Method and system for measuring sound velocity

A method and system for determining the speed of sound in a fluidic medium by determining the travel time of an acoustical signal a predetermined distance in a fluidic medium by generating a cyclical reference signal of a predetermined frequency and transmitting a portion of the reference signal through the medium. The transmitted portion of the reference signal is received after travelling a predetermined distance in the fluidic medium. The cycles of the cyclical reference signal are counted during the period of time between the transmitting and receiving of the portion of the reference signal wherein the travel time of the portion of the reference signal, is the number of cycle counts divided by the frequency. The speed of the acoustical signal through the fluidic medium is a function of the path length divided by the travel time

SeisCORK meeting report

SeisCORK meeting, November 15 and 16, 2004, Stress/Mohr Engineering, Houston, Texas 77041-1205The purpose of this meeting was to explore design options to simultaneously acquire borehole seismic data and hydro-geological data (pressure, temperature, fluid sampling and microbiological sampling) on a single CORK system. The scientific focus was to add a seismic component to the Juan de Fuca Hydrogeology program. By permanently installing a sensor string in the borehole our goal was to enable: l) time-lapse VSP's and offset VSP's with sufficient data quality to study amplitude versus offset, shear wave anisotropy, and lateral heterogeneity; 2) monitoring of micro- and nano- earthquake activity around the site for correlation with pressure transients. Because of the difficulty in ensuring adequate coupling through multiple casing strings we concluded that it was impractical to install the vertical seismic array with 10m spacing (50-60 nodes) that would be necessary for VSP's and time-lapse VSP's. We did describe a scenario for a vertical seismic array with approximately 100m spacing (5-6 nodes) that could be used for offset-VSP's and seismic monitoring. This uses some unique technology and involves two seismic strings: one in the annulus between the 4- 1/2" and 10-3/4" casings and one in the middle of the 4-1/2" casing.Funding was provided by the National Science Foundation under Grant No. OCE-0450318

Report of a workshop on technical approaches to construction of a seafloor geomagnetic observatory

This report considers the technical issues on sensors, data recording and transmission, control and timing, power, and packaging associated with constricting a seafloor geomagnetic observatory. Existing technologies either already in use for oceanographic purposes or adapted from terrestral geomagnetic observatories could be applied to measure the vector magnetic field components and absolute intensity with minimal development. The major technical challenge arises in measuring absolute direction on the seafloor because terrestral techniques are not transferrable to the deep ocean. Two solutions to this problem were identified. The first requires the development of an instrument which measures the instantaneous declination and inclination of the magnetic field relative to a north-seeking gyroscope and the local vertical. The second is a straightforward extension of a precision acoustic method for determining absolute position on the seafloor.Funding was provided by the National Science Foundation under grant EAR94-21712 and the National Aeronautics and Space Administration

Annotated record of the detailed examination of Mn deposits observed from bottom photography taken during the INDOMED-1 expedition

A near-bottom survey of a 24-km length of the East Pacific Rise (EPR) crest near the Leg 54 drill sites has established that the axial ridge is a 12- to 15-km-wide lava plateau, bounded by steep 300-meter-high slopes that in places are large outward-facing fault scarps. The plateau is bisected asymmetrically by a 1- to 2-km-wide crestal rift zone, with summit grabens, pillow walls, and axial peaks, which is the locus of dike injection and fissure eruption. About 900 sets of bottom photos of this rift zone and adjacent parts of the plateau show that the upper oceanic crust is composed of several different types of pillow and sheet lava. Sheet lava is more abundant at this rise crest than on slow-spreading ridges or on some other fastspreading rises. Beyond 2 km from the axis, most of the plateau has a patchy veneer of sediment, and its surface is increasingly broken by extensional faults and fissures. At the plateau's margins, secondary volcanism builds subcircular peaks and partly buries the fault scarps formed on the plateau and at its boundaries. Another deep-tow survey of a patch of young abyssal hills 20 to 30 km east of the spreading axis mapped a highly lineated terrain of inactive horsts and grabens. They were created by extension on inward- and outwardfacing normal faults, in a zone 12 to 20 km from the axis. Sediments sampled on the rise crest and flanks are mixtures of calcareous ooze and metalliferous precipitates, and they have been redistributed by southerly currents with average velocities of 9 cm/s

