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Results for “Pacific Geological Surveys”

Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 235 records · Page 13Linked to original sources
USGS2007

Airborne geophysics as a tool for geoscientific research in Antarctica: some recent examples

The polar regions play an important role in Earth's geodynamic and climatic systems. Modern airborne geophysical surveys combine radio-echo sounding, aeromagnetic and aerogravity methods to explore the geology of these regions. This paper reviews some recent aerogeophysical investigations undertaken by the British Antarctic Survey to: 1) Image subglacial rifts of Jurassic age in western Dronning Maud Land, which were associated with early Gondwana break-up; 2) Investigate crustal growth over the Antarctic Peninsula by Cretaceous arc magmatism and terrane accretion along the paleo-Pacific margin of Gondwana; 3) Analyse geological boundary conditions for presentday ice dynamics over Coats Land.

Open-File Report↗
USGS1947

Geologic features of dam sites in the Nehalem, Rogue, and Willamette River basins, Oregon, 1935-37

The present report comprises brief descriptions of geologic features at 19 potential dam sites in the Nehalem, Rogue, and Willamette River basins in western Oregon. The topography of these site and of the corresponding reservoir site was mapped in 1934-36 under an allocation of funds, by the Public Works Administration for river-utilization surveys by the Conservation Branch of the United States Geological Survey. The field program in Oregon has been under the immediate charge of R. O. Helland. The 19 dam sites are distributed as follows: three on the Nehalem River, on the west or Pacific slope of the Oregon Coast range; four on Little Butte Creek and two on Evans Creek, tributaries of the Rogue River in the eastern part of the Klamath Mountains; four on the South and Middle Santiam Rivers, tributaries of the Willamette River from the west slope of the Cascade mountains; and six on tributaries of the Willamette River from the east slope of the Coast Range. Except in the Evans Creek basin, all the rocks in the districts that were studied are of comparatively late geological age. They include volcanic rocks, crystalline rocks of several types, marine and nonmarine sedimentary rocks, and recent stream deposits. The study of geologic features has sought to estimate the bearing power and water-tightness of the rocks at each dam site, also to place rather broad limits on the type of dam for which the respective sites seem best suited. It was not considered necessary to study the corresponding reservoir sites in detail for excessive leakage appears to be unlikely. Except at three of the four site in the Santiam River basin, no test pits have been dug nor exploratory holes drilled, so that geologic features have been interpreted wholly from natural outcrops and from highway and railroad cuts. Because these outcrops and cuts are few, many problems related to the construction and maintenance of dams can not be answered at the this time and all critical features of the sites should be thoroughly explored by test pits and drilled holes before any dam is designed. This applied especially to sites in the Nehalem and Willamette River basins where commonly the cover of timber and brush is dense and the rocks are rather deeply weathered. On the Middle Santiam and South Santiam Rivers, the Cascadia, Greenpeter, and Sweet Home sits have been studies intensively by the United States Engineer Department, whose work included exploration by diamond-drill holes and test pits. Their conclusions as to geologic features are given in a report by McKitrick and have been reviewed by the writer. Data from this source have been used freely in the discussion of the respective sites in this report. The probability of destructive earthquakes in the region appears to be small but is not negligible. Prudence suggests that any high dam should embody features to assure stability against moderately strong earth motions.

