Koelsch Donald E.

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Koelsch
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Donald E.
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  • Working Paper
    A sea floor winch system for wire line re-entry of deep sea boreholes
    (Woods Hole Oceanographic Institution, 1990-12) Berteaux, Henri O. ; Bocconcelli, Alessandro ; Koelsch, Donald E. ; Stephen, Ralph A.
    The following report describes the scientific motivations for the use of a Sea Floor Winch System for Wireline Re-entry of Deep Sea Boreholes and presents a conceptual design for the winch system.
  • Technical Report
    A simple ocean bottom hydrophone with 200 megabyte data capacity
    (Woods Hole Oceanographic Institution, 1993-06) Peal, Kenneth R. ; Purdy, G. Michael ; Koelsch, Donald E. ; Wooding, Frank B.
    The Woods Hole Ocean Bottom Hydrophone instrument records the digitized output of a single hydrophone sensor at rates between 250 and 1200 samples per second with a dynamic range of 98 dB and can be deployed at depths to 600 meters. The unit's 200 megabyte disk recorder allows operation for periods up to 5 days. Designed for typical marine seismic refraction operations the unit is reliable and simple to deploy and recover. A detailed description is provided of the instrument design and application including transfer function, clock accuracy, data format, sample data and power requirements.
  • Technical Report
    The Woods Hole Oceanographic Institution digital ocean bottom hydrophone instrument : technical report
    (Woods Hole Oceanographic Institution, 1982-06) Koelsch, Donald E. ; Peal, Kenneth R. ; Purdy, G. Michael
    This report describes the design and capabilities of a new ocean bottom hydrophone instrument. The instrument is microprocessor controlled and records digitally on a commercially available cartridge tape recorder with a formatted capacity of 16.7 megabytes. It can operate at sampling intervals between 80 and 8500 Hz and has a dynamic range of 120dB. Both the hardware and software are designed to provide the maximum flexibility in operation allowing either preprogrammed or event detect operation for either short deployment high sampling rate experiments or extended deployment low data rate applications. The microprocessor and recording electronics are capable of handling four data channels and thus the existing recording package is suitable for the ocean bottom seismometer application (or similar} with little or no modification.
  • Working Paper
    Tests of the broadband borehole seismic system (B³S²) at Scripps IGPP and the Pinon Flat Observatory : October 1994 to June 1995
    (Woods Hole Oceanographic Institution, 1997-08) Stephen, Ralph A. ; Orcutt, John ; Peal, Kenneth R. ; Vernon, Frank L. ; Austin, Gary ; Bolmer, S. Thompson ; Gould, Matthew R. ; Koelsch, Donald E. ; Hollinshead, C. B. ; Offield, Glen ; Willoughby, David F.
    The broadband borehole seismic system (B3S2) is being developed as one component of the Ocean Seismic Network (OSN) Pilot Experiment which will be carried out at the OSN-1 Site off Hawaii in Winter 1998. The other major instruments being developed for the experiment are a Broadband Ocean Bottom Seismometer and a Shallow Buried Broadband Ocean Bottom Seismometer. B3S2 consists of four major components: 1) a borehole sonde with a re-entry guide, Teledyne 54000 broadband seismometer, and REFTEK digitizing system, 2) a seafloor acquisition and recording system (SEABASS), 3) a control vehicle for deploying the sonde in a borehole, and 4) shipboard command and control electronics. The deployment system is very similar to the SEABASS configuration used on LFASE (Stephen eta!, 1994). The purposes of the tests at Pinon Flat were: 1) to integrate the borehole sonde and seafloor and shipboard electronics which had been constructed by different groups: WHOI and SIO/IGPP; 2) test the combined subsystem in a wet borehole environment using actual cables and simulating seafloor conditions; and 3) acquire seismic ambient noise and earthquake data over approximately a three month period for comparison with known stations at the Pinon Flat Observatory.
