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Sample records for salton sea solar

  1. Salton Sea Project, Phase 1. [solar pond power plant

    NASA Technical Reports Server (NTRS)

    Peelgren, M. L.

    1982-01-01

    A feasibility study was made for a salt gradient solar pond power plant in or near the Salton Sea of California. The conclusions support continuance 5-MWe proof-of-concept experiment, and ultimate construction by an electric utility company of a 600-MWe plant. The Solar Pond concept would be an environmental benefit to the Salton Sea by reversing the increasing salinity trend. The greatest cost drivers are the lake dike construction and pond sealing. Problems to be resolved include method of brine production from Salton Sea water for the first unit (which requires evaporation pond area and time), the high turbidity and color content of the Salton Sea water (which requires pretreatment), and other questions related to pond permeability, bio-activity and soil/brine chemical reactions. All technical and environmental problems appear solvable and/or manageable if care is taken in mitigating impacts.

  2. Salton sea project, phase 1

    NASA Astrophysics Data System (ADS)

    Peelgren, M. L.

    1982-01-01

    A feasibility study was made for a salt gradient solar pond power plant in or near the Salton Sea of California. The conclusions support continuance 5-MWe proof-of-concept experiment, and ultimate construction by an electric utility company of a 600-MWe plant. The Solar Pond concept would be an environmental benefit to the Salton Sea by reversing the increasing salinity trend. The greatest cost drivers are the lake dike construction and pond sealing. Problems to be resolved include method of brine production from Salton Sea water for the first unit (which requires evaporation pond area and time), the high turbidity and color content of the Salton Sea water (which requires pretreatment), and other questions related to pond permeability, bio-activity and soil/brine chemical reactions. All technical and environmental problems appear solvable and/or manageable if care is taken in mitigating impacts.

  3. Site-Specific Research Conducted in Support of the Salton Sea Solar Pond Project - FY 1982 Report

    NASA Technical Reports Server (NTRS)

    French, R. L.; Marsh, H. E.; Roschke, E. J.; Wu, Y. C.

    1984-01-01

    The design and operation of a salt-gradient solar pond power plant at the Salton Sea presents problems not encountered at small research ponds that were built in the United States. The specific characteristics of the Salton Sea site and the desire to construct the pond using the local clay as a sealant represent major deviations from previous solar pond experience. The site-specific research in support of the plant design is described. The research activity included validation of the spectrophotometric light transmission measurement technique, a search for options for clarifying the turbid and colored water of the Salton Sea, development of water clarification specifications in terms common to industry practice, quantification of gas production from microbiological reactions in the ground, a determination of the combined effects of temperature and salinity on the permeation of the local clays, and a preliminary evaluation of material corrosion.

  4. Salton Sea ecosystem monitoring and assessment plan

    USGS Publications Warehouse

    Case(compiler), H. L., III; Boles, Jerry; Delgado, Arturo; Nguyen, Thang; Osugi, Doug; Barnum, Douglas A.; Decker, Drew; Steinberg, Steven; Steinberg, Sheila; Keene, Charles; White, Kristina; Lupo, Tom; Gen, Sheldon; Baerenklau, Ken A.

    2013-01-01

    The Salton Sea, California’s largest lake, provides essential habitat for several fish and wildlife species and is an important cultural and recreational resource. It has no outlet, and dissolved salts contained in the inflows concentrate in the Salton Sea through evaporation. The salinity of the Salton Sea, which is currently nearly one and a half times the salinity of ocean water, has been increasing as a result of evaporative processes and low freshwater inputs. Further reductions in inflows from water conservation, recycling, and transfers will lower the level of the Salton Sea and accelerate the rate of salinity increases, reduce the suitability of fish and wildlife habitat, and affect air quality by exposing lakebed playa that could generate dust. Legislation enacted in 2003 to implement the Quantification Settlement Agreement (QSA) stated the Legislature’s intent for the State of California to undertake the restoration of the Salton Sea ecosystem. As required by the legislation, the California Resources Agency (now California Natural Resources Agency) produced the Salton Sea Ecosystem Restoration Study and final Programmatic Environmental Impact Report (PEIR; California Resources Agency, 2007) with the stated purpose to “develop a preferred alternative by exploring alternative ways to restore important ecological functions of the Salton Sea that have existed for about 100 years.” A decision regarding a preferred alternative currently resides with the California State Legislature (Legislature), which has yet to take action. As part of efforts to identify an ecosystem restoration program for the Salton Sea, and in anticipation of direction from the Legislature, the California Department of Water Resources (DWR), California Department of Fish and Wildlife (CDFW), U.S. Bureau of Reclamation (Reclamation), and U.S. Geological Survey (USGS) established a team to develop a monitoring and assessment plan (MAP). This plan is the product of that effort. The

  5. Imperial Valley and Salton Sea, California

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Southern California's Salton Sea is a prominent visual for astronauts. This large lake supports the rich agricultural fields of the Imperial, Coachella and Mexicali Valleys in the California and Mexico desert. The Salton Sea formed by accident in 1905 when an irrigation canal ruptured, allowing the Colorado River to flood the Salton Basin. Today the Sea performs an important function as the sink for agricultural runoff; water levels are maintained by the runoff from the surrounding agricultural valleys. The Salton Sea salinity is high-nearly 1/4 saltier than ocean water-but it remains an important stopover point for migratory water birds, including several endangered species. The region also experiences several environmental problems. The recent increased demands for the limited Colorado River water threatens the amount of water allowed to flow into the Salton Sea. Increased salinity and decreased water levels could trigger several regional environmental crises. The agricultural flow into the Sea includes nutrients and agricultural by-products, increasing the productivity and likelihood of algae blooms. This image shows either a bloom, or suspended sediment (usually highly organic) in the water that has been stirred up by winds. Additional information: The Salton Sea A Brief Description of Its Current Conditions, and Potential Remediation Projects and Land Use Across the U.S.-Mexico Border Astronaut photograph STS111-E-5224 was taken by the STS-111 Space Shuttle crew that recently returned from the International Space Station. The image was taken June 12, 2002 using a digital camera. The image was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  6. Cyanobacteria toxins in the Salton Sea

    PubMed Central

    Carmichael, Wayne W; Li, RenHui

    2006-01-01

    Background The Salton Sea (SS) is the largest inland body of water in California: surface area 980 km2, volume 7.3 million acre-feet, 58 km long, 14–22 km wide, maximum depth 15 m. Located in the southeastern Sonoran desert of California, it is 85 m below sea level at its lowest point. It was formed between 1905 and 1907 from heavy river flows of the Colorado River. Since its formation, it has attracted both people and wildlife, including flocks of migratory birds that have made the Salton Sea a critical stopover on the Pacific flyway. Over the past 15 years wintering populations of eared grebe (Podiceps nigricollis) at the Salton Sea, have experienced over 200,000 mortalities. The cause of these large die-offs remains unknown. The unique environmental conditions of the Salton Sea, including salinities from brackish freshwater at river inlets to hypersaline conditions, extreme daily summer temperatures (>38°C), and high nutrient loading from rivers and agricultural drainage favor eutrophic conditions that encourage algal blooms throughout the year. A significant component of these algal blooms are the prokaryotic group – the Cyanophyta or blue-green algae (also called Cyanobacteria). Since many Cyanobacteria produce toxins (the cyanotoxins) it became important to evaluate their presence and to determine if they are a contributing factor in eared-grebe mortalities at the Salton Sea. Results From November 1999 to April 2001, 247 water and sediment samples were received for phytoplankton identification and cyanotoxin analyses. Immunoassay (ELISA) screening of these samples found that eighty five percent of all water samples contained low but detectable levels of the potent cyclic peptide liver toxin called microcystins. Isolation and identification of cyanobacteria isolates showed that the picoplanktonic Synechococcus and the benthic filamentous Oscillatoria were dominant. Both organisms were found to produce microcystins dominated by microcystin-LR and YR. A

  7. Salton Sea sampling program: baseline studies

    SciTech Connect

    Tullis, R.E.; Carter, J.L.; Langlois, G.W.

    1981-04-13

    Baseline data are provided on three species of fish from the Salton Sea, California. The fishes considered were the orange mouth corvina (Cynoscion xanthulus), gulf croaker (Bairdiella icistius) and sargo (Anisotremus davidsonii). Morphometric and meristic data are presented as a baseline to aid in the evaluation of any physiological stress the fish may experience as a result of geothermal development. Analyses were made on muscle, liver, and bone of the fishes sampled to provide baseline data on elemental tissue burdens. The elements measured were: As, Br, Ca, Cu, Fe, Ga, K, Mn, Mi, Pb, Rb, Se, Sr, Zn, and Zr. These data are important if an environmentally sound progression of geothermal power production is to occur at the Salton Sea.

  8. The Potential for Renewable Energy Development to Benefit Restoration of the Salton Sea. Analysis of Technical and Market Potential

    SciTech Connect

    Gagne, Douglas; Haase, Scott; Oakleaf, Brett; Hurlbut, David; Akar, Sertac; Wall, Anna; Turchi, Craig; Pienkos, Philip; Melius, Jennifer; Melaina, Marc

    2015-11-01

    This report summarizes the potential for renewable energy development in the Salton Sea region, as well as the potential for revenues from this development to contribute financially to Salton Sea restoration costs. It considers solar, geothermal, biofuels or nutraceutical production from algae pond cultivation, desalination using renewable energy, and mineral recovery from geothermal fluids.


  9. Avian disease at the Salton Sea

    USGS Publications Warehouse

    Friend, M.

    2002-01-01

    A review of existing records and the scientific literature was conducted for occurrences of avian diseases affecting free-ranging avifauna within the Salton Sea ecosystem. The period for evaluation was 1907 through 1999. Records of the U.S. Department of Agriculture, Bureau of Biological Survey and the scientific literature were the data sources for the period of 1907a??1939. The narrative reports of the U.S. Fish and Wildlife Service's Sonny Bono National Wildlife Refuge Complex and the epizootic database of the U.S. Geological Survey's National Wildlife Health Center were the primary data sources for the remainder of the evaluation. The pattern of avian disease at the Salton Sea has changed greatly over time. Relative to past decades, there was a greater frequency of major outbreaks of avian disease at the Salton Sea during the 1990s than in previous decades, a greater variety of disease agents causing epizootics, and apparent chronic increases in the attrition of birds from disease. Avian mortality was high for about a decade beginning during the mid-1920s, diminished substantially by the 1940s and was at low to moderate levels until the 1990s when it reached the highest levels reported. Avian botulism (Clostridium botulinum type C) was the only major cause of avian disease until 1979 when the first major epizootic of avian cholera (Pasteurella multocidia) was documented. Waterfowl and shorebirds were the primary species affected by avian botulism. A broader spectrum of species have been killed by avian cholera but waterfowl have suffered the greatest losses. Avian cholera reappeared in 1983 and has joined avian botulism as a recurring cause of avian mortality. In 1989, avian salmonellosis (Salmonella typhimurium) was first diagnosed as a major cause of avian disease within the Salton Sea ecosystem and has since reappeared several times, primarily among cattle egrets (Bubulcus ibis). The largest loss from a single epizootic occurred in 1992, when an estimated

  10. Salton Sea Solar Pond Power Plant Design Study and Regional Applicability

    NASA Technical Reports Server (NTRS)

    French, R. L.

    1984-01-01

    Ormat collected and organized the data base and conducted conceptual plant design, performance, and cost analysis. JPL conducted site-specific studies related to solar pond chemistry, soil biological activity, and dike design and construction. WESTEC conducted environmental investigation studies and performed an environmental assessment. SCE provided planning support for licensing and permitting and technical evaluations of the system design and cost estimate.

  11. 75 FR 55600 - Sonny Bono Salton Sea National Wildlife Refuge Complex (Sonny Bono Salton Sea National Wildlife...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-13

    ...We, the U.S. Fish and Wildlife Service (Service), intend to prepare a Comprehensive Conservation Plan (CCP) and Environmental Assessment (EA) for the Sonny Bono Salton Sea National Wildlife Refuge (NWR) Complex, which consists of the Sonny Bono Salton Sea NWR located in Imperial County, California, and the Coachella Valley NWR located in Riverside County, California. We provide this notice in......

  12. 75 FR 59285 - Sonny Bono Salton Sea National Wildlife Refuge Complex (Sonny Bono Salton Sea National Wildlife...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-27

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE INTERIOR Fish and Wildlife Service Sonny Bono Salton Sea National Wildlife Refuge Complex (Sonny Bono Salton Sea National Wildlife Refuge and Coachella Valley National Wildlife Refuge), Imperial and Riverside...

  13. Integrated Science Investigations of the Salton Sea, California, USA

    NASA Astrophysics Data System (ADS)

    Barnum, D.

    2006-12-01

    The Salton Sea is the latest waterbody to be formed by Colorado River floodwaters within the Salton Trough. Over the past 100 years, floodwaters have been replaced by agricultural drainage water and municipal discharges so that today, most of the water reaching the Salton Sea is agricultural drainwater flowing down the New, Alamo and Whitewater Rivers. An evaporation of about 6 feet per year and inputs of more than 4 million tons of salt per year have increased salinity of the waters of the Salton Sea. The current salinity level of approximately 46 parts per thousand is about 25% more saline than ocean water. Diverting water from the Imperial Valley agricultural lands to urban Southern California, and anticipated loss of inflows from Mexico and increasing water conservation activities will result in less water flowing into the Salton Sea. A Restoration Program is being conducted to evaluate the effects of diminished inflows on the Salton Sea Ecosystem and recommend alternatives to avoid or minimize those effects. The Salton Sea has become increasingly important as habitat for migratory birds because of wetland losses. California has lost approximately 91% of interior wetland acreage from pre-settlement until the mid-1980's. The Salton Sea provides critical habitat linking distant wetlands of Pacific and Central Flyways to wintering habitats in Mexico and Central and South America. More than 400 species of birds have been observed in the Salton Sea Ecosystem. Large percentages of the populations for several bird species such as the endangered Yuma Clapper Rail, the Eared Grebe, Snowy Plover and American White Pelican utilize the Salton Sea. Approximately 20 species of conservation concern utilize the Salton Sea ecosystem. Fish-eating birds such as Great Blue Herons, California Brown Pelicans, Double-crested Cormorants and several species of egrets are highly dependent upon the fishery of the Salton Sea. The Salton Sea fishery is now primarily comprised of tilapia

  14. Biogeochemistry of the Salton Sea, California

    NASA Astrophysics Data System (ADS)

    Amrhein, C.; Reese, B. K.; Anderson, M. A.

    2006-12-01

    The Salton Sea is a saline, closed basin lake 70 meters below MSL in the southern desert of California. It is the largest lake in California with a surface area of 945 km2 and an annual inflow of 1,600 million m3. The Sea is hypereutrophic due to nutrient inputs from farm runoff, and anaerobic conditions in the bottom water result in summer and fall releases of hydrogen sulfide and fish kills. The salinity of the Sea is 47 g/L and rising, with an annual salt load of 4 million metric tons. Plans are being developed for construction of a salt repository to control salinization, improve water quality, and maintain the Sea as a refuge for migratory waterfowl. We estimate 700,000 metric tons of calcite are precipitating in the Sea each year, along with 7,000 tons of iron sulfide minerals. Potentially, 70,000 metric tons of hydrogen sulfide are produced in the Sea each year. Measurements of hydrogen sulfide production, reoxidation in the water column, and atmospheric releases will be reported. Hydrodynamic modeling of the current Sea, and the proposed smaller Sea, indicate that partitioning the Sea could lead to persistent stratification and episodic releases of hydrogen sulfide during fall mixing.

  15. 75 FR 63502 - Sonny Bono Salton Sea National Wildlife Refuge Complex (Sonny Bono Salton Sea National Wildlife...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-15

    ... Order 5498). Additional leased lands have been added to the Refuge under the authorities of the... of migratory waterfowl, and other wildlife.'' Today, ] with the original Refuge lands covered by the waters of the Salton Sea, management activities are focused on about 2,000 acres of primarily leased...

  16. Cementation process for minerals recovery from Salton Sea geothermal brines

    SciTech Connect

    Maimoni, A.

    1982-01-26

    The potential for minerals recovery from a 1000-MWe combined geothermal power and minerals recovery plant in the Salton Sea is examined. While the possible value of minerals recovered would substantially exceed the revenue from power production, information is insufficient to carry out a detailed economic analysis. The recovery of precious metals - silver, gold, and platinum - is the most important factor in determining the economics of a minerals recovery plant; however, the precious metals content of the brines is not certain. Such a power plant could recover 14 to 31% of the US demand for manganese and substantial amounts of zinc and lead. Previous work on minerals extraction from Salton Sea brines is also reviewed and a new process, based on a fluidized-bed cementation reaction with metallic iron, is proposed. This process would recover the precious metals, lead, and tin present in the brines.

  17. Salton Sea Scientific Drilling Project Archival Reference, Final Draft

    SciTech Connect

    1991-03-13

    This report provides an archival reference to the scientific information and other pertinent documents and materials associated with the Salton Sea Scientific Drilling Project (SSDP). This archiving process ensures that valuable technical data and information obtained during the life of the project can be retrieved, organized and maintained as a historical record for future reference. This paper describes the background of the project and the process used for archiving the materials. [DJE-2005

  18. Analyses of organic and inorganic contaminants in Salton Sea fish.

    PubMed

    Riedel, Ralf; Schlenk, Daniel; Frank, Donnell; Costa-Pierce, Barry

    2002-05-01

    Chemical contamination of fish from the Salton Sea, a quasi-marine lake in Southern California, could adversely impact millions of birds using the Pacific Flyway and thousands of humans using the lake for recreation. Bairdiella icistia (bairdiella), Cynoscion xanthulus (orangemouth corvina), and Oreochromis spp. (tilapia) were sampled from two river mouths and two nearshore areas of the Salton Sea. Muscle tissues were analyzed for a complete suite of 14 trace metals and 53 pesticides. Fish muscle tissues had concentrations of selenium ranging between 1.89 and 2.73 microg/g wet weight. 4,4'-DDE accounted for 94% of the total DDT metabolites. Total DDTs ranged between 17.1 and 239.0 and total PCBs between 2.5 and 18.6 ng/g wet weight. PCB congeners 132, 138, 153, 168, and 180 comprised over 50% of the total PCBs. Given the potential implementation of a commercial fishing at the Salton Sea in the future, the presence of persistent organic pollutants and selenium warrants further research into the effects of these mixtures on fish populations, and on wildlife and humans consuming fish. PMID:12146823

  19. Proposed scientific activities for the Salton Sea Scientific Drilling Project

    SciTech Connect

    Not Available

    1984-05-01

    The Salton Sea Scientific Drilling Project (SSSDP) has been organized for the purpose of investigating a hydrothermal system at depths and temperatures greater than has been done before. Plans are to deepen an existing well or to drill a new well for research purposes for which temperatures of 300/sup 0/C will be reached at a depth of less than 3.7 km and then deepen that well a further 1.8 km. This report recounts the Congressional history of the appropriation to drill the hole and other history through March 1984, gives a review of the literature on the Salton Sea Geothermal Field and its relationship to other geothermal systems of the Salton Trough, and describes a comprehensive series of investigations that have been proposed either in the well or in conjunction with the SSSDP. Investigations in geophysics, geochemistry and petrology, tectonics and rock mechanics, and geohydrology are given. A tabulation is given of current commercial and state-of-the-art downhole tools and their pressure, temperature, and minimum hole size limitations.

  20. Crystallizer clarifier process spells success for first Salton Sea project

    SciTech Connect

    Anderson, D.N.

    1983-03-01

    This power plant project represents a milestone in geothermal technology because a method now exists to handle the high dissolved solids brine of the Imperial Valley. Presently, the sales price of the power supplied by the new plant is approximately one-half the cost to produce it. Although this project is not economically competitive, newer brine-handling systems are in the offing that will be more efficient and effective. This plant is paving the way for the development of the 3000 to 4000 MW potential of the Salton Sea Geothermal Field.

  1. Shallow Drilling In The Salton Sea Region, The Thermal Anomaly

    SciTech Connect

    Newmark, R. L.; Kasameyer, P. W.; Younker, L. W.

    1987-01-01

    During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09 C/m) to extreme (0.83 C/m) in only 2.4 km. The heat flow in the central part of the anomaly is >600 mW/m{sup 2} and in some areas exceeds 1200 mW/m{sup 2}. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes. These observations of the thermal anomaly provide important constraints for models of the circulation of the hydrothermal system. Thermal budgets based on a simple model for this hydrothermal system indicate that the heat influx rate for local ''hot spots'' in the region may be large enough to account for the rate of heat flux from the entire Salton Trough.

  2. Evaporation and radiation measurements at Salton Sea, California

    USGS Publications Warehouse

    Sturrock, Alex M.

    1977-01-01

    Evaporation from the Salton Sea, Calif., was computed for a 539-day period between July 14, 1967, and January 2, 1969, by use of energy-budget, mass-transfer, and water budget methods. The total evaporation computed by the three methods agreed within 5 percent. The values of heat transfer to and from the bed were used in the energy-budget computations. Monthly evaporation computed by the energy-budget method for 1968 showed that the Salton Sea exhibited a double wave evaporation similar to that of oceans in the same latitude. Weekly and montly comparisons were made to determine if radiation measured by the flat-plate radiometer is seasonally biased. These comparisons indicate that the measurements of radiation by the flat-plate radiometer are not seasonally biased, and that the Cummings Radiation Integrator gives reliable measurements of radiation for periods as short as 1 week. An empirical mass-transfer coefficient, N, as determined from energy-budget measurements. The value of this coefficient to give evaporation in inches per day is 0.00245 when the windspeed is expressed in miles per hour and the vapor pressure expressed in millibars. (Woodard-USGS)

  3. Evaporation and radiation measurements at Salton Sea, California

    USGS Publications Warehouse

    Sturrock, Alex M.

    1978-01-01

    Evaporation from Salton Sea, Calif. was computed for a 539-day period between duly 14, 1967, and January 2, 1969, by use of energy-budget, mass-transfer, and water-budget methods. The total evaporation computed by the three methods agreed within 5 percent. For computing evaporation by the mass-transfer method, vapor pressure measured at raft stations on the sea was considered to be more representative of the conditions over the sea than vapor pressure measured at land stations. The values of heat transfer to and from the bed were used in energy-budget computations. The inclusion of these heat transfer values improved the correlation of evaporation computed by the energy-budget and water-budget methods. Monthly evaporation computed by the energy budget method for 1968 showed that the Salton Sea exhibited a double-wave evaporation similar to that of oceans in the same latitude. Weekly and monthly comparisons were made to determine if radiation measured by the flat-plate radiometer is seasonally biased. Weekly totals of radiation from three flat-plate radiometers were compared to values of a Cummings Radiation Integrator. Monthly totals of radiation for each of the two types of instruments were compared to an empirical method for determining radiation. These comparisons indicate that the measurements of radiation by the flat-plate radiometer are not seasonally biased, and that the Cummings Radiation Integrator gives reliable measurements of radiation for periods as short as 1 week. The net incoming radiation was measured at three stations around the Salton Sea. The areal variation was less than 1 percent on an annual basis and the largest weekly variation was less than 6 percent. An empirical mass-transfer coefficient, N, was determined from energy-budget measurements. The value of this coefficient to give evaporation in inches per day is 0.00245 when the windspeed is expressed in miles per hour and vapor pressure is expressed in millibars. The coefficient is valid

  4. Downhole fluid sampling at the SSSDP (Salton Sea Scientific Drilling Project) California State 2-14 well, Salton Sea, California

    SciTech Connect

    Goff, F.; Shevenell, L.; Grigsby, C.O.; Dennis, B.

    1987-07-01

    In situ fluid sampling activities were conducted at the Salton Sea Scientific Drilling Project (SSSDP) well during late December 1985 and late March 1986 to obtain unflashed samples of Salton Sea brine. In late December, three sampling runs were made to depths of approximately 1800 m and temperatures of 300/sup 0/C. In late March, 10 sampling runs were made to depths of approximately 3150 m and temperatures of 350/sup 0/C. In brief, the Los Alamos tool obtained samples from four of eight runs; the Lawrence Berkeley tool obtained samples from one of one run; the Leutert Instruments, Inc., tool obtained samples from zero of three runs; and the USGS quartz crystal experiment was lost in the well. The most complete sample was obtained from run No. 11, using the Los Alamos sampler and Sandia battery pack/controller on a wireline. About 1635 ml of brine, two noble gas samples, and two bulk gas samples were collected from this run. Samples of brine and gas from productive runs have been distributed to about 15 researchers for various types of analyses. Chemical analyses by the Los Alamos and US Geological Survey analytical teams are presented in this report, although they are not corrected for flashing and precipitation.

  5. Groundwater Availability Within the Salton Sea Basin Final Report

    SciTech Connect

    Tompson, A; Demir, Z; Moran, J; Mason, D; Wagoner, J; Kollet, S; Mansoor, K; McKereghan, P

    2008-01-11

    It is widely recognized that increasing demands for water in Southern California are being affected by actions to reduce and redirect the amount of water imported from the Colorado River. In the Imperial Valley region, for example, import reductions will not only affect agricultural users but also could produce significant collateral impacts on the level and quality of water in the Salton Sea, its regional ecology, or even the long term air quality in the greater basin. The notion of using groundwater in the Imperial Valley as an additional source for agricultural or domestic needs, energy production, or Salton Sea restoration efforts, so as to offset reductions in imported water, is not a new concept. Even though it has been discussed recently (e.g., LLNL, 2002), the idea goes back, in part, to several studies performed by the US Department of Interior and other agencies that have indicated that there may be substantial, usable amounts of groundwater in some portions of the Imperial Valley. It has been estimated, for example, that between 1.1 and 3 billion acre-feet (AF) of groundwater lie within the extended, deep basin underlying the valley and Salton Sea region, even though much of it may be unrecoverable or too poor in its quality (Imperial County, 1997). This is a significant volume with respect to the total annual precipitation volume received in California, whose average is close to 200 million (or 0.2 billion) AF per year (DWR, 1998), and especially with respect to the total annual precipitation received in the Salton Sea watershed itself, which we estimate (Appendix A) to be approximately 2.5 million acre feet (MAF) per year. Clearly, a thorough appraisal of the groundwater resources in the Imperial Valley and Salton Sea region--i.e., an assessment of their overall physical availability--will be needed to determine how they can be used and managed to suit new or redirected demands in the region. Development of an improved or updated groundwater assessment

  6. Chemical evolution of the Salton Sea, California: Nutrient and selenium dynamics

    USGS Publications Warehouse

    Schroeder, R.A.; Orem, W.H.; Kharaka, Y.K.

    2002-01-01

    The Salton Sea is a 1000-km2 terminal lake located in the desert area of southeastern California. This saline (???44 000 mg l-1 dissolved solids) lake started as fresh water in 1905-07 by accidental flooding of the Colorado River, and it is maintained by agricultural runoff of irrigation water diverted from the Colorado River. The Salton Sea and surrounding wetlands have recently acquired substantial ecological importance because of the death of large numbers of birds and fish, and the establishment of a program to restore the health of the Sea. In this report, we present new data on the salinity and concentration of selected chemicals in the Salton Sea water, porewater and sediments, emphasizing the constituents of concern: nutrients (N and P), Se and salinity. Chemical profiles from a Salton Sea core estimated to have a sedimentation rate of 2.3 mm yr-1 show increasing concentrations of OC, N, and P in younger sediment that are believed to reflect increasing eutrophication of the lake. Porewater profiles from two locations in the Sea show that diffusion from bottom sediment is only a minor source of nutrients to the overlying water as compared to irrigation water inputs. Although loss of N and Se by microbial-mediated volatilization is possible, comparison of selected element concentrations in river inputs and water and sediments from the Salton Sea indicates that most of the N (from fertilizer) and virtually all of the Se (delivered in irrigation water from the Colorado River) discharged to the Sea still reside within its bottom sediment. Laboratory simulation on mixtures of sediment and water from the Salton Sea suggest that sediment is a potential source of N and Se to the water column under aerobic conditions. Hence, it is important that any engineered changes made to the Salton Sea for remediation or for transfer of water out of the basin do not result in remobilization of nutrients and Se from the bottom sediment into the overlying water.

  7. Results from shallow research drilling at Inyo Domes, Long Valley Caldera, California and Salton Sea geothermal field, Salton Trough, California

    SciTech Connect

    Younker, L.W.; Eichelberger, J.C.; Kasameyer, P.W.; Newmark, R.L.; Vogel, T.A.

    1987-09-01

    This report reviews the results from two shallow drilling programs recently completed as part of the United States Department of Energy Continental Scientific Drilling Program. The purpose is to provide a broad overview of the objectives and results of the projects, and to analyze these results in the context of the promise and potential of research drilling in crustal thermal regimes. The Inyo Domes drilling project has involved drilling 4 shallow research holes into the 600-year-old Inyo Domes chain, the youngest rhyolitic event in the coterminous United States and the youngest volcanic event in Long Valley Caldera, California. The purpose of the drilling at Inyo was to understand the thermal, chemical and mechanical behavior of silicic magma as it intrudes the upper crust. This behavior, which involves the response of magma to decompression and cooling, is closely related to both eruptive phenomena and the establishment of hydrothermal circulation. The Salton Sea shallow research drilling project involved drilling 19 shallow research holes into the Salton Sea geothermal field, California. The purpose of this drilling was to bound the thermal anomaly, constrain hydrothermal flow pathways, and assess the thermal budget of the field. Constraints on the thermal budget links the local hydrothermal system to the general processes of crustal rifting in the Salton Trough.

  8. Double Difference Earthquake Locations at the Salton Sea Geothermal Reservoir

    SciTech Connect

    Boyle, K L; Hutchings, L J; Bonner, B P; Foxall, W; Kasameyer, P W

    2007-08-08

    The purpose of this paper is to report on processing of raw waveform data from 4547 events recorded at 12 stations between 2001 and 2005 by the Salton Sea Geothermal Field (SSGF) seismic network. We identified a central region of the network where vertically elongated distributions of hypocenters have previously been located from regional network analysis. We process the data from the local network by first autopicking first P and S arrivals; second, improving these with hand picks when necessary; then, using cross-correlation to provide very precise P and S relative arrival times. We used the HypoDD earthquake location algorithm to locate the events. We found that the originally elongated distributions of hypocenters became more tightly clustered and extend down the extent of the study volume at 10 Km. However, we found the shapes to depend on choices of location parameters. We speculate that these narrow elongated zones of seismicity may be due to stress release caused by fluid flow.

  9. 78 FR 28835 - Salton Sea Power Generation Company; Supplemental Notice That Initial Market-Based Rate Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-16

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Salton Sea Power Generation Company; Supplemental Notice That Initial Market... in the above-referenced proceeding of Salton Sea Power Generation Company's application for...

  10. Investigating the Salton Sea geothermal region using seismic interferometry

    NASA Astrophysics Data System (ADS)

    Matzel, E.

    2011-12-01

    Seismic interferometry has proven to be a powerful method for imaging the Earth's interior. To date, much of the work in seismic interferometry has used ambient noise correlation, which isolates the seismic energy between pairs of seismometers. This has resulted in sharp images of the crust and upper mantle, particularly in areas with dense seismic networks. Curtis et al. (2009) demonstrated that we can reverse the geometry of the problem to focus instead on the energy between pairs of earthquakes. The Virtual Seismometer method (VSM) involves correlating the coda of pairs of events recorded at individual stations and then stacking the results over all stations to obtain an estimate of the Green's function between the sources. By effectively replacing each earthquake with a "virtual station" recording all the others, VSM isolates the portion of the data that is sensitive to the source region and significantly improves our ability to see into tectonically active features. VSM is proving to be a powerful method for studying individual earthquakes and the source region. Using this technique, we are able to recover the expected Green's function between pairs of earthquakes, relocate the earthquakes in time and space, measure the source-time function and source magnitude, and finally image the structure along the path between them. Here we investigate the capability of seismic interferometry for geothermal studies. First, we apply ambient noise correlation to dozens of vertical component seismic stations in Southern California with a particular focus on the Salton Sea geothermal fields. We use these correlations to create a 3 dimensional model of the crust in the region. We then apply VSM to well located earthquakes and explosions in the region to determine the scalability of that technique to very small magnitude events recorded by nearby seismic networks. Of particular interest are the highest frequencies and smallest magnitudes the VSM can resolve.

  11. Experimental evaluation of atmospheric effects on radiometric measurements using the EREP of Skylab. [Salton Sea and Great Salt Lake

    NASA Technical Reports Server (NTRS)

    Chang, D. T. (Principal Investigator); Isaacs, R. G.

    1975-01-01

    The author has identified the following significant results. Test sites were located near the Great Salt Lake and the Salton Sea. Calculations were performed for a set of atmospheric models corresponding to the test sites, in addition to standard models for summer and winter midlatitude atmospheres with respective integrated water vapor amount of 2.4 g/sq cm and 0.9 g/sq cm. Each atmosphere was found to contain an average amount of continental aerosol. Computations were valid for high solar elevation angles. Atmospheric attenuation quantities were computed in addition to simulated EREP S192 radiances.

  12. REVIEW OF THE FISHERIES OF THE SALTON SEA, CALIFORNIA, USA: PAST, PRESENT, FUTURE. (R826552)

    EPA Science Inventory

    The Salton Sea is an endorheic, 980-km2 salt lake in the Sonoran Desert of southern California. The historical fish community switched from freshwater to marine species as salinity increased due to evaporation and brackish water inflows. Three species, bairdiella (<...

  13. ANALYSES OF ORGANIC AND INORGANIC CONTAMINANTS IN SALTON SEA FISH. (R826552)

    EPA Science Inventory

    Chemical contamination of fish from the Salton Sea, a quasi-marine lake in Southern California, could adversely impact millions of birds using the Pacific Flyway and thousands of humans using the lake for recreation. Bairdiella icistia (bairdiella), Cynoscion xanthul...

  14. Salton Sea and Imperial Valley, California as seen from the Apollo 7 spacecra

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Salton Sea and Imperial Valley area of southern California, including a portion of northern Baja California, Mexico, as seen from the Apollo 7 spacecraft during its 17th revolution of the earth. Photographed from an altitude of 125 nautical miles, at ground elapsed time of 27 hours.

  15. Curie Depth Analysis of the Salton Sea Region, Southern California

    NASA Astrophysics Data System (ADS)

    Mickus, Kevin; Hussein, Musa

    2016-02-01

    Aeromagnetic data were analyzed to determine the bottom of magnetic bodies that might be related to the Curie point depth (CPD) by 2D spectral and 3D inversion methods within the Salton Trough and the surrounding region in southern California. The bottom of the magnetic bodies for 55 × 55 km windows varied in depth between 11 and 23 km in depth using 2D spectral methods. Since the 55 × 55 km square window may include both shallow and deep source, a 3D inversion method was used to provide better resolution of the bottom of the magnetic bodies. The 3D models indicate the depth to the bottom of the magnetic bodies varied between 5 and 23 km. Even though both methods produced similar results, the 3D inversion method produced higher resolution of the CPD depths. The shallowest depths (5-8 km) occur along and west of the Brawley Seismic Zone and the southwestern portion of the Imperial Valley. The source of these shallow CPD values may be related to geothermal systems including hydrothermal circulation and/or partially molten material. Additionally, shallow CPD depths (7-12 km) were found in a northwest-trending zone in the center of the Salton Trough. These depths coincide with previous seismic analyses that indicated a lower crustal low velocity region which is believed to be caused by partially molten material. Lower velocity zones in several regions may be related to fracturing and/or hydrothermal fluids. If the majority of these shallow depths are related to temperature, they are likely associated with the CPD, and the partially molten material extends over a wider zone than previously known. Greater depths within the Salton Trough coincide with the base of basaltic material and/or regions of intense metamorphism intruded by mafic material in the middle/lower crust.

  16. Borehole Gravity Measurements in the Salton Sea Scientific Drilling Program Well State 2-14

    SciTech Connect

    Kasameyer, P. W.; Hearst, J. R.

    1988-01-01

    Borehole gravity measurements over a depth range from 1737 to 1027 m, and the vertical gradient of gravity above ground were measured at the Salton Sea Scientific Drilling Program well State 2-14. Uncorrected borehole gravimetric densities match values from gamma-gamma logs, indicating that the high densities seen in State 2-14 in the depth range 0.5 to 3 km extend for a few kilometers from the well. The above-ground gradient was found to be 4.1 {micro}gal/m higher than expected; correcting for this value increases the gravimetric density in the borehole. Combining the borehole gravity and estimated vertical gravity gradients on the surface, they find that this densified zone coincides with much of a broad thermal anomaly that has been found to the northeast of the Salton Sea Geothermal Field.

  17. STS-49 Earth observation of the Salton Sea and the Gulf of California

    NASA Technical Reports Server (NTRS)

    1992-01-01

    STS-49 Earth observation taken aboard Endeavour, Orbiter Vehicle (OV) 105, shows the Salton Sea and the Gulf of California. The nearly cloud-free view follows the Colorado River Delta from the Gulf of California (Mexico) to the Salton Sea (California). The Colorado River enters its delta from the right (east), then turns directly south to form saline tidal flats at the edge of the gulf. Nearly all the water is used for irrigation. The United States (U.S.) / Mexican border shows clearly in the different field patterns and the intensity of the greenish color. The irrigated agricultural area offers a sharp contrast to the surrounding desert. The crew used a handheld HASSELBLAD camera with a 100-mm lens to record the image.

  18. Microearthquake Study of the Salton Sea Geothermal Field, California: Evidence of Stress Triggering - Masters Thesis

    SciTech Connect

    Holland, Austin Adams

    2002-02-01

    A digital network of 24 seismograph stations was operated from September 15, 1987 to September 30, 1988, by Lawrence Livermore National Laboratory and Unocal as part of the Salton Sea Scientific Drilling Project to study seismicity related to tectonics and geothermal activity near the drilling site. More than 2001 microearthquakes were relocated in this study in order to image any pervasive structures that may exist within the Salton Sea geothermal field. First, detailed velocity models were obtained through standard 1-D inversion techniques. These velocity models were then used to relocate events using both single event methods and Double-Differencing, a joint hypocenter location method. An anisotropic velocity model was built from anisotropy estimates obtained from well logs within the study area. During the study period, the Superstition wills sequence occurred with two moderate earthquakes of MS 6.2 and MS 6.6. These moderate earthquakes caused a rotation of the stress field as observed from the inversion of first motion data from microearthquakes at the Salton Sea geothermal field. Coulomb failure analysis also indicates that microearthquakes occurring after the Superstition Hills sequence are located within a region of stress increase suggesting stress triggering caused by the moderate earthquakes.

  19. An Isotopic Investigation of Groundwater Recharge in the East Mesa Area of the Salton Sea Basin

    NASA Astrophysics Data System (ADS)

    Moran, J. E.; Tompson, A. F.; Demir, Z.