Oregon↗
USGS1964

Water levels in observation wells in Santa Barbara County, California, 1963

The U.S. Geological Survey, in cooperation with the Santa Barbara County Water Agency, continued the study of the ground-water resources of Santa Barbara County (fig. 1) in 1963. As part of the study, the Geological Survey made monthly water-level measurements in 247 wells; 17 of which were equipped with automatic water-level recorders. These measurements and measurements made by the Santa Maria Valley Water Conservation District are included in this report— In addition, the U.S. Bureau of Reclamation measured the water levels in wells along the Santa Ynez River between Cachuma Dam and Rucker Crossing, but the measurements have not been included herein. In addition to the observation-well program, the Geological Survey is preparing interpretive reports on the ground-water conditions in the Ellwood-Gaviota area, the Lompoc and Santa Ynez upland areas of the Santa Ynez River basin, the Santa Barbara-Summerland area, and the Santa Maria Valley. The basic data from which these reports are being prepared can be consulted at the Santa Barbara office of the Geological Survey. This report was prepared by the Geological Survey, Water Resources Division, under the general supervision of Fred Kunkel, district geologist in charge of ground-water investigations In California, and under the immediate supervision of C. P. Zones, geologist in charge of the Santa Barbara subdistrict office. Measurements for the period 1941-55 were published in U.S. Geological Survey water-supply papers; measurements for the period 1956-62 were released locally in duplicated form.' A report by G. A. LaRocque, Jr., and others (1950) contains descriptions of 2,246 wells in the ground-water basins of the county in 1942. It also contains many water-level measurements made before 1942 by the city of Santa Barbara, the Santa Maria Valley Water Conservation District, the San Joaquin Power Division of the Pacific Gas and Electric Co., the Union Sugar Co., the Union Oil Co., and other organizations and individuals. Comprehensive reports on the geology and ground-water resources of the Santa Ynez River basin (Upson, Thomasson, and others, 1951; Wilson, 1959), the south-coast basins (Upson and others, 1951), the Santa Maria Valley area (Worts, 1951), the Cuyama Valley (Upson and Worts, 1951) and the San Antonio Creek valley (Muir; 1964) were published as Geological Survey water-supply papers. A report on stream runoff and ground-water storage capacity of the Santa Ynez River valley (Troxell and Wilson, 1952) was released to the open file in October 1952. A complete bibliography of reports of investigations made by the Water Resources Division, U.S. Geological Survey, in Santa Barbara County since 1940 is included in this report.

California↗
USGS1979

Outer Continental Shelf oil and gas information program; Pacific index

The Outer Continental Shelf Lands Act of 1953, as amended in 1978, (43 U.S.C. 1331 et seq.), grants to the Secretary of the Interior the authority to issue leases for minerals on the U.S. Outer Continental Shelf (OCS). It provides the authority and guidelines which the Secretary utilizes for expeditious exploration and development of the OCS while ensuring timely access to information by affected states and local governments in order that appropriate planning will anticipate and ameliorate impacts from such OCS activities. This document is prepared in accordance with Part 30 of the Code of Federal Regulations (CFR), Section 252.5 and 43 CFR, Section 3300.2, which require that the Directors of the U.S. Geological Survey and the Bureau of Land Management shall make available an Index, listing all relevant, actual or proposed programs, plans, reports, environmental impact statements and other lease sale information, on a regular basis, to each affected state and, upon request, to the executive of any local government whose jurisdiction covers an area affected by OCS activities. Accordingly, the Geological Survey and the Bureau of Land Management are cooperating in a joint effort to compile all relevant information on the OCS Oil and Gas Leasing Program in an Index with four volumes; Alaska, Atlantic, Gulf of Mexico and Pacific. This volume is a listing of documents used in the Pacific Area OCS decisionmaking process, and the sequence of information presented parallels this process. The bibliographic references are presented by lease sale number, in the sequence in which the documents are generated in the Federal OCS leasing program. Thus, the reader may compare all documents of one type in the Pacific Area or trace a single lease sale throughout the entire leasing process. Activities which generate information throughout the OCS lease sale process are described under Other Documentation and Supplemental Reading. Other Documentation pertains to Federal data gathering and analysis programs which are an integral part of the OCS decisionmaking process and are used throughout the process due to the usefulness of their subject matter. The Supplemental Reading documents (Appendix A) are not used in decisionmaking but are invaluable sources of general OCS information.

California, Oregon, Washington↗
USGS2011

Sediment dynamics and the burial and exhumation of bedrock reefs along an emergent coastline as elucidated by repetitive sonar surveys: Northern Monterey Bay, CA