The George H. Scripps Memorial Marine Biological Laboratory of the Scripps Institution of Oceanography, University of California, San Diego

The George H. Scripps Memorial Marine Biological Laboratory is the original building on the present site of the Scripps Institution of Oceanography (of the University of California, San Diego). Now frequently called "Old Scripps," the two-story reinforced concrete building was erected in 1909–1910, and thus was the first truly permanent structure of any of the shoreside marine biological stations in the western hemisphere. Although unpretentious, it is well suited to its purpose and typifies the direct approach of this renowned institution to the problems of learning about the sea. The building is now but one — and a small one — of the institution’s many buildings, but a surprisingly large number of the institution’s research projects have some relation to it. The building is also an architectural landmark, as one of the first monolithic concrete buildings designed by, and built under the supervision of, Irving J. Gill. Scripps Laboratory was one of two buildings designed by Gill that were said to have "marked the beginning of his mature style. . . . Both were utilitarian with cost a major consideration. This was Gill’s opportunity to experiment in concrete monolithic construction, to strip away ornament and projections and to flatten the roof." The other building (the Holly Sefton Memorial Hospital for Children, in San Diego) has been demolished. In these buildings Gill used the latest techniques in reinforced concrete — the Kahn method — and he designed the structure to the same static load-carrying capabilities as are normally specified today.Scripps Laboratory was built as part of the plan of zoologist William E. Ritter (University of California) to carry out a survey of the marine life of the coast of California. From 1892 to 1903 Ritter and his colleagues and students made piecemeal excursions along the Pacific coast, carrying out biological studies while seeking a suitable site for a permanent summer station. In 1903 an invitation from physician and conchologist Fred Baker moved them to San Diego, where Baker’s enthusiasm soon lined up support from San Diego citizens, including newspaper publisher E. W. Scripps and his half-sister (and partner) Ellen Browning Scripps.In the fall of 1903 the Marine Biological Association of San Diego was formed by about thirty people to support Ritter’s survey. The following year Ellen B. Scripps promised an eventual $50,000 to the association for its work and buildings. In 1905 the city of San Diego allowed the association to use land on Alligator Head (now La Jolla Cove Park) for a building. The offer was reversionary. A frame building 24 by 60 feet (designed by the architectural firm of Hebbard and Gill, possibly as a contribution) was constructed there in the spring of 1905, for about$1,000, paid by subscriptions raised chiefly by the La Jolla Improvement Society. That structure was built as a temporary one. Plans were initiated for a permanent laboratory building or even a group of buildings for the eventual marine station. The new buildings were assumed to be for the Alligator Head site, until E. W. Scripps changed the whole plan by urging the acquisition of Pueblo Lot 1298, the present site of the Scripps Institution, from the city of San Diego. This was carried out in 1907. Considerable discussion and planning followed that year and the next, simultaneously with plans for building a ship and negotiations to have the station become a unit of the University of California. In 1909 the several contracts for the first building were let, and by July, 1910 the building was completed.In 1912 the assets of the Marine Biological Association were transferred to the University of California — land, building, equipment, and a ship — and the association was dissolved. In 1914 it rose from its ashes to repeat the ceremony because the University had lost the transfer papers, and it dissolved again. From then the Biological Station was the Scripps Institution for Biological Research, until 1925 when, with a broadening of the laboratory programs, it was renamed Scripps Institution of Oceanography.As the sole building at the station, the George H. Scripps Laboratory housed everything at first. Director and Mrs. Ritter lived on the second floor of the building for three years, until a home for the director was built nearby. All research projects were housed in Scripps Laboratory. From his second-floor office Ritter planned and led the small institution into more than solely biological studies. The first outside field was physics; he brought physicist George F. McEwen to the station even before the laboratory was built. Other disciplines followed, and by the 1930s the full range of oceanographic disciplines — biological, physical, chemical, geological — had been housed in Scripps Laboratory. Until 1950 the director’s office was in the room at the southeast corner of the second floor (marked Library on the original plans), and the only classroom was in the southwest corner nearby. One can fairly say that the growth of the Scripps Institution, the origin of its fleet of research ships, the planning of its first major expeditions, and the beginnings of a great many research programs originated in this modest structure.With the arrival of geologist T.Wayland Vaughan