    2008-12-01

    The Salton Sea Basin, a closed topographic basin located in arid southeastern California and a portion of Baja California, Mexico, is home to some of the most productive agricultural lands in the United States. In the Imperial Valley, in the southern portion of the basin, groundwater use is limited owing to the wide availability of imported water, low urban demand, and water production and quality limitations. Intense interest in developing new water supplies and, separately, restoring the Salton Sea has led to renewed interest in the availability of groundwater in the Imperial Valley, especially the East Mesa area, where decades of leakage from unlined canals has likely impacted groundwater. This study uses isotopic tracers of the water molecule to examine the source of water and groundwater residence time in the East Mesa area between the All American and Coachella canals and the Salton Sea. Groundwater samples were collected from 12 wells and from the All American Canal at Drop 1 for stable isotopes of the water molecule and for tritium-helium groundwater age. Remote well locations, unfavorable well construction, and a dearth of monitoring wells with small open intervals, however, placed limitations on both sample integrity and on spatial coverage of the sampling area. The aridity of the Salton Sea area, and the long history of irrigation with Colorado River water, has marked the groundwater with an evaporated Colorado River water stable isotope signature. High tritium waters (captured in the extensive surface storage system of the Colorado River during peak fallout) that have infiltrated in the Salton Sea area make another good tracer of groundwater transport. Recently recharged groundwater, with tritium-helium apparent ages of less than 2 years, has a chemical and isotopic signature that closely matches water from the canal, and is found in wells directly adjacent to the All American canal. Mean apparent ages of 10 to 40 years were observed in wells at

  20. Diversity of terrestrial avifauna in response to distance from the shoreline of the Salton Sea

    USGS Publications Warehouse

    Mendelsohn, M.B.; Boarman, W.I.; Fisher, R.N.; Hathaway, S.A.

    2007-01-01

    Large aquatic bodies influence surrounding terrestrial ecosystems by providing water and nutrients. In arid landscapes, the increased primary productivity that results may greatly enhance vertebrate biodiversity. The Salton Sea, a large saline lake in the Colorado Desert of southern California, provides nutrients in the form of hundreds of thousands of dead fish carcasses, brine flies, and chemical compounds through windborne salt sea spray. We performed point counts for landbirds and shorebirds monthly or every other month between March 2001 and February 2002 across a sampling grid of 35 points along the west edge of Salton Sea. We found that avian diversity (numbers of species and numbers per species) was dependent on proximity to the Sea. Diversity was at a maximum nearest the shore, and was significantly lower away from the Sea's edge, at all surveyed distances up to 1 km from the shore. Cover by the dominant shrubs on the study site also corresponded to proximity to the water's edge. Whereas one may hypothesize that the avian diversity patterns are caused by these differences in vegetation structure, our data did not support this. Future studies should further investigate this potential correlation between vegetation and bird patterns. Until more is understood about the relationship between elevated avian diversity and the physical environment of the land-shore interface, our results suggest that the Sea's surface be stabilized near its present level. Future management schemes at the Salton Sea that include reductions of water sources should be carefully analyzed, so as to not jeopardize the terrestrial avifauna at this unique ecosystem. ?? 2006 Elsevier Ltd. All rights reserved.

  1. Born from a flood: The Salton Sea and its story of survival

    DOE PAGESBeta

    Tompson, Andrew F. B.

    2016-02-02

    The Salton Sea is a terminal lake located in the deepest point of the topographically closed Salton Trough in southeastern California. It is currently the largest lake in area in the state. It was created by a flooding event along the Colorado River in 1905–1907, similar to the way historical floods over past centuries created ephemeral incarnations of ancient Lake Cahuilla in the same location. Its position at the center of today’s Imperial Valley, a hot and arid locale home to some of the most productive irrigated agricultural lands in the United States, has ensured its ongoing survival through amore » delicate balance between agricultural runoff, its principal form of input, and vast evaporation losses. Nevertheless, its parallel role as a recreational resource and important wildlife habitat, established over its first century of existence, is threatened by increasing salinity decreasing water quality, and reduced water allocations from the Colorado River that feeds the valley’s agriculture. Furthermore, the Salton Sea faces an increasingly uncertain future that will be influenced by reduced water imports from the Colorado River, demands for additional water sources to support farming and energy industries in the valley, and needs to stabilize the lake salinity, maintain recreational resources, and preserve what have become important ecosystems and wildlife habitats.« less

  2. The epizootiology of type C botulism in fish-eating birds at Salton Sea, California

    USGS Publications Warehouse

    Nol, P.

    2002-01-01

    During 1996, type C avian botulism killed over 15,000 fish-eating birds at the Salton Sea in southern California. Amont those affected were nearly 10,000 western white pelicans (Pelecanus erythrorhynchos) and over 1,200 endangered California brown pelicans (Pelecanus occidentalis californicus). Since 1996, smaller epizootics have occurred every year. Type C botulism is not typically associated with fish-eating birds. In the case of the Salton Sea, Mozambique tilapia (Oreochromis mossambicus) are the suspected source of type C toxin, although the mechanism by which the fish acquire the toxin is still unknown. The goals of this study were to: 1) Determine presence/absence of active Clostridium botulinum type C and type C botulinum toxin in tilapia in the Salton Sea. 2) Use geospatial analyses to evaluate relationships between patterns of mortality in birds and fish and presence/absence of toxin and/or toxin-producing bacteria in sediments and fish. We investigated a method of detecting C. botulinum type C cells in the intestinal contents of Mozambique tilapia. This method involved extraction of predominantly cellular DNA and uses a polymerase chain reaction assay to detect presence of type C toxin gene. We collected sick, dead and healthy fish from various sites throughout the Sea during the summers of 1999 to 2001 in order to test them for the presence of active C. botulinum type C by PCR and for the presence of type C toxin by ELISA and mouse test. The results demonstrate that the tilapia population in the Salton Sea harbors C. botulinum type C cells within their gastrointestinal tract and the prevalence of this organism varies from year to year. The total number of fish with toxin-producing bacteria was significantly greater in 2000 than in 2001. No difference in the numbers of positives was detected between sick and dead fish compared to live fish, and there were no differences noted with regard to location of fish collection. The prevalence of active type C

  3. (Sulfide-oxide-silicate phase equilibria and associated fluid inclusion properties in the Salton Sea geothermal system, California)

    SciTech Connect

    McKibben, M.A.

    1988-06-01

    Our studies involved petrographic, fluid inclusion, geochemical and stable isotopic studies of drillcores and fluids from the Salton Sea geothermal system. Our initial studies revealed the presence of previously-unrecognized evaporitic anhydrite at depth throughout the geothermal system. The high salinity of the Salton Sea geothermal brines previously had been attributed to low-temperature dissolution of surficial evaporitic deposits by meteoric waters. Our microthermometric studies of halite--containing fluid inclusions in the meta-evaporites indicated that the high salinity of the geothermal brines is derived in part from the hydrothermal metamorphism of relatively deeply-buried salt and evaporites. In addition, our research concentrated on mineralized fractures in drillcores.

  4. Occurrence of west nile virus infection in raptors at the Salton Sea, California.

    PubMed

    Dusek, Robert J; Iko, William M; Hofmeister, Erik K

    2010-07-01

    We investigated the prevalence of West Nile virus (WNV)-neutralizing antibodies and infectious virus, and the occurrence of overwinter transmission in two raptor species during January and March 2006 at the Salton Sea, Imperial County, California. We captured 208 American Kestrels (Falco sparverius) (January, n=100; March, n=108) and 116 Burrowing Owls (Athene cunicularia) (January, n=52; March, n=64). Laboratory analysis revealed that 83% of American Kestrels and 31% of Burrowing Owls were positive for WNV-neutralizing antibodies. Additionally, two seroconversions were detected in Burrowing Owls between January and March. Infectious WNV, consistent with acute infection, was not detected in any bird. PMID:20688694

  5. Type C botulism in pelicans and other fish-eating birds at the Salton Sea

    USGS Publications Warehouse

    Rocke, T.E.; Nol, P.; Pelizza, C.; Sturm, K.K.

    2004-01-01

    In 1996, type C avian botulism killed over 10,000 pelicans and nearly 10,000 other fish-eating birds at the Salton Sea in southern California. Although botulism had been previously documented in waterbirds at the Sea, this die-off was unusual in that it involved primarily fish-eating birds. The American White Pelican (Pelecanus erythrorynchos) was the species with the greatest mortality in 1996. Since 1996, mortality has recurred every year but losses have declined (<2,000 birds/year), with relatively more Brown Pelicans (P. occidentalis) than White Pelicans afflicted. In 2000, morbidity and mortality of Brown Pelicans with type C botulism (1311) approached the numbers afflicted in 1996 (2034). In recent years, mortality reached a peak earlier in the summer, July and August, in contrast to 1996 when mortality reached a peak in September. An exotic fish species, tilapia (Oreochromis mossambicus), has been implicated as the source of toxin for birds at Salton Sea, but the source of toxin for fish is unknown.

  6. A linked hydrodynamic and water quality model for the Salton Sea

    USGS Publications Warehouse

    Chung, E.G.; Schladow, S.G.; Perez-Losada, J.; Robertson, D.M.

    2008-01-01

    A linked hydrodynamic and water quality model was developed and applied to the Salton Sea. The hydrodynamic component is based on the one-dimensional numerical model, DLM. The water quality model is based on a new conceptual model for nutrient cycling in the Sea, and simulates temperature, total suspended sediment concentration, nutrient concentrations, including PO4-3, NO3-1 and NH4+1, DO concentration and chlorophyll a concentration as functions of depth and time. Existing water temperature data from 1997 were used to verify that the model could accurately represent the onset and breakup of thermal stratification. 1999 is the only year with a near-complete dataset for water quality variables for the Salton Sea. The linked hydrodynamic and water quality model was run for 1999, and by adjustment of rate coefficients and other water quality parameters, a good match with the data was obtained. In this article, the model is fully described and the model results for reductions in external phosphorus load on chlorophyll a distribution are presented. ?? 2008 Springer Science+Business Media B.V.

  7. Body and Surface-wave ambient noise seismic interferometry in the Salton Sea Geothermal Field, California

    NASA Astrophysics Data System (ADS)

    Sabey, L.; Hole, J. A.; Han, L.; Stock, J. M.; Fuis, G. S.

    2013-12-01

    Seismic reflection and refraction data were acquired as a part of the Salton Seismic Imaging Project in March 2011. Alongside traditional explosive source recording, a dense array of 486 seismometers across the Salton Sea Geothermal Field and Brawley Seismic Zone recorded 135 hours of natural noise sources. The geothermal field is located within the Imperial Valley in Southern California and is bordered by the southern end of the Salton Sea. There is abundant microseismicity recorded in the area, including over 100-recorded earthquakes, wave action, geothermal pumping operations, a railroad, and two highways. Volcanism associated with rifting processes provides a prolific heat source to the system marking the Salton Sea Geothermal Field as one of the largest and hottest geothermal fields in California. Seismic interferometry is a technique that uses continuous recordings of natural noise to create a 'virtual source' by cross-correlation of receiver pairs followed by stacking. This method has been highly successful for surface waves and a few previous studies have shown evidence of body waves and reflections. As anticipated the abundant tectonic and induced noise sources within our study area produced visible surface and body waves. Inclusion of the earthquakes with normalized amplitudes improved overall data quality. The virtual shots from our data our compare well to our twelve explosive shots at near offsets. The highest quality virtual source gathers are produced near anthropogenic noise sources. In particular, one large geothermal plant acted as a sufficiently strong point source producing a gather similar to what we would see from an explosive source. Surface waves recorded on 4.5-Hz geophones were retrievable from 1-6Hz after cross-correlation and stacking. Up to 30km of body waves were also observed in the 25-30Hz range. Future studies will include surface wave dispersion analysis and attempt body wave reflection imaging. The 100-meter spacing of our

  8. Salton Sea Scientific Drilling Project: A summary of drilling and engineering activities and scientific results

    SciTech Connect

    Ross, H.P.; Forsgren, C.K.

    1992-04-01

    The Salton Sea Scientific g Project (SSSDP) completed the first major well in the United States Continental Scientific Drilling Program. The well (State 2-14) was drilled to 10,W ft (3,220 m) in the Salton Sea Geothermal Field in California's Imperial Valley, to permit scientific study of a deep, high-temperature portion of an active geothermal system. The program was designed to investigate, through drilling and testing, the subsurface thermal, chemical, and mineralogical environments of this geothermal area. Extensive samples and data, including cores, cuttings, geothermal fluids and gases, and geophysical logs, were collected for future scientific analysis, interpretation, and publication. Short duration flow tests were conducted on reservoirs at a depth of approximately 6,120 ft (1,865 m) and at 10,136 ft (3,089 m). This report summarizes all major activities of the SSSDP, from project inception in the fall of 1984 through brine-pond cleanup and site restoration, ending in February 1989. This report presents a balanced summary of drilling, coring, logging, and flow-test operations, and a brief summary of technical and scientific results. Frequent reference is made to original records, data, and publication of results. The report also reviews the proposed versus the final well design, and operational summaries, such as the bit record, the casing and cementing program, and the coring program. Summaries are and the results of three flow tests. Several teamed during the project.

  9. Preliminary report on shallow research drilling in the Salton Sea region

    SciTech Connect

    Newmark, R.L.; Kasameyer, P.W.; Younker, L.W.

    1988-01-14

    During two shallow thermal drilling programs, thermal measurements were obtained in 56 shallow (76.2 m) and one intermediate (457.3 m) depth holes located both onshore and offshore along the southern margin of the Salton Sea in the Imperial Valley, California. These data complete the surficial coverage of the thermal anomaly, revealing the shape and lateral extent of the hydrothermal system. The thermal data show the region of high thermal gradients to extend only a short distance offshore to the north of the Quaternary volcanic domes which are exposed along the southern shore of the Salton Sea. The central thermal anomaly has an arcuate shape, about 4 km wide and 12 km long. Across the center of the anomaly, the transition zone between locations exhibiting high thermal gradients and those exhibiting regional thermal gradients is quite narrow. Thermal gradients rise from near regional (0.09/degree/C/m) to extreme (0.83/degree/C/m) in only 2.4 km. The heat flow in the central part of the anomaly is greater than 600 mW/m/sup 2/ and in some areas exceeds 1200 mW/m/sup 2/. The shape of the thermal anomaly is asymmetric with respect to the line of volcanoes previously thought to represent the center of the field, with its center line offset south of the volcanic buttes. There is no broad thermal anomaly associated with the magnetic high that extends offshore to the northeast from the volcanic domes.

  10. Seismic monitoring of the June, 1988 Salton Sea Scientific Drilling Program flow/injection test

    SciTech Connect

    Jarpe, S.P.; Kasameyer, P.W.; Hutchings, L.J.; Hauk, T.F.

    1988-10-04

    The purpose of the seismic monitoring project was to characterize in detail the micro-seismic activity related to the Salton Sea Scientific Drilling Program (SSSDP) flow-injection test in the Salton Sea Geothermal Field. Our goal was to determine if any sources of seismic energy related to the test were observable at the surface. We deployed our recording stations so that we could detect and locate both impulsive microearthquakes and continuous seismic noise energy. Our network, which was sensitive enough to be triggered by magnitude 0.0 or larger events, found no impulsive microearthquakes in the vicinity of the flow test in the 8 month period before the test and only one event during the flow test. This event has provided the opportunity to compare the detection and location capabilities of small networks and arrays in a geothermal environment. At present, we are carefully scanning all of the data that we collected during the flow test for evidence of anomalous seismic noise sources and for impulsive events smaller than the network detection threshold (magnitude 0.0). 8 refs., 4 figs.

  11. Physical, chemical, and biological data for detailed study of irrigation drainage in the Salton Sea area, California, 1988-90

    USGS Publications Warehouse

    Schroeder, R.A.; Rivera, Mick

    1993-01-01

    This report contains physical, chemical, and biological data associated with irrigation drainage in the Salton Sea area collected during the late 1980's. The data were collected in support of the u.S. Department of the Interior's National Irrigation Water Quality Program in the Western United States to evaluate effects on the environment from potential toxics in irrigation-induced drainage. The data have been used to support interpretations in several recent publications. This data report is the companion to a comprehensive U.S. Geological Survey interpretive report that describes the geochemical and biological pathways of potential toxics, especially selenium, in the study area. The report contains data on concentra- tions of a broad suite of trace elements in soil, irrigation (Colorado River) water, drainwater, surface water (including the Salton Sea), ground- water, aquatic plants, invertebrates, amphibians, reptiles, fish, birds, bird eggs, and turtle eggs. Included, also, are light stable isotope (hydrogen, oxygen, carbon, nitrogen, and sulfur), tritium, and radiocarbon data for selected aqueous samples and organochlorine-pesticide concentrations in biota. Geochemical samples were collected from more than 100 drainwater-collection sites, several surface- water locations, 15 fields, 3 multiple-depth lysimeter and piezometer installations, and the Alamo River Delta on the southeastern shore of the Salton Sea, and from laboratory evaporations of Colorado River water. Biological samples were collected from 39 sites, including 16 Salton Sea shore locations, 5 streams, 7 freshwater impound- ments, 11 drainwater ditches, and 2 additional locations in the Imperial Valley. (USGS)

  12. Chemical Data for Detailed Studies of Irrigation Drainage in the Salton Sea Area, California, 1995?2001

    USGS Publications Warehouse

    Schroeder, Roy A.

    2004-01-01

    The primary purpose of this report is to present all chemical data from the Salton Sea area collected by the U.S. Geological Survey between 1995 and 2001. The data were collected primarily for the Department of the Interior's National Irrigation Water Quality Program (NIWQP). The report also contains a brief summary and citation to investigations done for the NIWQP between 1992 and 1995. The NIWQP began studies in the Salton Sea area in 1986 to evaluate effects on the environment from potential toxins, especially selenium, in irrigation-induced drainage. This data report is a companion to several reports published from the earlier studies and to interpretive publications that make use of historical and recent data from this area. Data reported herein are from five collection studies. Water, bottom material, and suspended sediment collected in 1995-96 from the New River, the lower Colorado River, and the All-American Canal were analyzed for elements, semi-volatile (extractable) organic compounds, and organochlorine compounds. Sufficient suspended sediment for chemical analyses was obtained by tangential-flow filtration. A grab sample of surficial bottom sediment collected from near the deepest part of the Salton Sea in 1996 was analyzed for 44 elements and organic and inorganic carbon. High selenium concentration confirmed the effective transfer (sequestration) of selenium into the bottom sediment. Similar grab samples were collected 2 years later (1998) from 11 locations in the Salton Sea and analyzed for elements, as before, and also for nutrients, organochlorine compounds, and polycyclic aromatic hydrocarbons. Nutrients were measured in bottom water, and water-column profiles were obtained for pH, conductance, temperature, and dissolved oxygen. Element and nutrient concentrations were obtained in 1999 from cores at 2 of the above 11 sites, in the north subbasin of the Salton Sea. The most-recent study reported herein was done in 2001 and contains element data on

  13. Loading of the San Andreas fault by flood-induced rupture of faults beneath the Salton Sea

    USGS Publications Warehouse

    Brothers, Daniel; Kilb, Debi; Luttrell, Karen; Driscoll, Neal W.; Kent, Graham

    2011-01-01

    The southern San Andreas fault has not experienced a large earthquake for approximately 300 years, yet the previous five earthquakes occurred at ~180-year intervals. Large strike-slip faults are often segmented by lateral stepover zones. Movement on smaller faults within a stepover zone could perturb the main fault segments and potentially trigger a large earthquake. The southern San Andreas fault terminates in an extensional stepover zone beneath the Salton Sea—a lake that has experienced periodic flooding and desiccation since the late Holocene. Here we reconstruct the magnitude and timing of fault activity beneath the Salton Sea over several earthquake cycles. We observe coincident timing between flooding events, stepover fault displacement and ruptures on the San Andreas fault. Using Coulomb stress models, we show that the combined effect of lake loading, stepover fault movement and increased pore pressure could increase stress on the southern San Andreas fault to levels sufficient to induce failure. We conclude that rupture of the stepover faults, caused by periodic flooding of the palaeo-Salton Sea and by tectonic forcing, had the potential to trigger earthquake rupture on the southern San Andreas fault. Extensional stepover zones are highly susceptible to rapid stress loading and thus the Salton Sea may be a nucleation point for large ruptures on the southern San Andreas fault.

  14. New Seismic CHIRP evidence for Transpression and Transtension Beneath the Salton Sea, California

    NASA Astrophysics Data System (ADS)

    Brothers, D.; Driscoll, N.; Kent, G.; Dingler, J.; Harding, A.; Babcock, J.

    2007-12-01

    The Salton Trough is a critical structure that separates spreading center dominated deformation in the Gulf of California and dextral strike-slip deformation along the San Andreas Fault (SAF) System. Geological and geophysical data suggest there is a transition within the Salton Trough near the town of Bombay Beach that separates transpression to the north from transtension in the south. To date, however, this transition remains poorly understood, in large part, due to a lack of geophysical subsurface data in the Salton Sea. We present preliminary analysis of > 350 line-km of high-resolution seismic CHIRP data acquired in 2006 and 2007 that imaged the different deformational styles beneath the Salton Sea, including several previously unidentified tectonic structures. The Extra Fault Zone (EFZ), which has been mapped onshore, is imaged in CHIRP profiles as an ~5 km wide deformation zone and can be traced offshore > 15 km along strike. Along the northern extent of the EFZ, ramp-flat deformation is observed with southward vergence. A marked angular unconformity between the Brawley and Cahuilla formations records fault-bend folding often predicted for ramp-flat thrust systems. Uplift and truncation of Pleistocene sediments along the northern edge of the EFZ is observed across the entire sea and appears to systematically increase towards the west. Onlapping sediments and growth folds in the Holocene Lake Cahuilla section to the north and south of the fault zone record ongoing uplift. Compression is also manifested in the bathymetry, with a mid-lake bathymetric high trending parallel the EFZ and separating southern and northern lake basins. The EFZ is interpreted to accommodate sinistral transpression related to clockwise- rotating crustal blocks. In contrast, at Bombay Beach the SAF takes an ~15 km releasing step towards the Imperial Fault, producing transtensional deformation through the Brawley Seismic Zone (BSZ). CHIRP profiles across the western margin of the BSZ

  15. Salton Sea Geothermal Field, Imperial Valley, California as a site for continental scientific drilling. [Abstract only

    SciTech Connect

    Elders, W.A.; Cohen, L.H.

    1983-03-01

    The Salton Trough, where seafloor spreading systems of the East Pacific Rise transition into the San Andreas transform fault system, is the site of such continental rifting and basin formation today. The largest thermal anomaly in the trough, the Salton Sea Geothermal Field (SSGF), is of interest to both thermal regimes and mineral resources investigators. At this site, temperatures >350/sup 0/C and metal-rich brines with 250,000 mg/L TDS have been encountered at <2 km depth. Republic Geothermal Inc. will drill a new well to 3.7 km in the SSGF early in 1983; we propose add-on experiments in it. If funded, we will obtain selective water and core samples and a large-diameter casing installed to 3.7 km will permit later deepening. In Phase 2, the well would be continuously cored to 5.5 km and be available for scientific studies until July 1985. The deepened well would encounter hydrothermal regimes of temperature and pressure never before sampled.

  16. Application of high-resolution thermal infrared sensors for geothermal exploration at the Salton Sea, California

    NASA Astrophysics Data System (ADS)

    Reath, K. A.; Ramsey, M.; Tratt, D. M.

    2010-12-01

    The Salton Sea geothermal field straddles the southeast margin of the Salton Sea in California, USA. This field includes approximately 20km2 of mud volcanoes and mud pots and centered on the Mullet Island thermal anomaly. The area has been previously exploited for geothermal power; there are currently seven power plants in the area that produce 1000 MW. The field itself is relatively un-vegetated, which provides for unfettered detection of the surface mineralogy, radiant heat, and emitted gases using air and spaceborne thermal infrared (TIR) sensors. On March 26, 2009, the airborne Spatially Enhanced Broadband Array Spectrograph System (SEBASS) sensor was flown over the Salton Sea-Mullet Island area. SEBASS has a spectral resolution of 128 bands in the 7.5-14.5 micron spectral region and a spatial resolution of 1m/pixel from the 3000-ft altitude flown for this study. A large portion of the Calipatria Fault, a NW/SE-trending geothermally active fault that bisects the Mullet Island thermal anomaly, was imaged during this flight and several thermal/mineralogical anomalies were noted. The orbital Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) has only 5 spectral bands at 90m/pixel resolution, but has acquired dozens of visible and TIR datasets over the geothermal field in the 10-year history of the instrument. The thermal-temporal trend of this dataset has been analyzed, and the November 2008 image studied in detail for comparison to SEBASS. The land-leaving TIR radiance data were separated into brightness temperature and surface emissivity. TIR emissivity data are unique to each mineral and a TIR mineral spectral library was used to determine their presence on the ground. Various mineral maps were created showing the distribution surrounding the most active geothermal features. The higher spectral/spatial resolution SEBASS data were used to validate the lower spectral/spatial resolution ASTER data (as well as the higher resolution laboratory TIR

  17. Corrosion tests in brine and steam from the Salton Sea KGRA

    SciTech Connect

    Carter, J.P.; McCawley, F.X.

    1982-03-01

    The Bureau of Mines tested 13 alloys for resistance to general corrosion, pitting corrosion, and stress corrosion cracking in the brine and steam environments produced from geothermal well Magmamax 1 in the Salton Sea Known Geothermal Resources Area in California. The tests provided seven process environments. The alloys most resistant to corrosion in all environments were Inconel 625, Hastelloy C-276, and stainless steel alloy 29-4. Hastelloys G and S were highly resistant to all types of corrosion decreases with time. The stainless steel alloys 430, E-Brite 26-1, and 6X had good resistance to general corrosion but were susceptible to pitting. Unstressed type 316 L stainless steel exhibited severe cracking. The 1020 carbon and 4130 alloy steels were the least resistant.

  18. Anthropogenic seismicity rates and operational parameters at the Salton Sea Geothermal Field.

    PubMed

    Brodsky, Emily E; Lajoie, Lia J

    2013-08-01

    Geothermal power is a growing energy source; however, efforts to increase production are tempered by concern over induced earthquakes. Although increased seismicity commonly accompanies geothermal production, induced earthquake rate cannot currently be forecast on the basis of fluid injection volumes or any other operational parameters. We show that at the Salton Sea Geothermal Field, the total volume of fluid extracted or injected tracks the long-term evolution of seismicity. After correcting for the aftershock rate, the net fluid volume (extracted-injected) provides the best correlation with seismicity in recent years. We model the background earthquake rate with a linear combination of injection and net production rates that allows us to track the secular development of the field as the number of earthquakes per fluid volume injected decreases over time. PMID:23845943

  19. Recent geothermal developments in the Imperial Valley: Brawley, Salton Sea, Heber

    SciTech Connect

    Papay, L.T.

    1983-01-01

    Imperial Valley programs in geothermal energy are reviewed. The Brawley plant has had a relatively high availability on line since its startup in 1980. The startup at Salton Sea plant was surprisingly smooth. Using these research projects, all of the technical parameters for commercial development of geothermal energy will be known in a year or two. Native brine handling processes, casing materials and configurations, and turbine modifications are being studied. The PUC's decision on the Heber plant was a temporary setback. PUC ruled that projects will not be approved unless they yield competitive busbar costs. The Avoided Cost concept has become the benchmark at PUC. But Avoided Cost does not account for the higher initial design costs and unknown parameters of startup as opposed to mature plant costs. Avoided Cost is seen as the only obstacle to commercial developement in all areas.

  20. Seismic monitoring of a flow test in the Salton Sea Geothermal Field

    SciTech Connect

    Jarpe, S.P.; Kasameyer, P.W.; Johnston, C.

    1989-06-01

    The purpose of this seismic monitoring project was to characterize in detail the micro-seismic activity related to the flow-injection test in the Salton Sea Geothermal Field. Our goal was to determine if any sources of seismic energy related to the test were observable at the surface, using both conventional seismic network techniques and relatively newer array techniques. These methods allowed us to detect and locate both impulsive microearthquakes and continuous sources of seismic energy. Our network, which was sensitive enough to be triggered by magnitude 0.0 or larger events, found no impulsive microearthquakes in the vicinity of the flow test in the 8 month period before the test and only one event during the flow test. We have observed some continuous seismic noise sources that may be attributed to the flow test. 4 refs., 4 figs.

  1. Chemistry and geothermometry of brine produced from the Salton Sea Scientific drill hole, Imperial Valley, California

    USGS Publications Warehouse

    Thompson, J.M.; Fournier, R.O.

    1988-01-01

    The December 29-30, 1985, flow test of the State 2-14 well, also known as the Salton Sea Scientific drill hole, produced fluid from a depth of 1865-1877 m at a reservoir temperature of 305????5??C. Samples were collected at five different flashing pressures. The brines are Na-Ca-K-Cl-type waters with very high metal and low SO4 and HCO3 contents. Compositions of the flashed brines were normalized relative to the 25??C densities of the solutions, and an ionic charge balance was achieved by adjusting the Na concentration. Calculated Na/K geothermometer temperatures, using equations suggested by different investigators, range from 326?? to 364??C. The Mg/K2 method gives a temperature of about 350??C, Mg/Li2 about 282??, and Na/Li 395??-418??C. -from Authors

  2. Development And Application Of A Hydrothermal Model For The Salton Sea Geothermal Field, California

    SciTech Connect

    Kasameyer, P.; Younker, L.; Hanson, J.

    1984-01-01

    A simple lateral flow model adequately explains many of the features associated with the Salton Sea Geothermal Field. Earthquake swarms, a magnetic anomaly, and aspects of the gravity anomaly are all indirect evidence for the igneous activity which is the ultimate source of heat for the system. Heat is transferred from this area of intrusion by lateral spreading of hot water in a reservoir beneath an impermeable cap rock. A two dimensional analytic model encompassing this transport mechanism matches general features of the thermal anomaly and has been used to estimate the age of the presently observed thermal system. The age is calculated by minimizing the variance between the observed surface heat-flow data and the model. Estimates of the system age for this model range from 3,000 to 20,000 years.

  3. Selenium in aquatic biota inhabiting agricultural drains in the Salton Sea Basin, California.

    PubMed

    Saiki, Michael K; Martin, Barbara A; May, Thomas W

    2012-09-01

    Resource managers are concerned that water conservation practices in irrigated farmlands along the southern border of the Salton Sea, Imperial County, California, could increase selenium concentrations in agricultural drainwater and harm the desert pupfish (Cyprinodon macularius), a federally protected endangered species. As part of a broader attempt to address this concern, we conducted a 3-year investigation to collect baseline information on selenium concentrations in seven agricultural drains inhabited by pupfish. We collected water, sediment, selected aquatic food-chain taxa (particulate organic detritus, filamentous algae, net plankton, and midge [Chironomidae] larvae), and two poeciliid fishes (western mosquitofish Gambusia affinis and sailfin molly Poecilia latipinna) for selenium determinations. The two fish species served as ecological surrogates for pupfish, which we were not permitted to sacrifice. Dissolved selenium ranged from 0.70 to 32.8 μg/L, with selenate as the major constituent. Total selenium concentrations in other environmental matrices varied widely among drains, with one drain (Trifolium 18) exhibiting especially high concentrations in detritus, 5.98-58.0 μg Se/g; midge larvae, 12.7-50.6 μg Se/g; mosquitofish, 13.2-20.2 μg Se/g; and mollies, 12.8-30.4 μg Se/g (all tissue concentrations are based on dry weights). Although toxic thresholds for selenium in fishes from the Salton Sea are still poorly understood, available evidence suggests that ambient concentrations of this element may not be sufficiently elevated to adversely affect reproductive success and survival in selenium-tolerant poeciliids and pupfish. PMID:21915593

  4. Use of a nesting platform by Gull-billed Terns and Black Skimmers at the Salton Sea, California

    USGS Publications Warehouse

    Molina, K.C.; Ricca, M.A.; Miles, A.K.; Schoneman, C.

    2009-01-01

    In 2006, we constructed an elevated nesting platform at the Salton Sea, California, and monitored its use by Gull-billed Terns and Black Skimmers over three subsequent breeding seasons. Black Skimmers were the first to colonize the platform with a total of five nests in 2006. In 2007 Gull-billed Terns colonized the platform with a total of 28 nests and the number of Black Skimmer nests increased to 20. Neither species nested on the platform in 2008. Low success for both species was probably influenced by at least two factors. First, when both species nested on the platform, nest densities were higher than is typical of their colonies on larger, earthen islands, and colony success may have been reduced by overcrowding. Second, lack of access to water may have reduced chicks' ability to thermoregulate effectively in the hot environment of the Salton Sea. Refinements to the size, design, and location of artificial nesting habitats are necessary to enhance productivity of colonial groundnesting birds at the Salton Sea successfully.

  5. Organochlorine pesticide, polychlorinated biphenyl, trace element and metal residues in bird eggs from Salton Sea, California, 2004

    USGS Publications Warehouse

    Henny, Charles J.; Anderson, T.W.; Crayon, J.J.

    2008-01-01

    The Salton Sea is a highly eutrophic, hypersaline terminal lake that receives inflows primarily from agricultural drainages in the Imperial and Coachella valleys. Impending reductions in water inflow at Salton Sea may concentrate existing contaminants which have been a concern for many years, and result in higher exposure to birds. Thus, waterbird eggs were collected and analyzed in 2004 and compared with residue concentrations from earlier years; these data provide a base for future comparisons. Eggs from four waterbird species (black-crowned night-heron [Nycticorax nycticorax], great egret [Ardea alba], black-necked stilt [Himantopus mexicanus], and American avocet [Recurvirostra Americana]) were collected. Eggs were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), metals, and trace elements, with current results compared to those reported for eggs collected from the same species and others during 1985a??1993. The two contaminants of primary concern were p,pa??-DDE (DDE) and selenium. DDE concentrations in night-heron and great egret eggs collected from the northwest corner of Salton Sea (Whitewater River delta) decreased 91 and 95%, respectively, by 2004, with a concomitant increase in eggshell thickness for both species. Decreases in bird egg DDE levels paralleled those in tissues of tilapia (Oreochromis mossambicus ?? O. urolepis), an important prey species for herons and egrets. Despite most nests of night-herons and great egrets failing in 2004 due to predation, predicted reproductive effects based on DDE concentrations in eggs were low or negligible for these species. The 2004 DDE findings were in dramatic contrast to those in the past decade, and included an 81% decrease in black-necked stilt eggs, although concentrations were lower historically than those reported in night-herons and egrets. Selenium concentrations in black-necked stilt eggs from the southeast corner of Salton Sea (Davis Road) were similar in 1993 and 2004, with 4

  6. Investigations of a large scale eared grebe (Podiceps nigricollis) die-off at the Salton Sea, California in 1992

    USGS Publications Warehouse

    Meteyer, C.U.; Audet, D.J.; Rocke, T.E.; Radke, W.; Creekmore, L.H.; Duncan, R.

    2004-01-01

    An estimated 150,000 Eared Grebes (Podiceps nigricollis) died at the Salton Sea between 16 December 1991 and 21 April 1992. This represented the largest documented mortality event of Eared Grebes at the time and approximately 6% of the North American population. During the die-off, grebes exhibited several uncharacteristic behaviors, such as congregating at freshwater tributaries, repeatedly gulping freshwater, preening excessively, moving onto land, and allowing close approach and/or capture. Avian cholera was diagnosed in Eared Grebes collected along the north and west shoreline of the Sea late in the die-off but not from the majority of the Eared Grebes dying along the south shore. Gross and histological examinations and diagnostic testing for viruses, bacteria, and parasites did not identify the cause of mortality in the majority of Eared Grebes examined from the south shore of the Sea. Liver concentrations of arsenic, chromium, DDE, mercury, selenium, and zinc were elevated in some Eared Grebes, but none of those contaminants exceeded known thresholds for independent lethality. Poisoning by heavy metals, organochlorine, organophosphorus, or carbamate pesticides, avian botulism, and salt were ruled out as the cause of mortality. Hypotheses for the die-off are interactive effects of contaminants, immunosuppression, a yet unidentified biotoxin or pathogen present in the Salton Sea, impairment of feather waterproofing leading to hypothermia, or a unique manifestation of avian cholera that evades laboratory detection.

  7. Atmospheric dry deposition in the vicinity of the Salton Sea, California - I: Air pollution and deposition in a desert environment

    USGS Publications Warehouse

    Alonso, R.; Bytnerowicz, A.; Boarman, W.I.

    2005-01-01

    Air pollutant concentrations and atmospheric dry deposition were monitored seasonally at the Salton Sea, southern California. Measurements of ozone (O 3), nitric acid vapor (HNO3), ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO 2) were performed using passive samplers. Deposition rates of NO 3-, NH4+, Cl-, SO 42-, Na+, K+ and Ca2+ to creosote bush branches and nylon filters as surrogate surfaces were determined for one-week long exposure periods. Maximum O3 values were recorded in spring with 24-h average values of 108.8 ??g m-3. Concentrations of NO and NO2 were low and within ranges of the non-urban areas in California (0.4-5.6 and 3.3-16.2 ??g m-3 ranges, respectively). Concentrations of HNO3 (2.0-6.7 ??g m-3) and NH 3 (6.4-15.7 ??g m-3) were elevated and above the levels typical for remote locations in California. Deposition rates of Cl-, SO42-, Na+, K+ and Ca2+ were related to the influence of sea spray or to suspended soil particles, and no strong enrichments caused by ions originated by human activities were detected. Dry deposition rates of NO3- and NH4+ were similar to values registered in areas where symptoms of nitrogen saturation and changes in species composition have been described. Deposition of nitrogenous compounds might be contributing to eutrophication processes at the Salton Sea. ?? 2005 Elsevier Ltd. All rights reserved.

  8. Deviations from self-similarity in barchan form and flux: The case of the Salton Sea dunes, California

    NASA Astrophysics Data System (ADS)

    Pelletier, Jon D.

    2013-12-01

    are the type of aeolian dune associated with a relatively uniform wind direction, incomplete sand coverage of the substrate, and low vegetation cover. Here I present an analysis of the morphology and migration rates of 40 dunes in the Salton Sea dune field using historical aerial orthophotographs, airborne laser swath mapping, terrestrial laser scanning, and measurements of the aerodynamic roughness length derived from wind velocity profiles. The data demonstrate that the Salton Sea dunes deviate from self-similarity such that smaller dunes have a lower ratio of slip face height to crest height and a lower slope, on average, compared with larger dunes and that smaller dunes migrate more slowly than would be predicted based on an inverse relationship between migration rate and dune height. The lack of self-similarity in barchans has been attributed to the dependence of speed-up ratios on dune size and the presence of a finite saturation length in the physics of aeolian transport. Here I argue that deviations from self-similarity at this study site are more likely due to the systematic decrease in aerodynamic roughness length with increasing elevation on stoss slopes. The data set I developed should prove useful to the aeolian geomorphic community for the further testing of models for barchan evolution.

  9. Prevalence of neurotoxic Clostridium botulinum type C in the gastrointestinal tracts of tilapis (Oreochromis mossambicus) in the Salton Sea

    USGS Publications Warehouse

    Nol, P.J.; Rocke, T.E.; Gross, K.; Yuill, Thomas M.

    2004-01-01

    Tilapia (Oreochromis mossambicus) have been implicated as the source of type C toxin in avian botulism outbreaks in pelicans (Pelecanus erythrorhynchos, Pelecanus occidentalis californicus) at the Salton Sea in southern California (USA). We collected sick, dead, and healthy fish from various sites throughout the Sea during the summers of 1999 through 2001 and tested them for the presence of Clostridium botulinum type C cells by polymerase chain reaction targeting the C1 neurotoxin gene. Four of 96 (4%), 57 of 664 (9%), and five of 355 (1%) tilapia tested were positive for C. botulinum type C toxin gene in 1999, 2000, and 2001, respectively. The total number of positive fish was significantly greater in 2000 than in 2001 (P<0.0001). No difference in numbers of positives was detected between sick and dead fish compared with live fish. In 2000, no significant relationships were revealed among the variables studied, such as location and date of collection.

  10. Analysis of P- and S-wave VSP (vertical seismic profile) data from the Salton Sea Geothermal Field

    SciTech Connect

    Daley, T.M.

