Introduction to special section: Hawaii Scientific Drilling Project

Intraplate or "hot spot" volcanic island chains, exemplified by Hawaii, play an important role in plate tectonic theory as reference points for absolute plate motions, but the origin of these volcanoes is not explained by the plate tectonic paradigm [Engebretson et al., 1985; Molnar and Stock, 1987; Morgan, 1971, 1981, 1983; Wilson, 1963]. The most widely held view is that these chains of volcanoes form from magma generated by decompression melting of localized, buoyant upwellings in the mantle [Ribe and Christensen, 1994; Richards et al., 1988; Sleep, 1990; Watson and McKenzie, 1991] . These upwellings, or "plumes," are believed to originate at boundary layers in the mantle (e.g., at the core-mantle boundary or near the boundary at-670 km between the upper and lower mantle), and the cause of the buoyancy may be both compositional and thermal [Campbell and Griffiths, 1990; Griffiths, 1986; Richards et al., 1988; Watson and McKenzie, 1991]. Mantle plumes are responsible for about 10% of the Earth's heat loss and constitute an important mechanism for cycling mass from the deep mantle to the Earth's surface. Studies of the chemical and isotopic compositions of lavas from intraplate volcanoes, especially ocean island volcanoes, have contributed significantly to our knowledge of magma genesis in the mantle [Carmichael et al., 1974; Macdonald et al., 1983] and the compositional heterogeneity of the mantle [Allègre et al., 1983; Hart, 1988; Hart et al., 1986; Kurz et al., 1983]. Of particular importance is the identification of distinct compositional end members in the mantle, the origin and distribution of which provide insight into the long-term differentiation of the mantle-crust system, the recycling of oceanic crust and continental sediment into the mantle, and the history of the lithosphere [Allègre et al., 1995; Farley et al., 1992; Hart, 1988; Hofmann and White, 1982; McKenzie and O'Nions, 1983; Weaver, 1991; Zindler and Hart, 1986]

Deep drilling into a Hawaiian volcano

Hawaiian volcanoes are the most comprehensively studied on Earth. Nevertheless, most of the eruptive history of each one is inaccessible because it is buried by younger lava flows or is exposed only below sea level. For those parts of Hawaiian volcanoes above sea level, erosion typically exposes only a few hundred meters of buried lavas (out of a total thickness of up to 10 km or more).Available samples of submarine lavas extend the time intervals of individual volcanoes that can be studied. However, the histories of individual Hawaiian volcanoes during most of their ~1-million-year passages across the zone of melt production are largely unknown

The history and significance of the Hawaii Geothermal Project

The Hawaii Geothermal Project, since its initiation in 1972, has not only demonstrated that there is a viable geothermal resource present on the Kilauea East Rift Zone, it has also produced a wealth of information about the characteristics of the resource and the operational requirements that must be met to generate electrical power on a long term reliable basis. The HGP-A well demonstrated that a high-temperature hydrothermal system was present on the East Rift Zone; the HGP-A Wellhead Generator Facility showed that electrical power could be generated on a long-term basis from the geothermal reservoir with an availability factor of more than 90'; and research at the facility tested several types of systems for control of hydrogen sulfide and scale deposition. The results of the Hawaii Geothermal Project have helped resolve many uncertainties about the reservoir and will provide guidance to private and regulatory interests as a commercial geothermal development comes on line in Hawaii

Geothermal resources assessment program : geosciences proposal

Sections: Geology Program and Budge

Distribution, movements, and habitat use of small striped bass (Morone saxatilis) across multiple spatial scales

Distribution, movements, and habitat use of small (<46 cm, juveniles and individuals of unknown maturity) striped bass (Morone saxatilis) were investigated with multiple techniques and at multiple spatial scales (surveys and tag-recapture in the estuary and ocean, and telemetry in the estuary) over multiple years to determine the frequency and duration of use of non-natal estuaries. These unique comparisons suggest, at least in New Jersey, that smaller individuals (<20 cm) may disperse from natal estuaries and arrive in non-natal estuaries early in life and take up residence for several years. During this period of estuarine residence, individuals spend all seasons primarily in the low salinity portions of the estuary. At larger sizes, they then leave these non-natal estuaries to begin coastal migrations with those individuals from nurseries in natal estuaries. These composite observations of frequency and duration of habitat use indicate that non-natal estuaries may provide important habitat for a portion of the striped bass population

Fatigue failure of regenerator screens in a high frequency Stirling engine

Failure of Stirling Space Power Demonstrator Engine (SPDE) regenerator screens was investigated. After several hours of operation the SPDE was shut down for inspection and on removing the regenerator screens, debris of unknown origin was discovered along with considerable cracking of the screens in localized areas. Metallurgical analysis of the debris determined it to be cracked-off-deformed pieces of the 41 micron thickness Type 304 stainless steel wire screen. Scanning electron microscopy of the cracked screens revealed failures occurring at wire crossovers and fatigue striations on the fracture surface of the wires. Thus, the screen failure can be characterized as a fatigue failure of the wires. The crossovers were determined to contain a 30 percent reduction in wire thickness and a highly worked microstructure occurring from the manufacturing process of the wire screens. Later it was found that reduction in wire thickness occurred because the screen fabricator had subjected it to a light cold-roll process after weaving. Installation of this screen left a clearance in the regenerator allowing the screens to move. The combined effects of the reduction in wire thickness, stress concentration (caused by screen movement), and highly worked microstructure at the wire crossovers led to the fatigue failure of the screens

