(Top) Sample bottles from a sediment trap located 4 meters (13 feet) above the bottom of Massachusetts Bay. Each bottle represents accumulations during about 9 days during the period from October 1990 to February 1991. (Middle) Suspended sediment concentration based on light transmission shows peaks in turbidity that correlate well with sample bottles. (The upward trend beginning in December was caused by algae fouling the lenses of the turbidity sensor.) (Bottom) There is a clear correlation between the four most intense periods of wave activity and the peaks in suspended sediment shown by the upper graph and the bottles. This correlation indicates that waves are the major cause of resuspension. The samples in bottles are also used to measure attributes (such as sediment characteristics and contaminant levels) during stormy and calm periods. discharge of wastes into the ocean conflicts with other uses of the marine environment, such as recreation, fishing, and transportation. Three-dimensional computer modeling of circulation in Massachusetts Bay, which is a major component of the USGS effort, not only has provided insight to scientists but also has played a key role in the debate about whether to complete the new outfall that redirects treated sewage effluent from the presently contaminated harbor to a location 9 miles into Massachusetts Bay. When the model was tested under winter conditions, it showed excellent agreement between what was observed and what was predicted for currents in Massachusetts Bay. The model results, which have been presented at a number of public forums, in court, and for a television documentary, have been used to compare effluent dilution at the present outfall site and the proposed site. The model shows that the present outfall maintains significant concentrations of effluent throughout Boston Harbor and southward along the shore of Massachusetts Bay. Effluent at equivalent concentrations from the deeper offshore outfall does not reach Boston Harbor and affects much less of the Massachusetts Bay shoreline. The amounts of heavy metals in bottom sediment and suspended matter in western Massachusetts Bay have also been established and provide a baseline for evaluating changes that may result from the new ocean outfall. Maps showing grain sizes of the sea floor in Boston Harbor and Massachusetts Bay have been generated by using sidescan sonar, seismic reflection, bottom photography, and sediment sampling. Because contaminants are commonly bound to fine-grained particles, maps that show particle sizes can be used to indicate where contaminants are most likely to accumulate. These maps have been used by State agencies to design baywide programs to monitor and evaluate the environmental impacts of the new outfall. Field measurements conducted around the future outfall site to determine the fate of particles show that surface waves during major winter storms are the principal agents in resuspending sediment. A time-series sediment trap used at a long-term instrumented mooring in Massachusetts Bay demonstrates the correlation between bottom currents caused by surface waves and sediment resuspension and provides material from individual storms for analysis. Fine particles that settle in western Massachusetts Bay during relatively tranquil summer periods may be eroded and redistributed to deeper waters of Stellwagen Basin during winter storms. Knowledge of these processes is critical to evaluating the longterm impacts of pollutants in this coastal area. The USGS Massachusetts Bay studies are providing information that is applicable to other coastal regions and may serve as a model for studies to assess the environmental consequences of waste disposal and contaminant accumulation in the coastal ocean areas. Michael Bothner and Bradford Butman have studied the geochemistry of shallow marine sediments for more than a decade Richard P. Signell is a physical oceanographer specializing in numerical models of circulation Surprising News of Recent Faulting in South San Francisco Bay The he USGS began acquiring ultra-highresolution seismic reflection profiles in San Francisco Bay in 1992 as part of a long-term study of the geology and environment of the Nation's largest urban estuary. In cooperation with scientists. from four Japanese universities, the USGS acquired profiles by sharing the use of a Japanese sonar system, which is capable of obtaining unusually precise records from layers as thin as 18 centimeters (7 inches) in the upper 20 meters (66 feet) of soft bay mud. Japanese scientists have used this instrument to study a large and active fault in Japan, called the Median Tectonic Line, and were inter Massachusetts Bay Program A long-term objective of the USGS Massachusetts Bay program is to develop the ability to predict patterns of sediment and contaminant transport and accumulation on a regional basis. The program addresses fundamental questions such as (1) what is the texture and structure of the sea-floor environment in the harbor and bay, (2) how are water and materials transported throughout the system, and (3) where do sediments and associated contaminants accumulate and at what rate? To answer these questions, the USGS study of the bay includes: Regional mapping of sediment types and areas of erosion and deposition. • Chemical analyses