    1987-09-01

    To understand any geophysical data, geologic information is necessary. This thesis will begin with a summary of the geology of the Salton Trough region and the Salton Sea Geothermal Field (SSGF). The information available from the SSSDP will also be summarized. After the geologic summary, the design of the VSP will be discussed, including acquisition equipment and procedures. The data processing procedures and software used will be discussed as a separate section. Processing procedures will also be described at various times in the thesis where more specialized procedures are used. Data analysis makes up the bulk of the thesis and it is divided into a number of sections detailing the basic VSP interpretation, the anisotropy analysis and the fracture detection and orientation analysis. A combined interpretation of the results, with probable geologic causes for observed events, is presented as a separate section from the data analysis. Finally, a summary of results for each of the goals stated above will be given. The reader should note that a large volume of data were collected and various display methods were used (from the standard wiggle-trace to three-component hodographs). Much of these data are left in the appendices with important or representative figures given in the body of the thesis. Also given in the appendices are listings of FORTRAN programs developed in conjunction with the thesis work. 46 refs., 63 figs., 12 tabs.

  11. Molecular characterization and morphology of the photosynthetic dinoflagellate Bysmatrum caponii from two solar saltons in western Korea

    NASA Astrophysics Data System (ADS)

    Jeong, Hae Jin; Jang, Se Hyeon; Kang, Nam Seon; Yoo, Yeong Du; Kim, Min Jeong; Lee, Kyung Ha; Yoon, Eun Young; Potvin, Éric; Hwang, Yeong Jong; Kim, Jong Im; Seong, Kyeong Ah

    2012-03-01

    Species belonging to the genus Bysmatrum are peridinoid, thecate, photosynthetic dinoflagellates. The plate formula of Bysmatrum spp., arranged in a Kofoidian series, is almost identical to that of Scrippsiella spp. Bysmatrum spp., which were originally classified as Scrippsiella spp., but were transferred to the genus Bysmatrum spp. because of separation of the intercalary plates 2a and 3a by plate 3'. Whether this transfer from Scrippsiella spp. to Bysmatrum spp. is reasonable should be genetically confirmed. Dinoflagellates were isolated from 2 solar saltons located in western Korea in 2009-2010 and 3 clonal cultures from Sooseong solar saltons and 2 clonal cultures from Garolim solar saltons were successfully established. All of these dinoflagellates were identified as Bysmatrum caponii based on morphology analysis by light and electron microscopy. The plates of all Korean strains of B. caponii were arranged in a Kofoidian series of Po, X, 4', 3a, 7″, 6c, 4s, 5‴, 0 (p), and 24'. When properly aligned, the ribosomal DNA (rDNA) sequences of the 3 Sooseong strains of B. caponii were identical, as were those of the 2 Garolim strains. Furthermore, the sequences of the 3 Sooseong strains were 0.01% different from those of the Garolim strains. However, the sequences of SSU rDNA of these Korean B. caponii strains were 9% different from that of Bysmatrum subsalsum and > 10% from that of any other dinoflagellate thus far reported. In the phylogenetic trees generated using SSU and LSU rDNA sequences, these Korean B. caponii strains formed a clade with B. subsalsum which was clearly divergent from the Scrippsiella clade. However, this Bysmatrum clade was phylogenetically close to the Protoperidinium and/or Peridinium clades. The results of the present study suggest that Bysmatrum spp. are markedly different genetically from Scrippsiella spp..

  12. Relationships among seismic velocity, metamorphism, and seismic and aseismic fault slip in the Salton Sea Geothermal Field region

    NASA Astrophysics Data System (ADS)

    McGuire, Jeffrey J.; Lohman, Rowena B.; Catchings, Rufus D.; Rymer, Michael J.; Goldman, Mark R.

    2015-04-01

    The Salton Sea Geothermal Field is one of the most geothermally and seismically active areas in California and presents an opportunity to study the effect of high-temperature metamorphism on the properties of seismogenic faults. The area includes numerous active tectonic faults that have recently been imaged with active source seismic reflection and refraction. We utilize the active source surveys, along with the abundant microseismicity data from a dense borehole seismic network, to image the 3-D variations in seismic velocity in the upper 5 km of the crust. There are strong velocity variations, up to ~30%, that correlate spatially with the distribution of shallow heat flow patterns. The combination of hydrothermal circulation and high-temperature contact metamorphism has significantly altered the shallow sandstone sedimentary layers within the geothermal field to denser, more feldspathic, rock with higher P wave velocity, as is seen in the numerous exploration wells within the field. This alteration appears to have a first-order effect on the frictional stability of shallow faults. In 2005, a large earthquake swarm and deformation event occurred. Analysis of interferometric synthetic aperture radar data and earthquake relocations indicates that the shallow aseismic fault creep that occurred in 2005 was localized on the Kalin fault system that lies just outside the region of high-temperature metamorphism. In contrast, the earthquake swarm, which includes all of the M > 4 earthquakes to have occurred within the Salton Sea Geothermal Field in the last 15 years, ruptured the Main Central Fault (MCF) system that is localized in the heart of the geothermal anomaly. The background microseismicity induced by the geothermal operations is also concentrated in the high-temperature regions in the vicinity of operational wells. However, while this microseismicity occurs over a few kilometer scale region, much of it is clustered in earthquake swarms that last from hours to a

  13. A comparison of long-term changes in seismicity at The Geysers, Salton Sea, and Coso geothermal fields

    NASA Astrophysics Data System (ADS)

    Trugman, Daniel T.; Shearer, Peter M.; Borsa, Adrian A.; Fialko, Yuri

    2016-01-01

    Geothermal energy is an important source of renewable energy, yet its production is known to induce seismicity. Here we analyze seismicity at the three largest geothermal fields in California: The Geysers, Salton Sea, and Coso. We focus on resolving the temporal evolution of seismicity rates, which provides important observational constraints on how geothermal fields respond to natural and anthropogenic loading. We develop an iterative, regularized inversion procedure to partition the observed seismicity rate into two components: (1) the interaction rate due to earthquake-earthquake triggering and (2) the smoothly varying background rate controlled by other time-dependent stresses, including anthropogenic forcing. We apply our methodology to compare long-term changes in seismicity to monthly records of fluid injection and withdrawal. At The Geysers, we find that the background seismicity rate is highly correlated with fluid injection, with the mean rate increasing by approximately 50% and exhibiting strong seasonal fluctuations following construction of the Santa Rosa pipeline in 2003. In contrast, at both Salton Sea and Coso, the background seismicity rate has remained relatively stable since 1990, though both experience short-term rate fluctuations that are not obviously modulated by geothermal plant operation. We also observe significant temporal variations in Gutenberg-Richter b value, earthquake magnitude distribution, and earthquake depth distribution, providing further evidence for the dynamic evolution of stresses within these fields. The differing field-wide responses to fluid injection and withdrawal may reflect differences in in situ reservoir conditions and local tectonics, suggesting that a complex interplay of natural and anthropogenic stressing controls seismicity within California's geothermal fields.

  14. Spatial and temporal assessment of environmental contaminants in water, sediments and fish of the Salton Sea and its two primary tributaries, California, USA, from 2002 to 2012.

    PubMed

    Xu, Elvis Genbo; Bui, Cindy; Lamerdin, Cassandra; Schlenk, Daniel

    2016-07-15

    The Salton Sea, the largest inland surface water body in California, has been designated as a sensitive ecological area by federal and state governments. Its two main tributaries, the New River and Alamo River are impacted by urban and agriculture land use wastes. The purpose of this study was to temporally and spatially evaluate the ecological risks of contaminants of concern in water, sediments and fish tissues. A total of 229 semivolatile organic compounds and 12 trace metals were examined. Among them Selenium, DDTs, PAHs, PCBs, chlorpyrifos and some current-use pesticides such as pyrethroids exceeded risk thresholds. From 2002 to 2012, measurements of chlorpyrifos in sediments generally declined and were not observed after 2009 at the river outlets. In contrast, pyrethroid concentrations in sediments rose consistently after 2009. In water samples, the outlets of the two rivers showed relatively higher levels of contamination than the main water body of the Salton Sea. However, sediments of the main water body of the Salton Sea showed relatively higher sediment concentrations of contaminants than the two rivers. This was particularly true for selenium which showed reductions in concentrations from 2002 to 2007, but then gradual increases to 2012. Consistent with water evaluations, contaminant concentrations in fish tissues tended to be higher at the New River boundary and at the drainage sites for the Alamo River compared to sites along each river. The persistent contaminants DDTs, PAHs, chlorpyrifos and several pyrethroid insecticides were associated with the toxicity of sediments and water collected from the rivers. Overall, assessment results suggested potential ecological risk in sediments of the Salton Sea as well as in water and fish from the two rivers. PMID:27058132

  15. Double-diffusive convection in geothermal systems: the salton sea, California, geothermal system as a likely candidate

    USGS Publications Warehouse

    Fournier, R.O.

    1990-01-01

    Much has been published about double-diffusive convection as a mechanism for explaining variations in composition and temperature within all-liquid natural systems. However, relatively little is known about the applicability of this phenomenon within the heterogeneous rocks of currently active geothermal systems where primary porosity may control fluid flow in some places and fractures may control it in others. The main appeal of double-diffusive convection within hydrothermal systems is-that it is a mechanism that may allow efficient transfer of heat mainly by convection, while at the same time maintaining vertical and lateral salinity gradients. The Salton Sea geothermal system exhibits the following reservoir characteristics: (1) decreasing salinity and temperature from bottom to top and center toward the sides, (2) a very high heat flow from the top of the system that seems to require a major component of convective transfer of heat within the chemically stratified main reservoir, and (3) a relatively uniform density of the reservoir fluid throughout the system at all combinations of subsurface temperature, pressure, and salinity. Double-diffusive convection can account for these characteristics very nicely whereas other previously suggested models appear to account either for the thermal structure or for the salinity variations, but not both. Hydrologists, reservoir engineers, and particularly geochemists should consider the possibility and consequences of double-diffusive convection when formulating models of hydrothermal processes, and of the response of reservoirs to testing and production. ?? 1990.

  16. Relation of desert pupfish abundance to selected environmental variables in natural and manmade habitats in the Salton Sea basin

    USGS Publications Warehouse

    Martin, B.A.; Saiki, M.K.

    2005-01-01

    We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected biological and physicochemical variables in natural and manmade habitats within the Salton Sea Basin. Field sampling in a natural tributary, Salt Creek, and three agricultural drains captured eight species including pupfish (1.1% of the total catch), the only native species encountered. According to Bray-Curtis resemblance functions, fish species assemblages differed mostly between Salt Creek and the drains (i.e., the three drains had relatively similar species assemblages). Pupfish numbers and environmental variables varied among sites and sample periods. Canonical correlation showed that pupfish abundance was positively correlated with abundance of western mosquitofish, Gambusia affinis, and negatively correlated with abundance of porthole livebearers, Poeciliopsis gracilis, tilapias (Sarotherodon mossambica and Tilapia zillii), longjaw mudsuckers, Gillichthys mirabilis, and mollies (Poecilia latipinnaandPoecilia mexicana). In addition, pupfish abundance was positively correlated with cover, pH, and salinity, and negatively correlated with sediment factor (a measure of sediment grain size) and dissolved oxygen. Pupfish abundance was generally highest in habitats where water quality extremes (especially high pH and salinity, and low dissolved oxygen) seemingly limited the occurrence of nonnative fishes. This study also documented evidence of predation by mudsuckers on pupfish. These findings support the contention of many resource managers that pupfish populations are adversely influenced by ecological interactions with nonnative fishes. ?? Springer 2005.

  17. Salton Sea Geothermal Field, California, as a near-field natural analog of a radioactive waste repository in salt

    SciTech Connect

    Elders, W.A.; Cohen, L.H.

    1983-11-01

    Since high concentrations of radionuclides and high temperatures are not normally encountered in salt domes or beds, finding an exact geologic analog of expected near-field conditions in a mined nuclear waste repository in salt will be difficult. The Salton Sea Geothermal Field, however, provides an opportunity to investigate the migration and retardation of naturally occurring U, Th, Ra, Cs, Sr and other elements in hot brines which have been moving through clay-rich sedimentary rocks for up to 100,000 years. The more than thirty deep wells drilled in this field to produce steam for electrical generation penetrate sedimentary rocks containing concentrated brines where temperatures reach 365/sup 0/C at only 2 km depth. The brines are primarily Na, K, Ca chlorides with up to 25% of total dissolved solids; they also contain high concentrations of metals such as Fe, Mn, Li, Zn, and Pb. This report describes the geology, geophysics and geochemistry of this system as a prelude to a study of the mobility of naturally occurring radionuclides and radionuclide analogs within it. The aim of this study is to provide data to assist in validating quantitative models of repository behavior and to use in designing and evaluating waste packages and engineered barriers. 128 references, 33 figures, 13 tables.

  18. Atmospheric dry deposition in the vicinity of the Salton Sea, California - II: Measurement and effects of an enhanced evaporation system

    USGS Publications Warehouse

    Alonso, R.; Bytnerowicz, A.; Yee, J.L.; Boarman, W.I.

    2005-01-01

    A study was conducted to determine the effects of salt spray drift from pilot technologies employed by the US Bureau of Reclamation on deposition rates of various air-born ions. An enhanced evaporation system (EES) was tested in the field at the Salton Sea, California. Dry deposition of NO3-, NH4+, SO42-, Cl-, Ca2+, Na+, K+ and Se was assessed by using nylon filters and branches of natural vegetation exposed for one-week long periods. The simultaneous exposure of both lyophilized branches and branches of live plants offered important information highlighting the dynamics of deposited ions on vegetation. The EES significantly increased the deposition rates of Cl-, SO42- and Na+ in an area of about 639-1062 m surrounding the sprayers. Similarly, higher deposition of Ca 2+ and K+ caused by the EES was detected only when deposition was assessed using nylon filters or lyophilized branches. Deposition fluxes of NO3-, NH4+ and Se were not affected by the spraying system. Techniques for measuring dry deposition and calculating landscape-level depositional loads in non-forested systems need further development. ?? 2005 Elsevier Ltd. All rights reserved.

  19. A numerical study of strike-slip bend formation with application to the Salton Sea pull-apart basin

    NASA Astrophysics Data System (ADS)

    Ye, Jiyang; Liu, Mian; Wang, Hui

    2015-03-01

    How stepovers of strike-slip faults connect to form bends is a question important for understanding the formation of push-up ranges (restraining bends) and pull-apart basins (releasing bends). We investigated the basic mechanics of this process in a simple three-dimensional viscoelastoplastic finite element model. Our model predicts localized plastic strain within stepovers that may eventually lead to the formation of strike-slip bends. Major parameters controlling strain localization include the relative fault strength, geometry of the fault system, and the plasticity model assumed. Using the Drucker-Prager plasticity model, in which the plastic yield strength of the crust depends on both shear and normal stresses, our results show that a releasing bend is easier to develop than a restraining bend under similar conditions. These results may help explain the formation of the Salton Sea pull-apart basin in Southern California 0.5-0.1 Ma ago, when the stepover between the Imperial Fault and the San Andreas Fault was connected by the Brawley seismic zone.

  20. Analysis of geophysical well logs obtained in the State 2-14 borehole, Salton Sea geothermal area, California

    USGS Publications Warehouse

    Paillet, Frederick L.; Morin, R.H.

    1988-01-01

    A complete suite of conventional geophysical well logs was obtained in the upper part of a 3220-m-deep borehole drilled into geothermally altered alluvial sediments on the southeastern edge of the Salton Sea. Geophysical logs obtained in the State 2-14 borehole indicate that neutron porosity, gamma-gamma, and deep-induction logs provide useful information on lithologic trends with depth. The natural gamma log contains almost continuous, high-frequency fluctuations that obscure lithologic trends and that may be related to recent radioisotope redistribution and departure from radiometric equilibrium. Acoustic transit time logs give unrealistically low in situ compressional velocities ranging from 1.8 to 3.0 km/s, whereas acoustic waveform logs indicate that sediment compressional velocities range from less than 3.0 km/s shallower than 1000 m in depth to almost 5.0 km/s at depths greater than 2000 m. Analyses indicate that most log values lie between two lithologic end points: an electrically conductive claystone with moderate neutron porosity, but no effective porosity, and an electrically nonconductive, fully cemented siltstone that has small but finite porosity. -from Authors

  1. Character and Implications of a Newly Identified Creeping Strand of the San Andreas fault NE of Salton Sea, Southern California

    NASA Astrophysics Data System (ADS)

    Janecke, S. U.; Markowski, D.

    2015-12-01

    The overdue earthquake on the Coachella section, San Andreas fault (SAF), the model ShakeOut earthquake, and the conflict between cross-fault models involving the Extra fault array and mapped shortening in the Durmid Hill area motivate new analyses at the southern SAF tip. Geologic mapping, LiDAR, seismic reflection, magnetic and gravity datasets, and aerial photography confirm the existence of the East Shoreline strand (ESS) of the SAF southwest of the main trace of the SAF. We mapped the 15 km long ESS, in a band northeast side of the Salton Sea. Other data suggest that the ESS continues N to the latitude of the Mecca Hills, and is >35 km long. The ESS cuts and folds upper Holocene beds and appears to creep, based on discovery of large NW-striking cracks in modern beach deposits. The two traces of the SAF are parallel and ~0.5 to ~2.5 km apart. Groups of east, SE, and ENE-striking strike-slip cross-faults connect the master dextral faults of the SAF. There are few sinistral-normal faults that could be part of the Extra fault array. The 1-km wide ESS contains short, discontinuous traces of NW-striking dextral-oblique faults. These en-echelon faults bound steeply dipping Pleistocene beds, cut out section, parallel tight NW-trending folds, and produced growth folds. Beds commonly dip toward the ESS on both sides, in accord with persistent NE-SW shortening across the ESS. The dispersed fault-fold structural style of the ESS is due to decollements in faulted mud-rich Pliocene to Holocene sediment and ramps and flats along the strike-slip faults. A sheared ladder-like geometric model of the two master dextral strands of the SAF and their intervening cross-faults, best explains the field relationships and geophysical datasets. Contraction across >40 km2 of the southernmost SAF zone in the Durmid Hills suggest that interaction of active structures in the SAF zone may inhibit the nucleation of large earthquakes in this region. The ESS may cross the northern Coachella

  2. Drilling investigations of crustal rifting processes in the Salton Trough, California. Revision 1

    SciTech Connect

    Kasameyer, P.W.; Younker, L.W.; Newmark, R.L.; Duba, A.G.

    1986-01-01

    The results of CSDP activities in the Salton Sea Geothermal Field (SSGF) are briefly described, concentrating on a shallow heat flow survey, but also discussing preliminary results from the Salton Sea Scientific Drilling Program (SSSDP). The hypothesis that localized thermal zones are the source of all the heat in the Salton Trough is examined. (ACR)

  3. Drilling investigations of crustal rifting processes in the Salton Trough, California

    SciTech Connect

    Kasameyer, P.W.; Younker, L.W.; Newmark, R.L.; Duba, A.G.

    1986-01-01

    The paper describes the results of CSDP activities in the Salton Sea Geothermal Field (SSGF), concentrating on a shallow heat-flow survey, but also considering preliminary results from the Salton Sea Scientific Drilling Program (SSSDP). Whether the heat input rate to localized systems is high enough to account for the overall thermal budget of the Salton Trough is examined. (ACR)

  4. Discovering new events beyond the catalogue—application of empirical matched field processing to Salton Sea geothermal field seismicity

    NASA Astrophysics Data System (ADS)

    Wang, Jingbo; Templeton, Dennise C.; Harris, David B.

    2015-10-01

    Using empirical matched field processing (MFP), we compare 4 yr of continuous seismic data to a set of 195 master templates from within an active geothermal field and identify over 140 per cent more events than were identified using traditional detection and location techniques alone. In managed underground reservoirs, a substantial fraction of seismic events can be excluded from the official catalogue due to an inability to clearly identify seismic-phase onsets. Empirical MFP can improve the effectiveness of current seismic detection and location methodologies by using conventionally located events with higher signal-to-noise ratios as master events to define wavefield templates that could then be used to map normally discarded indistinct seismicity. Since MFP does not require picking, it can be carried out automatically and rapidly once suitable templates are defined. In this application, we extend MFP by constructing local-distance empirical master templates using Southern California Earthquake Data Center archived waveform data of events originating within the Salton Sea Geothermal Field. We compare the empirical templates to continuous seismic data collected between 1 January 2008 and 31 December 2011. The empirical MFP method successfully identifies 6249 additional events, while the original catalogue reported 4352 events. The majority of these new events are lower-magnitude events with magnitudes between M0.2-M0.8. The increased spatial-temporal resolution of the microseismicity map within the geothermal field illustrates how empirical MFP, when combined with conventional methods, can significantly improve seismic network detection capabilities, which can aid in long-term sustainability and monitoring of managed underground reservoirs.

  5. Solar Sea Power

    ERIC Educational Resources Information Center

    Zener, Clarence

    1976-01-01

    In their preoccupation with highly complex new energy systems, scientists and statesmen may be overlooking the possibilities of Ocean Thermal Energy Conversion (OTEC). That is the view of a Carnegie-Mellon University physicist who is in the forefront of solar sea power investigation. (Author/BT)

  6. Fault History and Architecture of the Southernmost San Andreas Fault and Brawley Seismic Zone: New Constraints from CHIRP Data Acquired in the Salton Sea

    NASA Astrophysics Data System (ADS)

    Brothers, D.; Seitz, G.; Williams, P.; Driscoll, N.; Kent, G.

    2006-12-01

    The Salton Trough is the boundary between spreading-center dominated extension in the Gulf of California and dextral strike-slip deformation along the San Andreas Fault (SAF) system. The Salton Trough provides an ideal opportunity to image this transition in modes of deformation. The critical portion of this system, namely the intersection of the SAF and the Brawley Seismic Zone (BSZ) in the southern Salton Sea has not been imaged by geophysical methods. To address this problem, we conducted a pilot, high-resolution seismic CHIRP survey in the Salton Sea offshore Bombay Beach. CHIRP imaging, together with onshore field mapping and paleoseismic investigations, has the potential to define the interaction between the SAF and the BSZ, as well as delineate fault architecture and strain partitioning in the central Salton Trough. Preliminary onshore examination of Lake Cahuilla sediments reveal lake-level changes and earthquake event chronology for the last ~1,000 years, and suggest a relatively long period of seismic quiescence for the southern SAF preceded by several events with shorter recurrence intervals. Fault excavations have revealed several lake episodes separated by terrestrial horizons that include distinct features such as mud-cracks. New CHIRP data show potential correlation of faulted offshore stratigraphy with paleoseismic deformation documented at an excavation site 15 km to the north adjacent to Salt Creek. Profiles image a well-defined fault trending obliquely to the strike of the onshore SAF, and the observed trend is sub-parallel to the BSZ. Offset stratigraphy across the fault imaged in CHIRP profiles increases with depth, with a maximum vertical offset of ~6-8 m. Relief of ~.5 m exists across the post-1905 surface and most likely represents deposition mantling an older scarp. Assuming high amplitude reflectors observed in CHIRP data correlate with lowered lake levels associated with weathering and/or desiccation horizons, then we can correlate the

  7. Correlation of wireline log characteristics with hydrothermal alteration and other reservoir properties of the Salton Sea and Westmorland geothermal fields, Imperial Valley, California, USA

    SciTech Connect

    Muramoto, F.S.; Elders, W.A.

    1984-05-01

    A detailed study of wireline logs from 11 wells in the Salton Sea and Westmorland geothermal systems was undertaken in order to determine the effects of hydrothermal alteration on the response of electrical and gamma-gamma density well logs. For the Salton Sea geothermal field, definite correspondence between log responses and hydrothermal mineralogy is evident, which in turn is related to the physical properties of the rocks. Three hydrothermal and one unaltered zone can be identified from log data on shales. These are: (1) the unaltered montmorillonite zone (<100/sup 0/ to 190/sup 0/C); (2) the illite zone (100/sup 0/ to 190/sup 0/C to 230/sup 0/ to 250/sup 0/C); (3) the chlorite zone (230/sup 0/ to 250/sup 0/C to 290/sup 0/ to 300/sup 0/C); and (4) the feldspar zone (>290/sup 0/ to 300/sup 0/C). The characteristic responses on well logs by which these zones are identified result primarily from changes in clay mineralogy of the shales and increases in density with progressive hydrothermal metamorphism. In the Westmorland geothermal field, differentiating mineral zones from log responses was only partially successful. However, analyses of both well log and petrologic data for wells Landers 1 and Kalin Farms 1 suggest that the former is heating up and the latter is cooling.

  8. Detailed study of water quality, bottom sediment, and biota associated with irrigation drainage in the Salton Sea area, California, 1988-90

    USGS Publications Warehouse

    Setmire, J.G.; Schroeder, R.A.; Densmore, J.N.; Goodbred, S.O.; Audet, D.J.; Radke, W.R.

    1993-01-01

    Results of a detailed study by the National Irrigation Water-Quality Program (NIWQP), U.S. Department of the Interior, indicate that factors controlling contaminant concentrations in subsurface irrigation drainwater in the Imperial Valley are soil characteristics, hydrology, and agricultural practices. Higher contaminant concentrations commonly were associated with clayey soils, which retard the movement of irrigation water and thus increase the degree of evaporative concentration. Regression of hydrogen- and oxygen-isotope ratios in samples collected from sumps yields a linear drainwater evaporation line that extrapolates through the isotopic composition of Colorado River water, thus demonstrating that Colorado River water is the sole source of subsurface drainwater in the Imperial Valley. Ratios of selenium to chloride indicate that selenium present in subsurface drainwater throughout the Imperial Valley originates from the Colorado River. The selenium load discharged to the Salton Sea from the Alamo River, the largest contributor, is about 6.5 tons/yr. Biological sampling and analysis showed that drainwater contaminants, including selenium, boron, and DDE, are accumulating in tissues of migratory and resident birds that use food sources in the Imperial Valley and the Salton Sea. Selenium concentration in fish-eating birds, shorebirds, and the endangered Yuma clapper rail were at levels that could affect reproduction. Boron concentrations in migratory waterfowl and resident shorebirds were at levels that potentially could cause reduced growth in young. As a result of DDE contamination of food sources, waterfowl and fish-eating birds in the Imperial Valley may be experiencing reproductive impairment.

  9. In-Flight Validation of Mid and Thermal Infrared Remotely Sensed Data Using the Lake Tahoe and Salton Sea Automated Validation Sites

    NASA Technical Reports Server (NTRS)

    Hook, Simon J.

    2008-01-01

    The presentation includes an introduction, Lake Tahoe site layout and measurements, Salton Sea site layout and measurements, field instrument calibration and cross-calculations, data reduction methodology and error budgets, and example results for MODIS. Summary and conclusions are: 1) Lake Tahoe CA/NV automated validation site was established in 1999 to assess radiometric accuracy of satellite and airborne mid and thermal infrared data and products. Water surface temperatures range from 4-25C.2) Salton Sea CA automated validation site was established in 2008 to broaden range of available water surface temperatures and atmospheric water vapor test cases. Water surface temperatures range from 15-35C. 3) Sites provide all information necessary for validation every 2 mins (bulk temperature, skin temperature, air temperature, wind speed, wind direction, net radiation, relative humidity). 4) Sites have been used to validate mid and thermal infrared data and products from: ASTER, AATSR, ATSR2, MODIS-Terra, MODIS-Aqua, Landsat 5, Landsat 7, MTI, TES, MASTER, MAS. 5) Approximately 10 years of data available to help validate AVHRR.

  10. Fluid origin, gas fluxes and plumbing system in the sediment-hosted Salton Sea Geothermal System (California, USA)

    NASA Astrophysics Data System (ADS)

    Mazzini, Adriano; Svensen, Henrik; Etiope, Giuseppe; Onderdonk, Nathan; Banks, David

    2011-08-01

    The Salton Sea Geothermal System (California) is an easily accessible setting for investigating the interactions of biotic and abiogenic geochemical processes in sediment-hosted hydrothermal systems. We present new temperature data and the molecular and isotopic composition of fluids seeping at the Davis-Schrimpf seep field during 2003-2008. Additionally, we show the first flux data for CO 2 and CH 4 released throughout the field from focused vents and diffuse soil degassing. The emitted gases are dominated by CO 2 (~ 98%) and CH 4 (~ 1.5%). By combining δ 13C CO2 (as low as - 5.4‰) and δ 13C CH4 (- 32‰ to - 17.6‰) with 3He/ 4He (R/Ra > 6) and δD CH4 values (- 216‰ to - 150‰), we suggest, in contrast to previous studies, that CO 2 may have a significant Sub-Continental Mantle source, with minimal crustal contamination, and CH 4 seems to be a mixture of high temperature pyrolitic (thermogenic) and abiogenic gas. Water seeps show that δD and δ 18O increase proportionally with salinity (Total Dissolved Solids in g/L) ranging from 1-3 g/L (gryphons) to 145 g/L (hypersaline pools). In agreement with elemental analyses, the isotopic composition of the waters indicate a meteoric origin, modified by surface evaporation, with little or no evidence of deep fossil or magmatic components. Very high Cl/Br (> 3,000) measured at many seeping waters suggests that increased salinities result from dissolution of halite crusts near the seep sites. Gas flux measurements from 91 vents (pools and gryphons) give a conservative estimate of ~ 2,100 kg of CO 2 and 11.5 kg of CH 4 emitted per day. In addition soil degassing measured at 81 stations (20x20 m grid over 51,000 m 2) revealed that 7,310 kg/d CO 2 and 33 kg/d CH 4 are pervasively released to the atmosphere. These results emphasise that diffuse gas emission from soil can be dominant (~ 75%) even in hydrothermal systems with large and vigorous gas venting. Sediment-hosted hydrothermal systems may represent an

  11. New insights into North America-Pacific Plate boundary deformation from Lake Tahoe, Salton Sea and southern Baja California

    NASA Astrophysics Data System (ADS)

    Brothers, Daniel Stephen

    Five studies along the Pacific-North America (PA-NA) plate boundary offer new insights into continental margin processes, the development of the PA-NA tectonic margin and regional earthquake hazards. This research is based on the collection and analysis of several new marine geophysical and geological datasets. Two studies used seismic CHIRP surveys and sediment coring in Fallen Leaf Lake (FLL) and Lake Tahoe to constrain tectonic and geomorphic processes in the lakes, but also the slip-rate and earthquake history along the West Tahoe-Dollar Point Fault. CHIRP profiles image vertically offset and folded strata that record deformation associated with the most recent event (MRE). Radiocarbon dating of organic material extracted from piston cores constrain the age of the MRE to be between 4.1--4.5 k.y. B.P. Offset of Tioga aged glacial deposits yield a slip rate of 0.4--0.8 mm/yr. An ancillary study in FLL determined that submerged, in situ pine trees that date to between 900-1250 AD are related to a medieval megadrought in the Lake Tahoe Basin. The timing and severity of this event match medieval megadroughts observed in the western United States and in Europe. CHIRP profiles acquired in the Salton Sea, California provide new insights into the processes that control pull-apart basin development and earthquake hazards along the southernmost San Andreas Fault. Differential subsidence (>10 mm/yr) in the southern sea suggests the existence of northwest-dipping basin-bounding faults near the southern shoreline. In contrast to previous models, the rapid subsidence and fault architecture observed in the southern part of the sea are consistent with experimental models for pull-apart basins. Geophysical surveys imaged more than 15 ˜N15°E oriented faults, some of which have produced up to 10 events in the last 2-3 kyr. Potentially 2 of the last 5 events on the southern San Andreas Fault (SAF) were synchronous with rupture on offshore faults, but it appears that ruptures on

  12. Occurrence, distribution, and transport of pesticides, trace elements, and selected inorganic constituents into the Salton Sea Basin, California, 2001-2002

    USGS Publications Warehouse

    LeBlanc, Lawrence A.; Schroeder, Roy A.; Orlando, James L.; Kuivila, Kathyrn M.

    2004-01-01

    A study of pesticide distribution and transport within the Salton Sea Basin, California, was conducted from September 2001 to October 2002. Sampling for the study was done along transects for the three major rivers that flow into the Salton Sea Basin: the New and Alamo Rivers at the southern end of the basin and the Whitewater River at the northern end. Three stations were established on each river: an outlet station approximately 1 mile upstream of the river discharge, a near-shore station in the river delta, and off-shore station in the Salton Sea. Water and suspended and bed sediments were collected at each station in October 2001, March-April 2002, and September 2002, coinciding with peak pesticide applications in the fall and spring. Fourteen current-use pesticides were detected in the water column. Concentrations of dissolved pesticides typically decreased from the outlets to the sea in all three rivers, consistent with the off-shore transport of pesticides from the rivers to the sea. Dissolved concentrations ranged from the limits of detection to 151 nanograms per liter (ng/L); however, diazinon, eptam (EPTC), and malathion were detected at much higher concentrations (940?3,830 ng/L) at the New and Alamo River outlet and near-shore stations. Concentrations of carbaryl, dacthal, diazinon, and eptam were higher during the two fall sampling periods, whereas concentrations of atrazine, carbofuran, and trifluralin were higher during the spring. Current-use pesticides also were detected on suspended and bed sediments in concentrations ranging from method detection limits to 106 ng/g (nanograms per gram). Chlorpyrifos, dacthal, eptam, trifluralin, and DDE were the most frequently detected pesticides on sediments from all three rivers. The number and concentrations of pesticides associated with suspended sediments frequently were similar for the river outlet and near-shore sites, consistent with the downstream transport of sediment-associated pesticides out of the

  13. Use of stable isotopes, tritium, soluble salts, and redox-sensitive elements to distinguish ground water from irrigation water in the Salton Sea basin

    USGS Publications Warehouse

    Schroeder, Roy A.; Setmire, James G.; Densmore, Jill N.

    1991-01-01

    Evaporative concentration of irrigation water diverted from the Colorado River to the Salton Sea basin for several decades has produced an overlying system (that includes drainwater and surface waters) whose composition is highly variable and differs from that of the shallow regional ground water beneath it. The role of hydrologic and geochemical processes in causing these differences (and the variability) is inferred from analyses of selected isotopes (3H, D, 18O, 15N, 34S) and elements (As, B, Br, Cl, Fe, N, Se). Selected element-to-Cl ratios establish the relative importance and location of the various processes. Isotopes of H O are used in estimating the relative contribution of leakage from an unlined canal and regional ground water to a nearby spring.

  14. Final Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin, California

    USGS Publications Warehouse

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2010-01-01

    This report summarizes comprehensive findings from a 4-year-long field investigation to document baseline environmental conditions in 29 agricultural drains and ponds operated by the Imperial Irrigation District along the southern border of the Salton Sea. Routine water-quality collections and fish community assessments were conducted on as many as 16 sampling dates at roughly quarterly intervals from July 2005 to April 2009. The water-quality measurements included total suspended solids and total (particulate plus dissolved) selenium. With one exception, fish were surveyed with baited minnow traps at quarterly intervals during the same time period. However, in July 2007, fish surveys were not conducted because we lacked permission from the California Department of Fish and Game for incidental take of desert pupfish (Cyprinodon macularius), an endangered species. During April and October 2006-08, water samples also were collected from seven intensively monitored drains (which were selected from the 29 total drains) for measurement of particulate and dissolved selenium, including inorganic and organic fractions. In addition, sediment, aquatic food chain matrices [particulate organic detritus, filamentous algae, net plankton, and midge (chironomid) larvae], and two fish species (western mosquitofish, Gambusia affinis; and sailfin molly, Poecilia latipinna) were sampled from the seven drains for measurement of total selenium concentrations. The mosquitofish and mollies were intended to serve as surrogates for pupfish, which we were not permitted to sacrifice for selenium determinations. Water quality (temperature, dissolved oxygen, pH, specific conductance, and turbidity) values were typical of surface waters in a hot, arid climate. A few drains exhibited brackish, near-anoxic conditions, especially during summer and fall when water temperatures occasionally exceeded 30 degrees Celsius. Total selenium concentrations in water were directly correlated with salinity and

  15. The Obsidian Creep Project: Seismic Imaging in the Brawley Seismic Zone and Salton Sea Geothermal Field, Imperial County, California

    NASA Astrophysics Data System (ADS)

    Catchings, R. D.; Rymer, M. J.; Goldman, M.; Lohman, R. B.; McGuire, J. J.

    2010-12-01

    In March 2010, we acquired medium- and high-resolution P- and S-wave seismic reflection and refraction data across faults in the Brawley seismic zone (BSZ) and across part of the Salton Sea Geothermal Field (SSGF), Imperial Valley, California. Our objectives were to determine the dip, possible structural complexities, and seismic velocities associated with the BSZ and SSGF. We acquired multiple seismic data sets along a north-south profile and a high-resolution P-wave profile along an east-west profile. The north-south profile included: 1) a 6.4-km-long P-wave (main) profile that was recorded on 320 Texan seismographs spaced at 20-m intervals, 2) a 1.2-km-long cabled, high-resolution profile along the northern end of the main profile, and 3) an approximately 1.2-km-long S-wave profile along the cabled profile. P-wave sources along the main profile were generated by 0.15- to 0.45-kg buried explosions spaced every 40 m, and P-wave sources along the cabled profile were generated by Betsy-Seisgun ‘shots’ spaced every 10 m. S-waves sources were generated by hammer impacts on the ends of an aluminum block. The east-west profile consisted of a 3.4-km-long high-resolution P-wave seismic profile with shots (Betsy-Seisgun) and geophones spaced every 10 m. Preliminary interpretation of shot gathers from blasts in the north-south profile suggests that the BSZ and SSGF are structurally complex, with abundant faults extending to or near the ground surface. Also, we observe relatively high-velocity material, apparent velocities of about 4.0 km/s in one direction and about 2.8 km/s in another relative to about 1.6 km/s for shallower material, that shallows beneath the SSGF. This may be due to high temperatures and resultant metamorphism of buried materials in the SSGF. From preliminary interpretation of shot gathers along the east-west profile we interpret a prominent fault that extends to the ground surface. This fault is on projection of the Kalin fault, from about 40 m to

  16. Field, Laboratory and Imaging spectroscopic Analysis of Landslide, Debris Flow and Flood Hazards in Lacustrine, Aeolian and Alluvial Fan Deposits Surrounding the Salton Sea, Southern California

    NASA Astrophysics Data System (ADS)

    Hubbard, B. E.; Hooper, D. M.; Mars, J. C.