  • Working Paper
    Seafloor borehole array seismic system (SEABASS)
    (Woods Hole Oceanographic Institution, 1993-01) Stephen, Ralph A. ; Koelsch, Donald E. ; Berteaux, Henri O. ; Bocconcelli, Alessandro ; Bolmer, S. Thompson ; Cretin, J. ; Etourmy, N. ; Fabre, A. ; Goldsborough, Robert G. ; Gould, Matthew R. ; Kery, Sean M. ; Laurent, J. ; Omnes, G. ; Peal, Kenneth R. ; Swift, Stephen A. ; Turpening, R. ; Zani, A. Cleo
    The Seafloor Borehole Array Seismic System (SEABASS) has been developed to measure the pressure and three dimensional particle velocity of the VLF sound field (2-50HZ) below the seafloor in the deep ocean (water depths of up to 6km). The system consists off our three-component borehole seismometers (with an optional hydrophone), a borehole digitizing unit, and a seafloor control and recording package. The system can be deployed using a wire line re-entry capability from a conventional research vessel in Deep Sea Drilling Project (DSDP) and Ocean Drilling Project (ODP) boreholes. Data from below the seafloor are acquired either on-board the research vessel via coaxial tether or remotely on the seafloor in a self-contained package. If necessary the data module from the seafloor package can be released independently and recovered on the surface. This paper describes the engineering specifications of SEABASS, the tests that were carried out, and preliminary results from an actual deep sea deployment. Ambient noise levels beneath the seafloor acquired on the Low Frequency Acoustic-Seismic Experiment (LFASE) are within 20dB of levels from previous seafloor borehole seismic experiments and from land borehole measurements. The ambient noise observed on LFASE decreases by up to 12dB in the upper 100m of the seafloor in a sedimentary environment.
  • Working Paper
    Progress report on the development of the seafloor borehole array seismic system (phase II) : July 14, 1992 to January 31, 1996
    (Woods Hole Oceanographic Institution, 1996-06) Stephen, Ralph A. ; Peal, Kenneth R. ; Bolmer, S. Thompson ; Gould, Matthew R. ; Koelsch, Donald E. ; Orcutt, John A. ; Vernon, Frank L. ; Offield, G. ; Willoughby, David F. ; Hollinshead, C. B. ; Spiess, Fred N. ; Hildebrand, John A. ; Zimmerman, Richard ; Austin, Gary
    The Seafloor Borehole Array Seismic System (SEABASS) was originally developed to record autonomously on the seafloor the signals received on a four-sonde three-component borehole geophone array in the VLF band (2-50Hz)(Stephen eta!., 1994). The system is designed to use the wireline re-entry capability (Spiess, 1993; Spiess eta!., 1992) to install and retrieve the seafloor instrumentation (Figures 1 and 2). Following the successful demonstration of this technology on the LFASE (Low Frequency Acoustic-Seismic Experiment) project in September 1989, it was decided to extend the capability to broadband (1000sec-5Hz) borehole seismometers which could be used for permanent seafloor seismic observatories in the Ocean Seismic Network (Orcutt and Stephen, 1993; Purdy and Dziewonski, 1988; Purdy and Orcutt, 1995; Stephen, 1995; Sutton and Barstow, 1990; Sutton eta!., 1988; Sutton eta!., 1965). The Broadband Borehole Seismic System (B3S2) is the prototype system for permanent broadband borehole seismic observatories on the seafloor. It has three major components: i) a broadband borehole seismometer, the Teledyne 54000, modified for seafloor operations by Scripps-IGPP; ii) the re-entry system provided by Scripps-MPL; and iii) the seafloor recording system developed by WHO I. Because of the similarity of the seafloor recording system to SEABASS we have named this new system SEABASS-ll. This report discusses the development of SEABASS-Il at WHOI in the period from July 14, 1992 to January 31, 1996. The motivation for the project and a work statement are contained in WHOI proposals 7016 and 7016.1. This report is a collection of documentation prepared while the work was being carried out. Some of the issues discussed in early memos were subsequently changed. Modifications and further testing of SEABASS-ll, as well as final system integration tests with the borehole andreentry systems (both of which are also still being modified and tested) have still to be carried out in preparation for the OSN Pilot Experiment Cruise in Spring 1997. This is a preliminary report only and presents work in progress. It will be useful to the engineering team as a historical reference of the sequence of events in the development of SEABASS-ll but it should not be considered as a technical manual for the instrumentation.