of sediment to determine present levels of contaminants. • Direct measurement of ocean currents and computer modeling of regional circulation. • Assembly of existing information to describe the spatial distributions and temporal trends in sediment and contaminant conditions. • Long-term monitoring of ocean conditions and sediment properties to evaluate seasonal and annual variability and the infrequent catastrophic events that may be responsible for most sediment transport. ested in acquiring data on other strikeslip faults such as the Hayward fault, which crosses the San Pablo Bay area of north San Francisco Bay. As part of the cooperative study, the USGS extended its surveys into southcentral San Francisco Bay. Previous airborne surveys of the magnetic field of the bay had shown that long linear aeromagnetic anomalies were known to cross this part of the bay from northwest to southeast. USGS researchers suggested in the late 1970's that the anomalies delineate fault zones. These faults are exposed on the peninsula beneath the city of San Francisco in a mass of rock called the Franciscan Formation along the Hunters Point-Fort Point shear zone. Because the faults separate bodies of rock that are more than 65 million years old, they were thought to be old and inactive. The new seismic profiles confirmed earlier speculation that the faults extend offshore along the linear magnetic anomalies but also show that some faulting occurred less than 10,000 years ago. Two major fault zones have been identified, each 2 to 3 kilometers (1.3–1.8 miles) wide and consisting of dozens of strands (a fault strand is a short segment For more information on contamination of a fault). The northern fault zone, called the Hunters Point fault zone, is known to extend about 5 kilometers (3 miles) from the shear zones exposed on Hunters Point to the central part of the bay, but it may be longer; the shallow depth of the bay to the southeast prevented surveying there. The area will be surveyed this year by using a shallowdraft vessel on loan from San Francisco State University. The Hunters Point fault zone may be as long as 120 kilometers (75 miles) (as long as the adjacent Hayward fault) if it follows the regional extension of a pronounced magnetic anomaly. The second fault zone, called the Coyote Point fault zone, extends from the end of the runways of San Francisco International Airport to the southeast past Coyote Point and may extend into the shallow part of the bay or beyond. Separating the two fault zones is a large suspected fold and thrust structure called the San Bruno Shoal anticline, which has uplifted the bay floor to less than a meter (3 feet) deep in the center of south San Francisco Bay. A month after the surveys, the USGS began collecting a series of cores in the south-central bay to date the layers that have been offset by fault movement. Colleagues at Stanford University and the Lawrence Berkeley Laboratory have been assisting USGS scientists in dating shells found in some layers by means of a precise carbon-14 dating technique. The preliminary results indicate that all the faults in the bay offset layers that were deposited 5,000 years ago and that some of the faults offset beds deposited only 1,600 years ago. At least two fault strands offset the bay floor, an indication that faulting may have been active within the past 1,000 years, but further studies are needed to determine the actual age of faulting. Because of the young age of the faulting and the proximity of the faults to large urban areas and critical infrastructure, the USGS has held a series of briefings with officials from the airport, city emergency and transportation services, and others to advise them of the newly mapped faults. Future plans include a cooperative study with the State transportation agency to assist in the analysis of deep borings (to bedrock) that will be collected near the bay bridges. USGS scientists have recently finished an extensive survey of the rest of the south San Francisco Bay. Other USGS scientists will extend the fault studies on land across the San Francisco Peninsula and into the Pacific Ocean. They hope to find the area where the San Andreas fault intersects these newly delineated faults, near the epicenter of the great 1906 San Francisco earthquake. The U.S. Energy Mix The energy consumption of the United States continues to grow at a steady pace. Ninety-nine percent of the energy used in this country is based on natural, nonrenewable resources-91 percent on fossil fuels, including coal, oil, and natural gas, and 8 percent on nuclear power. The remaining 1 percent comes from hydroelectric, solar, and wind power and other renewable sources. The mix of energy used by the United States is the foundation of the Nation's infrastructure and economy and significantly influences the environment. The USGS Energy Program provides fundamental scientific knowledge on the abundance of energy resources and the environmental consequences of their use, information that is vital in order to effect any substantial changes in the energy mix of the Nation. Energy Resources and the Economy The he bulk of domestic energy consumption comprises oil-based fuels. Domestic oil production satisfies only about half of the Nation's oil appetite, however, and domestic oil production is declining