    2015-12-01

    High resolution satellite imagery, field spectral measurements using a portable ASD spectrometer, and 2013 hyperspectral AVIRIS imagery were used to evaluate the age of the Martinez Mountain Landslide (MML) near the Salton Sea, in order to determine the relative ages of adjacent alluvial fan surfaces and the potential for additional landslides, debris flows, and floods. The Salton Sea (SS) occupies a pluvial lake basin, with ancient shorelines ranging from 81 meters to 113 meters above the modern lake level. The highest shoreline overlaps the toe of the 0.24 - 0.38 km3 MML deposit derived from hydrothermally altered granites exposed near the summit of Martinez Mountain. The MML was originally believed to be of early Holocene age. However, AVIRIS mineral maps show abundant desert varnish on the top and toe of the landslide. Desert varnish can provide a means of relative dating of alluvial fan (AF) or landslide surfaces, as it accumulates at determinable rates over time. Based on the 1) highest levels of desert varnish accumulation mapped within the basin, 2) abundant evaporite playa minerals on top of the toe of the landslide, and 3) the highest shoreline of the ancestral lake overtopping the toe of the landslide with gastropod and bivalve shells, we conclude that the MML predates the oldest alluvial fan terraces and lake sediments exposed in the Coachella and Imperial valleys and must be older than early Holocene (i.e. Late Pleistocene?). Thus, the MML landslide has the potential to be used as a spectral endmember for desert varnish thickness and thus proxy for age discrimination of active AF washes versus desert pavements. Given the older age of the MML landslide and low water levels in the modern SS, the risk from future rockslides of this size and related seiches is rather low. However, catastrophic floods and debris flows do occur along the most active AF channels; and the aftermath of such flows can be identified spectrally by montmorillonite crusts forming in

  17. A Strategy for Interpretation of Microearthquake Tomography Results in the Salton Sea Geothermal Field Based upon Rock Physics Interpretations of State 2-14 Borehole Logs

    SciTech Connect

    Bonner, B; Hutchings, L; Kasameyer, P

    2006-06-14

    We devise a strategy for analysis of Vp and Vs microearthquake tomography results in the Salton Sea geothermal field to identify important features of the geothermal reservoir. We first interpret rock properties in State 2-14 borehole based upon logged core through the reservoir. Then, we interpret seismic recordings in the well (Daley et al., 1988) to develop the strategy. We hypothesize that mapping Poisson's ratio has two applications for the Salton Sea geothermal reservoir: (1) to map the top of the reservoir, and (2) as a diagnostic for permeable zones. Poisson's ratio can be obtained from Vp and Vs. In the State 2-14 borehole, Poisson's ratio calculated from large scale averages ({approx} 150 m) shows a monotonic decrease with depth to about 1300 m, at which point it increases with depth. Our model is that the monotonic decrease is due to compaction, and the increase below 1300 m is due to the rocks being hydrothermally altered. We hypothesize we can map the depth to alteration by identifying the transition from decreasing to increasing values; and thus, map the top of the reservoir, which is associated with a known increase in sulfite, chlorite, and epidote alteration that may be indicative of hydrothermal activity. We also observe (from Daley et. al. plots) an anomalous drop in Poisson's ratio at a depth of about 900 m, within a sandstone formation. The sandstone has a P-wave velocity significantly higher than the siltstone above it but a lower velocity in the lower half of the formation relative to the upper half. We interpret the relative decrease in velocity to be due to fracturing and chemical alteration caused by permeability. We conclude that using Vp and Vs tomography results to obtain images of Poisson's ratio has the potential to identify significant features in the geothermal reservoir in this geologic setting. Seismic attenuation tomography results (mapped as Qp and Qs) should also be useful for evaluating geothermal reservoirs, but that is not

  18. Seismicity rate changes in the Salton Sea Geothermal Field and the San Jacinto Fault Zone after the 2010 Mw 7.2 El Mayor-Cucapah earthquake

    NASA Astrophysics Data System (ADS)

    Meng, Xiaofeng; Peng, Zhigang

    2014-06-01

    Whether static or dynamic stress changes play the most important role in triggering earthquakes in the near field is still in debate. Here, we examine the seismicity rate changes in southern California following the 2010 Mw 7.2 El Mayor-Cucapah earthquake. We focus on the Salton Sea Geothermal Field (SSGF) and the San Jacinto Fault Zone (SJFZ) because of high-sensitivity continuous borehole recordings and ample background seismicity. A significant increase in seismic activity is found in both study regions immediately following the main shock. However, near the SSGF where the static Coulomb stress decreased, the seismicity rate dropped below the pre-main-shock rate after ˜1 month. In comparison, along the SJFZ with an increase in the static Coulomb stress, the seismicity rate remained higher than the background rate with several moderate-size earthquakes occurring in the subsequent months. While we cannot completely rule out other mechanisms, these observations are best consistent with a widespread increase in seismicity from dynamic stress changes immediately after the main shock, and longer term seismicity rate changes from static stress changes. Our observation, together with other recent studies, suggests that both static and dynamic stress changes are important in triggering near-field earthquakes, but their affected regions and timescales are different.

  19. Sea shell solar collector

    DOEpatents

    Rabl, Ari

    1976-01-01

    A device is provided for the collection and concentration of solar radiant energy including a longitudinally extending structure having a wall for directing radiant energy. The wall is parabolic with its focus along a line parallel to an extreme ray of the sun at one solstice and with its axis along a line parallel to an extreme ray of the sun at the other solstice. An energy absorber is positioned to receive the solar energy thereby collected.

  20. Source properties of earthquakes near the Salton Sea triggered by the 16 October 1999 M 7.1 Hector Mine, California, earthquake

    USGS Publications Warehouse

    Hough, S.E.; Kanamori, H.

    2002-01-01

    We analyze the source properties of a sequence of triggered earthquakes that occurred near the Salton Sea in southern California in the immediate aftermath of the M 7.1 Hector Mine earthquake of 16 October 1999. The sequence produced a number of early events that were not initially located by the regional network, including two moderate earthquakes: the first within 30 sec of the P-wave arrival and a second approximately 10 minutes after the mainshock. We use available amplitude and waveform data from these events to estimate magnitudes to be approximately 4.7 and 4.4, respectively, and to obtain crude estimates of their locations. The sequence of small events following the initial M 4.7 earthquake is clustered and suggestive of a local aftershock sequence. Using both broadband TriNet data and analog data from the Southern California Seismic Network (SCSN), we also investigate the spectral characteristics of the M 4.4 event and other triggered earthquakes using empirical Green's function (EGF) analysis. We find that the source spectra of the events are consistent with expectations for tectonic (brittle shear failure) earthquakes, and infer stress drop values of 0.1 to 6 MPa for six M 2.1 to M 4.4 events. The estimated stress drop values are within the range observed for tectonic earthquakes elsewhere. They are relatively low compared to typically observed stress drop values, which is consistent with expectations for faulting in an extensional, high heat flow regime. The results therefore suggest that, at least in this case, triggered earthquakes are associated with a brittle shear failure mechanism. This further suggests that triggered earthquakes may tend to occur in geothermal-volcanic regions because shear failure occurs at, and can be triggered by, relatively low stresses in extensional regimes.

  1. Year 3 Summary Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin

    USGS Publications Warehouse

    Saiki, Michael K.; Martin, Barbara A.; May, Thomas W.

    2008-01-01

    This report summarizes findings from the third year of a 4-year-long field investigation to document selected baseline environmental conditions in 29 agricultural drains and ponds operated by the Imperial Irrigation District along the southern border of the Salton Sea. Routine water quality and fish species were measured at roughly quarterly intervals from April 2007 to January 2008. The water quality measurements included total suspended solids and total (particulate plus dissolved) selenium. In addition, during April and October 2007, water samples were collected from seven intensively monitored drains for measurement of particulate and dissolved selenium, including inorganic and organic fractions. In addition, sediment, aquatic food chain matrices (particulate organic detritus, filamentous algae, net plankton, and midge [chironomid] larvae), and two fish species (western mosquitofish, Gambusia affinis; and sailfin molly, Poecilia latipinna) were sampled from the seven drains for measurement of total selenium concentrations. The mosquitofish and mollies were intended to serve as surrogates for desert pupfish (Cyprinodon macularius), an endangered species that we were not permitted to take for selenium determinations. Water quality values were typical of surface waters in a hot desert climate. A few drains exhibited brackish, near anoxic conditions especially during the summer and fall when water temperatures occasionally exceeded 30 degrees C. In general, total selenium concentrations in water varied directly with conductivity and inversely with pH. Although desert pupfish were found in several drains, sometimes in relatively high numbers, the fish faunas of most drains and ponds were dominated by nonnative species, especially red shiner (Cyprinella lutrensis), mosquitofish, and mollies. Dissolved selenium in water samples from the seven intensively monitored drains ranged from 0.700 to 24.1 ug/L, with selenate as the major constituent in all samples. Selenium

  2. Solar distillation of sea water

    SciTech Connect

    Subramanyam, S. )

    1989-01-01

    Indian coastal and fishing villages suffer from scarcity of potable water. Solar distillation could provide a solution to this problem by adopting the following criteria: (1) Integration of distillation and storage systems with the house design. (2) Public supply of sea water and a public drain pipe system to periodically drain away the concentrated brine. (3) Harvest and store rain water to tide over cloudy rainy periods. In India there has been a thrust towards centralized non-conventional energy systems. Decentralized non-conventional energy devices and centralized service support units may offer a better solution. 1 fig.

  3. Crustal structure during active rifting in the central Salton Trough, California, constrained by the Salton Seismic Imaging Project (SSIP)

    NASA Astrophysics Data System (ADS)

    Han, L.; Hole, J. A.; Stock, J. M.; Fuis, G. S.; Driscoll, N. W.; Kell, A. M.; Kent, G.; Harding, A. J.; Gonzalez-Fernandez, A.; Lazaro-Mancilla, O.

    2013-12-01

    Seismic refraction and reflection travel times from the Salton Seismic Imaging Project (SSIP) were used to constrain crustal structure during active continental rifting in the central Salton Trough, California. SSIP, funded by NSF and USGS, acquired seismic data in and across the Salton Trough in 2011 to investigate rifting processes at the northern end of the Gulf of California extensional province and earthquake hazards at the southern end of the San Andreas Fault system. Seven lines of refraction and low-fold reflection data were acquired onshore, two lines and a grid of airgun and OBS data were acquired in the Salton Sea, and onshore-offshore data were recorded. North American lithosphere in the central Salton Trough appears to have been rifted apart and replaced by new crust added by magmatism from below and sedimentation from above. Ongoing active rifting of this new crust is manifested by shallow (<10km depth) seismicity in the oblique Brawley Seismic Zone (connecting the Imperial and San Andreas transform faults), the small Salton Buttes volcanoes, and very high heat flow that enables geothermal energy production. Analyses of the onshore-offshore seismic line that extends along the axis of the Salton Trough, parallel to the direction of plate motion, constrains rifted crustal structure. Crystalline basement (~5 km/s) generally occurs at ~4 km depth, but is at 2-3 km depth in a localized region beneath the Salton Buttes and Salton Sea geothermal field. This crystalline rock is interpreted to be late Pliocene to Quaternary Colorado River sediment that has been metamorphosed by high heat flow to a depth of at least 10km. The shallower basement under the volcanic and geothermal field is due to more intense metamorphism and hydrothermal alteration in this region of extreme heat flow. Faster velocity (6.2-6.4 km/s) observed at 10-13 km depth might be the remains of ruptured pre-existing crust or might be produced by deeper magmatism. Seismic travel times indicate

  4. Uranium-thorium series radionuclides in brines and reservoir rocks from two deep geothermal boreholes in the Salton Sea Geothermal Field, southeastern California

    NASA Astrophysics Data System (ADS)

    Zukin, Jeffrey G.; Hammond, Douglas E.; Teh-Lung, Ku; Elders, Wilfred A.

    1987-10-01

    Naturally occurring U and Th series radionuclides have been analyzed in high temperature brines (~300°C, 25 wt% dissolved solids) and associated rocks from two deep geothermal wells located on the northeastern margin of the Salton Sea Geothermal Field (SSGF). These data are part of a study of the SSGF as a natural analog of possible radionuclide behavior near a nuclear waste repository constructed in salt beds, and permit evaluation of some characteristics of water-rock interaction in the SSGF. Rock/Brine concentration ratios ( Rc = (dpm/ g) rock/(dpm/ g) brine) were found to vary from near unity for isotopes of Ra, Pb and Rn to about 5 × 10 5 for 232Th. The high sorptivity of 232Th is closely followed by that of 238U and 234U ( Rc ~ 5 × 10 4), suggesting that U is retained in the +4 oxidation state by the reducing conditions in the brines. The relatively high solubility of 210Pb and 212Pb is attributed to formation of chloride complexes, while the high Ra solubility is attributed to chloride complexing, a lack of suitable adsorption sites due to the high brine salinity and temperature, and the reducing conditions that prevent MnO 2 and RaSO 4 from forming. The 228Ra /226Ra ratios in the brines are approximately equal to those of their parents ( 232Th /230Th ) in associated rocks, indicating that Ra equilibration in the brine-rock system is achieved within the mean life of 228Ra (8.3 years). The 224Ra /228Ra ratios in these brines are about 0.7, indicating that either (1) brine composition is not homogeneous and 224Ra decays in fracture zones deficient in Ra and Th as the brine travels to the wellhead or (2) Ra equilibration in the brine-host rock system is not complete within the mean life of 224Ra (5.2 days) because the desorption of 224Ra from the solid phase is impeded. The 228Ac /228Ra activity ratio in the SSGF brines studied is <0.1, and from this ratio the residence time of 228Ac in the brine before sorption onto solid surfaces is estimated to be <70

  5. Pesticides in Water and Suspended Sediment of the Alamo and New Rivers, Imperial Valley/Salton Sea Basin, California, 2006-2007

    USGS Publications Warehouse

    Orlando, James L.; Smalling, Kelly L.; Kuivila, Kathryn M.

    2008-01-01

    Water and suspended-sediment samples were collected at eight sites on the Alamo and New Rivers in the Imperial Valley/Salton Sea Basin of California and analyzed for both current-use and organochlorine pesticides by the U.S. Geological Survey. Samples were collected in the fall of 2006 and spring of 2007, corresponding to the seasons of greatest pesticide use in the basin. Large-volume water samples (up to 650 liters) were collected at each site and processed using a flow-through centrifuge to isolate suspended sediments. One-liter water samples were collected from the effluent of the centrifuge for the analysis of dissolved pesticides. Additional samples were collected for analysis of dissolved organic carbon and for suspended-sediment concentrations. Water samples were analyzed for a suite of 61 current-use and organochlorine pesticides using gas chromatography/mass spectrometry. A total of 25 pesticides were detected in the water samples, with seven pesticides detected in more than half of the samples. Dissolved concentrations of pesticides observed in this study ranged from below their respective method detection limits to 8,940 nanograms per liter (EPTC). The most frequently detected compounds in the water samples were chlorpyrifos, DCPA, EPTC, and trifluralin, which were observed in more than 75 percent of the samples. The maximum concentrations of most pesticides were detected in samples from the Alamo River. Maximum dissolved concentrations of carbofuran, chlorpyrifos, diazinon, and malathion exceeded aquatic life benchmarks established by the U.S. Environmental Protection Agency for these pesticides. Suspended sediments were analyzed for 87 current-use and organochlorine pesticides using microwave-assisted extraction, gel permeation chromatography for sulfur removal, and either carbon/alumina stacked solid-phase extraction cartridges or deactivated Florisil for removal of matrix interferences. Twenty current-use pesticides were detected in the suspended

  6. Pesticide concentrations in water and in suspended and bottom sediments in the New and Alamo rivers, Salton Sea Watershed, California, April 2003

    USGS Publications Warehouse

    LeBlanc, Lawrence A.; Orlando, James L.; Kuivila, Kathryn M.

    2004-01-01

    This report contains pesticide concentration data for water, and suspended and bed sediment samples collected in April 2003 from twelve sites along the New and Alamo Rivers in the Salton Sea watershed, in southeastern California. The study was done in collaboration with the California State Regional Water Quality Control Board, Colorado River Region, to assess inputs of current-use pesticides associated with water and sediment into the New and Alamo Rivers. Five sites along the New River and seven sites along the Alamo River, downstream of major agricultural drains, were selected and covered the lengths of the rivers from the international boundary to approximately 1.5 km from the river mouths. Sampling from bridges occurred at seven of the twelve sites. At these sites, streamflow measurements were taken. These same sites were also characterized for cross-stream homogeneity by measuring dissolved oxygen, pH, specific conductance, temperature, and suspended solids concentration at several vertical (depths) and horizontal (cross-stream) points across the river. Large volume water samples (200?300 L) were collected for isolation of suspended sediments by flow-through centrifugation. Water from the outflow of the flow-through centrifuge was sampled for the determination of aqueous pesticide concentrations. In addition, bottom sediments were sampled at each site. Current-use pesticides and legacy organochlorine compounds (p,p'-DDT, p,p'-DDE and p,p'-DDD) were extracted from sediments and measured via gas chromatography/mass spectrometry (GC/MS). Organic carbon and percentage of fines were also determined for suspended and bottom sediments. Cross-stream transects of dissolved constituents and suspended sediments showed that the rivers were fairly homogeneous at the sites sampled. Streamflow was higher at the outlet sites, with the Alamo River having higher flow (1,240 cfs) than the New River (798 cfs). Twelve current-use pesticides, one legacy organochlorine compound (p

  7. Controls on the geomorphic expression and evolution of gryphons, pools, and caldera features at hydrothermal seeps in the Salton Sea Geothermal Field, southern California

    NASA Astrophysics Data System (ADS)

    Onderdonk, Nathan; Mazzini, Adriano; Shafer, Luke; Svensen, Henrik

    2011-07-01

    In the Salton Sea Geothermal Field in southern California, expulsion of gas, sediment and water creates unique geomorphic features similar to those seen on the surface of dormant mud volcanoes. These include pools of water or highly fluid mud named “mud pots” and 0.5 to 2.5 m-tall gryphons. The features vary in size, shape, and type of eruptive activity and change form over time. To evaluate controls on the surface morphology and evolution of these features we used repeated differential GPS surveys, observations of eruptive activity, and measurements of erupted mud properties to document the physical characteristics and changes in the system over a 28-month period. We find that the morphology of the gryphons is primarily a function of the mud expulsion style. Taller (1.5 m to 2.4 m) gryphons form where narrower vents (5 cm to 15 cm diameter) expel mud to the surface in discrete Strombolian-type eruptions caused by individual gas bubbles pushing mud up through the gryphon conduit and exploding at the surface. Smaller (0.6 m to 1.5 m) gryphons form where wider vents allow a greater amount of gas to pass through, which creates 0.25 to 1 m diameter mud craters that bubble continuously, often from multiple points within the crater. Although viscous mud is required to create these positive topographic features, variations in erupted mud temperature (30 °C to 68.5 °C), density (1.44 g/cm3 to 1.59 g/cm3), and water content (36% to 44%) between different gryphons did not correlate with gryphon size. All the active gryphons experienced periods of growth and erosion over the study period due to changes in the degree of activity or small variations in the vent locations within the gryphons, but the net change in height distributions over time was negligible. Pools directly adjacent to gryphon clusters are surficial features whose water level depends on seasonal rainfall and temperature. Isolated pools are also present and do not show similar response to seasonal changes

  8. Explosive and effusive volcanism in the Salton Trough, Salton Buttes, CA

    NASA Astrophysics Data System (ADS)

    Wright, H. M.; Mangan, M.; Champion, D. E.; Bindeman, I. N.; Vazquez, J. A.

    2013-12-01

    Five mid-late Holocene rhyolitic obsidian domes lie along the southern margin of the Salton Sea, California. The domes are aligned parallel to the axis of spreading along the boundary between the Pacific and North American plates in the Salton Trough pull apart basin in an area of rapid subsidence and high sedimentation (0.2-2.0 cm/year; Schmitt and Hulen 2008; Brothers et al. 2009). These volcanic domes are spatially associated with a broad area of high heat flow (tens of kilometers wide) and active geothermal energy production in the Salton Sea Geothermal Field. Here, we present new petrologic, paleomagnetic, and isotopic data that yield insight into the origin and eruption styles of the Salton Buttes rhyolites. Magmatic rocks in the Salton Trough are bimodal in composition, including buried rhyolites and subsurface diabase dikes (Schmitt and Hulen 2008). Previous work concluded that rhyolites were generated via partial melting of hydrothermally altered basalt (based on heterogeneous and low δ18O of zircon crystals; Schmitt and Vazquez 2006). Newly determined δ18O compositions for anorthoclase (6.1-6.3 ‰) and rhyolite glass (6.4-6.6 ‰) for all five domes are consistent with rhyolite evolution by fractional crystallization of basalt. The five domes differ slightly in composition, forming compositional trends on Harker-type diagrams, (e.g., FeO [2.7 to 1.9 wt%] or Ba [500 to 350 ppm] vs. SiO2 73.6-76.4 wt%). The most evolved dome, Mullet Island, is aphyric except for accessory zircon and magnetite. Other domes contain 1-2 vol% of phenocrystic anorthoclase, Fe-Ti oxides, and accessory zircon and likely antecrystic corroded pyroxene, fayalite, and amphibole. Our work reveals that temperatures of pre-eruptive rhyolites based on several geothermometers are: 770-790 °C (Zr in melt), 725 - 780 °C (Ti in zircon), and 700-800 °C (Fe-Ti oxides). Volcanism at the Salton Buttes is characterized by explosive and effusive eruptions, where a pyroclastic fall deposit

  9. Geochemistry and petrology of surface samples, six boreholes and brines from the Salton Sea geothermal field: A natural analog of a nuclear waste repository in salt: Report No. 3

    SciTech Connect

    Not Available

    1987-05-01

    Cuttings from six wells in the Salton Sea geothermal field, and rocks at outcrop that are correlative in age with those encountered at depth in the wells were analyzed in detail. Mineralogy, petrography, x-ray diffraction, electron microprobe, instrumental neutron activation analysis, fission track radiography, oxygen and stable carbon isotopic, uranium-thorium series disequilibrium, and fluid inclusion analyses are reported. Where fluids were being produced from wells, brine chemistry as well as stable isotope and uranium-thorium series analyses are reported. Particular attention has been paid to defining zones of fluid-rock interaction in which analyses of coexisting geothermal reservoir brine and hydrothermally altered sediments could be acquired. A wide span of temperatures, from surficial to greater than 300/degree/C, and salinities ranging from relatively dilute ground waters up to brines of 25 wt% total dissolved solids, span a range of environments that might be encountered in a waste repository in salt. Progressive hydrothermal alteration, mineral formation and element mobility are documented in the data presented. 52 refs., 25 figs., 49 tabs.

  10. Solar radiation interactions with seasonal sea ice

    NASA Astrophysics Data System (ADS)

    Ehn, Jens Kristian

    Presently, the Arctic Ocean is undergoing an escalating reduction in sea ice and a transition towards a seasonal sea ice environment. This warrants detailed investigations into improving our understanding of the seasonal evolution of sea ice and snow covers, and their representation in climate models. The interaction of solar radiation with sea ice is an important process influencing the energy balance and biological activity in polar seas, and consequently plays a key role in the earth's climate system. This thesis focuses on characterization of the optical properties---and the underlying physical properties that determine them---of seasonal sea ice during the fall freeze-up and the spring melt periods. Both periods display high spatial heterogeneity and rapid temporal changes in sea ice properties, and are therefore poorly understood. Field data were collected in Amundsen Gulf/Franklin Bay (FB), southern-eastern Beaufort Sea, in Oct.-Nov. 2003 and Apr. 2004 and in Button Bay (BB), western Hudson Bay, in Mar.-May 2005 to address (1) the temporal and spatial evolution of surface albedo and transmittance, (2) how radiative transfer in sea ice is controlled by its physical nature, and (3) the characteristics of the bottom ice algae community and its effect on the optical properties. The fall study showed the importance of surface features such as dry or slushy bare ice, frost flowers and snow cover in determining the surface albedo. Ice thickness was also important, however, mostly because surface features were associated with thickness. For example, nilas (<10 cm thick) was typically not covered by a snow layer as snow grains were dissolved or merged with the salty and warm brine skim layer on the surface, while surface conditions on thicker ice types were cold and dry enough to support a snow cover. In general, the surface albedo increased exponentially with an ice thickness increase, however, variability within ice thickness types were very large. It is apparent

  11. Geodetic investigation into the deformation of the Salton Trough

    NASA Astrophysics Data System (ADS)

    Crowell, Brendan W.; Bock, Yehuda; Sandwell, David T.; Fialko, Yuri

    2013-09-01

    Salton Trough represents a complex transition between the spreading center in Baja California and the strike-slip San Andreas fault system and is one of the most active zones of deformation and seismicity in California. We present a high-resolution interseismic velocity field for the Salton Trough derived from 74 continuous GPS sites and 109 benchmarks surveyed in three GPS campaigns during 2008-2009 and previous surveys between 2000 and 2005. We also investigate small-scale deformation by removing the regional velocity field predicted by an elastic block model for Southern California from the observed velocities. We find a total extension rate of 11 mm/yr from the Mesquite Basin to the southern edge of the San Andreas Fault, coupled with 15 mm/yr of left-lateral shear, the majority of which is concentrated in the southern Salton Sea and Obsidian Buttes and is equivalent to 17 mm/yr oriented in the direction of the San Andreas Fault. Differential shear strain is exclusively localized in the Brawley Seismic Zone, and dilatation rate indicates widespread extension throughout the zone. In addition, we infer clockwise rotation of 10°/Ma, consistent with northwestward propagation of the Brawley Seismic Zone over geologic time.

  12. Crustal and upper mantle velocity structure of the Salton Trough, southeast California

    USGS Publications Warehouse

    Parsons, T.; McCarthy, J.

    1996-01-01

    This paper presents data and modelling results from a crustal and upper mantle wide-angle seismic transect across the Salton Trough region in southeast California. The Salton Trough is a unique part of the Basin and Range province where mid-ocean ridge/transform spreading in the Gulf of California has evolved northward into the continent. In 1992, the U.S. Geological Survey (USGS) conducted the final leg of the Pacific to Arizona Crustal Experiment (PACE). Two perpendicular models of the crust and upper mantle were fit to wide-angle reflection and refraction travel times, seismic amplitudes, and Bouguer gravity anomalies. The first profile crossed the Salton Trough from the southwest to the northeast, and the second was a strike line that paralleled the Salton Sea along its western edge. We found thin crust (???21-22 km thick) beneath the axis of the Salton Trough (Imperial Valley) and locally thicker crust (???27 km) beneath the Chocolate Mountains to the northeast. We modelled a slight thinning of the crust further to the northeast beneath the Colorado River (???24 km) and subsequent thickening beneath the metamorphic core complex belt northeast of the Colorado River. There is a deep, apparently young basin (???5-6 km unmetamorphosed sediments) beneath the Imperial Valley and a shallower (???2-3 km) basin beneath the Colorado River. A regional 6.9-km/s layer (between ???15-km depth and the Moho) underlies the Salton Trough as well as the Chocolate Mountains where it pinches out at the Moho. This lower crustal layer is spatially associated with a low-velocity (7.6-7.7 km/s) upper mantle. We found that our crustal model is locally compatible with the previously suggested notion that the crust of the Salton Trough has formed almost entirely from magmatism in the lower crust and sedimentation in the upper crust. However, we observe an apparently magmatically emplaced lower crust to the northeast, outside of the Salton Trough, and propose that this layer in part

  13. Investigating Earthquake Hazards in the Northern Salton Trough, Southern California, Using Data From the Salton Seismic Imaging Project (SSIP)

    NASA Astrophysics Data System (ADS)

    Fuis, G.; Hole, J. A.; Stock, J. M.; Driscoll, N. W.; Kent, G.; Harding, A. J.; Kell, A. M.; Goldman, M.; Rose, E.; Catchings, R. D.; Rymer, M. J.; Langenheim, V. E.; Scheirer, D. S.; Athens, N. D.; Tarnowski, J. M.

    2012-12-01

    The southernmost San Andreas fault (SAF) system, in the northern Salton Trough (Salton Sea and Coachella Valley), is considered likely to produce a large-magnitude, damaging earthquake in the near future. The geometry of the SAF and the velocity and geometry of adjacent sedimentary basins will strongly influence energy radiation and strong ground shaking during a future rupture. The Salton Seismic Imaging Project (SSIP) was undertaken, in part, to provide more accurate information on the SAF and basins in this region. We report preliminary results from modeling four seismic profiles (Lines 4-7) that cross the Salton Trough in this region. Our southernmost line, Line 7, crosses the SAF near its southern terminus in the Salton Sea (near Salt Creek). Line 4 crosses the SAF at the northern end of the Salton Sea (at Box Canyon). Line 5 crosses the SAF (2 strands) in the Indio Hills (at Thousand Palms Oasis). Line 6, our northernmost line, crosses the SAF (3 strands) in the northern Coachella Valley (along a line from Palm Springs to Yucca Valley). Lines 4 to 6 terminate on the SW in the Peninsular Ranges, underlain by Mesozoic batholithic rocks, and terminate on the NE in or near the Little San Bernardino or Orocopia Mountains, underlain by Precambrian and Mesozoic igneous and metamorphic rocks. These lines cross the Coachella Valley, which is underlain by Miocene to Holocene sedimentary deposits. Line 7 crosses the Salton Sea and sedimentary basin deposits to the northeast similar to those of the Coachella Valley. On three lines (7, 4, 6) there is evidence from our seismic imaging, potential-field studies, and (or) earthquakes that active strands of the SAF dip moderately NE. From south to north, on Lines 7, 4, 5, and 6, maximum sedimentary basin depths are approximately 5.5?, 5.5, 3.5, and 3.5 km, respectively, as measured from the surface to the 5.3 km/s velocity contour. (In prior studies of the Imperial Valley, unmetamorphosed sediment is interpreted to lie above

  14. Understanding strain transfer and basin evolution complexities in the Salton pull-apart basin near the Southern San Andreas Fault

    NASA Astrophysics Data System (ADS)

    Kell, A. M.; Sahakian, V. J.; Kent, G. M.; Driscoll, N. W.; Harding, A. J.; Baskin, R. L.; Barth, M.; Hole, J. A.; Stock, J. M.; Fuis, G. S.

    2015-12-01

    Active source seismic data in the Salton Sea provide insight into the complexity of the pull-apart system development. Seismic reflection data combined with tomographic cross sections give constraints on the timing of basin development and strain partitioning between the two dominant dextral faults in the region; the Imperial fault to the southwest and the Southern San Andreas fault (SSAF) to the northeast. Deformation associated with this step-over appears young, having formed in the last 20-40 k.a. The complexity seen in the Salton Sea is similar to that seen in pull-apart basins worldwide. In the southern basin of the Salton Sea, a zone of transpression is noted near the southern termination of the San Andreas fault, though this stress regime quickly transitions to a region of transtension in the northern reaches of the sea. The evolution seen in the basin architecture is likely related to a transition of the SSAF dying to the north, and giving way to youthful segments of the Brawley seismic zone and Imperial fault. Stratigraphic signatures seen in seismic cross-sections also reveal a long-term component of slip to the southwest on a fault 1-2 km west of the northeastern Salton Sea shoreline. Numerous lines of evidence, including seismic reflection data, high-resolution bathymetry within the Salton Sea, and folding patterns in the Borrego Formation to the east of the sea support an assertion of a previously unmapped fault, the Salton Trough fault (STF), parallel to the SAF and just offshore within the Salton Sea. Seismic observations are seen consistently within two datasets of varying vertical resolutions, up to depths of 4-5 km, suggesting that this fault strand is much longer-lived than the evolution seen in the southern sub-basin. The existence of the STF unifies discrepancies between the onshore seismic studies and data collected within the sea. The STF likely serves as the current bounding fault to the active pull-apart system, as it aligns with the "rung

  15. High mortality of Red Sea zooplankton under ambient solar radiation.

    PubMed

    Al-Aidaroos, Ali M; El-Sherbiny, Mohsen M O; Satheesh, Sathianeson; Mantha, Gopikrishna; Agustī, Susana; Carreja, Beatriz; Duarte, Carlos M

    2014-01-01

    High solar radiation along with extreme transparency leads to high penetration of solar radiation in the Red Sea, potentially harmful to biota inhabiting the upper water column, including zooplankton. Here we show, based on experimental assessments of solar radiation dose-mortality curves on eight common taxa, the mortality of zooplankton in the oligotrophic waters of the Red Sea to increase steeply with ambient levels of solar radiation in the Red Sea. Responses curves linking solar radiation doses with zooplankton mortality were evaluated by exposing organisms, enclosed in quartz bottles, allowing all the wavelengths of solar radiation to penetrate, to five different levels of ambient solar radiation (100%, 21.6%, 7.2%, 3.2% and 0% of solar radiation). The maximum mortality rates under ambient solar radiation levels averaged (±standard error of the mean, SEM) 18.4±5.8% h(-1), five-fold greater than the average mortality in the dark for the eight taxa tested. The UV-B radiation required for mortality rates to reach ½ of maximum values averaged (±SEM) 12±5.6 h(-1)% of incident UVB radiation, equivalent to the UV-B dose at 19.2±2.7 m depth in open coastal Red Sea waters. These results confirm that Red Sea zooplankton are highly vulnerable to ambient solar radiation, as a consequence of the combination of high incident radiation and high water transparency allowing deep penetration of damaging UV-B radiation. These results provide evidence of the significance of ambient solar radiation levels as a stressor of marine zooplankton communities in tropical, oligotrophic waters. Because the oligotrophic ocean extends across 70% of the ocean surface, solar radiation can be a globally-significant stressor for the ocean ecosystem, by constraining zooplankton use of the upper levels of the water column and, therefore, the efficiency of food transfer up the food web in the oligotrophic ocean. PMID:25309996

  16. Salton Trough regional deformation estimated from combined trilateration and survey-mode GPS data

    USGS Publications Warehouse

    Anderson, G.; Agnew, D.C.; Johnson, H.O.

    2003-01-01

    The Salton Trough in southeastern California, United States, has one of the highest seismicity and deformation rates in southern California, including 20 earthquakes M 6 or larger since 1892. From 1972 through 1987, the U.S. Geological Survey (USGS) measured a 41-station trilateration network in this region. We remeasured 37 of the USGS baselines using survey-mode Global Positioning System methods from 1995 through 1999. We estimate the Salton Trough deformation field over a nearly 30-year period through combined analysis of baseline length time series from these two datasets. Our primary result is that strain accumulation has been steady over our observation span, at a resolution of about 0.05 ??strain/yr at 95% confidence, with no evidence for significant long-term strain transients despite the occurrence of seven large regional earthquakes during our observation period. Similar to earlier studies, we find that the regional strain field is consistent with 0.5 ?? 0.03 ??strain/yr total engineering shear strain along an axis oriented 311.6?? ?? 23?? east of north, approximately parallel to the strike of the major regional faults, the San Andreas and San Jacinto (all uncertainties in the text and tables are standard deviations unless otherwise noted). We also find that (1) the shear strain rate near the San Jacinto fault is at least as high as it is near the San Andreas fault, (2) the areal dilatation near the southeastern Salton Sea is significant, and (3) one station near the southeastern Salton Sea moved anomalously during the period 1987.95-1995.11.

  17. Sea, soil, sky - Testing solar's limits

    NASA Astrophysics Data System (ADS)

    Hopkinson, J.

    1981-12-01

    The potentials and actualities of large scale biomass, ocean thermal, and satellite solar power systems are discussed. Biomass is an energy already on-line in installations ranging from home-sized wood-burning stoves to utility sized generators fueled by sawdust and forest residue. Uses of wheat straw, fast-growing trees such as eucalyptus and alder, and euphorbia as biofuels are examined, noting restrictions imposed by land use limitations and the necessity for genetic engineering for more suitable plants. Pyrolysis and thermochemical gasification of biomass to form gaseous, solid, and liquid fuels are explored, and mention is made of utility refuse and sewage incineration for power generation. OTEC, satellite solar power systems, and tidal generator plants are considered as promising for further investigation and perhaps useful in limited applications, while solar pond power plants require extremely large areas to be effective.

  18. Deformation and Seismicity Within the Salton Trough

    NASA Astrophysics Data System (ADS)

    Lohman, R. B.; McGuire, J. J.

    2005-12-01

    We examine ground deformation and seismicity within the Salton Trough of Southern California with Interferometric Synthetic Aperture Radar (InSAR). The Salton Trough is the landward extension of the spreading centers and transforms within the Gulf of California, and is associated with a higher heat flow than is found further north along the San Andreas system. The Salton Trough region is characterized by seismicity swarms similar to those that are characteristic of fault systems on the East Pacific Rise. Transient episodes of shallow and deep creep occur on the southern San Andreas, Imperial, and Superstition Hills faults, and pronounced afterslip and triggered slip are associated with local and regional earthquakes. Documentation of the temporal and spatial evolution of transient and triggered slip phenomena is vital to development of stress transfer and strain partitioning models explaining the dynamics of interactions within the North America-Pacific plate boundary. We determine the extent to which aseismic fault slip can be observed with SAR data, and perform specific investigations of the time periods surrounding several of the ~10 major earthquake swarms that have occurred within the Salton Trough since 1992. We seek to determine whether seismic swarm activity is associated with aseismic slip transients. Extensive agricultural activity in the region limits the utility of traditional InSAR, so we explore use of the persistent scatterer method to isolate roads, buildings and other features that retain interferometric coherence over time. Because a large number of SAR acquisitions are available (>30), and because of the large spatial and temporal variations in coherence between urban, agricultural, water-covered and desert landscapes within the scene, the Salton trough provides an interesting test scenario for the persistent scatterer method. We use spatially and temporally varying fault slip to model observed activity on the Superstition Hills fault. We explore

  19. Tidal Currents between Titan's Seas Detected by Solar Glints

    NASA Astrophysics Data System (ADS)

    Sotin, C.; Barnes, J. W.; Lawrence, K. J.; Soderblom, J. M.; Audi, E.; Brown, R. H.; Le Mouelic, S.; Baines, K. H.; Buratti, B. J.; Clark, R. N.; Nicholson, P. D.

    2015-12-01

    Titan is the only place in the solar system, besides Earth, to have stable bodies of liquids on its surface. The three large seas and most of the lakes are located in the northern pole area [1]. They are major reservoirs of organic material [2]. Questions related to the variability in composition of the seas [2] and their interaction [3] can be addressed by dedicated observations. For this purpose, the Visual and Infrared Mapping Spectrometer (VIMS) observed the area between Ligeia Mare and Kraken Mare, Titan's two largest seas on February 12, 2015. The location of the specular point was close to the strait that has been suggested to link Ligeia and Kraken [4]. As demonstrated by previous observations of specular reflections on the lakes and seas [5, 6], such observations provide a means to assess the presence of liquids and the dynamics of the liquid surface. The VIMS observation provides images of the strait, named Trevize fretum, with a footprint of about 3 km. It shows a remarkable correlation with the radar images, suggesting that no major changes in the level of the seas have occurred in the last 10 years, a third of a Titan year. Very strong values of I/F at 5-μm suggest specular reflection away from the specular point on the Ligiea outlet. This is consistent with the presence of waves which can be generated by either winds or strong currents between Kraken Mare and Ligeia mare. Such currents can be generated during Titan's orbital motion around Saturn. We have investigated the volume of liquids that would transit through Trevize fretum during a Titan day and have found that the flow would be in a turbulent regime for the value of the mean anomaly at the time of the VIMS observation. Although subsurface communication between the two seas cannot be ruled out, the present observation underlines the role of the strait in providing exchange of fluids between the two large seas. This work has been performed at the Jet Propulsion Laboratory, California Institute

  20. The incident solar irradiance at the sea surface

    NASA Technical Reports Server (NTRS)

    Van Tran, AN; Collins, Donald J.

    1990-01-01

    Computations have been performed of the incident spectral irradiance at the sea surface using LOWTRAN-7 as the basis to describe the incident scalar and vector irradiance in terms of the true solar zenith angle and the nominal visibility in the atmosphere. These computations have been used to describe the contributions to the incident irradiance from the direct and the sky components of the total irradiance and the average cosine of the sky component as a measure of the radiance distribution of the sky for varying atmospheric conditions. Comparisons of the computations from LOWTRAN-7 have been made with the results from other models, and with data obtained from field measurements, and excellent agreement has been obtained for the daily profiles of the vector and scalar irradiance at the surface. These computations have been used to provide a description of the irradiance at the sea surface for use in the analysis of remotely sensed data based on information on the radiative transfer through the atmosphere above the sea surface.

