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doi:10.2204/iodp.proc.327.107.2011

Design, deployment, and status of borehole observatory systems used for single-hole and cross-hole experiments, IODP Expedition 327, eastern flank of Juan de Fuca Ridge1

A.T. Fisher,2 C.G. Wheat,2 K. Becker,2 J. Cowen,2 B. Orcutt,2 S. Hulme,2 K. Inderbitzen,2 A. Haddad,2 T.L. Pettigrew,3 E.E. Davis,4 H. Jannasch,5 K. Grigar,6 R. Aduddell,6 R. Meldrum,4 R. Macdonald,4 and K.J. Edwards7

Abstract

Integrated Ocean Drilling Program (IODP) Expedition 327 installed two new subseafloor borehole observatory systems (“CORKs”) in 3.5 m.y. old upper ocean crust on the eastern flank of Juan de Fuca Ridge in Holes U1362A and U1362B. Expedition 327 participants also recovered part of an instrument string previously deployed in a CORK in Hole U1301B and deployed a short replacement string. These observatories are part of a network of six CORKs that was designed to monitor, sample, and complete multidisciplinary cross-hole experiments. We present an overview of project goals and describe the design, construction, and deployment of new CORK systems. We also provide an update on the status of preexisting CORK systems as of the start of Expedition 327. Additional CORK servicing and sampling are scheduled for summer 2011 and 2012, including a long-term free-flow perturbation experiment that will test the large-scale directional properties of the upper ocean crust around the observatories.

1Fisher, A.T., Wheat, C.G., Becker, K., Cowen, J., Orcutt, B., Hulme, S., Inderbitzen, K., Haddad, A., Pettigrew, T.L., Davis, E.E., Jannasch, H., Grigar, K., Aduddell, R., Meldrum, R., Macdonald, R., and Edwards, K.J., 2011. Design, deployment, and status of borehole observatory systems used for single-hole and cross-hole experiments, IODP Expedition 327, eastern flank of Juan de Fuca Ridge. In Fisher, A.T., Tsuji, T., Petronotis, K., and the Expedition 327 Scientists, Proc. IODP, 327: Tokyo (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/iodp.proc.327.107.2011

2Expedition 327 Scientists’ addresses.

3Mohr Engineering Division, Stress Engineering Services, Houston TX 77041, USA.

4Pacific Geoscience Centre, Geological Survey of Canada, Sidney BC V8L 4B2, Canada.

5Monterey Bay Aquarium Research Institute, Moss Landing CA 95039, USA.

6Integrated Ocean Drilling Program, Texas A&M University, College Station TX 77845, USA.

7Department of Earth Sciences and Department of Biological Sciences, University of Southern California, Los Angeles CA 90089, USA.

Initial receipt: 4 November 2010
Acceptance: 31 March 2011
Publication: 5 September 2011
MS 327-107