at an alarming rate. Imported oil accounts for a significant proportion of the national trade deficit. Natural gas and coal are alternatives to oil-based fuel and are considered to be abundant in the United States. Scientists do not have a comprehensive understanding of the geological occurrences of natural gas, however, and this lack of knowledge inhibits exploration and development of domestic natural gas resources. Domestic coal resources also are thought to be vast, but a comprehensive understanding of the quantity and quality of minable coal has still not been achieved. Moreover, the use of coal poses potential environmental hazards that must be addressed if coal is to remain a viable energy resource in coming decades. USGS scientists conduct scientifically based assessments of specific energy resources, including oil, natural gas, coal, uranium, and oil shale. In addition, they evaluate the Nation's energy mix on a regular basis. World assessments of oil, natural gas, and coal QUADS New Energy Assessment Underway The USGS, in cooperation with the Minerals Management Service (MMS), is currently conducting a new assessment of U.S. oil and gas resources. The USGS assesses all onshore lands and State offshore waters; the MMS assesses Federal offshore waters. The assessment provides an independent, scientifically based set of hypotheses concerning the amounts of oil and gas that could be added to U.S. reserves. The new assessment includes (1) undiscovered, conventionally recoverable oil and natural gas; (2) selected recoverable, unconventional resources of oil and natural gas; and (3) reserve appreciation (field growth). The USGS assessment will be completed by January 1995; results will be published early in 1996. All results of the new assessment will be released in digital form, including on CD-ROM's. The geographic information system approach-being used for the first time in this assessment-allows results to be identified in relation to specific geologic provinces and geographic areas. For example, resource estimates will be available for individual Federal land-management areas, sedimentary basins, or States. This capability will make it easier for Federal landmanagement agencies, State agencies, and industry to use the assessment results. Moreover, it will provide a base of digital information that will be the foundation of continuing USGS efforts to improve assessment results. Coal-Quality Data Base Sets Standards The Environmental Protection Agency has recently designated the USGS coal-quality data base as the sole data base on which policy recommendations concerning trace-metal emissions from coalburning powerplants will be made. The electric power industry also has recognized the uniqueness of this data base and the high quality of information it contains. Representatives of the Electric Power Research Institute, the Edison Electric Institute, and the Utility Air Regulations Group recently expressed a strong desire to work cooperatively with the USGS to expand the coverage of the coal-quality data base. These developments establish the USGS coal-quality data base as the primary source of independent scientific data recognized and used by both regulators and industry to address airquality issues. For more information about the Energy Resources Surveys program, contact David Houseknecht at: Telephone (703) 648-6470 Internet dhousekn@usgs.gov to predict the occurrence of relatively clean fossil fuels and to develop technology for removing hazardous elements from fuels before use. Increased use of natural gas in place of coal and oil-based fuels would significantly reduce the amounts of greenhouse gases and hazardous elements released to the atmosphere. Expanded research on natural gas will build a comprehensive understanding of this vital resource. Research topics of particular interest include the volume and distribution of economically and technically recoverable domestic natural gas resources and the earth-science background needed for the optimal development of those resources. The results of this research will establish a scientific basis for evaluating the environmental impacts of various energy-use scenarios and will provide predictive models to use in exploring for environmentally benign energy resources. An added benefit is an improved understanding of geological constraints in designing technology for removing harmful elements from fossil fuels before use. USGS maintains formal liaisons with the U.S. Forest Service and with other Department of the Interior bureaus, including the Bureau of Land Management, the National Park Service, and the Bureau of Indian Affairs. Results of energy-resource assessments are shared with the Bureau of Mines and incorporated into the National Energy Strategy, largely through cooperation among various agencies in the U.S. Department of Energy, including the Energy Information Administration, the Office of Oil and Gas Exploration and Development, and the Office of Basic Energy Sciences. Similarly, the environmental impact assessments conducted by the USGS are cooperative ventures with the Bureau of Reclamation, the Bureau of Mines, and the Environmental Protection Agency. Interaction with agencies in every State having oil, natural gas, or coal potential is an essential part of most Energy Program research. |