  1. Sun-stirred Kraken Mare: Circulation in Titan's seas induced by solar heating and methane precipitation

    NASA Astrophysics Data System (ADS)

    Tokano, T.; Lorenz, R. D.

    2015-10-01

    Density-driven circulation in Titan's seas forced by solar heating and methane evaporation/precipitation is simulated by an ocean circulation model. If the sea is transparent to sunlight, solar heating can induce anti-clockwise gyres near the sea surface and clockwise gyres near the sea bottom. The gyres are in geostrophic balance between the radially symmetric pressure gradient force and Coriolis force. If instead the sea is turbid and most sunlight is absorbed near the sea surface, the sea gets stratified in warm seasons and the circulation remains weak. Strong summer precipitation at high latitudes causes compositional stratification and increase of the nearsurface methane mole fraction towards the north pole. The resultant latitudinal density contrast drives a meridional overturning with equatorward currents near the sea surface and poleward currents near the sea bottom. Weak precipitation induces gyres rather than meridional overturning.

  2. Sun-stirred Kraken Mare: Circulation in Titan's seas induced by solar heating and methane precipitation

    NASA Astrophysics Data System (ADS)

    Tokano, Tetsuya; Lorenz, Ralph D.

    2016-05-01

    Density-driven circulation in Titan's seas forced by solar heating and methane evaporation/precipitation is simulated by an ocean circulation model. If the sea is transparent to sunlight, solar heating can induce anti-clockwise gyres near the sea surface and clockwise gyres near the sea bottom. The gyres are in geostrophic balance between the radially symmetric pressure gradient force and Coriolis force. If instead the sea is turbid and most sunlight is absorbed near the sea surface, the sea gets stratified in warm seasons and the circulation remains weak. Precipitation causes compositional stratification of the sea to an extent that the sea surface temperature can be lower than the sea interior temperature without causing a convective overturning. Non-uniform precipitation can also generate a latitudinal gradient in the methane mole fraction and density, which drives a meridional overturning with equatorward currents near the sea surface and poleward currents near the sea bottom. However, gyres are more ubiquitous than meridional overturning.

  3. Calibration Shots Recorded for the Salton Seismic Imaging Project, Salton Trough, California

    NASA Astrophysics Data System (ADS)

    Murphy, J. M.; Rymer, M. J.; Fuis, G. S.; Stock, J. M.; Goldman, M.; Sickler, R. R.; Miller, S. A.; Criley, C. J.; Ricketts, J. W.; Hole, J. A.

    2009-12-01

    The Salton Seismic Imaging Project (SSIP) is a collaborative venture between the U.S. Geological Survey, California Institute of Technology, and Virginia Polytechnic Institute and State University, to acquire seismic reflection/wide angle refraction data, and currently is scheduled for data acquisition in 2010. The purpose of the project is to get a detailed subsurface 3-D image of the structure of the Salton Trough (including both the Coachella and Imperial Valleys) that can be used for earthquake hazards analysis, geothermal studies, and studies of the transition from ocean-ocean to continent-continent plate-boundary. In June 2009, a series of calibration shots were detonated in the southern Imperial Valley with specific goals in mind. First, these shots were used to measure peak particle velocity and acceleration at various distances from the shots. Second, the shots were used to calibrate the propagation of energy through sediments of the Imperial Valley. Third, the shots were used to test the effects of seismic energy on buried clay drainage pipes, which are abundant throughout the irrigated parts of the Salton Trough. Fourth, we tested the ODEX drilling technique, which uses a down-hole casing hammer for a tight casing fit. Information obtained from the calibration shots will be used for final planning of the main project. The shots were located in an unused field adjacent to Hwy 7, about 6 km north of the U.S. /Mexican border (about 18 km southeast of El Centro). Three closely spaced shot points (16 meters apart) were aligned N-S and drilled to 21-m, 23.5-m, and 27-m depth. The holes were filled with 23-kg, 68-kg, and 123-kg of ammonium-nitrate explosive, respectively. Four instrument types were used to record the seismic energy - six RefTek RT130 6-channel recorders with a 3-component accelerometer and a 3-component 2-Hz velocity sensor, seven RefTek RT130 3-channel recorders with a 3-component 4.5-Hz velocity sensor, 35 Texans with a vertical component 4

  4. Investigation of indigenous water, salt and soil for solar ponds

    NASA Technical Reports Server (NTRS)

    Marsh, H. E.

    1983-01-01

    The existence of salt-gradient solar ponds in nature is a strong indication that the successful exploitation of this phenomenon must account adequately for the influences of the local setting. Sun, weather and other general factors are treated elsewhere. This paper deals with water, salt, and soil. A general methodology for evaluating and, where feasible, adjusting the effects of these elements is under development. Eight essential solar pond characteristics have been identified, along with a variety of their dependencies upon properties of water, salt and soil. The comprehensive methodology, when fully developed, will include laboratory investigation in such diverse areas as brine physical chemistry, light transmission, water treatment, brine-soil interactions, sealants, and others. With the Salton Sea solar pond investigation as an example, some methods under development will be described.

  5. SeaWiFS technical report series. Volume 10: Modeling of the SeaWiFS solar and lunar observations

    NASA Technical Reports Server (NTRS)

    Woodward, Robert H.; Barnes, Robert A.; Mcclain, Charles R.; Esaias, Wayne E.; Barnes, William L.; Mecherikunnel, Ann T.; Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor)

    1993-01-01

    Post-launch stability monitoring of the Sea-viewing Wide Field-of-view Sensor (SeaWifs) will include periodic sweeps of both an onboard solar diffuser plate and the moon. The diffuser views will provide short-term checks and the lunar views will monitor long-term trends in the instrument's radiometric stability. Models of the expected sensor response to these observations were created on the SeaWiFS computer at the National Aeronautics and Space Administration's (NASA) Goddard Space Flight Center (GSFC) using the Interactive Data Language (IDL) utility with a graphical user interface (GUI). The solar model uses the area of intersecting circles to simulate the ramping of sensor response while viewing the diffuser. This model is compared with preflight laboratory scans of the solar diffuser. The lunar model reads a high-resolution lunar image as input. The observations of the moon are simulated with a bright target recovery algorithm that includes ramping and ringing functions. Tests using the lunar model indicate that the integrated radiance of the entire lunar surface provides a more stable quantity than the mean of radiances from centralized pixels. The lunar model is compared to ground-based scans by the SeaWiFS instrument of a full moon in December 1992. Quality assurance and trend analyses routines for calibration and for telemetry data are also discussed.

  6. Microearthquake Studies at the Salton Sea Geothermal Field

    DOE Data Explorer

    Templeton, Dennise

    2013-10-01

    The objective of this project is to detect and locate microearthquakes to aid in the characterization of reservoir fracture networks. Accurate identification and mapping of the large numbers of microearthquakes induced in EGS is one technique that provides diagnostic information when determining the location, orientation and length of underground crack systems for use in reservoir development and management applications. Conventional earthquake location techniques often are employed to locate microearthquakes. However, these techniques require labor-intensive picking of individual seismic phase onsets across a network of sensors. For this project we adapt the Matched Field Processing (MFP) technique to the elastic propagation problem in geothermal reservoirs to identify more and smaller events than traditional methods alone.

  7. NAKED AMOEBAE (PROTOZOA) OF THE SALTON SEA, CALIFORNIA. (R826552)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  8. FREELIVING NEMATODES FROM THE SALTON SEA. (R826552)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  9. 78 FR 44144 - Sonny Bono Salton Sea National Wildlife Refuge Complex (Sonny Bono Salton Sea National Wildlife...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-23

    ... of intent published on October 15, 2010 (75 FR 63502), two planning updates, and two public scoping... management to protect nesting western gull-billed terns (Gelochelidon nilotica vanrossemi) and black...

  10. Design, development and fabrication of a Solar Experiment Alignment Sensor (SEAS)

    NASA Technical Reports Server (NTRS)

    Bancroft, J. R.; Fain, M. Z.; Johnson, D. F.

    1971-01-01

    The design, development and testing of a laboratory SEAS (Solar Experiment Alignment Sensor) system are presented. The system is capable of overcoming traditional alignment and calibration problems to permit pointing anywhere on the solar disc to an accuracy of five arc seconds. The concept, development and laboratory testing phases of the program are discussed, and particular attention has been given to specific problems associated with selection of materials, and components. The conclusions summarize performance capability and discuss areas for further study including the effects of solar limb darkening and effects of annual variations in the apparent solar diameter.

  11. DESALINATION AND DEMINERALIZATION WITH SOLAR EVAPORATION ARRAY (SEA)

    EPA Science Inventory

    Over the last year, we produced a hand-made SEA unit to test the feasibility of our initial research. Initial results encouraged us to produce a unit that would closely resemble a deployable, mass-produced SEA unit. This required full-sized industrial plastic molds and thermof...

  12. Detecting Strain Transients in the Salton Trough (Invited)

    NASA Astrophysics Data System (ADS)

    McGuire, J. J.; Segall, P.; Herring, T.

    2009-12-01

    The Salton Trough region routinely experiences fault creep transients with time-scales of days to weeks, and previous studies have documented a temporal relationship between these aseimsic transients and earthquake swarms. The Plate Boundary Observatory has greatly increased the density of continuous geodetic data available in the Salton Trough, and we are analyzing this dataset to detect time periods when aseismic transients occurred in the Salton Trough. We are searching the daily GPS solutions for the time period from 2005-2009 for transients using Kalman Filter based detection algorithm called the Network Strain Filter [Ohtani, McGuire, and Segall, 2009]. The NSF solves for estimates of the secular velocity field and a time-vary transient displacement field that are expanded in basis functions. We utilize two dimensional wavelets as the basis functions. Spatial smoothing of the transient and secular velocity field are achieved by weighting the prior covariance matrix elements based on the scale of the individual wavelet basis. Site specific colored noise (seasonal terms, etc) is estimated as an random walk for each component. The vast majority of the Salton Trough GPS records are well explained by a combination of secular velocity and seasonal terms. However, we do find two spatially coherent transient episodes visible at multiple stations in the GPS data. The largest occurs near the southern extension of the Superstition Hills fault (Weinert Fault) during the second half of 2007. About 1 cm of extra motion to the northwest is observed at station P494, P496, and P497. The time scale of this transient is a few months. A second, smaller more abrupt transient is observed at stations P500 and P744 at the time of the February 2008 earthquake swarm at Cerro Prieto. We are investigating whether these two transients can be explained by slip on the Superstition Hills and Imperial faults respectively.

  13. Device for desalting sea or brackish water by using solar energy

    SciTech Connect

    Clavier, P.

    1981-09-29

    A device is described for desalting sea or brackish water using solar energy. It includes two adjacent canals or equivalent structures fed with the sea or brackish water, a green house type structure over one of the canals to vaporize water from it and a structure for condensation of water and for collecting softwater, the structure being in communication with the greenhouse structure and largely immersed in the other canal, which acts as the cold source for the condensating unit.

  14. Tree rings, solar radiation and ice cover of the Barents sea

    NASA Astrophysics Data System (ADS)

    Kasatkina, Elena; Shumilov, Oleg; Timonen, Mauri; Kanatjev, Alexandr

    2015-04-01

    Intercomparisons of the Kola Peninsula tree-ring records, ice cover of the Barents sea and sea and surface temperatures have been made. Tree-ring series over the last 100 years showed a highly significant correlation with the sea surface temperatures and ice cover (r=-0.57, p<0.05). It should be noted that the correlation between the tree-ring widths and local temperatures was not so high. We suppose that a possible reason seems to be the prevailing influence of solar irradiance and their UV components on tree growth in the Kola North. It is known that solar variability and fluctuations of solar irradiance in the UV band of the spectrum has increased over the last decades. In addition, there are frequent cases of total ozone content depletions (or so-called ozone mini-holes) resulting in increased UV-B. The recent studies demonstrate that many boreal and subarctic plants have increased susceptibility to UV-B radiation. An indirect confirmation of the hypothesis proposed is a close relationship between solar total irradiance and global sea surface temperature (Reid, 2000). The results of spectral MTM-analysis also revealed periodicities close to the solar cycles in the ice cover and tree-ring records. These results confirm the above-mentioned interpretation.

  15. Response of decadal climatic variations to solar signals in the coastal region of the Barents Sea

    NASA Astrophysics Data System (ADS)

    Raspopov, O. M.; Dergachev, V. A.; Shumilov, O. I.; Nevanlinna, H.

    2003-04-01

    Variations in annual temperatures in the coastal region of the Barents sea in Murmansk (69 N, 33 E) for the period of instrumental records since 1878 have been analyzed. Annual temperature variations have been found to exhibit a pronounced decadal periodicity of the order of 1-1.8 degrees Celsius. Comparison of temperature variations with variations in solar activity (Wolf numbers W) point to the synchronism between decadal temperature variations and the 11-year Schwabe solar cycle. Spectral analysis of the tree ring growth (Pinus Sylvestris L.) in Tuloma Valley near Murmansk for the last 350 years has revealed variations in the tree ring growth with a period of 11-12 years. Thus, decadal climatic variations with the period of the Schwabe solar cycle are typical of the coastal region of the Barents sea. The amplitudes of the observed temperature variations (1-1.8 degrees Celsius) cannot be interpreted as resulting from changes in solar irradiation during the 11-year cycle. These changes are of the order of 0.15%, which can lead to the global temperature response of the order of 0.1-0.3 degrees Celsius. Therefore, a 5-6-fold enhancement of the solar signals takes place in the coastal region of the Barents sea. A similar solar signal enhancement was revealed earlier in variations in the Sea Surface Temperature (SST) in the Pacific Ocean. Possible reasons for enhancement of solar signals in variations in SST in the Pacific Ocean were considered by White et al.(2000) on the basis of the model of the delayed action oscillator in the ocean-atmosphere-terrestrial system. It is probable that in the Northern Atlantic region a similar solar signal enhancement occurs in the ocean-atmosphere-terrestrial system. This work was supported by INTAS, Grant 97-31008; PFBR, Grant 00-05-64921 and NorFa.

  16. Plate boundary deformation at the latitude of the Salton Trough - northern Gulf of California (Invited)

    NASA Astrophysics Data System (ADS)

    Stock, J. M.

    2013-12-01

    Along the Pacific-North America plate boundary zone, the segment including the southern San Andreas fault to Salton Trough and northern Gulf of California basins has been transtensional throughout its evolution, based on Pacific-North America displacement vectors calculated from the global plate circuit (900 × 20 km at N54°W since 20 Ma; 460 × 20 km at N48°W since 11 Ma). Nevertheless, active seismicity and focal mechanisms show a broad zone of plate boundary deformation within which the inferred stress regime varies locally (Yang & Hauksson 2013 GJI), and fault patterns in some regions suggest ongoing tectonic rotation. Similar behavior is inferred to have occurred in this zone over most of its history. Crustal structure in this region is constrained by surface geology, geophysical experiments (e.g., the 2011 Salton Seismic Imaging Project (SSIP), USGS Imperial Valley 1979, PACE), and interdisciplinary marine and onland studies in Mexico (e.g., NARS-Baja, Cortes, and surveys by PEMEX). Magnetic data (e.g., EMAG-2) aids in the recognition of large-scale crustal provinces and fault boundaries in regions lacking detailed geophysical surveys. Consideration of existing constraints on crustal thickness and architecture, and fault and basin evolution suggests that to reconcile geological deformation with plate motion history, the following additional factors need to be taken into account. 1) Plate boundary displacement via interacting systems of rotating blocks, coeval with slip on steep strike slip faults, and possibly related to slip on low angle extensional faults (e.g, Axen & Fletcher 1998 IGR) may be typical prior to the onset of seafloor spreading. This fault style may have accommodated up to 150 km of plate motion in the Mexican Continental Borderland and north of the Vizcaino Peninsula, likely between 12 and 15 Ma, as well as explaining younger rotations adjacent to the Gulf of California and current deformation southwest of the Salton Sea. 2) Geophysical

  17. The effects of thick sediment upon continental breakup: seismic imaging and thermal modeling of the Salton Trough, southern California

    NASA Astrophysics Data System (ADS)

    Han, L.; Hole, J. A.; Lowell, R. P.; Stock, J. M.; Fuis, G. S.; Driscoll, N. W.; Kell, A. M.; Kent, G. M.; Harding, A. J.; Gonzalez-Fernandez, A.; Lázaro-Mancilla, O.

    2015-12-01

    Continental rifting ultimately creates a deep accommodation space for sediment. When a major river flows into a late-stage rift, thick deltaic sediment can change the thermal regime and alter the mechanisms of extension and continental breakup. The Salton Trough, the northernmost rift segment of the Gulf of California plate boundary, has experienced the same extension as the rest of the Gulf, but is filled to sea level by sediment from the Colorado River. Unlike the southern Gulf, seafloor spreading has not initiated. Instead, seismicity, high heat flow, and minor volcanoes attest to ongoing rifting of thin, transitional crust. Recently acquired controlled-source seismic refraction and wide-angle reflection data in the Salton Trough provide constraints upon crustal architecture and active rift processes. The crust in the central Salton Trough is only 17-18 km thick, with a strongly layered but relatively one-dimensional structure for ~100 km in the direction of plate motion. The upper crust includes 2-4 km of Colorado River sediment. Crystalline rock below the sediment is interpreted to be similar sediment metamorphosed by the high heat flow and geothermal activity. Meta-sediment extends to at least 9 km depth. A 4-5 km thick layer in the middle crust is either additional meta-sediment or stretched pre-existing continental crust. The lowermost 4-5 km of the crust is rift-related mafic magmatic intrusion or underplating from partial melting in the hot upper mantle. North American lithosphere in the Salton Trough has been almost or completely rifted apart. The gap has been filled by ~100 km of new transitional crust created by magmatism from below and sedimentation from above. These processes create strong lithologic, thermal, and rheologic layering. While heat flow in the rift is very high, rapid sedimentation cools the upper crust as compared to a linear geotherm. Brittle extension occurs within new meta-sedimentary rock. The lower crust, in comparison, is

  18. Structure of the active rift zone and margins of the northern Imperial Valley from Salton Seismic Imaging Project (SSIP) data

    NASA Astrophysics Data System (ADS)

    Livers, A.; Han, L.; Delph, J. R.; White-Gaynor, A. L.; Petit, R.; Hole, J. A.; Stock, J. M.; Fuis, G. S.

    2012-12-01

    First-arrival refraction data were used to create a seismic velocity model of the upper crust across the actively rifting northern Imperial Valley and its margins. The densely sampled seismic refraction data were acquired by the Salton Seismic Imaging Project (SSIP) , which is investigating rift processes in the northern-most rift segment of the Gulf of California extensional province and earthquake hazards at the southern end of the San Andreas Fault system. A 95-km long seismic line was acquired across the northern Imperial Valley, through the Salton Sea geothermal field, parallel to the five Salton Butte volcanoes and perpendicular to the Brawley Seismic Zone and major strike-slip faults. Nineteen explosive shots were recorded with 100 m seismometer spacing across the valley and with 300-500 m spacing into the adjacent ranges. First-arrival travel times were picked from shot gathers along this line and a seismic velocity model was produced using tomographic inversion. Sedimentary basement and seismic basement in the valley are interpreted to be sediment metamorphosed by the very high heat flow. The velocity model shows that this basement to the west of the Brawley Seismic Zone is at ~4-km depth. The basement shallows to ~2-km depth in the active geothermal field and Salton Buttes volcanic field which locally coincide with the Brawley Seismic Zone. At the eastern edge of the geothermal field, the basement drops off again to ~3.5-km depth. The eastern edge of the valley appears to be fault bounded by the along-strike extension of the Sand Hills Fault, an inactive strike-slip fault. The seismic velocities to the east of the fault correspond to metamorphic rock of the Chocolate Mountains, different from the metamorphosed basement in the valley. The western edge of the valley appears to be fault bounded by the active Superstition Hills Fault. To the west of the valley, >4-km deep valley basement extends to the active Superstition Hills Fault. Basement then shallows

  19. The Salton Seismic Imaging Project: Tomographic characterization of a sediment-filled rift valley and adjacent ranges, southern California

    NASA Astrophysics Data System (ADS)

    Davenport, K.; Hole, J. A.; Stock, J. M.; Fuis, G. S.; Carrick, E.; Tikoff, B.

    2011-12-01

    The Salton Trough in Southern California represents the northernmost rift of the Gulf of California extensional system. Relative motion between the Pacific and North American plates is accommodated by continental rifting in step-over zones between the San Andreas, Imperial, and Cerro Prieto transform faults. Rapid sedimentation from the Colorado River has isolated the trough from the southern portion of the Gulf of California, progressively filling the subsiding rift basin. Based on data from previous seismic surveys, the pre-existing continent has ruptured completely, and a new ~22 km thick crust has been created entirely by sedimentation overlying rift-related magmatism. The MARGINS, EarthScope, and USGS-funded Salton Seismic Imaging Project (SSIP) was designed to investigate the nature of this new crust, the ongoing process of continental rifting, and associated earthquake hazards. SSIP, acquired in March 2011, comprises 7 lines of onshore seismic refraction / wide-angle reflection data, 2 lines of refraction / reflection data in the Salton Sea, and a line of broadband stations. This presentation focuses on the refraction / wide-angle reflection line across the Imperial Valley, extending ~220 km across California from Otay Mesa, near Tijuana, to the Colorado River. The data from this line includes seventeen 100-160 kg explosive shots and receivers at 100 m spacing across the Imperial Valley to constrain the structure of the Salton Trough rift basin, including the Imperial Fault. Eight larger shots (600-920 kg) at 20-35 km spacing and receivers at 200-500 m spacing extend the line across the Peninsular Ranges and the Chocolate Mountains. These data will contrast the structure of the rift to that of the surrounding crust and provide constraints on whole-crust and uppermost mantle structure. Preliminary work has included tomographic inversion of first-arrival travel times across the Valley, emphasizing a minimum-structure approach to create a velocity model of the

  20. The impact of stored solar heat on Arctic sea ice growth

    NASA Astrophysics Data System (ADS)

    Timmermans, M.-L.

    2015-08-01

    High-resolution measurements of ocean temperature and salinity in the Arctic Ocean's Canada Basin reveal the importance of the release of solar-derived stored ocean heat on sea ice growth. Locally absorbed summer solar heat is stored in a near-surface temperature maximum (NSTM) layer underlying the mixed layer. The heat content of the NSTM layer was anomalously large following summer 2007, which saw considerable sea ice losses and intense solar absorption into the exposed surface ocean. Measurements provide evidence for the entrainment of NSTM layer heat in fall/winter 2007-2008 by shear-driven mixing, and convective mixing by the release of dense, salty plumes during sea ice growth. While at least a portion of the NSTM layer was eroded, deeper warm ocean layers remained unaffected. It is shown that the release of solar heat stored following summer 2007 was sufficient to have reduced sea ice thickness at the end of the 2008 growth season by about 25%.

  1. Sea of Bubbles at Edge of Solar System

    NASA Video Gallery

    This animation summarizes the new heliospheric scenario and the formation of the “sea” of bubbles in the heliosheath. The Sun’s magnetic field points toward the Sun in the Northern hemisphere...

  2. Glacial Influences on Solar Radiation in a Subarctic Sea.

    EPA Science Inventory

    Understanding macroscale processes controlling solar radia­tion in marine systems will be important in interpreting the potential effects of global change from increasing ultraviolet radiation (UV) and glacial retreat. This study provides the first quantitative assessment of UV i...

  3. SeaWiFS long-term solar diffuser reflectance and sensor noise analyses.

    PubMed

    Eplee, Robert E; Patt, Frederick S; Barnes, Robert A; McClain, Charles R

    2007-02-10

    The NASA Ocean Biology Processing Group's Calibration and Validation (Cal/Val) team has undertaken an analysis of the mission-long Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) solar calibration time series to assess the long-term degradation of the solar diffuser reflectance over 9 years on orbit. The SeaWiFS diffuser is an aluminum plate coated with YB71 paint. The bidirectional reflectance distribution function of the diffuser was not fully characterized before launch, so the Cal/Val team has implemented a regression of the solar incidence angles and the drift in the node of the satellite's orbit against the diffuser time series to correct for solar incidence angle effects. An exponential function with a time constant of 200 days yields the best fit to the diffuser time series. The decrease in diffuser reflectance over the mission is wavelength dependent, ranging from 9% in the blue (412 nm) to 5% in the red and near infrared (670-865 nm). The Cal/Val team has developed a methodology for computing the signal-to-noise ratio (SNR) for SeaWiFS on orbit from the diffuser time series corrected for both the varying solar incidence angles and the diffuser reflectance degradation. A sensor noise model is used to compare on-orbit SNRs computed for radiances reflected from the diffuser with prelaunch SNRs measured at typical radiances specified for the instrument. To within the uncertainties in the measurements, the SNRs for SeaWiFS have not changed over the mission. The on-orbit performance of the SeaWiFS solar diffuser should offer insight into the long-term on-orbit performance of solar diffusers on other instruments, such as the Moderate-Resolution Imaging Spectrometer [currently flying on the Earth Observing System (EOS) Terra and Aqua satellites], the Visible and Infrared Radiometer Suite [scheduled to fly on the NASA National Polar-orbiting Operational Environmental Satellite System (NPOESS) and NPOESS Preparatory Project (NPP) satellites] and the Advanced

  4. SeaWiFS long-term solar diffuser reflectance and sensor noise analyses

    SciTech Connect

    Eplee, Robert E. Jr.; Patt, Frederick S.; Barnes, Robert A.; McClain, Charles R

    2007-02-10

    The NASA Ocean Biology Processing Group's Calibration and Validation(Cal/Val) team has undertaken an analysis of the mission-long Sea-Viewing Wide Field-of-View Sensor (SeaWiFS)solar calibration time series to assess the long-term degradation of the solar diffuser reflectance over 9 years on orbit. The SeaWiFS diffuser is an aluminum plate coated with YB71 paint. The bidirectional reflectance distribution function of the diffuser was not fully characterized before launch,so the Cal/Val team has implemented a regression of the solar incidence angles and the drift in the node of the satellite's orbit against the diffuser time series to correct for solar incidence angle effects. An exponential function with a time constant of 200 days yields the best fit to the diffuser time series.The decrease in diffuser reflectance over the mission is wavelength dependent,ranging from 9% in the blue(412 nm) to 5% in the red and near infrared(670-865 nm). The Cal/Val team has developed a methodology for computing the signal-to-noise ratio (SNR) for SeaWiFS on orbit from the diffuser time series corrected for both the varying solar incidence angles and the diffuser reflectance degradation. A sensor noise model is used to compare on-orbit SNRs computed for radiances reflected from the diffuser with prelaunch SNRs measured at typical radiances specified for the instrument. To within the uncertainties in the measurements, the SNRs for SeaWiFS have not changed over the mission. The on-orbit performance of the SeaWiFS solar diffuser should offer insight into the long-term on-orbit performance of solar diffusers on other instruments, such as the Moderate-Resolution Imaging Spectrometer [currently flying on the Earth Observing System (EOS) Terra and Aqua satellites], the Visible and Infrared Radiometer Suite [scheduled to fly on the NASA National Polar-orbiting Operational Environmental Satellite System (NPOESS) and NPOESS Preparatory Project (NPP) satellites] and the Advanced Baseline

  5. Investigating the San Andreas Fault System in the Northern Salton Trough by a Combination of Seismic Tomography and Pre-stack Depth Migration: Results from the Salton Seismic Imaging Project (SSIP)

    NASA Astrophysics Data System (ADS)

    Bauer, K.; Ryberg, T.; Fuis, G. S.; Goldman, M.; Catchings, R.; Rymer, M. J.; Hole, J. A.; Stock, J. M.

    2013-12-01

    The Salton Trough in southern California is a tectonically active pull-apart basin which was formed in migrating step-overs between strike-slip faults, of which the San Andreas fault (SAF) and the Imperial fault are current examples. It is located within the large-scale transition between the onshore SAF strike-slip system to the north and the marine rift system of the Gulf of California to the south. Crustal stretching and sinking formed the distinct topographic features and sedimentary successions of the Salton Trough. The active SAF and related fault systems can produce potentially large damaging earthquakes. The Salton Seismic Imaging Project (SSIP), funded by NSF and USGS, was undertaken to generate seismic data and images to improve the knowledge of fault geometry and seismic velocities within the sedimentary basins and underlying crystalline crust around the SAF in this key region. The results from these studies are required as input for modeling of earthquake scenarios and prediction of strong ground motion in the surrounding populated areas and cities. We present seismic data analysis and results from tomography and pre-stack depth migration for a number of seismic profiles (Lines 1, 4-7) covering mainly the northern Salton Trough. The controlled-source seismic data were acquired in 2011. The seismic lines have lengths ranging from 37 to 72 km. On each profile, 9-17 explosion sources with charges of 110-460 kg were recorded by 100-m spaced vertical component receivers. On Line 7, additional OBS data were acquired within the Salton Sea. Travel times of first arrivals were picked and inverted for initial 1D velocity models. Alternatively, the starting models were derived from the crustal-scale velocity models developed by the Southern California Earthquake Center. The final 2D velocity models were obtained using the algorithm of Hole (1992; JGR). We have also tested the tomography packages FAST and SIMUL2000, resulting in similar velocity structures. An

  6. Solar forcing as an important trigger for West Greenland sea-ice variability over the last millennium

    NASA Astrophysics Data System (ADS)

    Sha, Longbin; Jiang, Hui; Seidenkrantz, Marit-Solveig; Muscheler, Raimund; Zhang, Xu; Knudsen, Mads Faurschou; Olsen, Jesper; Knudsen, Karen Luise; Zhang, Weiguo

    2016-01-01

    Arctic sea ice represents an important component of the climate system, and the present reduction of sea ice in the Arctic is of major concern. Despite its importance, little is known about past changes in sea-ice cover and the underlying forcing mechanisms. Here, we use diatom assemblages from a marine sediment core collected from the West Greenland shelf to reconstruct changes in sea-ice cover over the last millennium. The proxy-based reconstruction demonstrates a generally strong link between changes in sea-ice cover and solar variability during the last millennium. Weaker (or stronger) solar forcing may result in the increase (or decrease) in sea-ice cover west of Greenland. In addition, model simulations show that variations in solar activity not only affect local sea-ice formation, but also control the sea-ice transport from the Arctic Ocean through a sea-ice-ocean-atmosphere feedback mechanism. The role of solar forcing, however, appears to have been more ambiguous during an interval around AD 1500, after the transition from the Medieval Climate Anomaly to the Little Ice Age, likely to be driven by a range of factors.

  7. Tension between reducing sea-level rise and global warming through solar-radiation management

    NASA Astrophysics Data System (ADS)

    Irvine, P. J.; Sriver, R. L.; Keller, K.

    2012-02-01

    Geoengineering using solar-radiation management (SRM) is gaining interest as a potential strategy to reduce future climate change impacts. Basic physics and past observations suggest that reducing insolation will, on average, cool the Earth. It is uncertain, however, whether SRM can reduce climate change stressors such as sea-level rise or rates of surface air temperature change. Here we use an Earth system model of intermediate complexity to quantify the possible response of sea levels and surface air temperatures to projected climate forcings and SRM strategies. We find that SRM strategies introduce a potentially strong tension between the objectives to reduce (1) the rate of temperature change and (2) sea-level rise. This tension arises primarily because surface air temperatures respond faster to radiative forcings than sea levels. Our results show that the forcing required to stop sea-level rise could cause a rapid cooling with a rate similar to the peak business-as-usual warming rate. Furthermore, termination of SRM was found to produce warming rates up to five times greater than the maximum rates under the business-as-usual CO2 scenario, whereas sea-level rise rates were only 30% higher. Reducing these risks requires a slow phase-out of many decades and thus commits future generations.

  8. The Salton Seismic Imaging Project: Seismic velocity structure of the Brawley Seismic Zone, Salton Buttes and Geothermal Field, Salton Trough, California

    NASA Astrophysics Data System (ADS)

    Delph, J.; Hole, J. A.; Fuis, G. S.; Stock, J. M.; Rymer, M. J.

    2011-12-01

    The Salton Trough is an active rift in southern California in a step-over between the plate-bounding Imperial and San Andreas Faults. In March 2011, the Salton Seismic Imaging Project (SSIP) investigated the rift's crustal structure by acquiring several seismic refraction and reflection lines. One of the densely sampled refraction lines crosses the northern-most Imperial Valley, perpendicular to the strike-slip faults and parallel to a line of small Quaternary rhyolitic volcanoes. The line crosses the obliquely extensional Brawley Seismic Zone and goes through one of the most geothermally productive areas in the United States. Well logs indicate the valley is filled by several kilometers of late Pliocene-recent lacustrine, fluvial, and shallow marine sediment. The 42-km long seismic line was comprised of eleven 110-460 kg explosive shots and receivers at a 100 m spacing. First arrival travel times were used to build a tomographic seismic velocity image of the upper crust. Velocity in the valley increases smoothly from <2 km/s to >5 km/s, indicating diagenesis and gradational metamorphism of rift sediments at very shallow depth due to an elevated geotherm. The velocity gradient is much smaller in the relatively low velocity (<6 km/s) crystalline basement comprised of recently metamorphosed sediment reaching greenschist to lower amphibolite facies. The depth of this basement is about 4-km below the aseismic region of the valley west of the Brawley Seismic Zone, but rises sharply to ~2 km depth beneath the seismically, geothermally, and volcanically active area of the Brawley Seismic Zone. The basement deepens to the northeast of the active tectonic zone and then is abruptly offset to shallower depth on the northeast side of the valley. This offset may be the subsurficial expression of a paleofault, most likely an extension of the Sand Hills Fault, which bounds the basin to the east. Basement velocity east of the fault is ~5.7 km/s, consistent with the granitic rocks

  9. Characterization of MODIS and SeaWiFS solar diffuser on-orbit degradation

    NASA Astrophysics Data System (ADS)

    Xiong, X.; Eplee, R. E., Jr.; Sun, J.; Patt, F. S.; Angal, A.; McClain, C. R.

    2009-08-01

    MODIS has 20 reflective solar bands (RSB), covering the VIS, NIR, and SWIR spectral regions. They are calibrated on-orbit using a solar diffuser (SD) panel, made of space-grade Spectralon. The SD bi-directional reflectance factor (BRF) was characterized pre-launch by the instrument vendor with reference to the NIST reflectance standard. Its on-orbit degradation is tracked by an on-board solar diffuser stability monitor (SDSM). The SeaWiFS on-orbit calibration strategy uses monthly lunar observations to monitor the long-term radiometric stability of the instrument and applies daily observations of its solar diffuser (an aluminum plate coated with YB71 paint) to track the short-term changes in the instrument response. This paper provides an overview of MODIS and SeaWiFS SD observations, applications, and approaches used to track their on-orbit degradations. Results from both sensors are presented with emphasis on the spectral dependence and temporal trends of the SD degradation. Lessons and challenges from the use of SD for sensor on-orbit calibration are also discussed.

  10. Characterization of MODIS and SeaWiFS Solar Diffuser On-Orbit Degradation

    NASA Technical Reports Server (NTRS)

    Xiong, X.; Eplee, R. E., Jr.; Sun, J.; Patt, F. S.; Angal, A.; McClain, C. R.

    2009-01-01

    MODIS has 20 reflective solar bands (RSB), covering the VIS, NIR, and SWIR spectral regions. They are calibrated on-orbit using a solar diffuser (SD) panel, made of space-grade Spectralon. The SD bi-directional reflectance factor (BRF) was characterized pre-launch by the instrument vendor reference to the NIST reflectance standard. Its on-orbit degradation is tracked by an on-board solar diffuser stability monitor (SDSM). The SeaWifS on-orbit calibration strategy uses monthly lunar observations to monitor the long-term radiometric stability of the instrument and applies daily observations of its solar diffuser (an aluminum plate coated with YB71 paint) to track the short-term changes in the instrument response. This paper provides an overview of MODIS and SeaWiFS SD observations, applications, and approaches used to track their on-orbit degradations. Results from sensors are presented with emphasis on the spectral dependence and temporal trends of the SD degradation. Lessons and challenges from the use of SD for sensor on-orbit calibration are also discussed.

  11. Simulation Study of Effects of Solar Irradiance and Sea Surface Temperature on Monsoons and Global Circulation

    NASA Technical Reports Server (NTRS)

    Sud, Y. C.; Walker, G. K.; Mehta, V.; Lau, W. K.-M.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    A recent version of the GEOS 2 GCM was used to isolate the roles of the annual cycles of solar irradiation and/or sea-surface temperatures (SSTs) on the simulated circulation and rainfall. Four 4-year long integrations were generated with the GCM. The first integration, called Control Case, used daily-interpolated SSTs from a 30 year monthly SST climatology that was obtained from the analyzed SST-data, while the solar irradiation at the top of the atmosphere was calculated normally at hourly intervals. The next two cases prescribed the SSTs or the incoming solar irradiance at the top of the atmosphere at their annual mean values, respectively while everything else was kept the same as in the Control Case. In this way the influence of the annual cycles of both external forcings was isolated.

  12. Chronostratigraphy of the Fish Creek-Vallecito Basin, SW Salton Trough: A High-Fidelity Record of Slip on the West Salton Detachment Fault and Subsidence in its Upper Plate

    NASA Astrophysics Data System (ADS)

    Dorsey, R. J.; Housen, B. A.; Janecke, S. U.; McDougall, K.; Fanning, M.; Fluette, A.; Axen, G. J.; Shirvell, C. R.

    2006-12-01

    The Fish Creek-Vallecito basin contains a 5.1-km thick section of sedimentary rocks in the SW Salton Trough that range in age from 8.1 to 0.9 Ma. The section preserves a record of basin subsidence related to slip on the West Salton detachment fault (WSDF), which formed the main western rift-flank structure of the Salton Trough. We obtained a well-constrained chronology from compilation of existing (Johnson et al., 1983) and new paleomagnetic data, ages of two tuffs high in the section, and thicknesses calculated from the geologic map of Winker (1987) and our work in the lower 1.3 km. The tuffs yielded SHRIMP U-Pb ages of 2.56 ± 0.09 and 2.54 ± 0.09 Ma from single zircons. Geohistory analysis, corrected for paleobathymetry and global sea- level change, yields a decompacted subsidence curve with 5 segments bounded by abrupt changes in subsidence rate: (1) 0.46 mm/yr from 8.1 to 5.5 Ma; (2) 1.8 mm/yr from 5.5 to 5.2 Ma; (3) zero subsidence or slight uplift from 5.2 to 4.6 Ma; (4) 1.9 mm/yr from 4.6 to 3.2 Ma; and (5) 0.4 mm/yr from 3.2 to 0.9 Ma. The base of the Elephant Trees Fm, dated here at 8.1 Ma, provides the earliest well dated record of extension in the SW Salton Trough. Earliest marine incursion is dated at 6.3 Ma, and the first appearance of Colorado River sand coincides closely with the Miocene-Pliocene boundary (5.33 Ma). Because the base of the marine Imperial Group does not coincide with a change in subsidence rate, we suggest that initial marine incursion resulted from a latest Miocene global sea-level highstand superposed on steady subsidence. Thus, the inflections at 8.1 and 5.5 Ma are the two most likely ages for onset of slip on the WSDF, but 4.6 Ma is also possible. Variations in subsidence rate are not predicted by models for extensional detachment faults, and may reflect episodic pulsed fault slip and/or long-wavelength folding related to dextral-wrench tectonics. Rapid subsidence in segment 4 began during progradation of the Colorado River

  13. Seismic Reflectivity of the Crust in the Northern Salton Trough

    NASA Astrophysics Data System (ADS)

    Bauer, K.; Fuis, G. S.; Goldman, M.; Persaud, P.; Ryberg, T.; Langenheim, V. E.; Scheirer, D. S.; Rymer, M. J.; Hole, J. A.; Stock, J. M.; Catchings, R.