Formation of a Stress-Induced Check Mark on the Otoliths of Juvenile Fishes: Implications for Mesocosm Studies

Daily otolith increment widths of spot Leiostomus xanthurus and spotted seatrout Cynoscion nebulosus were examined experimentally in field mesocosms for 5 to 7 days in various habitat types. Daily otolith increments were used as a surrogate for daily somatic growth so that growth prior to capture and handling could be examined. For both species, possible effects of habitat types were confounded by an overall decrease in daily increment widths during the experimental period when compared to increment widths prior to capture. Several spotted seatrout inadvertently captured during mesocosm deployment provided a means for assessing if there was a significant mesocosm effect or if capture and handling may have caused the decreased increment widths. These “volunteers” were distinguishable from experimental fish by the occurrence of a check mark on the otoliths of the experimental fish. Because experimental increment widths of “volunteers” were not different from pre-experimental widths, handling rather than caging effects appeared responsible for reduced increment widths. While there appeared to be no “mesocosm” effect, handling stress potentially affected growth longer than the 24 h acclimation period we anticipated. Short-term effects of capture and handling of wild fish for mesocosm use should be explored and accounted for in future studies

Status Update on the Threat of Babesiosis Returning to the United States

Babesiosis is a hemolytic disease caused by protozoan parasites in the genus Babesia, transmitted through the saliva of infected ticks. The most economically important species, Babesia bigemina and B. bovis, infect cattle and are the etiological agents of bovine babesiosis. In the southern United States, eradication efforts directed against the tick vectors, Boophilus spp., began in the early 1900s. A quarantine zone in south Texas along the US/Mexico border was subsequently established following the eradication of the disease in the US. The permanent quarantine zone, spanning approximately 33% of the total shared border between Texas and Mexico, has helped limit the reintroduction of the vector and disease, and reduced the incidence of the tick vectors. Further, a strict regimen of broad monitoring and surveillance activities coupled with a rapid response and systematic application of containment procedures under the joint jurisdiction of the Texas Animal Health Commission and the United States Department of Agriculture has proven effective in enforcing the permanent quarantine zone and preventing the emergence of babesiosis into the United States. However, the presence of exotic game animals has helped facilitate the spread of the tick vectors and, when coupled with expanding populations of native deer that can host the tick vectors, the prevalence of Boophilus spp. ticks suggests an increased risk of the return of bovine babesiosis to the United States. This mini-review will examine the efforts in south Texas during 2018 to prevent the spread of cattle fever ticks

Dispatch and Delay: Post Conviction Relief Act Litigation in Non-Capital Cases

The article examines post-conviction delays in Pennsylvania, providing a quantitative study of post-trial collateral view. The first empirical study of its kind, the article employs a range of empirical methods for systematically measuring litigation times, and presents a descriptive analysis of the factors accelerating or impeding disposition. The article concludes that trial court collateral relief litigation in Pennsylvania can be improved by adopting several recommendations that will achieve the goal of fair and just post-conviction relief procedures

Technical Report EL-88-18: Reliability of the Federally Owned Water Main System

The reliability of the Federally Owned Water Main (FOWM) system was examined, and recommendations to improve system reliability are made. The existing FOWM system is very dependent upon three different pipe links. The first and most important link is the Francis Scott Key Bridge river crossing. This link carries the entire FOWM supply, and if taken out of service, an alternate means of supply must be used. At present, the only alternate source of supply is through interconnections with the adjacent Arlington County, Virginia, system. The second vital link is the 30-in. steel main which extends from the Key Bridge river crossing to the Pentagon. This line carries approximately 83 percent of the total delivery to the FOWM system. If taken out of service, all flow in the FOWM system would have to be routed through the 16-in. main along George Washington Parkway and Eisenhower Drive. During periods of high water use, flow in this 16-in. line would cause excessive friction losses. As a result, adequate system pressures cannot be maintained, and system demands cannot be fully met. The final critical pipe link is the feed to National Airport. This link consists of a 24-in. pipe and a 16-in. pipe connected in series. At present, this is the only source of water for National Airport. If this line were taken out of service, an alternate source of supply must be found. Furthermore, the available fire flow to the airport through this line during maximum daily demands falls below Insurance Services Office requirements. Several system improvements were evaluated to determine their contribution to the overall reliability of the FOWM system. System improvements consisted of operating existing and new interconnections, constructing new river crossings, installing a new storage tank, new line construction, and combinations of the above. System improvements were evaluated and ranked based on hydraulic performance, engineering impact, and total cost