG frame has slots that guide the MEG-191 pressure vessel to the correct position and a handle to help the connection and disconnection of the UMCs attached to the bottom bulkhead of the MEG-191. E (089), F (090). The handle was modified so it could be placed into the clearance between the riser/hanger and the PAT during the installation of the PAT.

Figure 4. Photos 099, 100, 101, 102, 103. The signals from the two OBH sensors to the MEG-191 are fed by the four UMC receptacles attached on the stab plate, which is located on the bottom of the MEG-191 frame. The alignments of the UMCs were adjusted carefully before installation.

Figure 5. Photos 104, 105, 106, 107, 108, 109. Preparation of the DL. The DL records current and voltage of the seawater battery system DC/DC converter. After the condition of the system was checked, the electrical components were installed in a stainless steel pressure vessel.

Figure 6. Photos 110, 111, 112, 113, 114, 115. The power for the NEREID-191 system is supplied by the seawater battery system. Four seawater battery SWB-1200 (Kongsberg Simrad, Norway) cells were placed in the PAT frame. Magnesium alloy rods are used as anodes. Cathode elements consist of titanium wires with carbon fibers oriented radially. The conditions of the contacts between the anodes and the seawater battery frame were checked.

Figure 7. Photos 116, 117, 118, 119. Preparation of the PAT. The UMC cables were fixed on the top of the PAT. Three handles were welded at the side edges of the top panel. The PAT was hung at these three handle positions by three cables during its installation in the reentry cone.

Figure 8. Photos 120, 121, 122, 123. Installation of the SAM frame to the top panel of the PAT. The top part of the SAM-191 recorder sticks out of the panel. The UMC at the bottom of the SAM-191 bulkhead is mated by gravity into the UMC receptacle, mounted on the stab plate located at the bottom of the SAM-191 hole when the SAM-191 recorder is dropped in the hole. The SAM frame has a lever that an ROV can access to connect and disconnect the UMCs correctly.

Figure 9. Photos 124, 125, 126, 127, 128. Three stainless steel pressure vessels for the seawater battery system were installed on the PAT frame. The DC/DC, PCS, DL, and accumulator were installed in the vessels. The pressure vessels were coated with tar-epoxy paint in order to protect them from corrosion. The DC/DC, PCS, and accumulator units were mounted on the lower part of the PAT frame with PVC insulation. The DL was placed on the top panel of the PAT frame.

Figure 10. Photos 004, 005, 006. Overview of the riser/hanger. The top part of the riser/hanger sticks out of the top panel of the PAT. The MEG-191 was mounted there.

Figure 11. Photos 007, 008. The instrument cables that connect the borehole instruments to the PAT have almost neutral buoyancy in seawater to minimize cable stresses.

Figure 12. Photos 009. Installation of the reentry cone. The reentry cone was lowered into the moonpool.

Figure 13. Photos 010, 011, 012. Preparation of the BIA. The main frame of the BIA is a 76-mm-diameter x 710-mm-long steel pipe with two blades with a 62° angle between them. The steel pipe serves as a conduit for cement. The surface area of the frame pipe where the pressure vessels of the OBH housings touch is covered with FRP sheets to insulate the instruments from the frame pipe.

Figure 14. Photos 013, 014, 015. Assembly of the BIA. Two OBH sensors were placed and fixed on the frame pipe in the area between two blades. The two blades protect the instruments from being hit and rubbed by the hole during the installation of the BIA.

Figure 15. Photos 016, 017, 018, 019, 020. Installation of the BIA. A 3.2-m-long "stinger" pipe with centralizers was bolted onto the bottom of the BIA and moved to the moonpool area just before the installation into the borehole.

Figure 16. Photos 021, 022, 023, 024, 025, 026, 027, 028. Installation of the BIA in the moonpool area. After connecting the instrument cables to the OBH sensors, the cables were tied to the BIA with plastic tie wraps and adhesive tape. Each of the two instrument cables were fed off of their respective reels over the sheaves hung below the rotary tables.