    2015-12-01

    The Salton Trough in southern California is a tectonically active pull-apart basin that was formed by migrating step-overs between strike-slip faults, of which the San Andreas Fault (SAF) and the Imperial Fault are the current, northernmost examples. The Salton Seismic Imaging Project (SSIP) was undertaken to improve our knowledge of fault geometry and seismic velocities within the sedimentary basins and underlying crystalline crust around the SAF. Such data are useful as input for modeling scenarios of strong ground shaking in the surrounding high-population areas. We used pre-stack depth migration of line segments from shot gathers in several seismic profiles that were acquired in the northern part of the SSIP study area (Lines 4 - 7). Our migration approach can be considered as an infinite-frequency approximation of the Fresnel volume pre-stack depth migration method. We use line segments instead of the original waveform data. We demonstrate the method using synthetic data and analyze real data from Lines 4 - 7 to illustrate the relationship between distinct phases in the time domain and their resulting image at depth. We show both normal-moveout reflections from sub-horizontal interfaces and reverse-moveout reflections from steep interfaces, such as faults. Migrated images of dipping faults, such as the SAF and the Pinto Mountain Fault, are presented in this way. The SAF is imaged along Line 4, through the Mecca Hills, as a number of steeply dipping fault segments that collectively form a flower structure, above 5 km depth, that sole into a moderately NE-dipping fault below that depth. The individual migrated reflection packages correlate with mapped surface fault traces in the Mecca Hills. A similar geometry is seen on Line 6, from Palm Springs through Yucca Valley, where fault splays sole or project into a moderately dipping SAF below 10-km depth. We also show and discuss the reflectivity pattern of the middle and lower crust for Lines 4 - 7.

  14. Spectral albedos of sea ice and incident solar irradiance in the southern Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Grenfell, Thomas C.; Perovich, Donald K.

    1984-01-01

    Spectral albedos and incident spectral irradiances have been measured over the wavelength range 400 to 2400 nm on the sea ice near the Naval Arctic Research Laboratory (NARL) at Pt. Barrow, Alaska. The observation interval extended from mid-May, when the ice was still relatively cold, until mid-June, when summer melting was fully established. The temporal dependence of albedo for the available surface types was obtained over this time interval showing a general decrease from snow and snow-covered ice to blue ice and melt ponds. Data were also obtained for glacier ice on the Athabasca glacier, for melting lake ice, and for certain other nonice surfaces in the vicinity of NARL. Snow and ice albedos are characteristically highest at visible wavelengths, decreasing strongly in the infrared because of the increase in absorption by ice and water. Local maxima in the spectra correspond to minima in the ice and water absorption. Variations in albedo are due primarily to differences in the vapor bubble density, crystal structure, and free water content of the upper layers of the ice. Incident spectral shortwave radiation was measured as a function of cloudiness, and the optical thickness of arctic clouds is significantly less than the thickest clouds at lower latitudes. The decrease of the infrared component relatiave to the visible portion of the irradiance with increasing cloud cover is determined. This can give rise to an increase in wavelength-integrated albedos of as much as 15%. Using the present data, a graphical method is outlined by which visible near-infrared satellite imagery can be used to distinguish among melt ponds, open leads, and other spring and summer sea ice surface types.

  15. The application of active-source seismic imaging techniques to transtensional problems the Walker Lane and Salton Trough

    NASA Astrophysics Data System (ADS)

    Kell, Anna Marie

    The plate margin in the western United States is an active tectonic region that contains the integrated deformation between the North American and Pacific plates. Nearly focused plate motion between the North American and Pacific plates within the northern Gulf of California gives way north of the Salton Trough to more diffuse deformation. In particular a large fraction of the slip along the southernmost San Andreas fault ultimately bleeds eastward, including about 20% of the total plate motion budget that finds its way through the transtensional Walker Lane Deformation Belt just east of the Sierra Nevada mountain range. Fault-bounded ranges combined with intervening low-lying basins characterize this region; the down-dropped features are often filled with water, which present opportunities for seismic imaging at unprecedented scales. Here I present active-source seismic imaging from the Salton Sea and Walker Lane Deformation Belt, including both marine applications in lakes and shallow seas, and more conventional land-based techniques along the Carson range front. The complex fault network beneath the Salton Trough in eastern California is the on-land continuation of the Gulf of California rift system, where North American-Pacific plate motion is accommodated by a series of long transform faults, separated by small pull-apart, transtensional basins; the right-lateral San Andreas fault bounds this system to the north where it carries, on average, about 50% of total plate motion. The Salton Sea resides within the most youthful and northerly "spreading center" in this several thousand-kilometer-long rift system. The Sea provides an ideal environment for the use of high-data-density marine seismic techniques. Two active-source seismic campaigns in 2010 and 2011 show progression of the development of the Salton pull-apart sub-basin and the northerly propagation of the Imperial-San Andreas system through time at varying resolutions. High fidelity seismic imagery

  16. The West Salton Detachment Fault, Salton Trough, California: a Primary Low-Angle Normal Fault in an Evolving Dextral Wrench Zone

    NASA Astrophysics Data System (ADS)

    Axen, G. J.; Janecke, S.; Steely, A.; Shirvell, C.; Fluette, A.; Kairouz, M.; Housen, B.; Stockli, D.; Dorsey, R.; Grove, M.

    2006-12-01

    The west Salton detachment fault (WSDF), bounded the W rift flank, and was largely coeval with the southern San Andreas fault (SSAF). The WSDF is exposed in ~E-trending folds: broad, apparently primary corrugations S. Santa Rosa Mts., Borrego Valley-Pinyon Mts., Whale Peak, Vallecito Valley, and Tiera Blanca Mts) and narrow, post-WSDF folds (e.g., adjacent to San Felipe and Earthquake Valley faults). WSDF slip may have begun at ~12+, ~8.1, 5.5 or 4.6 Ma and was probably rapid from ~5 to 2 Ma. Two (U-Th)/He vertical transects from the WSDF footwall show rapid cooling since 12 Ma, and very rapid cooling between ~5.5-4.5 and ~2 Ma. Subsidence curves from the Fish Creek Vallecito basin (FCVB; Dorsey et al., this session) show increased rates at ~8.1 Ma, 5.5, and 4.6 Ma. Syntectonic conglomerate (base ~8.1 Ma) there records earliest extension, but may have been only local. Widespread marine deposits (~6.3 to 4.25 Ma) locally contain syndetachment fault-scarp facies; eustatic sea level rise may have controlled initial marine flooding. Subsidence was most rapid from ~4.6 to 3 Ma. Upper-plate normal faults are rare but folds formed locally. At Borrego Mtn. a WNW-trending anticline formed by ~6 Ma and persisted until after 4 Ma, coeval with WSDF slip. Folding at Split Mtn may have begun earlier. The WSDF has at least 5 km of E or NE slip, from offset basement but higher WSDF strands carry syntectonic conglomerates some additional distance. (U-Th)/He apatite ages from the upper and lower plates suggest ~2.4 km of footwall exhumation, yielding 5-15 km of slip, depending upon dip assumed. WSDF striae scatter widely, but concentrate at 090-110, probably the main or most recent slip direction. CW vertical- axis rotations have occurred (Housen et al., this session): ~3-4 m.y. old FCVB strata are rotated 19° ± 12°, and footwall La Posta pluton at Whale Peak rotated perhaps 36° (relative to the Peninsular Range La Posta). Similar rotations were common in N Baja CA in latest

  17. Unexpected pronounced heating in the uppermost layer of the Dead Sea after a sharp drop in noon surface solar radiation

    NASA Astrophysics Data System (ADS)

    Kishcha, Pavel; Starobinets, Boris; Gertman, Isaac; Ozer, Tal; Alpert, Pinhas

    2016-04-01

    A passage of frontal cloudiness accompanied by dust pollution over the Judean Mountains and the Dead Sea valley, which occurred on March 22, 2013, led to a sharp drop in noon solar radiation under weak winds (from 860 W m-2 to 50 W m-2). Solar radiation measurements showed that the transition from clear-sky to overcast conditions was sharper over the Dead Sea than over the Israel Mediterranean coast. The maximal rate of decrease in noon solar radiation at the Dead Sea almost doubled that near the Mediterranean coast (17 W m-2 min-1 vs. 10 W m-2 min-1). The temperature stratification was observed in the uppermost layer of the Dead Sea before the aforementioned drop in noon solar radiation. This temperature stratification was evidence that the weak winds were incapable of producing significant mixing in the Dead Sea. Buoy measurements showed that, unexpectedly, a sharp decrease in noon solar radiation caused pronounced heating in the uppermost layer of the Dead Sea. Evaporation from the Dead Sea surface leads to an increase in salinity in the surface layer. In the presence of significant solar radiation, this increased salinity in the surface layer did not lead to an increase in water density. The gravitational stability and temperature stratification in the uppermost layer were observed. By contrast, after the drop in solar radiation, the increased salinity in the surface layer led to an increase in water density and, consequently, to gravitational instability, because of higher density of surface seawater compared to the density in the layers below. The gravitational instability switched on a pronounced heating process in the 2-m uppermost layer of the Dead Sea. This temperature increase took place under weak winds, which were incapable of creating significant mechanical mixing in the Dead Sea. The heating of seawater in the 2-m uppermost layer was switched off later by the sharp influx of hot foehn winds up to 20 m/s from the lee side of the Judean Mts. into the

  18. Solar wind: A possible factor driving the interannual sea surface temperature tripolar mode over North Atlantic

    NASA Astrophysics Data System (ADS)

    Xiao, Ziniu; Li, Delin

    2016-06-01

    The effect of solar wind (SW) on the North Atlantic sea surface temperature (SST) in boreal winter is examined through an analysis of observational data during 1964-2013. The North Atlantic SSTs show a pronounced meridional tripolar pattern in response to solar wind speed (SWS) variations. This pattern is broadly similar to the leading empirical orthogonal function (EOF) mode of interannual variations in the wintertime SSTs over North Atlantic. The time series of this leading EOF mode of SST shows a significant interannual period, which is the same as that of wintertime SWS. This response also appears as a compact north-south seesaw of sea level pressure and a vertical tripolar structure of zonal wind, which simultaneously resembles the North Atlantic Oscillation (NAO) in the overlying atmosphere. As compared with the typical low SWS winters, during the typical high SWS winters, the stratospheric polar night jet (PNJ) is evidently enhanced and extends from the stratosphere to the troposphere, even down to the North Atlantic Ocean surface. Notably, the North Atlantic Ocean is an exclusive region in which the SW signal spreads downward from the stratosphere to the troposphere. Thus, it seems that the SW is a possible factor for this North Atlantic SST tripolar mode. The dynamical process of stratosphere-troposphere coupling, together with the global atmospheric electric circuit-cloud microphysical process, probably accounts for the particular downward propagation of the SW signal.

  19. Are solar activity and sperm whale Physeter macrocephalus strandings around the North Sea related?

    NASA Astrophysics Data System (ADS)

    Vanselow, Klaus Heinrich; Ricklefs, Klaus

    2005-04-01

    In the final decades of the last century, an increasing number of strandings of male sperm whales ( Physeter macrocephalus) around the North Sea led to an increase in public interest. Anthropogenic influences (such as contaminants or intensive sound disturbances) are supposed to be the main causes, but natural environmental effects may also explain the disorientation of the animals. We compared the documented sperm whale strandings in the period from 1712 to 2003 with solar activity, especially with sun spot number periodicity and found that 90% of 97 sperm whale stranding events around the North Sea took place when the smoothed sun spot period length was below the mean value of 11 years, while only 10% happened during periods of longer sun spot cycles. The relation becomes even more pronounced (94% to 6%, n = 70) if a smaller time window from November to March is used (which seems to be the main southward migration period of male sperm whales). Adequate chi-square tests of the data give a significance of 1% error probability that sperm whale strandings can depend on solar activity. As an alternative explanation, we suggest that variations of the earth's magnetic field, due to variable energy fluxes from the sun to the earth, may cause a temporary disorientation of migrating animals.

  20. Salt-gradient solar ponds: design, construction and power production

    SciTech Connect

    Wittenberg, L.J.

    1980-01-01

    Salt-gradient solar ponds are combined solar energy collectors and thermal storage systems. The ponds are made non-convective by the formation of a density-gradient composed of salt solutions whose concentrations increase with depth. The depth of the various layers of the pond determine the efficiency and thermal storage capacity of the system. The construction of the largest such pond in the US, 2000 m/sup 2/, was completed in 1978 for approximately $35/m/sup 2/. The pond is estimated to produce 1015 GJ/y of low-temperature heat at a cost of $8.95/GJ, when the installation costs are amortized over 15 y. Construction changes are suggested to improve the reliability of the system. Electrical power generation by the use of Rankine cycle turbogenerators connected to solar ponds has been demonstrated in Israel. Feasibility studies are in progress to propose electricity production of up to 2000 MW for projects near the Dead Sea in Israel, and 600 MW in a proposed project at the California Salton Sea.

  1. Solar total irradiance variations and the global sea surface temperature record

    SciTech Connect

    Reid, G.C. Univ. of Colorado, Boulder )

    1991-02-20

    The record of globally averaged sea surface temperature (SST) over the past 130 years shows a highly significant correlation with the envelope of the 11-year cycle of solar activity over the same period. This correlation could be explained by a variation in the sun's total irradiance (the solar constant) that is in phase with the solar-cycle envelope, supporting and updating an earlier conclusion by Eddy (1976) that such variations could have played a major role in climate change over the past millennium. Measurements of the total irradiance from spacecraft, rockets, and balloons over the past 25 years have provided evidence of long-term variations and have been used to develop a simple linear relationship between irradiance and the envelope of the sunspot cycle. This relationship has been used to force a one-dimensional model of the thermal structure of the ocean, consisting of a 100-m mixed layer coupled to a deep ocean and including a thermohaline circulation. The model was started in the mid-seventeenth century, at the time of the Maunder Minimum of solar activity, and mixed-layer temperatures were calculated at 6-month intervals up to the present. The total range of irradiance values during the period was about 1%, and the total range of SST was about 1C. Cool periods, when temperatures were about 0.5C below present-day values, were found in the early decades of both the nineteenth and twentieth centuries. The results can be taken as indicating that solar variability has been an important contributor to global climate variations in recent decades. The growing atmospheric burden of greenhouse gases may well have played an important role in the immediate past.

  2. SeaWiFS Postlaunch Technical Report Series. Volume 5; The SeaWiFS Solar Radiation-Based Calibration and the Transfer-to-Orbit Experiment

    NASA Technical Reports Server (NTRS)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Barnes, Robert A.; Eplee, Robert E., Jr.; Biggar, Stuart F.; Thome, Kurtis J.; Zalewski, Edward F.; Slater, Philip N.; Holmes, Alan W.

    1999-01-01

    The solar radiation-based calibration (SRBC) of the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) was performed on 1 November 1993. Measurements were made outdoors in the courtyard of the instrument manufacturer. SeaWiFS viewed the solar irradiance reflected from the sensor's diffuser in the same manner as viewed on orbit. The calibration included measurements using a solar radiometer designed to determine the transmittances of principal atmospheric constituents. The primary uncertainties in the outdoor measurements are the transmission of the atmosphere and the reflectance of the diffuser. Their combined uncertainty is about 5 or 6%. The SRBC also requires knowledge of the extraterrestrial solar spectrum. Four solar models are used. When averaged over the responses of the SeaWiFS bands, the irradiance models agree at the 3.6% level, with the greatest difference for SeaWiFS band 8. The calibration coefficients from the SRBC are lower than those from the laboratory calibration of the instrument in 1997. For a representative solar model, the ratios of the SRBC coefficients to laboratory values average 0.962 with a standard deviation of 0.012. The greatest relative difference is 0.946 for band 8. These values are within the estimated uncertainties of the calibration measurements. For the transfer-to-orbit experiment, the measurements in the manufacturer's courtyard are used to predict the digital counts from the instrument on its first day on orbit (August 1, 1997). This experiment requires an estimate of the relative change in the diffuser response for the period between the launch of the instrument and its first solar measurements on orbit (September 9, 1997). In relative terms, the counts from the instrument on its first day on orbit averaged 1.3% higher than predicted, with a standard deviation of 1.2% and a greatest difference of 2.4% or band 7. The estimated uncertainty for the transfer-to-orbit experiment is about 3 or 4%.

  3. Discussion on common errors in analyzing sea level accelerations, solar trends and global warming

    NASA Astrophysics Data System (ADS)

    Scafetta, N.

    2013-05-01

    Herein I discuss common errors in applying regression models and wavelet filters used to analyze geophysical signals. I demonstrate that: (1) multidecadal natural oscillations (e.g. the quasi 60 yr Multidecadal Atlantic Oscillation (AMO), North Atlantic Oscillation (NAO) and Pacific Decadal Oscillation (PDO)) need to be taken into account for properly quantifying anomalous background accelerations in tide gauge records such as in New York City; (2) uncertainties and multicollinearity among climate forcing functions also prevent a proper evaluation of the solar contribution to the 20th century global surface temperature warming using overloaded linear regression models during the 1900-2000 period alone; (3) when periodic wavelet filters, which require that a record is pre-processed with a reflection methodology, are improperly applied to decompose non-stationary solar and climatic time series, Gibbs boundary artifacts emerge yielding misleading physical interpretations. By correcting these errors and using optimized regression models that reduce multicollinearity artifacts, I found the following results: (1) the relative sea level in New York City is not accelerating in an alarming way, and may increase by about 350 ± 30 mm from 2000 to 2100 instead of the previously projected values varying from 1130 ± 480 mm to 1550 ± 400 mm estimated using the methods proposed, e.g., by Sallenger Jr. et al. (2012) and Boon (2012), respectively; (2) the solar activity increase during the 20th century contributed at least about 50% of the 0.8 °C global warming observed during the 20th century instead of only 7-10% (e.g.: IPCC, 2007; Benestad and Schmidt, 2009; Lean and Rind, 2009; Rohde et al., 2013). The first result was obtained by using a quadratic polynomial function plus a 60 yr harmonic to fit a required 110 yr-long sea level record. The second result was obtained by using solar, volcano, greenhouse gases and aerosol constructors to fit modern paleoclimatic temperature

  4. Clear-Sky Surface Solar Radiation During South China Sea Monsoon Experiment

    NASA Technical Reports Server (NTRS)

    Lin, Po-Hsiung; Chou, Ming-Dah; Ji, Qiang; Tsay, Si-Chee; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Downward solar fluxes measured at Dungsha coral island (20 deg. 42 min. N, 116 deg. 43 min. E) during the South China Sea Monsoon Experiment (May-June 1998) have been calibrated and compared with radiative transfer calculations for three clear-sky days. Model calculations use water vapor and temperature profiles from radiosound measurements and the aerosol optical thickness derived from sunphotometric radiance measurements at the surface. Results show that the difference between observed and model-calculated downward fluxes is less than 3% of the daily mean. Averaged over the three clear days, the difference reduces to 1%. The downward surface solar flux averaged over the three days is 314 W per square meters from observations and 317 W per square meters from model calculations, This result is consistent with a previous study using TOGA CAORE measurements, which found good agreements between observations and model calculations. This study provides an extra piece of useful information on the modeling of radiative transfer, which fills in the puzzle of the absorption of solar radiation in the atmosphere.

  5. Evaporation and solar irradiance as regulators of sea surface temperature in annual and interannual changes

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Zhang, Anzhen; Bishop, James K. B.

    1994-01-01

    Seven years of net surface solar irradiance (S) derived from cloud information provided by the International Satellite Cloud Climatology Project (ISCCP) and 4 years of surface latent heat flux (E) derived from the observations of the special sensor microwave imager (SSM/I) were used to examine the relation between surface heat fluxes and sea surface temperature (T(sub s)) in their global geographical distribution, seasonal cycle, and interannual variation. The relations of seasonal changes imply that evaporation cooling is significant over most of the ocean and that solar heating is the main drive for the change of T(sub s) away from the equatorial wave guide where ocean dynamics may be more important. However, T(sub s) is not the most direct and significant factor in the seasonal changes of S and E over most of the ocean; the solar incident angle may be more important to S, and wind speed and air humidity are found to correlate better with E. Significant local correlations between anomalies of T(sub s) and S and between anomalies of T(sub s) and E are found in the central equatorial Pacific; both types of correlation are negative. The influence of ocean dynamics in changing T(sub s) in the tropical ocean cannot be ignored.

  6. Photocatalytic activity of sea water using TiO₂ catalyst under solar light.

    PubMed

    Shinde, S S; Bhosale, C H; Rajpure, K Y

    2011-05-01

    Wastewater is generally released into the rivers and streams in developing countries. Industrial wastewater usually contains highly toxic pollutants, cyanides, chlorinated compounds. Ultraviolet (UV) radiation from sunlight also decomposes organic compounds by oxidation process. However, the process is less effective due to large amount of toxic effluent entering in the main stream of water. The solar radiation can effectively be applied to accelerate the process by using suitable catalyst for economically cleaning the water sources. This paper describes the photocatalytic degradation of the sea water using novel approach of photoelectrochemical (PEC) reactor module consisting of nine photoelectrochemical cells equipped with spray deposited TiO₂ catalysts under solar light. The resulted water samples were studied for physicochemical and bacteriological analysis. The complete mineralization of degraded sample was confirmed by total organic carbon (TOC) analysis, COD measurement and estimation of the formation of inorganic ions such as NH₄(+), NO₃⁻, Cl⁻ and SO²⁻₄. Microbiological examinations are performed to determine the bacterial analysis. This implies that photoelectrocatalysis could be a promising way for improving water quality in developing countries with low cost and clean energy reliable resource. PMID:21377373

  7. Midwestern streamflow, precipitation, and atmospheric vorticity influenced by Pacific sea-surface temperatures and total solar-irradiance variations

    USGS Publications Warehouse

    Perry, C.A.

    2006-01-01

    A solar effect on streamflow in the Midwestern United States is described and supported in a six-step physical connection between total solar irradiance (TSI), tropical sea-surface temperatures (SSTs), extratropical SSTs, jet-stream vorticity, surface-layer vorticity, precipitation, and streamflow. Variations in the correlations among the individual steps indicate that the solar/hydroclimatic mechanism is complex and has a time element (lag) that may not be constant. Correct phasing, supported by consistent spectral peaks between 0.092 and 0.096 cycles per year in all data sets within the mechanism is strong evidence for its existence. A significant correlation exists between total solar irradiance and the 3-year moving average of annual streamflow for Iowa (R = 0.67) and for the Mississippi River at St Louis, Missouri (R = 0.60), during the period 1950-2000. Published in 2005 by John Wiley & Sons, Ltd.

  8. Borehole-explosion and air-gun data acquired in the 2011 Salton Seismic Imaging Project (SSIP), southern California: description of the survey

    USGS Publications Warehouse

    Rose, Elizabeth J.; Fuis, Gary S.; Stock, Joann M.; Hole, John A.; Kell, Annie M.; Kent, Graham; Driscoll, Neal W.; Goldman, Mark; Reusch, Angela M.; Han, Liang; Sickler, Robert R.; Catchings, Rufus D.; Rymer, Michael J.; Criley, Coyn J.; Scheirer, Daniel S.; Skinner, Steven M.; Slayday-Criley, Coye J.; Murphy, Janice M.; Jensen, Edward G.; McClearn, Robert; Ferguson, Alex J.; Butcher, Lesley A.; Gardner, Max A.; Emmons, Iain; Loughran, Caleb L.; Svitek, Joseph R.; Bastien, Patrick C.; Cotton, Joseph A.; Croker, David S.; Harding, Alistair J.; Babcock, Jeffrey M.; Harder, Steven H.; Rosa, Carla M.

    2013-01-01

    detailed images we need for earthquake hazard assessment. Air gun bursts, generated in the Salton Sea along extensions of our onshore seismic lines, also were utilized as sound-wave sources. Temporary deployments of portable land seismometers, as well as ocean-bottom seismometers (OBSs) on the floor of the Salton Sea, recorded the energy from the land shots and air gun bursts. SSIP is similar to the Los Angeles Regional Seismic Experiments of 1994 and 1999 (LARSE I and II, respectively; Murphy and others, 1996; Fuis and others, 2001). The LARSE surveys demonstrated that the USGS and collaborators can safely and effectively conduct seismic imaging surveys in urban and nonurban areas, on lands owned and/or managed by many different types of agencies and entities. Information was produced that could not have been obtained any other way, and this information was key to changing the leading ideas about earthquake hazards at that time in the Los Angeles region. These surveys produced no significant environmental impact or damage to structures, and they did not trigger earthquakes.

  9. Fluctuations of the Caspian Sea level in the quasi-two-year and 11-year cycles of solar activity

    SciTech Connect

    Nuzhdina, M.A.

    1995-07-01

    Fluctuations of the Caspian Sea level due to dynamics of solar activity in its quasi-two-year and 11-year cycles, as well as to the influence of the 22-to 23-year magnetic cycle are analyzed. Perturbation of the geomagnetic field and the atmospheric circulation are regarded as a transmitting mechanism of the Sun`s influence on the Earth`s hydrosphere.

  10. Fault tectonics and earthquake hazards in parts of southern California. [penninsular ranges, Garlock fault, Salton Trough area, and western Mojave Desert

    NASA Technical Reports Server (NTRS)

    Merifield, P. M. (Principal Investigator); Lamar, D. L.; Gazley, C., Jr.; Lamar, J. V.; Stratton, R. H.

    1976-01-01

    The author has identified the following significant results. Four previously unknown faults were discovered in basement terrane of the Peninsular Ranges. These have been named the San Ysidro Creek fault, Thing Valley fault, Canyon City fault, and Warren Canyon fault. In addition fault gouge and breccia were recognized along the San Diego River fault. Study of features on Skylab imagery and review of geologic and seismic data suggest that the risk of a damaging earthquake is greater along the northwestern portion of the Elsinore fault than along the southeastern portion. Physiographic indicators of active faulting along the Garlock fault identifiable in Skylab imagery include scarps, linear ridges, shutter ridges, faceted ridges, linear valleys, undrained depressions and offset drainage. The following previously unrecognized fault segments are postulated for the Salton Trough Area: (1) An extension of a previously known fault in the San Andreas fault set located southeast of the Salton Sea; (2) An extension of the active San Jacinto fault zone along a tonal change in cultivated fields across Mexicali Valley ( the tonal change may represent different soil conditions along opposite sides of a fault). For the Skylab and LANDSAT images studied, pseudocolor transformations offer no advantages over the original images in the recognition of faults in Skylab and LANDSAT images. Alluvial deposits of different ages, a marble unit and iron oxide gossans of the Mojave Mining District are more readily differentiated on images prepared from ratios of individual bands of the S-192 multispectral scanner data. The San Andreas fault was also made more distinct in the 8/2 and 9/2 band ratios by enhancement of vegetation differences on opposite sides of the fault. Preliminary analysis indicates a significant earth resources potential for the discrimination of soil and rock types, including mineral alteration zones. This application should be actively pursued.

  11. The effect of sea ice on the solar energy budget in the astmosphere-sea ice-ocean system: A model study

    NASA Technical Reports Server (NTRS)

    Jin, Z.; Stamnes, Knut; Weeks, W. F.; Tsay, Si-Chee

    1994-01-01

    A coupled one-dimensional multilayer and multistream radiative transfer model has been developed and applied to the study of radiative interactions in the atmosphere, sea ice, and ocean system. The consistent solution of the radiative transfer equation in this coupled system automatically takes into account the refraction and reflection at the air-ice interface and allows flexibility in choice of stream numbers. The solar radiation spectrum (0.25 micron-4.0 micron) is divided into 24 spectral bands to account adequately for gaseous absorption in the atmosphere. The effects of ice property changes, including salinity and density variations, as well as of melt ponds and snow cover variations over the ice on the solar energy distribution in the entire system have been studied quantitatively. The results show that for bare ice it is the scattering, determined by air bubbles and brine pockets, in just a few centimeters of the top layer of ice that plays the most important role in the solar energy absorption and partitioning in the entire system. Ice thickness is important to the energy distribution only when the ice is thin, while the absorption in the atmosphere is not sensitive to ice thickness exceeds about 70 cm. The presence of clouds moderates all the sensitivities of the absorptive amounts in each layer to the variations in the ice properties and ice thickness. Comparisons with observational spectral albedo values for two simple ice types are also presented.

  12. Seasonal Evolution and Interannual Variability of the Local Solar Energy Absorbed by the Arctic Sea Ice-Ocean System

    NASA Technical Reports Server (NTRS)

    Perovich, Donald K.; Nghiem, Son V.; Markus, Thorsten; Schwieger, Axel

    2007-01-01

    The melt season of the Arctic sea ice cover is greatly affected by the partitioning of the incident solar radiation between reflection to the atmosphere and absorption in the ice and ocean. This partitioning exhibits a strong seasonal cycle and significant interannual variability. Data in the period 1998, 2000-2004 were analyzed in this study. Observations made during the 1997-1998 SHEBA (Surface HEat Budget of the Arctic Ocean) field experiment showed a strong seasonal dependence of the partitioning, dominated by a five-phase albedo evolution. QuikSCAT scatterometer data from the SHEBA region in 1999-2004 were used to further investigate solar partitioning in summer. The time series of scatterometer data were used to determine the onset of melt and the beginning of freezeup. This information was combined with SSM/I-derived ice concentration, TOVS-based estimates of incident solar irradiance, and SHEBA results to estimate the amount of solar energy absorbed in the ice-ocean system for these years. The average total solar energy absorbed in the ice-ocean system from April through September was 900 MJ m(sup -2). There was considerable interannual variability, with a range of 826 to 1044 MJ m(sup -2). The total amount of solar energy absorbed by the ice and ocean was strongly related to the date of melt onset, but only weakly related to the total duration of the melt season or the onset of freezeup. The timing of melt onset is significant because the incident solar energy is large and a change at this time propagates through the entire melt season, affecting the albedo every day throughout melt and freezeup.

  13. Changes in sea-level pressure over South Korea associated with high-speed solar wind events

    NASA Astrophysics Data System (ADS)

    Cho, Il-Hyun; Kwak, Young-Sil; Marubashi, Katsuhide; Kim, Yeon-Han; Park, Young-Deuk; Chang, Heon-Young

    2012-09-01

    We explore a possibility that the daily sea-level pressure (SLP) over South Korea responds to the high-speed solar wind event. This is of interest in two aspects: first, if there is a statistical association this can be another piece of evidence showing that various meteorological observables indeed respond to variations in the interplanetary environment. Second, this can be a very crucial observational constraint since most models proposed so far are expected to preferentially work in higher latitude regions than the low latitude region studied here. We have examined daily solar wind speed V, daily SLP difference ΔSLP, and daily log(BV2) using the superposed epoch analysis in which the key date is set such that the daily solar wind speed exceeds 800 km s-1. We find that the daily ΔSLP averaged out of 12 events reaches its peak at day +1 and gradually decreases back to its normal level. The amount of positive deviation of ΔSLP is +2.5 hPa. The duration of deviation is a few days. We also find that ΔSLP is well correlated with both the speed of solar wind and log(BV2). The obtained linear correlation coefficients and chance probabilities with one-day lag for two cases are r ≃ 0.81 with P > 99.9%, and r ≃ 0.84 with P > 99.9%, respectively. We conclude by briefly discussing future direction to pursue.

  14. On the correlation of spatial wind speed and solar irradiance variability above the North Sea

    NASA Astrophysics Data System (ADS)

    Rieke Mehrens, Anna; von Bremen, Lueder

    2016-04-01

    Mesoscale wind fluctuations on a time scale of tens of minutes to several hours lead to high wind power fluctuations. Enhanced mesoscale wind variability emerges during cold air outbreaks and resulting cellular convection. The study investigates spatial wind and solar variability and their correlation during cellular convection. Cellular convection leads to simultaneous high solar and wind variability, but the highest solar or wind variability occurs due to other meteorological phenomena.

  15. SUMMER MOVEMENTS OF DESERT PUPFISH AMONG HABITATS AT THE SALTON SEA. (R826552)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  16. INVERTEBRATES OF THE SALTON SEA: A SCANNING ELECTRON MICROSCOPY PORTFOLIO. (R826552)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  17. THE BENTHIC INVERTEBRATES OF THE SALTON SEA: DISTRIBUTION AND SEASONAL DYNAMICS. (R826552)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  18. METAZOOPLANKTON DYNAMICS IN THE SALTON SEA, CALIFORNIA, 1997-1999. (R826552)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  19. THERMAL, MIXING, AND OXYGEN REGIMES OF THE SALTON SEA, CALIFORNIA, 1997-1999. (R826552)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  20. Possible Solar-Linked Climate Controls on Recurring Dispersal of Sediment-Bearing Sea Ice During the Holocene

    NASA Astrophysics Data System (ADS)

    Bond, G. C.; Bauerfiend, E.; Almasi, P.; Dwyer, G. S.

    2002-12-01

    Records of Holocene IRD (ice rafted debris) in the subpolar North Atlantic have recently been tied to variations in solar output. That finding underscores the importance of understanding how coarse (sand-sized) lithic sediment comprising the IRD is linked to ice in the ocean and to climate. New data from sediment traps in the Greenland and Norwegian Seas suggests that the Holocene IRD is released from melting multiyear sea ice exiting the Arctic through Fram Strait. Analyses of over 50 sediment trap samples demonstrate that large numbers of sand sized grains settle through the water column during all months of the year. Fluxes of those grains are higher by factors of 3 to 4 than those estimated at the sites of the Holocene records, consistent with those locations in warmer waters to the south. In addition, 15 to 20 percent of the sediment trap lithic grains have hematite staining, which is a robust petrologic tracer of the sea ice trajectories associated with the Holocene IRD. New evidence from NCEP-NCAR reanalysis demonstrates that anomalous north to northwesterly winds in the eastern North Atlantic, which are required to explain the record of hematite-stained grains in that region during the Holocene, occurred at rather specific times during the last several decades. Those times correspond to increases in extreme drift ice sightings and to a 1 to 2 degree cooling of the ocean surface. Similar temperature changes during the Holocene IRD events are suggested by Mg/Ca measurements in planktic foraminifera from eastern North Atlantic coring sites. The most persistent north to northwesterly winds occurred during spring and summer and at times when pressure increased in both the Azores and Hawaiian highs. A link therefore appears to exist between the Holocene shifts in North Atlantic drift ice and subtropical atmospheric circulation, which in turn, based on results of recent GCM models, may be influenced by solar variability.

  1. A Study of Tropical Cyclones over India (Bay of Bengal and Arabian Sea) and Solar Influence on It

    NASA Astrophysics Data System (ADS)

    Banerjee, Dhruba

    2016-07-01

    A prominent example of extreme weather event in India is Cyclonic Storm. In this paper annual variation of tropical Cyclonic Storm (CS), Severe Cyclonic Storm (SCS), Very Severe Cyclonic Storm (VSCS) and Super Cyclonic Storm (SuCS) over Bay Of Bengal (BOB) and Arabian Sea (ARS) during last 20 years (1990-2009) have been analyzed .The analysis revels that the total number of cyclone (TNC) has increased with high rate(gradient being +1.67 per year) and although C.S. is more over BOB than that over ARS.The rate of increase of C.S. over Arabian Sea is more than that over Bay of Bengal. Furthermore, two interesting features have been noted: (i) Monsoon tends to prohibit the formation of C.S (ii) Cyclonic Storm(C.S.) increases with the increase of Global Sea Surface Temperature (GSST) during said period.. Attempt has also been made to find out the influence of solar activity on these extreme weather events. Keeping in mind that the Sun Spot Number (SSN) is an indicator of the strength of solar effects, it has been found that in most of the times the high value of SSN is associated with small number of total cyclone (C.S.). Specifically, when only the years of high Sun's Spot Number (approximately greater than 90) are taken into consideration then Correlation Coefficient (C.C.) between SSN and number of cyclones comes out to be quite high (-0.78) significance at 99.99% level while Correlation Coefficient (C.C.) of cyclones with time is 0.53 and with SSN < 60 it is..095 . Thus it appears that although C.S. frequency is increasing with time, Sun's Spot's influence is such that it basically opposes the formation of cyclone provided SSN exceeds certain critical value (roughly 90). In principle, this is very important for any such event, and it is consistent with the trend of different phenomena occurring in nature. Key words: India, cyclone, solar influence, Critical Sun's Spot Number

  2. Evaporation and Solar Irradiance as Regulators of Sea Surface Temparature in Annual and Interrannual Changes

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy

    1994-01-01

    After numerical studies showed that global climate is sensitive to small changes in sea surface temperature (Ts), considerabel effort has been devoted to examine the role of surface fluxes in changing upper ocean heat balance and Ts, particularly in the tropical Pacific where interannual signals, such as El Nino Southern Oscillation (ENSO), have major economic and ecological impacts.

  3. Observed relationship between Arctic sea ice, cloud, and solar radiation and its implication for ice-albedo feedback

    NASA Astrophysics Data System (ADS)

    Choi, Y. S.; Kim, B. M.; Hur, S. K.; Kim, S. J.; Kim, J. H.; Ho, C. H.

    2014-12-01

    This study demonstrates that absorbed solar radiation (ASR) at the top of the atmosphere in early summer (May-July) plays a precursory role in determining the Arctic sea ice concentration (SIC) in late summer (August-October). The monthly ASR anomalies are obtained over the Arctic Ocean (65°N-90°N) from the Clouds and the Earth's Radiant Energy System during 2000-2013. The ASR anomaly changes primarily with cloud variation that determines relative contributions of cloud and surface albedo to the ASR. We found that the ASR anomaly in early summer is significantly negatively correlated with the SIC anomaly in late summer (correlation coefficient, r ≈ -0.8 with a lag of 1 to 4 months). The region exhibiting high (low) ASR anomalies and low (high) SIC anomalies varies yearly. This intimate delayed ASR-SIC relationship is not represented in most of current climate models. Rather, the models tend to over-emphasize internal sea ice processes in summer. Implication of the observed results for ice-albedo feedback will be presented.

  4. Early Pliocene Hiatus in Sand Output by the Colorado River: Evidence From Marine Deposits in the Salton Trough, Southern California

    NASA Astrophysics Data System (ADS)

    Dorsey, R. J.; Bykerk-Kauffman, A.

    2015-12-01

    Early Pliocene deposits in the western Salton Trough preserve a high-fidelity record of sediment dispersal into the marine realm during initiation and early evolution of the Colorado River (CR). Grain-size fractionation, sediment routing, and transport dynamics of the early CR delta are recorded in sediments of the Fish Creek - Vallecito basin, which was located ~100 km south of Yuma along the transform plate boundary at 5 Ma. Early Pliocene delivery of CR sand to the basin took place in two distinct pulses: (1) deposition of sandy turbidites (Wind Caves Mbr of the Latrania Fm) in a restricted submarine canyon at Split Mt Gorge between ~5.3 and 5.1 Ma; and (2) progradation of a thick, widespread, coarsening-up deltaic sequence of marine mudstone, sandstone, and coquinas (Deguynos Fm) between ~4.8 and 4.2 Ma. Estimated flux of CR sediment during Wind Caves deposition was weak (~3-5 Mt/yr) compared to the long-term average (172±64 Mt/yr). The two pulses of CR sand input are separated by the Coyote Clay (CC, ~5.1-4.8 Ma), a regionally correlable, greenish-yellow-weathering marine claystone unit at the base of the Deguynos Fm. CC gradationally overlies Wind Caves turbidites in the area of the paleocanyon. In contrast, in the Coyote Mts 15-23 km to the south and SE, CC rests on coarse-grained locally-derived late Miocene sedimentary rocks, Alverson volcanics, and metamorphic basement rock along a regional unconformity. Identical claystone facies occur in the NW Indio Hills (restores to Yuma at the mouth of the CR at 5 Ma), and Sierra Cucapa in Mexico (~200 km south of Yuma at 5 Ma). Marine localities outside of the Wind Caves paleocanyon experienced slow to negligible sedimentation along a rugged rocky shoreline until abrupt arrival of CR-derived clay. CC accumulated in a sand-starved, pro-delta marine setting (Winker, 1987) over an inferred N-S distance of ~200 km. We therefore reject an alternate hypothesis that CC accumulated on the muddy slope of the prograding CR

  5. Estimation of sea surface solar radiation at 400-700 nm using satellite ocean color data, and its validation by ship data.