as director in 1924, and the change in name and emphasis of the institution in 1925, the variety of work housed by Scripps Laboratory became both more diverse and more oceanographic. The studies of the genetics of deer-mice carried out for many years by biologist Francis B. Sumner were ended, and he turned to studies of the coloration of fishes; a major portion of the first floor became the "laboratory for the study of fishes" in 1932. Other changes in the building were made to house the extensive collections of marine sediments, corals, and foraminifera that represented the specific interests of Vaughan. More students found their way to the institution, not just for occasional classes in the second-floor classroom but for full-time research leading to a doctoral degree. (The degrees, however, were awarded in those early years first from the Berkeley campus, later from the University of California Los Angeles, and sometimes from other institutions for work actually done at Scripps.)The third director, Harald U. Sverdrup, soon after his arrival in 1936, began compiling in this building the first comprehensive oceanographic text; The Oceans, by Sverdrup, MartinW. Johnson, and Richard H. Fleming (Prentice-Hall, 1942) was typed by secretary Ruth Ragan in the room adjacent to the director’s office. During World War II, Sverdrup and student Walter H. Munk worked in an upstairs office to devise the methods of surf-predicion that were used for troop landings in North Africa and Europe.Immediately following World War II there was rapid growth in oceanography throughout the nation, both in ocean research and in education. Scripps Institution offered the only advanced-degree program then in oceanography, and the single classroom had a sudden influx of students. The basic courses in oceanography were taught there, seminars were held, and dissertation defenses were held in that room. For many years the scientific staff gathered there weekly, to lunch and to discuss their latest researches, their latest expeditions and their plans for the next one, and to hear visiting scientists. When the postwar expansion finally resulted in addition of new buildings on the campus, Scripps Laboratory became the domain of marine geologists and marine biologists. API Project 51, a large program directed by Francis P. Shepard, was on the second floor, and biologists occupied the wet laboratories on the first floor. By the 1970s the geologists had also moved out, and the building was back to biology only. Carl L. Hubbs occupied the second floor, and with collaborators and students worked on fishes, marine mammals, and archeology; his extensive personal library of books and reprints occupied the original library room. In 1977, after completion of the Marine Biology Building, the remaining staff moved out, and the building was left empty, for demolishing or restoration.An incomplete tally of the oceanographers who have been at one time or another located in Scripps Laboratory includes a large number of the leaders in the field. Eleven of them were members of the National Academy of Sciences, an appreciable fraction of the oceanographers in that body, and others have received a wide variety of awards for ocean research and public service. At least eleven oceanographic institution or department leaders were educated here: Roger R. Revelle, who directed Scripps itself; Richard H. Fleming at the University of Washington; Wayne V. Burt, and more recently, G. Ross Heath at Oregon State; Dale F. Leipper at Texas A & M; Donald W. Pritchard at Johns Hopkins; John A. Knauss, at Rhode Island; Warren S. Wooster at University of Miami; Harris B. Stewart, Jr., at the NOAA Miami Laboratory; T. K. Treadwell as Commander of the Naval Oceanographic Office; and Charles Bates as Chief Scientist for the U. S. Coast Guard.The Scripps Laboratory thus played a major part in the history of oceanography, was the site of major research programs, and was the place where a large percentage of the nation’s oceanographers were trained. Given the explosive growth in ocean science, it seems unlikely that any other single building will occupy such a prestigious position again

Progress report on the development of the seafloor borehole array seismic system (phase II) : July 14, 1992 to January 31, 1996

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

Broadband borehole seismic system integration tests : report of the system integration tests at MPL/SIO

This report describes a series of tests performed at SIO/MPL, Point Lorna the week of 17 November 1997 designed to achieve integration of the Broadband Borehole Seismic System (BBBSS) in preparation for the OSN Pilot Experiment cruise on RN Thompson during January 1997. Representatives from all groups were present (see appendix A), with their respective parts of the system and support equipment. It was anticipated that these tests would result in the complete integration of the various components of the borehole seismometer system in preparation for the January cruise. The system would be assembled and tested following a plan (see appendix C) that would culminate in the fully integrated borehole seismometer being wet tested off the MPL pier.This work is sponsored by the National Science Foundation Grant Nos. OCE 9522114and OCE 9523541 with additional support from Scripps Institute of Oceanography and Woods Hole Oceanographic Institutio