Figure 17. Photo 029. Cementing the OBH sensors. After finishing the installation of the BIA and the riser/hanger with the MEG-191, cement was pumped into the drill pipes. The cement flooded out of the lower end of the stinger and came upward to fill the space between the instruments and the borehole wall.

Figure 18. Photos 030, 031. Attaching of centralizers to the drill pipes. Centralizers were attached on the drill pipes every 1.7 m to prevent the cables from being hit and rubbed by the hole.

Figure 19. Photos 032, 033, 034. Instrument cable termination procedure.

Figure 20. Photos 039, 040, 041, 042, 043. Installation of the riser/hanger. The MEG frame and the newly terminated instrument cables were placed and fixed on the riser/hanger.

Figure 21. Photos 044, 045, 046. The MEG-191 was placed on its frame set on the riser/hanger. The riser/hanger was lowered through the moonpool.

Figure 22. Photos 047, 048, 049, 050, 051. Preparation of the PAT. Just before installation of the PAT, two halves of the PAT frame were moved to the moonpool area from the outside and they were welded together. All the UMC jumper cables were fixed on the top panel and frames of the PAT.

Figure 23. Photos 052, 053, 054, 055, 056, 057, 058, 059, 060, 061. Installation of the PAT. The PAT was lowered through the moonpool. The three lines hanging the PAT were released by a redundant acoustic release mechanism.

Figure 24. Photos 062, 063, 064, 065, 066, 067, 068. Snapshots from the VIT/subsea TV. D (065). The BIA being lowered into Hole 1179E. E (066). The PAT landed properly on the top of the reentry cone of Hole 1179E. F (067). The riser/hanger with the MEG-191 placed in the proper position on the reentry cone. G (060). Drill pipes were decoupled from the riser/hanger at the J-type decoupler.

Figure 25. Photos 069, 070, 071. A (069). JAMSTECs deep-sea ROV, KAIKO. It can be operated at depths to 11,000 m. (JAMSTEC = Japan Marine Science & Technology Center). B (070). Preparation of the SAM-191 for installation. Cakes of syntactic foam were attached to the SAM-191 so that the weight of the SAM-191 would be in KAIKO's safe operational range. C (071). SAM-191 was set on the basket of the KAIKO before its dive.

Figure 26. Photos 072, 073. The KAIKO found and approached the WP-2 observatory at Hole 1179E.

Figure 27. Photos 074, 075, 076, 077, 078. A series of SAM-191 installation procedures. A (074), B (075), C (076). Remove a dummy SAM (a protective lid for the UMC receptacle) from the SAM's seating frame located on the top of the PAT frame. D (077). Insert the SAM-191 to its seating frame. E (078). Complete the connection between the UMCs by operating the lever on the SAM seating frame.

Figure 28. Photos 079, 080, 081, 082. A series of procedures to connect the MEG-191 and the PAT with the UMCs. A (079), B (080). Remove the protective UMC cap from the MEG-191. C (081). Remove the UMC jumper cable from the parking position on the top of the PAT. D (082). The KAIKO activated the system by making connection between the MEG-191 and the PAT.

Figure 29. Photos 083, 084. The condition of the WP-2 system was checked using the SAM—ROV communication interface. The data from the system were sent to the surface ship. The photos show the procedure to make a connection between the SAM-191 and the SAM—ROV communication interface.

Figure 30. Photos 092, 093, 094, 095, 096. The titanium-sphere SAM-191 with internal batteries was launched to the sea bottom before the KAIKO started to dive. After finishing the condition check of the WP-2 system, the KAIKO approached the titanium-sphere SAM-191 and cut off a sinker. The titanium-sphere SAM-191 was carried to the WP-2 observatory and placed on the top platform of the PAT.

Figure 31. Photos 097, 098. Recovery of the seawater battery system DL.

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