    PubMed

    Vazyulya, S V; Kopelevich, O V; Sheberstov, S V; Artemiev, V A

    2016-03-21

    We present results of validating the algorithms used to estimate sea surface solar radiation at 400-700 nm, photosynthetically available radiation (PAR), from satellite ocean color data and an appropriate validation procedure when data are collected using a moving ship. The validation was performed using field measurements of PAR during a transit cruise from the Baltic to the White Sea during the summer of 2014. The PAR was measured at 10-minute intervals using a deck radiometer throughout the daylight hours. The satellite estimate of daily surface PAR with an acceptable error, on the scale of 1 day-102 km, is shown. PMID:27136880

  6. Effect of sea-ice melt on inherent optical properties and vertical distribution of solar radiant heating in Arctic surface waters

    NASA Astrophysics Data System (ADS)

    Granskog, Mats A.; Pavlov, Alexey K.; Sagan, Sławomir; Kowalczuk, Piotr; Raczkowska, Anna; Stedmon, Colin A.

    2015-10-01

    The inherent optical properties (IOPs) of Polar Waters (PW) exiting the Arctic Ocean in the East Greenland Current (EGC) and of the inflowing Atlantic waters (AW) in the West Spitsbergen Current (WSC) were studied in late summer when surface freshening due to sea-ice melt was widespread. The absorption and attenuation coefficients in PW were significantly higher than previous observations from the western Arctic. High concentrations of colored dissolved organic matter (CDOM) resulted in 50-60% more heat deposition in the upper meters relative to clearest natural waters. This demonstrates the influence of terrigenous organic material inputs on the optical properties of waters in the Eurasian basin. Sea-ice melt in CDOM-rich PW decreased CDOM absorption, but an increase in scattering nearly compensated for lower absorption, and total attenuation was nearly identical in the sea-ice meltwater layer. This suggests a source of scattering material associated with sea-ice melt, relative to the PW. In the AW, melting sea-ice forms a stratified surface layer with lower absorption and attenuation, than well-mixed AW waters in late summer. It is likely that phytoplankton in the surface layer influenced by sea-ice melt are nutrient limited. The presence of a more transparent surface layer changes the vertical radiant heat absorption profile to greater depths in late summer both in EGC and WSC waters, shifting accumulation of solar heat to greater depths and thus this heat is not directly available for ice melt during periods of stratification.

  7. Single and Double ITCZ in Aqua-Planet Models with Globally Uniform Sea Surface Temperature and Solar Insolation: An Interpretation

    NASA Technical Reports Server (NTRS)

    Chao, Winston C.; Chen, Baode; Einaudi, Franco (Technical Monitor)

    2001-01-01

    It has been known for more than a decade that an aqua-planet model with globally uniform sea surface temperature and solar insolation angle can generate ITCZ (intertropical convergence zone). Previous studies have shown that the ITCZ under such model settings can be changed between a single ITCZ over the equator and a double ITCZ straddling the equator through one of several measures. These measures include switching to a different cumulus parameterization scheme, changes within the cumulus parameterization scheme, and changes in other aspects of the model design such as horizontal resolution. In this paper an interpretation for these findings is offered. The latitudinal location of the ITCZ is the latitude where the balance of two types of attraction on the ITCZ, both due to earth's rotation, exists. The first type is equator-ward and is directly related to the earth's rotation and thus not sensitive to model design changes. The second type is poleward and is related to the convective circulation and thus is sensitive to model design changes. Due to the shape of the attractors, the balance of the two types of attractions is reached either at the equator or more than 10 degrees away from the equator. The former case results in a single ITCZ over the equator and the latter case a double ITCZ straddling the equator.

  8. Solar PAR and UVR modify the community composition and photosynthetic activity of sea ice algae.

    PubMed

    Enberg, Sara; Piiparinen, Jonna; Majaneva, Markus; Vähätalo, Anssi V; Autio, Riitta; Rintala, Janne-Markus

    2015-10-01

    The effects of increased photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) on species diversity, biomass and photosynthetic activity were studied in fast ice algal communities. The experimental set-up consisted of nine 1.44 m(2) squares with three treatments: untreated with natural snow cover (UNT), snow-free (PAR + UVR) and snow-free ice covered with a UV screen (PAR). The total algal biomass, dominated by diatoms and dinoflagellates, increased in all treatments during the experiment. However, the smaller biomass growth in the top 10-cm layer of the PAR + UVR treatment compared with the PAR treatment indicated the negative effect of UVR. Scrippsiella complex (mainly Scrippsiella hangoei, Biecheleria baltica and Gymnodinium corollarium) showed UV sensitivity in the top 5-cm layer, whereas Heterocapsa arctica ssp. frigida and green algae showed sensitivity to both PAR and UVR. The photosynthetic activity was highest in the top 5-cm layer of the PAR treatment, where the biomass of the pennate diatom Nitzschia frigida increased, indicating the UV sensitivity of this species. This study shows that UVR is one of the controlling factors of algal communities in Baltic Sea ice, and that increased availability of PAR together with UVR exclusion can cause changes in algal biomass, photosynthetic activity and community composition. PMID:26310455

  9. The solar hydrogen from sea water using Cu/TiO2

    NASA Astrophysics Data System (ADS)

    Selvaraj, Baraniruben A./l.; Kait, Chong Fai; Bustam, M. Azmi; Nurlaela, Ela

    2012-09-01

    H2 production from water under visible light radiation has great potential for sustainable energy supply. The incorporation of 10 wt% Cu onto TiO2 via precipitation method in the presence of glycerol, followed by activation at 180°C and 200°C, was investigated for H2 production from sea water under visible light radiation. The photocatalysts were also characterized using Fourier Transform Infrared Spectroscopy (FTIR), powder X-Ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), temperature-programmed reduction (TPR) and diffuse reflectance UV-visible spectrophotometry (DR-UV-Vis). Results indicated that photocatalyst calcined at 180°C for 30 min displayed the best performance for H2 production (9.1 mL) compared to TiO2 which produced merely 4.4 mL H2. The bandgap energy of this photocatalyst was lower (3.10 eV) compare to that for TiO2 (3.16 eV). Details of the synthesis procedure, photocatalysts characterization, and photoreaction are presented in this paper.

  10. Heat Flow in the Salton Trough Revisited and Implications for Regional Tectonics

    NASA Astrophysics Data System (ADS)

    Williams, C.; DeAngelo, J.; Galanis, P.

    2012-12-01

    As part of research into the geothermal energy resources of the Salton Trough, we have assembled a database of 1060 temperature-gradient and heat-flow measurements acquired by the geothermal industry, universities, national labs, and the US Geological Survey (USGS) throughout the region from the early 1970s to the present. In addition to using the data to examine the nature and occurrence of hydrothermal systems, we have estimated the total heat flux through the Trough and investigated relationships between subsurface thermal conditions and the character of faulting and seismicity. Our analysis for the Imperial Valley and other portions of the Salton Trough physiographic province gives an average heat flow of ~160 mW/m2 compared to the 140 mW/m2 average determined by Lachenbruch and others in the last regional study (JGR, v.90, n. B8, 1986). The higher average reflects a larger contribution to the total heat flux from hydrothermal systems that was not recognized in earlier studies due to incomplete spatial coverage. Most of these hydrothermal systems are associated with step-overs and other structural complexities in the fault zones that pass through the region, and the dense coverage of the new heat flow database allows for a detailed examination of the degree to which variations of convective and conductive heat transfer in this region influence, and are influenced by, active tectonic processes. We compared estimated subsurface temperatures from a conductive heat transfer model with the observed depth variation of the upper and lower boundaries of the seismogenic zone along active faults both within and along the margins of the Imperial Valley, and for those areas characterized by average heat flow less than or equal to 150 mW/m2, the base of the seismogenic zone is near the estimated depth of the 400 °C isotherm, a result that is consistent with observations in other seismically active regions. The base of seismicity continues to shallow where heat flow

  11. Evolution of Rotations in the Fish Creek Vallecito Basin, Western Salton Trough, CA

    NASA Astrophysics Data System (ADS)

    Housen, B. A.; Dorsey, R. J.; Janecke, S. U.; Axen, G. J.

    2006-12-01

    Rocks in the Western Salton Trough region record the history of slip on the transtensional West Salton detachment fault and initiation of younger strike-slip faults in this plate boundary zone. Spatial and temporal patterns of vertical axis rotations as determined by paleomagnetism can be used to provide valuable constraints on the structural-tectonic evolution of this area. Prior work includes the magnetostratigraphy of Plio-Pleistocene sedimentary rocks in the Fish Creek-Vallecito Basin (FCVB) (Opdyke et al., 1977; Johnson et al., 1983), who found that these rocks contain a complete record of geomagnetic field reversals spanning Pliocene-Pleistocene time. Johnson et al. (1983) also concluded that the FCVB had undergone 35° of CW rotation during the past 0.9 Ma. We resampled and reanalyzed their section, and sampled additional sedimentary and plutonic rocks in the Western Salton Trough in order to better document the history of vertical axis rotation recorded by these rocks. Results from 29 sites in the FCVB have well-defined magnetizations with two components. The first removed component in all samples is unblocked between 90 and 220 °C, and the second-removed components are unblocked between 300 and 590 °C. The second-removed components have either normal or reversed polarity. Sites from the Diablo Fm are predominantly reversed and have a mean of D = 204, I = -48.3, k = 37, α95 = 12.7°, N = 5. Sites from the middle of the section (Olla and Tapiado Fms) are predominantly normal and have a mean of D = 8.1, I = 48, k = 32, α95= 8.7°, N = 10. Sites from the upper portion of the section (Hueso Fm) have predominantly reversed polarity with means of D = 179.6, I = -43.4, k = 82, α95 = 10.2°, N = 4. Results from weakly-magnetized and deformed rocks of the La Posta pluton, on the south side of Whale Peak, have well-defined magnetizations with a group mean direction of D = 16.3, I = 37.3, k = 44, α95 = 7.4°, N = 10. The stratigraphic distribution of declination

  12. Shallow hydrothermal regime of the East Brawley and Glamis known geothermal resource areas, Salton Trough, California

    SciTech Connect

    Mase, C.W.; Sass, J.H.; Brook, C.A.; Munroe, R.J.

    1981-01-01

    Thermal gradients and thermal conductivities were obtained in real time using an in situ heat-flow technique in 15 shallow (90 to 150 m) wells drilled between Brawley and Glamis in the Imperial Valley, Southern California. The in situ measurements were supplemented by follow-up conventional temperature logs in seven of the wells and by laboratory measurements of thermal conductivity on drill cuttings. The deltaic sedimentary material comprising the upper approx. 100 m of the Salton Trough generally is poorly sorted and high in quartz resulting in quite high thermal conductivities (averaging 2.0 Wm/sup -1/ K/sup -1/ as opposed to 1.2 to 1.7 for typical alluvium). A broad heat-flow anomaly with maximum of about 200 mWm/sup -2/ (approx. 5 HFU) is centered between Glamis and East Brawley and is superimposed on a regional heat-flow high in excess of 100 mWm/sup -2/ (> 2.5 HFU). The heat-flow high corresponds with a gravity maximum and partially with a minimum in electrical resistivity, suggesting the presence of a hydrothermal system at depth in this area.

  13. Faults on Skylab imagery of the Salton Trough area, Southern California

    NASA Technical Reports Server (NTRS)

    Merifield, P. M.; Lamar, D. L. (Principal Investigator)

    1975-01-01

    The author has identified the following significant results. Large segments of the major high angle faults in the Salton Trough area are readily identifiable in Skylab images. Along active faults, distinctive topographic features such as scarps and offset drainage, and vegetation differences due to ground water blockage in alluvium are visible. Other fault-controlled features along inactive as well as active faults visible in Skylab photography include straight mountain fronts, linear valleys, and lithologic differences producing contrasting tone, color or texture. A northwestern extension of a fault in the San Andreas set, is postulated by the regional alignment of possible fault-controlled features. The suspected fault is covered by Holocene deposits, principally windblown sand. A northwest trending tonal change in cultivated fields across Mexicali Valley is visible on Skylab photos. Surface evidence for faulting was not observed; however, the linear may be caused by differences in soil conditions along an extension of a segment of the San Jacinto fault zone. No evidence of faulting could be found along linears which appear as possible extensions of the Substation and Victory Pass faults, demonstrating that the interpretation of linears as faults in small scale photography must be corroborated by field investigations.

  14. The measurement and analysis of normal incidence solar UVB radiation and its application to the photoclimatherapy protocol for psoriasis at the Dead Sea, Israel.

    PubMed

    Kudish, Avraham I; Harari, Marco; Evseev, Efim G

    2011-01-01

    The broad-band normal incidence UVB beam radiation has been measured at Neve Zohar, Dead Sea basin, using a prototype tracking instrument composed of a Model 501A UV-Biometer mounted on an Eppley Solar Tracker Model St-1. The diffuse and beam fraction of the solar global UVB radiation have been determined using the concurrently measured solar global UVB radiation. The diffuse fraction was observed to exceed 80% throughout the year. The application of the results of these measurements to the possible revision of the photoclimatherapy protocol for psoriasis patients at the Dead Sea medical spas is now under investigation. The suggested revision would enable the sun-exposure treatment protocol to take advantage of the very high diffuse fraction by allowing the patient to receive the daily dose of UVB radiation without direct exposure to the sun, viz. receive the diffuse UVB radiation under a sunshade. This would require an increase in sun-exposure time intervals, as the UVB radiation intensity beneath a sunshade is less than that on an exposed surface. PMID:21091490

  15. Episodic Holocene eruption of the Salton Buttes rhyolites, California, from paleomagnetic, U-Th, and Ar/Ar dating

    USGS Publications Warehouse

    Wright, Heather M.; Vazquez, Jorge A.; Champion, Duane E.; Calvert, Andrew T.; Mangan, Margaret T.; Stelten, Mark E.; Cooper, Kari M.; Herzig, Charles; Schriener Jr., Alexander

    2015-01-01

    In the Salton Trough, CA, five rhyolite domes form the Salton Buttes: Mullet Island, Obsidian Butte, Rock Hill, North and South Red Hill, from oldest to youngest. Results presented here include 40Ar/39Ar anorthoclase ages, 238U-230Th zircon crystallization ages, and comparison of remanent paleomagnetic directions with the secular variation curve, which indicate that all domes are Holocene. 238U-230Th zircon crystallization ages are more precise than but within uncertainty of 40Ar/39Ar anorthoclase ages, suggesting that zircon crystallization proceeded until shortly before eruption in all cases except one. Remanent paleomagnetic directions require three eruption periods: (1) Mullet Island, (2) Obsidian Butte, and (3) Rock Hill, North Red Hill, and South Red Hill. Borehole cuttings logs document up to two shallow tephra layers. North and South Red Hills likely erupted within 100 years of each other, with a combined 238U-230Th zircon isochron age of: 2.83 ± 0.60 ka (2 sigma); paleomagnetic evidence suggests this age predates eruption by hundreds of years (1800 cal BP). Rock Hill erupted closely in time to these eruptions. The Obsidian Butte 238U-230Th isochron age (2.86 ± 0.96 ka) is nearly identical to the combined Red Hill age, but its Virtual Geomagnetic Pole position suggests a slightly older age. The age of aphyric Mullet Island dome is the least well constrained: zircon crystals are resorbed and the paleomagnetic direction is most distinct; possible Mullet Island ages include ca. 2300, 5900, 6900, and 7700 cal BP. Our results constrain the duration of Salton Buttes volcanism to between ca. 5900 and 500 years.

  16. Episodic Holocene eruption of the Salton Buttes rhyolites, California, from paleomagnetic, U-Th, and Ar/Ar dating

    NASA Astrophysics Data System (ADS)

    Wright, Heather M.; Vazquez, Jorge A.; Champion, Duane E.; Calvert, Andrew T.; Mangan, Margaret T.; Stelten, Mark; Cooper, Kari M.; Herzig, Charles; Schriener, Alexander

    2015-04-01

    In the Salton Trough, CA, five rhyolite domes form the Salton Buttes: Mullet Island, Obsidian Butte, Rock Hill, North and South Red Hill, from oldest to youngest. Results presented here include 40Ar/39Ar anorthoclase ages, 238U-230Th zircon crystallization ages, and comparison of remanent paleomagnetic directions with the secular variation curve, which indicate that all domes are Holocene. 238U-230Th zircon crystallization ages are more precise than but within uncertainty of 40Ar/39Ar anorthoclase ages, suggesting that zircon crystallization proceeded until shortly before eruption in all cases except one. Remanent paleomagnetic directions require three eruption periods: (1) Mullet Island, (2) Obsidian Butte, and (3) Rock Hill, North Red Hill, and South Red Hill. Borehole cuttings logs document up to two shallow tephra layers. North and South Red Hills likely erupted within 100 years of each other, with a combined 238U-230Th zircon isochron age of: 2.83 ± 0.60 ka (2 sigma); paleomagnetic evidence suggests this age predates eruption by hundreds of years (1800 cal BP). Rock Hill erupted closely in time to these eruptions. The Obsidian Butte 238U-230Th isochron age (2.86 ± 0.96 ka) is nearly identical to the combined Red Hill age, but its Virtual Geomagnetic Pole position suggests a slightly older age. The age of aphyric Mullet Island dome is the least well constrained: zircon crystals are resorbed and the paleomagnetic direction is most distinct; possible Mullet Island ages include ca. 2300, 5900, 6900, and 7700 cal BP. Our results constrain the duration of Salton Buttes volcanism to between ca. 5900 and 500 years.

  17. How effective is albedo modification (solar radiation management geoengineering) in preventing sea-level rise from the Greenland Ice Sheet?

    NASA Astrophysics Data System (ADS)

    Applegate, Patrick J.; Keller, Klaus

    2015-08-01

    Albedo modification (AM) is sometimes characterized as a potential means of avoiding climate threshold responses, including large-scale ice sheet mass loss. Previous work has investigated the effects of AM on total sea-level rise over the present century, as well as AM’s ability to reduce long-term (≫103 yr) contributions to sea-level rise from the Greenland Ice Sheet (GIS). These studies have broken new ground, but neglect important feedbacks in the GIS system, or are silent on AM’s effectiveness over the short time scales that may be most relevant for decision-making (<103 yr). Here, we assess AM’s ability to reduce GIS sea-level contributions over decades to centuries, using a simplified ice sheet model. We drive this model using a business-as-usual base temperature forcing scenario, as well as scenarios that reflect AM-induced temperature stabilization or temperature drawdown. Our model results suggest that (i) AM produces substantial near-term reductions in the rate of GIS-driven sea-level rise. However, (ii) sea-level rise contributions from the GIS continue after AM begins. These continued sea level rise contributions persist for decades to centuries after temperature stabilization and temperature drawdown begin, unless AM begins in the next few decades. Moreover, (iii) any regrowth of the GIS is delayed by decades or centuries after temperature drawdown begins, and is slow compared to pre-AM rates of mass loss. Combined with recent work that suggests AM would not prevent mass loss from the West Antarctic Ice Sheet, our results provide a nuanced picture of AM’s possible effects on future sea-level rise.

  18. Constraints on Shallow Crustal Structure across the San Andreas Fault Zone, Coachella Valley, Southern California: Results from the Salton Seismic Imaging Project (SSIP)

    NASA Astrophysics Data System (ADS)

    Hernandez, A.; Persaud, P.; Bauer, K.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.

    2015-12-01

    The strong influence of basin structure and crustal heterogeneities on seismic wave propagation suggests that these factors should be included in calculations of strong ground shaking. Knowledge of the shallow subsurface is thus essential for an accurate seismic hazard estimate for the densely populated Coachella Valley, the region north of the potential M7.8 rupture near the Salton Sea. Using SSIP data, we analyzed first arrivals from nine 65-911 kg explosive shots recorded along a profile in the Coachella Valley in order to evaluate the interpretation of our 2D tomographic results and give added details on the structural complexity of the shallow crust. The line extends 37 km from the Peninsular Ranges to the Little San Bernardino Mountains crossing the major strands of the San Andreas Fault Zone. We fit traveltime curves to our picks with forward modeling ray tracing, and determined 1D P-wave velocity models for traveltime arrivals east and west of each shot, and a 2D model for the line. We also inferred the geometry of near-vertical faults from the pre-stack line migration method of Bauer et al. (2013). In general, the 1D models east of individual shots have deeper basement contacts and lower apparent velocities, ~5 km/s at 4 km depth, whereas the models west of individual shots have shallower basement and velocities up to 6 km/s at 2 km depth. Mismatches in basement depths (assuming 5-6 km/s) between individual 1D models indicate a shallowly dipping basement, deepening eastward towards the Banning Fault and shoaling abruptly farther east. An east-dipping structure in the 2D model also gives a better fit than horizontal layers. Based on high velocity zones derived from traveltimes at 9-20 km from the western end of the line, we included an offset from ~2 km to 4 km depth near the middle of the line, which significantly improved the 2D model fit. If fault-related, this offset could represent the Garnet Hill Fault if it continues southward in the subsurface.

  19. Geothermal alteration of sediments in the Salton Sea scientific drill hole: Petrophysical properties and mass changes during alteration: Final report

    SciTech Connect

    McDowell, S.D.

    1987-12-11

    This report has been divided into two sections. The first deals with the results of the petrophysical measurements, and the second concentrates on the distribution of alteration minerals and textures, and on a series of calculations of geochemical changes that occurred during alteration. 32 refs., 23 figs., 10 tabs.

  20. Studies of brine chemistry and scaling at the Salton Sea geothermal field, 1977-1979. Final report

    SciTech Connect

    Harrar, J.E.

    1981-01-01

    Summarized are the results of investigations of brine chemistry, the effects of brine acidification and organic additives on the rate of scale formation and scale composition, and the use of other additives for scale control. A bibliography of reports describing these studies is included. Recommendations are given for techniques and approaches for further testing of additives for silica scale control.

  1. PLATYAMOEBA PSEUDOVANNELLIDA N. SP., A NAKED AMOEBA WITH WIDE SALT TOLERANCE ISOLATED FROM THE SALTON SEA, CALIFORNIA. (R826552)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  2. Determination of aerosol content in the atmosphere from ERTS-1 data. [San Diego, California and Salton Sea

    NASA Technical Reports Server (NTRS)

    Griggs, M.; Ludwig, C. B.; Malkmus, W. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Significant results, relating the radiance over water surfaces to the atmospheric aerosol content, have been obtained. The results indicate that the MSS channels 4, 5, and 6 centered at 0.55, 0.65, and 0.75 microns have comparable sensitivity, and that the aerosol content can be determined within + or - 10% with the assumed measurement errors of the MSS. The fourth channel, MSS 7, is not useful for aerosol determination due to the water radiance values from this channel generally being less than the instrument noise. The accuracy of the aerosol content measurement could be increased by using an instrument specifically designed for this purpose. This radiance-aerosol content relationship can possibly provide a basis for monitoring the atmospheric aerosol content on a global basis, allowing a base-line value of aerosols to be established. The contrast-aerosol content investigation shows useful linear relationships in MSS channels 4 and 5, allowing the aerosol content to be determined within + or - 10%. MSS 7 is not useful due to the low accuracy in the water radiance, and MSS 6 is found to be too insensitive. These results rely on several assumptions due to the lack of ground truth data, but do serve to indicate which channels are most useful.

  3. Imaging the San Andreas Fault between Parkfield and the Salton Sea Using Wavelet Analysis of Airborne Laser Swath Mapping Data

    NASA Astrophysics Data System (ADS)

    Cheung, K.; Hilley, G. E.; Moon, S.; Saltzman, J.; Sanquini, A.

    2011-12-01

    The distribution of fault related landforms may be used to divulge the spatial and temporal evolution of fault ruptures within a fault zone. In this study, wavelet analysis was performed on high-resolution Airborne Laser Swath Mapping (ALSM) topographic data to image the morphologic structure of the San Andreas Fault Zone (SAFZ) between Parkfield, CA and the US-Mexico border. ASLM data were collected by the National Center for Airborne Laser Mapping as part of the B4 project and were processed these data to produce a 2-m-resolution Digital Elevation Model (DEM). The DEM tiles were imported to ArcMap, which was used to mosaic, rotate, and crop them. Matlab was used to perform a progressive filling of NODATA values within each of the tiles using an iterative nearest-neighbor averaging scheme on these data. Next, scarp-like features roughly paralleling the average trend of the SAFZ were identified using a previously developed wavelet analysis method. This method convolves the second derivative of an elongated template of a scarp-like topography with the directional curvature of the ALSM DEM that is represented by each of the tiles. In this way, the analysis recovers, in a least-squares best-fitting sense, the amplitude of a particular scarp geometry and orientation. The Signal-to-Noise Ratio (SNR) is then computed at each point in the ALSM DEM for a given template scarp geometry and orientation-- this process is repeated for all scarp geometries and orientations to determine those that have the highest SNR. Such scarp forms are automatically identified as the best-fitting scarp geometry, amplitude, and orientation at each point in the DEM. The geometry gives a quantitative measure of the "roundness" of the profile of the scarp form, and supposing that sharper scarps have been created more recently than those whose forms have been rounded by prolonged erosion, a relative chronology of activity of various fault strands within the fault zone can be reconstructed. With the data from Matlab, the tiles are then imported back to ArcMap for further processing. In ArcMap, the individual tiles from Matlab were mosaicked together to create a model of the swath. To complete this process, the mosaicked dataset was then rotated to mimic the orientation of the fault in the real world. The comparison of the location of the identified scarps to those that have been mapped in the field is currently being made to determine the fidelity of this method. Preliminary results indicate that this analysis reveals the locations of recently active fault ruptures, and as such, these computer-generated maps may provide valuable information about the history of rupture within the fault zone and evaluation of its seismic hazard potential.

  4. Salton Sea 1/sup 0/ x 2/sup 0/ NTMS area California and Arizona: data report (abbreviated)

    SciTech Connect

    Heffner, J.D.

    1980-09-01

    Surface sediment samples were collected at 997 sites. Ground water samples were collected at 76 sites. Neutron activation analysis results are given for uranium and 16 other elements in sediments, and for uranium and 9 other elements in ground water. Mass spectrometry results are given for helium in ground water. Data from ground water sites include (1) water chemistry measurements (pH, conductivity, and alkalinity) (2) physical measurements (water temperature, well description where applicable, and scintillometer reading) and (3) elemental analyses (U, Al, Br, Cl, Dy, F, He, Mg, Mn, Na and V). Data from sediment sites include (1) stream water chemistry measurements from sites where water was available and (2) elemental analyses (U, Th, Hf, Al, Ce, Dy, Eu, Fe, La, Lu, Mn, Sc, Sm, Na, Ti, V, and Yb). Sample site descriptors are given. Areal distribution maps, histograms, and cumulative frequency plots for the elements listed above; U/Th and U/Hf ratios; and scintillometer readings at sediment sample sites are included. Analyses of the sediment fraction finer than 149..mu..m show high uranium values clustered in the Eagle and Chuckwalla Mountains. High uranium values in the 420 ..mu..m to 1000 ..mu..m fraction are clustered in the McCoy Mountains. Both fractions show groups of high values in the Chocolate Mountains at the Southeastern edge of the Chocolate Mountains Aerial Gunnery Range. Aerial distribution of analytical values shows that high values of many elements in both size fractions are grouped around the Eagle Mountains and the Chuckwalla Mountains. Fe, Mn, Ti, V, Sc, Hf, and the rare earth elements, all of which typically occur in high-density minerals, have higher average (log mean) concentrations in the finer fraction than in the coarser fraction.

  5. Sea grass like arranged TiO2 nanorods sensitized by natural dyes for solar cell applications

    NASA Astrophysics Data System (ADS)

    Akila, Y.; Muthukumarasamy, N.; Agilan, S.; Senthilarasu, S.; Velauthapillai, Dhayalan

    2016-08-01

    Rutile-phase seagrass-like-arranged TiO2 nanorods have been synthesized by low-temperature template-free hydrothermal method. These TiO2 nanorods have been sensitized by flowers of Sesbania grandiflora, leaves of Camellia sinensis and roots of Rubia tinctorum. The sensitized TiO2 nanorods-based films have been used as photoanode in natural dye-sensitized solar cells. The films were photoelectrochemically active, and the fabricated solar cells had short-circuit photocurrent density (JSC) lying in the range of 3.7-4.7mAcm-2. The efficiency of the fabricated natural dye-sensitized solar cells was found to lie in the range of 0.6-1.036 %, respectively

  6. The effects of arctic stratus clouds on the solar energy budget in the atmosphere-sea ice-ocean system

    SciTech Connect

    Jin, Z.; Stamnes, K.; Zak, B.D.

    1995-04-01

    This article describes a comprehensive radiative transfer model pertinent to the atmosphere-sea ice-ocean system. The main features of the model include: The atmosphere, sea ice, and ocean each represented by a sufficient number of layers to resolve the change in the optical properties of each stratum; An appropriate quadrature structure to take into account the total reflection at the air-ice or air-water interface, as well as to solve the radiative transfer equation in the coupled system consistently; Provision for a different number of streams (quadrature points) in the atmosphere, ice, and ocean, chosen based on the optical properties in each stratum and the computational accuracy method.

  7. Solar-, monsoon- and Kuroshio-influenced thermocline depth and sea surface salinity in the southern Okinawa Trough during the past 17,300 years

    NASA Astrophysics Data System (ADS)

    Wang, Libo; Li, Jun; Zhao, Jingtao; Wei, Helong; Hu, Bangqi; Dou, Yanguang; Sun, Zhilei; Zou, Liang; Bai, Fenglong

    2016-08-01

    Factors influencing millennial-scale variability in the thermocline depth (vertical mixing) and sea surface salinity (SSS) of the southern Okinawa Trough (OT) during the past 17,300 years were investigated based on foraminifer oxygen isotope records of the surface dweller Globigerinoides ruber sensu stricto and the thermocline dweller Pulleniatina obliquiloculata in the AMS 14C dated OKT-3 core. The thermocline depth is influenced by surface thermal buoyancy (heat) flux, in turn controlled by the annual mean insolation at 30°N and the strength of the East Asian winter monsoon (EAWM). Strong insolation and weak EAWM tend to increase buoyancy gain (decrease buoyancy loss), corresponding to shallow thermocline depths, and vice versa. Regional SSS is influenced by the global ice volume, the Kuroshio Current (KC), and vertical mixing. A deep thermocline coincides with a high SSS because strong vertical mixing brings more, saltier subsurface KC water to the surface, and vice versa. Local SSS (excluding the global ice volume effect) became lower in the northern OT than in the southern OT after ~9.2 ka, implying that Changjiang diluted water had stronger influence in the northern sector. SSS show no major changes during the Bølling/Allerød and Younger Dryas events, probably because the KC disturbed the North Atlantic signals. This argues against earlier interpretations of sea surface temperature records of this core. Wavelet and spectral analyses of the Δδ18OP-G (δ18O of P. obliquiloculata minus G. ruber s.s.) and δ18Olocal records display 1,540-, 1,480-, 1,050-, 860-, 640-, and 630-year periods. These are consistent with published evidence of a pervasive periodicity of 1,500 years in global climate as well as EAWM and KC signatures, and a fundamental solar periodicity of 1,000 years and intermediary derived periodicity of 700 years.

  8. Solar-, monsoon- and Kuroshio-influenced thermocline depth and sea surface salinity in the southern Okinawa Trough during the past 17,300 years

    NASA Astrophysics Data System (ADS)

    Wang, Libo; Li, Jun; Zhao, Jingtao; Wei, Helong; Hu, Bangqi; Dou, Yanguang; Sun, Zhilei; Zou, Liang; Bai, Fenglong

    2016-04-01

    Factors influencing millennial-scale variability in the thermocline depth (vertical mixing) and sea surface salinity (SSS) of the southern Okinawa Trough (OT) during the past 17,300 years were investigated based on foraminifer oxygen isotope records of the surface dweller Globigerinoides ruber sensu stricto and the thermocline dweller Pulleniatina obliquiloculata in the AMS 14C dated OKT-3 core. The thermocline depth is influenced by surface thermal buoyancy (heat) flux, in turn controlled by the annual mean insolation at 30°N and the strength of the East Asian winter monsoon (EAWM). Strong insolation and weak EAWM tend to increase buoyancy gain (decrease buoyancy loss), corresponding to shallow thermocline depths, and vice versa. Regional SSS is influenced by the global ice volume, the Kuroshio Current (KC), and vertical mixing. A deep thermocline coincides with a high SSS because strong vertical mixing brings more, saltier subsurface KC water to the surface, and vice versa. Local SSS (excluding the global ice volume effect) became lower in the northern OT than in the southern OT after ~9.2 ka, implying that Changjiang diluted water had stronger influence in the northern sector. SSS show no major changes during the Bølling/Allerød and Younger Dryas events, probably because the KC disturbed the North Atlantic signals. This argues against earlier interpretations of sea surface temperature records of this core. Wavelet and spectral analyses of the Δδ18OP-G (δ18O of P. obliquiloculata minus G. ruber s.s.) and δ18Olocal records display 1,540-, 1,480-, 1,050-, 860-, 640-, and 630-year periods. These are consistent with published evidence of a pervasive periodicity of 1,500 years in global climate as well as EAWM and KC signatures, and a fundamental solar periodicity of 1,000 years and intermediary derived periodicity of 700 years.

  9. 3-D Velocity Model of the Coachella Valley, Southern California Based on Explosive Shots from the Salton Seismic Imaging Project

    NASA Astrophysics Data System (ADS)

    Persaud, P.; Stock, J. M.; Fuis, G. S.; Hole, J. A.; Goldman, M.; Scheirer, D. S.

    2014-12-01

    We have analyzed explosive shot data from the 2011 Salton Seismic Imaging Project (SSIP) across a 2-D seismic array and 5 profiles in the Coachella Valley to produce a 3-D P-wave velocity model that will be used in calculations of strong ground shaking. Accurate maps of seismicity and active faults rely both on detailed geological field mapping and a suitable velocity model to accurately locate earthquakes. Adjoint tomography of an older version of the SCEC 3-D velocity model shows that crustal heterogeneities strongly influence seismic wave propagation from moderate earthquakes (Tape et al., 2010). These authors improve the crustal model and subsequently simulate the details of ground motion at periods of 2 s and longer for hundreds of ray paths. Even with improvements such as the above, the current SCEC velocity model for the Salton Trough does not provide a match of the timing or waveforms of the horizontal S-wave motions, which Wei et al. (2013) interpret as caused by inaccuracies in the shallow velocity structure. They effectively demonstrate that the inclusion of shallow basin structure improves the fit in both travel times and waveforms. Our velocity model benefits from the inclusion of known location and times of a subset of 126 shots detonated over a 3-week period during the SSIP. This results in an improved velocity model particularly in the shallow crust. In addition, one of the main challenges in developing 3-D velocity models is an uneven stations-source distribution. To better overcome this challenge, we also include the first arrival times of the SSIP shots at the more widely spaced Southern California Seismic Network (SCSN) in our inversion, since the layout of the SSIP is complementary to the SCSN. References: Tape, C., et al., 2010, Seismic tomography of the Southern California crust based on spectral-element and adjoint methods: Geophysical Journal International, v. 180, no. 1, p. 433-462. Wei, S., et al., 2013, Complementary slip distributions

  10. Relationship of photosynthetic carbon fixation with environmental changes in the Jiulong River estuary of the South China Sea, with special reference to the effects of solar UV radiation.

    PubMed

    Li, Gang; Gao, Kunshan; Yuan, Dongxing; Zheng, Ying; Yang, Guiyuan

    2011-08-01

    Phytoplankton cells in estuary waters usually experience drastic changes in chemical and physical environments due to mixing of fresh and seawaters. In order to see their photosynthetic performance in such dynamic waters, we measured the photosynthetic carbon fixation by natural phytoplankton assemblages in the Jiulong River estuary of the South China Sea during April 24-26 and July 24-26 of 2008, and investigated its relationship with environmental changes in the presence or the absence of UV radiation. Phytoplankton biomass (Chl a) decreased sharply from the river-mouth to seawards (17.3-2.1 μg L(-1)), with the dominant species changed from chlorophytes to diatoms. The photosynthetic rate based on Chl a at noon time under PAR-alone increased from 1.9 μg C (μg Chl a)(-1) L(-1) in low salinity zone (SSS<10) to 12.4 μg C (μg Chl a)(-1) L(-1) in turbidity front (SSS within 10-20), and then decreased to 2.1 μg C (μg Chl a)(-1) L(-1) in mixohaline zone (SSS>20); accordingly, the carbon fixation per volume of seawater increased from 12.8 to 149 μg C L(-1) h(-1), and decreased to 14.3 μg C L(-1) h(-1). Solar UVR caused the inhibition of carbon fixation in surface water of all the investigated zones, by 39% in turbidity area and 7-10% in freshwater or mixohaline zones. In the turbidity zone, higher availability of CO2 could have enhanced the photosynthetic performance; while osmotic stress might be responsible for the higher sensitivity of phytoplankton assemblages to solar UV radiation. PMID:21714975

  11. Prediction of Triggered Slip and Aftershocks in the Salton Trough: Which is Better, Dynamic or Static Coulomb Failure Stresses?

    NASA Astrophysics Data System (ADS)

    Clark, J.; Verdugo, D.; Olsen, K.; Mellors, R.

    2005-12-01

    We have modeled static (CFS) and dynamic (dCFS(t)) Coulomb failure stresses within a 140 km by 140 km area in southern California for four recent historical M>6 earthquakes (1968 Borrego Valley, 1979 Imperial Valley, 1987 Elmore Ranch and 1987 Superstition Hills events) using a fourth-order finite-difference method and a layered crustal model. The dynamic stresses, quantified as the peak values of the dCFS(t), are computed using slip models estimated from measured surface offsets and extended down to the bottom of the fault. The CFS and dCFS(t) are correlated with aseismic slip recorded on nearby structures in the Salton Trough, as well as aftershocks from the four events. Our simple models suggest that, compared to static Coulomb failure stress patterns, the patterns of peak dCFS(t) show a higher correlation with triggered slip along nearby faults, and for some of the events, with the location of aftershocks that occurred up to four years after the events. This finding is due to the rupture propagation effects, particularly directivity, included in the dCFS(t) (e.g., Kilb et al, 2000), but omitted for the CFS. Future studies should include a 3D crustal model and refined rupture propagation in the dCFS(t) computation.

  12. Solar Influence on Recurring Global, Decadal, Climate Cycles Recorded by Glacial Fluctuations, Ice Cores, Sea Surface Temperatures, and Historic Measurements Over the Past Millennium

    NASA Astrophysics Data System (ADS)

    Easterbrook, D. J.

    2008-12-01

    Global, cyclic, decadal, climate patterns can be traced over the past millennium in glacier fluctuations, oxygen isotope ratios in ice cores, sea surface temperatures, and historic observations. The recurring climate cycles clearly show that natural climatic warming and cooling have occurred many times, long before increases in anthropogenic atmospheric CO2 levels. The Medieval Warm Period and Little Ice Age are well known examples of such climate changes, but in addition, at least 23 periods of climatic warming and cooling have occurred in the past 500 years. Each period of warming or cooling lasted about 25-30 years (average 27 years). Two cycles of global warming and two of global cooling have occurred during the past century, and the global cooling that has occurred since 1998 is exactly in phase with the long term pattern. Global cooling occurred from 1880 to ~1915; global warming occurred from ~1915 to ~1945; global cooling occurred from ~1945-1977;, global warming occurred from 1977 to 1998; and global cooling has occurred since 1998. All of these global climate changes show exceptionally good correlation with solar variation since the Little Ice Age 400 years ago. The IPCC predicted global warming of 0.6° C (1° F) by 2011 and 1.2° C (2° F) by 2038, whereas Easterbrook (2001) predicted the beginning of global cooling by 2007 (± 3-5 yrs) and cooling of about 0.3-0.5° C until ~2035. The predicted cooling seems to have already begun. Recent measurements of global temperatures suggest a gradual cooling trend since 1998 and 2007-2008 was a year of sharp global cooling. The cooling trend will likely continue as the sun enters a cycle of lower irradiance and the Pacific Ocean changed from its warm mode to its cool mode. Comparisons of historic global climate warming and cooling, glacial fluctuations, changes in warm/cool mode of the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO), and sun spot activity over the past century

  13. Seismic calibration shots conducted in 2009 in the Imperial Valley, southern California, for the Salton Seismic Imaging Project (SSIP)

    USGS Publications Warehouse

    Murphy, Janice; Goldman, Mark; Fuis, Gary; Rymer, Michael; Sickler, Robert; Miller, Summer; Butcher, Lesley; Ricketts, Jason; Criley, Coyn; Stock, Joann; Hole, John; Chavez, Greg

    2011-01-01

    Rupture of the southern section of the San Andreas Fault, from the Coachella Valley to the Mojave Desert, is believed to be the greatest natural hazard facing California in the near future. With an estimated magnitude between 7.2 and 8.1, such an event would result in violent shaking, loss of life, and disruption of lifelines (freeways, aqueducts, power, petroleum, and communication lines) that would bring much of southern California to a standstill. As part of the Nation's efforts to prevent a catastrophe of this magnitude, a number of projects are underway to increase our knowledge of Earth processes in the area and to mitigate the effects of such an event. One such project is the Salton Seismic Imaging Project (SSIP), which is a collaborative venture between the United States Geological Survey (USGS), California Institute of Technology (Caltech), and Virginia Polytechnic Institute and State University (Virginia Tech). This project will generate and record seismic waves that travel through the crust and upper mantle of the Salton Trough. With these data, we will construct seismic images of the subsurface, both reflection and tomographic images. These images will contribute to the earthquake-hazard assessment in southern California by helping to constrain fault locations, sedimentary basin thickness and geometry, and sedimentary seismic velocity distributions. Data acquisition is currently scheduled for winter and spring of 2011. The design and goals of SSIP resemble those of the Los Angeles Region Seismic Experiment (LARSE) of the 1990's. LARSE focused on examining the San Andreas Fault system and associated thrust-fault systems of the Transverse Ranges. LARSE was successful in constraining the geometry of the San Andreas Fault at depth and in relating this geometry to mid-crustal, flower-structure-like decollements in the Transverse Ranges that splay upward into the network of hazardous thrust faults that caused the 1971 M 6.7 San Fernando and 1987 M 5

  14. Effects of Typhoon Kaemi on coastal phytoplankton assemblages in the South China Sea, with special reference to the effects of solar UV radiation

    NASA Astrophysics Data System (ADS)

    Li, Gang; Wu, Yaping; Gao, Kunshan

    2009-12-01

    In order to see how physical and chemical changes in coastal environment caused by tropical cyclones would affect primary productivity of phytoplankton, we investigated the photosynthetic carbon fixation, the chlorophyll a concentration, and the species composition of phytoplankton assemblages in the surface coastal waters of the South China Sea, during 18 July to 7 August 2006, before and after Typhoon Kaemi's landing (on 25 July, 122 km away from the experimental site). Chlorophyll a concentration started to decrease from 12.3 μg L-1 30 h before to 1.5 μg L-1 40 h after its landing, reducing the capacity of photosynthetic carbon fixation in the seawater to one eighth. Prior to the typhoon's arrival, microplankton (>20 μm) accounted for 50% of the total chl a, being mainly dominated by the diatom Thalassiosira sp.; during the period 30 h before and 6 days after the typhoon, however, pico-nanoplankton (<20 μm) comprised 98% of the total chl a. By 2 weeks after the typhoon, microcells (>20 μm) dominated the species again, and occupied 60% of the total chl a, with the diatom Nitzschia sp. being the dominant group. Since the typhoon induced changes in taxonomic structure and environmental factors, the apparent photosynthetic efficiency (α) of phytoplankton assemblages was markedly enhanced after the typhoon, while both the light-saturating point (Ek) and noontime photosynthetic rates were significantly reduced. Solar ultraviolet radiation (UVR, >55 W m-2) significantly inhibited the photosynthetic carbon fixation by 17% and 28% before and after the typhoon, respectively, reflecting a higher UVR sensitivity of the posttyphoon phytoplankton assemblages.

  15. Completion of the Southern California Plate Boundary Observatory GPS Network and Implementation of the Low Latency Salton Trough Network

    NASA Astrophysics Data System (ADS)

    Walls, C.; Miller, S.; Lawrence, S.; Wilson, B.; Jackson, M.; Feaux, K.

    2008-12-01

    Between 2003-2008 875 permanent PBO GPS stations have been built throughout the United States. Concomitant with construction of the PBO the majority of pre-existing GPS stations that meet stability specifications have been upgraded with Trimble NetRS and IP based communications to PBO standards under the EarthScope PBO Nucleus project. In October 2008, with completed construction of the Plate Boundary Observatory, more than 1100 GPS stations now share common design specifications and have identical receivers with common communications making it the most homogeneous geodetic network in the World. Of the 875 total Plate Boundary Observatory GPS stations, 216 sites are distributed throughout the Southern California region. 102 of the sites are built as SDBM, 111 DDBM, and 3 as strainmeter GPS hybrids. Fifteen second data is archived for each station and 1 Hz and 5 Hz data is buffered to be triggered for download in the event of an earthquake. Additionally, 125 of the existing former-SCIGN GPS stations have been integrated into the SoCal region of PBO, of which 25 have real-time data streams. The Salton Trough Radio Network (STRN) comprises of 20 stations equipped with Ethernet bridge Intuicom EB6+ (900 MHz) radios to transmit a high rate low latency data stream from each permanent GPS site. The high-rate low latency UStream data will be available to researchers who are developing prototype earthquake early warning systems in Southern California. A goal of the STRN is to make the data available rapidly enough for GPS-derived coseismic and dynamic displacements to be integrated into early warning system earthquake models. The improved earthquake models will better assist emergency response. UStream data will also aid surveyors who wish to use PBO GPS stations as permanent, high-quality base stations in real- time kinematic surveys. Requests for streaming data access at available GPS sites and latency statistics are located at http://pboweb.unavco.org/?pageid=107

  16. Heat balance in the Chukchi Sea

    NASA Astrophysics Data System (ADS)

    Ohta, N.; Ueno, H.; Itoh, M.; Kikuchi, T.; Mizobata, K.; Watanabe, E.; Nishino, S.

    2014-12-01

    Interannual variation of heat balance in the Chukchi Sea in summer was investigated through analysis of satellite-derived sea-ice concentrations and reanalysis products during 1999-2010. The solar heat input varied from 4.3 to 8.0 × 1020 J over the Chukchi Sea defined in this study (5.9 × 105 km2). These values were larger than the heat transport from the Bering Strait ranging from 2.9 to 5.1 × 1020 J, suggesting that the Chukchi Sea was the area where the Pacific Water from the Bering Sea was strongly modified, affecting the interannual variation of the heat transport to the interior Arctic basin. Interannual variation in the latent, sensible, longwave radiation fluxes and the heat of fusion of sea ice in the Chukchi Sea are small compared with the heat transport from the Bering Strait as well as the solar heat input in the Chukchi Sea.

  17. Solar energy from the sea

    SciTech Connect

    Tabata, R.S.

    1981-10-01

    Questions addressed include: what is OTEC, what could OTEC mean for the future, what are some advantages and disadvantages of OTEC, who's working on OTEC, what's happening with OTEC in Hawaii, and what are some possible environmental concerns now being studied. A list of publications, films, and information sources is included. The OTEC resource of the Pacific Ocean is mapped and the closed-cycle OTEC process is explained in elementary terms. (LEW)

  18. Effects of time-dependent large-scale forcing, solar zenith angle, and sea surface temperature on time-mean rainfall: a partitioning analysis based on surface rainfall budget

    NASA Astrophysics Data System (ADS)

    Gao, Shouting; Li, Xiaofan

    2011-06-01

    Effects of time-dependent large-scale forcing, solar zenith angle, and sea surface temperature on time-mean rainfall during the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE) are examined through a partitioning analysis of a series of sensitivity cloud-resolving model experiment data based on surface rainfall budget. The model is forced by time-dependent large-scale forcing (LSF), solar zenith angle (SZA), and sea surface temperature (SST) in the control experiment and is forced only by either time-dependent LSF, SZA, or SST while others are replaced with their time averages in the sensitivity experiments. The rainfall associated with water vapor divergence and local atmospheric drying and hydrometeor loss/convergence has the largest contribution to total rainfall among eight rainfall types. The largest rainfall contribution is increased in the simulations where either time-dependent LSF, SZA, or SST is replaced with its average, whereas it is decreased in the simulation where COARE-derived large-scale vertical velocity is replaced with zero vertical velocity. The contribution of the rainfall associated with water vapor convergence to total rainfall is decreased in the simulations with time-mean LSF, SZA, and SST, whereas it is increased in the simulation without large-scale vertical velocity.

  19. Cytogenetic, cellular, and developmental responses in antarctic sea urchins (Sterechinus neumayeri) following laboratory ultraviolet-B and ambient solar radiation exposures

    SciTech Connect

    Anderson, S.; Hoffman, J.; Wild, G. ); Bosch, I. ); Karentz, D. )

    1993-01-01

    Increasing ultraviolet-B radiation as a consequence of springtime ozone depletion, could harm antarctic ecosystems. This study uses several techniques for studying genotoxic effects to evaluate UV-B effects in sea urchins from Antarctica. 6 refs., 2 figs.

  20. Dynamic triggering of creep events in the Salton Trough, Southern California by regional M ≥ 5.4 earthquakes constrained by geodetic observations and numerical simulations

    NASA Astrophysics Data System (ADS)

    Wei, Meng; Liu, Yajing; Kaneko, Yoshihiro; McGuire, Jeffrey J.; Bilham, Roger

    2015-10-01

    Since a regional earthquake in 1951, shallow creep events on strike-slip faults within the Salton Trough, Southern California have been triggered at least 10 times by M ≥ 5.4 earthquakes within 200 km. The high earthquake and creep activity and the long history of digital recording within the Salton Trough region provide a unique opportunity to study the mechanism of creep event triggering by nearby earthquakes. Here, we document the history of fault creep events on the Superstition Hills Fault based on data from creepmeters, InSAR, and field surveys since 1988. We focus on a subset of these creep events that were triggered by significant nearby earthquakes. We model these events by adding realistic static and dynamic perturbations to a theoretical fault model based on rate- and state-dependent friction. We find that the static stress changes from the causal earthquakes are less than 0.1 MPa and too small to instantaneously trigger creep events. In contrast, we can reproduce the characteristics of triggered slip with dynamic perturbations alone. The instantaneous triggering of creep events depends on the peak and the time-integrated amplitudes of the dynamic Coulomb stress change. Based on observations and simulations, the stress change amplitude required to trigger a creep event of a 0.01-mm surface slip is about 0.6 MPa. This threshold is at least an order of magnitude larger than the reported triggering threshold of non-volcanic tremors (2-60 kPa) and earthquakes in geothermal fields (5 kPa) and near shale gas production sites (0.2-0.4 kPa), which may result from differences in effective normal stress, fault friction, the density of nucleation sites in these systems, or triggering mechanisms. We conclude that shallow frictional heterogeneity can explain both the spontaneous and dynamically triggered creep events on the Superstition Hills Fault.

  1. San Andreas Fault dip, Peninsular Ranges mafic lower crust and partial melt in the Salton Trough, Southern California, from ambient-noise tomography

    NASA Astrophysics Data System (ADS)

    Barak, Shahar; Klemperer, Simon L.; Lawrence, Jesse F.

    2015-11-01

    We use ambient-noise tomography to improve CVM-H11.9, a community velocity model of southern California. Our new 3-D shear-velocity model with 0.05° x 0.05° lateral and 1 km vertical blocks reveals new structure beneath the San Andreas Fault (SAF), Peninsular Ranges batholith (PRB), southern Sierra Nevada batholith (SNB), and the Salton Trough (ST). We use 4 years of data recorded on 849 broadband stations, vastly more than previous studies and including our own broadband Salton Seismic Imaging Project, a 40 station transect across the ST, as well as other campaign stations in both Mexico and the United States. Mean lower crust and upper mantle wave speeds (3.6 km/s at 20 km, 4.2 km/s at 40 km) are low by global standards. Across the SAF, southeast of San Gorgonio Pass, we observe vertical to steeply dipping lateral velocity contrasts that extend beneath the Moho. Beneath the western PRB and westernmost southern SNB, we observe relatively high shear velocities (≥3.8 km/s) in the lower crust that we interpret as the mafic roots of the overlying arc. Relatively high-velocity upper mantle (up to ˜4.5 km/s) may be part of the intact arc, or possibly a remnant of the Farallon plate. Beneath the ST, we observe zones of low shear-velocity in the lower crust and upper mantle which permit up to ˜4.5% melt in the lower crust and up to ˜6% melt in the upper mantle, depending on the assumed composition and pore geometry. Our results preclude the existence of older continental crust beneath the ST and support the creation of new crust beneath the ST.

  2. Rotation of Plio-Pleistocene Sedimentary Rocks in the Fish Creek Vallecito Basin, Western Salton Trough, CA

    NASA Astrophysics Data System (ADS)

    Housen, B. A.; Dorsey, R. J.; Janecke, S. U.; Axen, G. J.

    2005-12-01

    directions that are best clustered at 0-40% untilting, and sites from the base of the section have directions that are best-clustered at 80-100% untilting. For this initial interpretation, results are tilt-corrected for maximum degree of clustering. Sites from near the base of the section (Diablo Fm) are predominately reverse and have a mean of D = 204, I = -48.3, k = 37, α95 = 12.7°, N = 5. Sites from the middle of the section (Olla and Tapiado Fms) are predominantly normal and have a mean of D = 8.1, I = 48, k = 32, α95 = 8.7°, N = 10. Sites from the upper portion of the section (Hueso Fm) have predominately reverse polarity with means of D = 179.6, I = -43.4, k = 82, α95 = 10.2°, N = 4. Based on these results and correlations between the magnetostratigraphy of this section with the polarity timescale we tentatively conclude that little or no CW rotation has occurred in the FCVB during the past 2 Ma. Larger (24° CW) rotations are recorded by the 3-4 Ma rocks of the Diablo Fm, indicating that significant rotation occurred between 2 and 3 Ma. We tentatively ascribe slowing of the rotation rate in the FCVB to still poorly understood evolution of the west Salton detachment fault system. The relative lack of rotation since 2 Ma suggests that younger, post-detachment strike-slip faulting has not produced significant CW rotation between the San Jacinto and Elsinore faults.

  3. Sea ice radiative forcing, sea ice area, and climate sensitivity

    NASA Astrophysics Data System (ADS)

    Caldeira, Ken; Cvijanovic, Ivana

    2014-05-01

    Changes in sea ice cover affect climate sensitivity by modifying albedo and surface heat flux exchange, which in turn affect the absorbed solar radiation at the surface as well as cloud cover, atmospheric water content and poleward atmospheric heat transport. Here, we use a configuration of the Community Earth System Model 1.0.4 with a slab ocean model and a thermodynamic-dynamic sea ice model to investigate the overall net effect of feedbacks associated with the sea ice loss. We analyze the strength of the overall sea ice feedback in terms of two factors: the sensitivity of sea ice area to changes in temperature, and the sensitivity of sea ice radiative forcing to changes in sea ice area. In this model configuration, sea ice area decreases by ~3 × 1012 m2 per K of global warming, while the effective global radiative forcing per square meter of sea ice loss is ~0.1 × 10-12 W m-2. The product of these two terms (~0.3 W m-2 K-1) approximately equals the difference in climate feedback parameter found in simulations with sea ice response (1.05 W m-2 K-1) and simulations without sea ice response (1.31 W m-2 K-1 or 1.35 W m-2 K-1, depending on the method used to disable changes in sea ice cover). Thus, we find that in our model simulations, sea ice response accounts for about 20% to 22% of the climate sensitivity to an imposed change in radiative forcing. In our model, the additional radiative forcing resulting from a loss of all sea ice in the 'pre-industrial' state is comparable to but somewhat less than the radiative forcing from a doubling of atmospheric CO2 content.

  4. Sea Ice Radiative Forcing, Sea Ice Area, and Climate Sensitivity

    NASA Astrophysics Data System (ADS)

    Caldeira, K.; Cvijanovic, I.

    2014-12-01

    Changes in sea ice cover affect climate sensitivity by modifying albedo and surface heat flux exchange, which in turn affect the absorbed solar radiation at the surface as well as cloud cover, atmospheric water content and poleward atmospheric heat transport. Here, we use a configuration of the Community Earth System Model 1.0.4 with a slab ocean model and a thermodynamic-dynamic sea ice model to investigate the overall net effect of feedbacks associated with the sea ice loss. We analyze the strength of the overall sea ice feedback in terms of two factors: the sensitivity of sea ice area to changes in temperature, and the sensitivity of sea ice radiative forcing to changes in sea ice area. In this model configuration, sea ice area decreases by ~3 × 1012 m2 per K of global warming, while the effective global radiative forcing per unit area of sea ice loss is ~0.1 × 10-12 W m-2. The product of these two terms (~0.3 W m-2 K-1) approximately equals the difference in climate feedback parameter found in simulations with sea ice response (1.05 W m-2 K-1) and simulations without sea ice response (1.31 W m-2 K-1 or 1.35 W m-2 K-1, depending on the method used to disable the changes in sea ice cover). Thus, we find that in our model simulations, sea ice response accounts for about 20% to 22% of the climate sensitivity to an imposed change in radiative forcing. In our model, the additional radiative forcing resulting from a loss of all sea-ice in the "pre-industrial" state is comparable to but somewhat less than the radiative forcing from a doubling of atmospheric CO2 content.

  5. Assessing long-term postseismic deformation following the M7.2 4 April 2010, El Mayor-Cucapah earthquake with implications for lithospheric rheology in the Salton Trough

    NASA Astrophysics Data System (ADS)

    Spinler, Joshua C.; Bennett, Richard A.; Walls, Chris; Lawrence, Shawn; González García, J. Javier

    2015-05-01

    The 4 April 2010 Mw 7.2 El Mayor-Cucapah (EMC) earthquake provides the best opportunity to date to study the lithospheric response to a large (>M6) magnitude earthquake in the Salton Trough region through analysis of Global Positioning System (GPS) data. In conjunction with the EarthScope Plate Boundary Observatory (PBO), we installed six new continuous GPS stations in the months following the EMC earthquake to increase station coverage in the epicentral region of northern Baja California, Mexico. We modeled the pre-EMC deformation field using available campaign and continuous GPS data for southern California and northern Baja California and inferred a pre-EMC secular rate at each new station location. Through direct comparison of the pre- and post-EMC secular rates, we calculate long-term changes associated with viscoelastic relaxation in the Salton Trough region. We fit these velocity changes using numerical models employing an elastic upper crustal layer underlain by a viscoelastic lower crustal layer and a mantle half-space. Forward models that produce the smallest weighted sum of squared residuals have an upper mantle viscosity in the range 4-6 × 1018 Pa s and a less well-resolved lower crustal viscosity in the range 2 × 1019 to 1 × 1022 Pa s. A high-viscosity lower crust, despite high heat flow in the Salton Trough region, is inconsistent with felsic composition and might suggest accretion of mafic lower crust associated with crustal spreading obscured by thick sedimentary cover.

  6. Determination of aerosol content in the atmosphere from LANDSAT data. [San Diego, Salton Sea, Miami, Adrigole, Atlantic City, Barrow, and Burke, Divide, Hill, and Toole Counties

    NASA Technical Reports Server (NTRS)

    Griggs, M. (Principal Investigator)

    1978-01-01

    The author has identified the following significant results. A large set of LANDSAT 2 data, obtained at San Diego, showed excellent linear relationships, particularly for MSS 5 and MSS 6, between the radiance over the ocean and the atmospheric aerosol content. Two other data points obtained at Adrigole, Ireland, representing a different ocean and a different ground truth instrument, showed very good agreement with the San Diego data. It appeared that the technique could be used for global monitoring of the atmospheric aerosol content over the oceans. Results obtained at several inland bodies of water showed that MSS 4, MSS 5, and MSS 6 cannot be used due to the effect of water pollution generally present. However, the LANDSAT 1 results suggested that MSS 7, which operates at longer wavelengths, was not very sensitive to water pollution, and might be useful for inland measurements of aerosol content. Use of the longer wavelength would also minimize the effects of adjacent high albedo land, since atmospheric scattering was reduced at longer wavelengths.

  7. Aeromagnetic maps of the Colorado River region including the Kingman, Needles, Salton Sea, and El Centro 1 degree by 2 degrees quadrangles, California, Arizona, and Nevada

    USGS Publications Warehouse

    Mariano, John; Grauch, V.J.

    1988-01-01

    Aeromagnetic anomalies are produced by variations in the strength and direction of the magnetic field of rocks that include magnetic minerals, commonly magnetite. Patterns of anomalies on aeromagnetic maps can reveal structures - for example, faults which have juxtaposed magnetic rocks against non-magnetic rocks, or areas of alteration where magnetic minerals have been destroyed by hydrothermal activity. Tectonic features of regional extent may not become apparent until a number of aeromagnetic surveys have been compiled and plotted at the same scale. Commonly the compilation involves piecing together data from surveys that were flown at different times with widely disparate flight specifications and data reduction procedures. The data may be compiled into a composite map, where all the pieces are plotted onto one map without regard to the difference in flight elevation and datum, or they may be compiled into a merged map, where all survey data are analytically reduced to a common flight elevation and datum, and then digitally merged at the survey boundaries. The composite map retains the original resolution of all the survey data, but computer methods to enhance regional features crossing the survey boundaries may not be applied. On the other hand, computer methods can be applied to the merged data, but the accuracy of the data may be slightly diminished.

  8. PREVALENCE OF NEUROTOXIC CLOSTRIDIUM BOTULINUM TYPE C IN THE GASTROINTESTINAL TRACTS OF TILAPIS (OREOCHROMIS MOSAMBICUS) IN THE SALTON SEA. (R826552)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  9. Trophic relationships of small nonnative fishes in a natural creek and several agricultural drains flowing into the Salton Sea, and their potential, effects on the endangered desert pupfish

    USGS Publications Warehouse

    Martin, Barbara A.; Saiki, Michael K.

    2009-01-01

    This study was conducted to characterize trophic relationships of small nonnative fishes and to determine if predation by these fishes contributes to the decline of desert pupfish (Cyprinodon macularius), an endangered cyprinodont on the verge of extinction. We sampled 403 hybrid Mozambique tilapias (Oreochromis mossambica by O. urolepis), 107 redbelly tilapias (Tilapia zillii), 32 longjaw mudsuckers (Gillkhthys mirabilis), 182 western mosquitofish (Gambusia affinis), 222 sailfin mollies (Poecilia latipinna), 63 shortfin mollies (Poecilia mexicana), and 235 porthole livebearers (Poecilurpsis gracilis) from a natural creek and four agricultural drains during September 1999- December 2001. Evidence of piscivory was in gastrointestinal contents of 14 hybrid Mozambique tilapias, 3 redbelly tilapias, 10 longjaw mudsuckers, 8 western mosquitofish, 2 sailfin mollies, and 8 porthole livebearers. Although digestion often was too advanced for identification of fishes consumed by nonnative fishes, remains of desert pupfish were in gastrointestinal contents of a longjaw mudsucker. Our findings, along with Field evidence from other studies that inverse relationships exist between abundances of desert pupfish and nonnative species, are consistent with the hypothesis that predation by nonnative species is contributing to decline of desert pupfish. We suspect that competitive interactions with nonnative fishes might also adversely affect abundance of desert pupfish.

  10. Bering Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Much of the Bering Sea is clear in this SeaWiFS image. The large expanse of bright aquamarine water is clearly visible. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  11. Bering Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The skies of the Bering Sea were relatively clear again in this SeaWiFS image showing a band of aquamarine colored water. Credit: Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  12. Red Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  The Red Sea     View Larger Image ... Imaging SpectroRadiometer (MISR) image of the Red Sea was acquired on August 13, 2000. Located between the East African coast and the Saudi Arabian peninsula, the Red Sea got its name because the blooms of a type of algae,  Trichodesmium ...

  13. Solar Electricity

    NASA Technical Reports Server (NTRS)

    1988-01-01

    ARCO Solar manufactures PV Systems tailored to a broad variety of applications. PV arrays are routinely used at remote communications installations to operate large microwave repeaters, TV and radio repeaters rural telephone, and small telemetry systems that monitor environmental conditions. Also used to power agricultural water pumping systems, to provide electricity for isolated villages and medical clinics, for corrosion protection for pipelines and bridges, to power railroad signals, air/sea navigational aids, and for many types of military systems. ARCO is now moving into large scale generation for utilities.

  14. Solar neutrinos, solar flares, solar activity cycle and the proton decay

    NASA Technical Reports Server (NTRS)

    Raychaudhuri, P.

    1985-01-01

    It is shown that there may be a correlation between the galactic cosmic rays and the solar neutrino data, but it appears that the neutrino flux which may be generated during the large solar cosmic ray events cannot in any way effect the solar neutrino data in Davis experiment. Only initial stage of mixing between the solar core and solar outer layers after the sunspot maximum in the solar activity cycle can explain the higher (run number 27 and 71) of solar neutrino data in Davis experiment. But solar flare induced atmospheric neutrino flux may have effect in the nucleon decay detector on the underground. The neutrino flux from solar cosmic rays may be a useful guide to understand the background of nucleon decay, magnetic monopole search, and the detection of neutrino flux in sea water experiment.

  15. Solar desalination system and method

    SciTech Connect

    Kruse, C.L.

    1985-03-12

    A solar desalination system in which fresh water is derived from sea water by focussing solar ray energy from a collecting reflector onto an evaporator tube located at substantially the focal apex of the reflector. The reflector/evaporator tube assembly is mounted on a horizontal open grid platform which may support a plurality of parallel reflector/evaporator tube assemblies. The reflectors may serve as pontoons to support the desalination system unit on a body of sea water. The solar heat generated vapor is condensed in condenser tubes immersed in the sea water. Intermittently sea water concentrate is withdrawn from the evaporator tubes. Velocity of the vapor passing from the evaporator tubes to the condensers may be utilized for generating power.

  16. Implication of the visual system in the regulation of activity cycles in the absence of solar light: 2-[125I]iodomelatonin binding sites and melatonin receptor gene expression in the brains of demersal deep-sea gadiform fish

    PubMed Central

    Priede, I. G.; Williams, L. M.; Wagner, H.-J.; Thom, A.; Brierley, I.; Collins, M. A.; Collin, S. P.; Merrett, N. R.; Yau, C.

    1999-01-01

    Relative eye size, gross brain morphology and central localization of 2-[125I]iodomelatonin binding sites and melatonin receptor gene expression were compared in six gadiform fish living at different depths in the north-east Atlantic Ocean: Phycis blennoides (capture depth range 265 to 1260 m), Nezumia aequalis (445 to 1512 m), Coryphaenoides rupestris (706 to 1932 m), Trachyrincus murrayi (1010 to 1884 m), Coryphaenoides guentheri (1030 m) and Coryphaenoides (Nematonurus) armatus (2172 to 4787 m). Amongst these, the eye size range was 0.15 to 0.35 of head length with a value of 0.19 for C. (N.) armatus, the deepest species. Brain morphology reflected behavioural differences with well-developed olfactory regions in P. blennoides, T. murrayi and C. (N.) armatus and evidence of olfactory deficit in N. aequalis, C. rupestris and C. guentheri. All species had a clearly defined optic tectum with 2-[125I]iodomelatonin binding and melatonin receptor gene expression localized to specific brain regions in a similar pattern to that found in shallow-water fish. Melatonin receptors were found throughout the visual structures of the brains of all species. Despite living beyond the depth of penetration of solar light these fish have retained central features associated with the coupling of cycles of growth, behaviour and reproduction to the diel light–dark cycle. How this functions in the deep sea remains enigmatic.

  17. Solar desalting process

    SciTech Connect

    Liu, P.J.

    1983-03-15

    A solar desalting method and apparatus includes a storage tank for receiving heated sea water at a first rate from a solar collector during daylight hours and for delivering the same to a flash evaporator a second rate. The flash evaporator is connected for delivery of the evaporated and unevaporated portions of the feed water as the heating vapor and feed liquid, respectively, to a serially connected multi-effect film evaporator. Sea water is used to condense the vapor from the last evaporator effect as the distillate product of the system. The storage tank permits nighttime operation with the brine from the last effect and a portion of the cooling water being fed to the solar collector during the daytime and discharged at night.

  18. Solar desalting plant

    SciTech Connect

    Liu, P.J.

    1982-05-18

    A solar desalting method and apparatus includes a storage tank for receiving heated sea water at a first rate from a solar collector during daylight hours and for delivering the same to a flash evaporator a second rate. The flash evaporator is connected for delivery of the evaporated and unevaporated portions of the feed water as the heating vapor and feed liquid, respectively, to a serially connected multi-effect film evaporator. Sea water is used to condense the vapor from the last evaporator effect as the distillate product of the system. The storage tank permits nighttime operation with the brine from the last effect and a portion of the cooling water being fed to the solar collector during the daytime and discharged at night.

  19. Solar astronomy

    NASA Technical Reports Server (NTRS)

    Rosner, Robert; Noyes, Robert; Antiochos, Spiro K.; Canfield, Richard C.; Chupp, Edward L.; Deming, Drake; Doschek, George A.; Dulk, George A.; Foukal, Peter V.; Gilliland, Ronald L.

    1991-01-01

    An overview is given of modern solar physics. Topics covered include the solar interior, the solar surface, the solar atmosphere, the Large Earth-based Solar Telescope (LEST), the Orbiting Solar Laboratory, the High Energy Solar Physics mission, the Space Exploration Initiative, solar-terrestrial physics, and adaptive optics. Policy and related programmatic recommendations are given for university research and education, facilitating solar research, and integrated support for solar research.

  20. The temporal and spatial distribution of deformation in the western Salton trough from 1992-2001 as observed by InSAR

    NASA Astrophysics Data System (ADS)

    Mellors, R. J.; van Zandt, A.; Rojas, O.

    2005-12-01

    We use InSAR data to examine the temporal and spatial distribution of deformation in the Western Salton trough in Southern California. A set of 87 ERS-1 and ERS-2 interferograms (track 356, frame 2943, descending) covering the region and spanning a time period from 1992 to 2000 have been compiled. The interferograms show a combination of both tectonic (mainly along the Superstition Hills and Elmore Ranch faults) and groundwater related (centered in farming areas) deformation signals. We invert the dataset to resolve the evolution of slip over time using a least-squares approach constrained with GPS data. Error terms for the DEM, orbital, and atmospheric effects are addressed using a combination of spatial and temporal filtering. The results show that the tectonic slip decreases with time, as expected for long-term post-seismic slip following the 1987 Superstition Hill/Elmore Ranch earthquakes. The tectonic slip also appears to be episodic in nature. In contrast, the groundwater-related subsidence shows a more linear trend with time. 2D modeling of the observed tectonic slip (assuming purely horizontal movement along a vertical strike-slip fault) indicates that slip along the Superstition Hills fault extends from the surface to an average depth of 4 km. The average horizontal slip from 1992 to 2001 varies from 5 to 10 mm per year along the fault. Slip along the Elmore Ranch fault is slower and appears to be distributed over a wider zone, possibly suggesting that creep does not extend to the surface.

  1. Sea Legs

    NASA Astrophysics Data System (ADS)

    Macdonald, Kenneth C.

    Forty-foot, storm-swept seas, Spitzbergen polar bears roaming vast expanses of Arctic ice, furtive exchanges of forbidden manuscripts in Cold War Moscow, the New York city fashion scene, diving in mini-subs to the sea floor hot srings, life with the astronauts, romance and heartbreak, and invading the last bastions of male exclusivity: all are present in this fast-moving, non-fiction account of one woman' fascinating adventures in the world of marine geology and oceanography.

  2. Strike-slip Fault Structure in the Salton Trough and Deformation During and After the 2010 M7.2 El Mayor-Cucapah Earthquake from Geodetic and Seismic Data

    NASA Astrophysics Data System (ADS)

    Fielding, E. J.; Sun, J.; Gonzalez-Ortega, A.; González-Escobar, M.; Freed, A. M.; Burgmann, R.; Samsonov, S. V.; Gonzalez-Garcia, J.; Fletcher, J. M.; Hinojosa, A.

    2013-12-01

    The Pacific-North America plate boundary character changes southward from the strike-slip and transpressional configuration along most of California to oblique rifting in the Gulf of California, with a transitional zone of transtension beneath the Salton Trough in southernmost California and northern Mexico. The Salton Trough is characterized by extremely high heat flow and thin lithosphere with a thick fill of sedimentary material delivered by the Colorado River during the past 5-6 million years. Because of the rapid sedimentation, most of the faults in Salton Trough are buried and reveal themselves when they slip either seismically or aseismically. They can also be located by refraction and reflection of seismic waves. The 4 April 2010 El Mayor-Cucapah earthquake (Mw 7.2) in Baja California and Sonora, Mexico is probably the largest earthquake in the Salton Trough for at least 120 years, and had primarily right-lateral strike-slip motion. The earthquake ruptured a complex set of faults that lie to the west of the main plate boundary fault, the Cerro Prieto Fault, and shows that the strike-slip fault system in the southern Salton Trough has multiple sub-parallel active faults, similar to southern California. The Cerro Prieto Fault is still likely absorbing the majority of strain in the plate boundary. We study the coseismic and postseismic deformation of the 2010 earthquake with interferometric analysis of synthetic aperture radar (SAR) images (InSAR) and pixel tracking by subpixel correlation of SAR and optical images. We combine sampled InSAR and subpixel correlation results with GPS (Global Positioning System) offsets at PBO (Plate Boundary Observatory) stations to estimate the likely subsurface geometry of the major faults that slipped during the earthquake and to derive a static coseismic slip model. We constrained the surface locations of the fault segments to mapped locations in the Sierra Cucapah to the northwest of the epicenter. SAR along-track offsets

  3. Effects of sea spray geoengineering

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-03-01

    Anthropogenic climate warming is leading to consideration of options for geoengineering to offset rising carbon dioxide levels. One potential technique involves injecting artificial sea spray into the atmosphere. The sea salt particles would affect Earth's radiation budget directly, by scattering incoming solar radiation, and indirectly, by acting as cloud condensation nuclei, which could lead to whiter clouds that reflect more radiation. However, the potential effects of this method, especially the direct effects, are not fully known. Partanen et al. studied the effects of artificial sea spray using climate model simulations. They found that outside of the most heavily clouded regions the direct effect of scattering of radiation was an important part of the total effect. They also examined the effect of particle size and found that decreasing the size of injected particles could improve the efficiency of the geoengineering technique.

  4. Sea Ice

    NASA Technical Reports Server (NTRS)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  5. Aral Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This series of MODIS images shows the dwindling Aral Sea. Once one of the world's largest freshwater lakes, the Aral Sea has decreased by as much as 60% over the past few decades due to diversion of the water to grow cotton and rice. These diversion have dropped the lake levels, increased salinity, and nearly decimated the fishing industry. The previous extent of the lake is clearly visible as a whitish perimeter in these image from April 16, May 18, and June 3, 2002. s. Credit: Jacques Descloitres, MODIS Land Rapid Response Team, NASA/GSFC

  6. Black Sea

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Black Sea in eastern Russia is experiencing an ongoing phytoplankton bloom. This image, the most recent in a series that began in early may, shows the waters to be even more colorful than before. part of the increased brightness may be due to the presence of sun glint , especially in the center of the sea. However, more organisms appear to be present as well, their photosynthetic pigments reflecting different wavelengths of light.This Moderate Resolution Imaging Spectroradiometer (MODIS) image was captured on June 15, 2002.

  7. Ross Sea

    Atmospheric Science Data Center

    2013-04-16

    article title:  Icebergs in the Ross Sea     View Larger Image Two large icebergs, designated B-15A and C-16, are captured in this Multi-angle Imaging ... the longitudinal quadrant in which it is first seen, and new icebergs sighted in that quadrant are sequentially numbered. B-15 divided from ...

  8. Loss of sea ice in the Arctic.

    PubMed

    Perovich, Donald K; Richter-Menge, Jacqueline A

    2009-01-01

    The Arctic sea ice cover is in decline. The areal extent of the ice cover has been decreasing for the past few decades at an accelerating rate. Evidence also points to a decrease in sea ice thickness and a reduction in the amount of thicker perennial sea ice. A general global warming trend has made the ice cover more vulnerable to natural fluctuations in atmospheric and oceanic forcing. The observed reduction in Arctic sea ice is a consequence of both thermodynamic and dynamic processes, including such factors as preconditioning of the ice cover, overall warming trends, changes in cloud coverage, shifts in atmospheric circulation patterns, increased export of older ice out of the Arctic, advection of ocean heat from the Pacific and North Atlantic, enhanced solar heating of the ocean, and the ice-albedo feedback. The diminishing Arctic sea ice is creating social, political, economic, and ecological challenges. PMID:21141043

  9. Internet Relaying of Total Solar Eclipse on 11 August,1999

    NASA Astrophysics Data System (ADS)

    Nagai, T.; Takahashi, N.; Okyudo, M.; Suginaka, M.; Matsumoto, N.; Team Of Live! Eclipse

    The total solar eclipse was relayed live through the Internet from Siberia, Russia, on 9 March 1997. Subsequently, the total solar eclipse was relayed from Venezuela and Guadeloupe in the Caribbean Sea in 26 February 1998, the annular solar eclipse from Malaysia on 21 August 1998, and the annular solar eclipse from Australia on 16 February 1999. The Internet was used to relay the total solar eclipse to be seen in Europe, Rumania, Turkey, and Iran. We succeeded in transmitting images from Turkey.

  10. From Sea to Shining Sea

    ERIC Educational Resources Information Center

    Scott, Beverly

    2005-01-01

    Deep down in the depths of the sea, beautiful fish, mysterious ocean life, and unusual plants glimmer and glow in the eerie atmosphere of an ever-changing ocean. This article describes how, with this vision and a purpose in mind, three teachers pulled open classroom walls and joined forces so their second graders could create a mammoth 30 x 75"…