Two high-resolution bathymetric and acoustic backscatter sonar surveys were conducted along the energetic emergent inner shelf of northern Monterey Bay, CA, USA, in the fall of 2005 and the spring of 2006 to determine the impact of winter storm waves, beach erosion, and river floods on biologically-important siliclastic bedrock reef habitats. The surveys extended from water depths of 4 m to 22 m and covered an area of 3.14 km2, 45.8% of which was bedrock, gravel, and coarse-grained sand and 54.2% was fine-grained sand. Our analyses of the bathymetric and acoustic backscatter data demonstrates that during the 6 months between surveys, 11.4% of the study area was buried by fine-grained sand while erosion resulted in the exposure of bedrock or coarse-grained sand over 26.5% of the study area. The probability of burial decreased with increasing water depth and rugosity; the probability of exhumation increased with increasing wave-induced near-bed shear stress, seabed slope and rugosity. Much of the detected change was at the boundary between bedrock and unconsolidated sediment due to sedimentation and erosion burying or exhuming bedrock, respectively. In a number of cases, however, the change in seabed character was apparently due to changes in sediment grain size when scour exposed what appeared to be an underlying coarser-grained lag or the burial of coarser-grained sand and gravel by fine-grained sand. These findings suggest that, in some places, (a) burial and exhumation of nearshore bedrock reefs along rocky, energetic inner shelves occurs over seasonal timescales and appears related to intrinsic factors such as seabed morphology and extrinsic factors such as wave forces, and (b) single acoustic surveys typically employed for geologic characterization and/or habitat mapping may not adequately characterize the geomorphologic and sedimentologic nature of these types of environments that typify most of the Pacific Ocean and up to 50% of the world's coastlines.

Monterey Bay↗
USGS2002

Vulnerability assessment of a port and harbor community to earthquake and tsunami hazards: Integrating technical expert and stakeholder input

Research suggests that the Pacific Northwest could experience catastrophic earthquakes and tsunamis in the near future, posing a significant threat to the numerous ports and harbors along the coast. A collaborative, multiagency initiative is underway to increase the resiliency of Pacific Northwest ports and harbors to these hazards, involving Oregon Sea Grant, Washington Sea Grant, the National Oceanic and Atmospheric Administration Coastal Services Center, and the U.S. Geological Survey Center for Science Policy. One element of this research, planning, and outreach initiative is a natural hazard mitigation and emergency preparedness planning process that combines technical expertise with local stakeholder values and perceptions. This paper summarizes and examines one component of the process, the vulnerability assessment methodology, used in the pilot port and harbor community of Yaquina River, Oregon, as a case study of assessing vulnerability at the local level. In this community, stakeholders were most concerned with potential life loss and other nonstructural vulnerability issues, such as inadequate hazard awareness, communication, and response logistics, rather than structural issues, such as damage to specific buildings or infrastructure.

Oregon↗
USGS2006

Preliminary estimate of coal resources in the Gillette coalfield affected by the location of the Burlington Northern/Union Pacific joint mainline railroad

This publication, primarily in graphic form, presents a preliminary resource assessment related to a major, near-term restriction to mining in that portion of the Gillette coalfield, Wyoming, that is traversed by the Burlington Northern/Union Pacific joint mainline railroad. This assessment is part of a current Powder River Basin regional coal assessment, including both resources and reserves, being conducted by the U.S. Geological Survey. The slides were used to illustrate a presentation of study results at a meeting of the Bureau of Land Management's Regional Coal Team in Casper, Wyoming on April 19, 2006 by the senior author.

Open-File Report↗
USGS2012

Long term mean annual water temperature for stream reaches in Pacific Northwest United States

Long-term mean annual water temperature (degrees Celsius) was estimated for the E2RF1 stream network (Brakebill and Terziotti, 2011) located within the Pacific Northwest region of the United States (HUC2 = 17; the Columbia River basin, the Puget Sound watershed, the coastal drainages of Washington and Oregon, and the closed basins in southern Oregon). Multiple linear regressions were used to select reach-scale watershed attributes (explanatory variables) for predicting the long-term mean annual water temperature (dependent variable) at a set of USGS water-quality monitoring stations. The results from the multiple linear regressions were used to predict the long-term mean water temperature for the Pacific Northwest reaches in the E2RF1 network.

Report↗
USGS2009

Aeromagnetic survey map of the central California Coast Ranges

This aeromagnetic survey was flown as part of a Cooperative Research and Development Agreement (CRADA) with the Pacific Gas and Electric Company and is intended to promote further understanding of the geology and structure in the central California Coast Ranges by serving as a basis for geophysical interpretations and by supporting geological mapping, mineral and water resource investigations, and other topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on aeromagnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals can commonly mark lithologic or structural boundaries. Bodies of serpentinite and other mafic and ultramafic rocks tend to produce the most intense magnetic anomalies, but such generalizations must be applied with caution because rocks with more felsic compositions, such as the porphyritic granodiorite-granite of the La Panza Range, and even some sedimentary units, also can cause measurable magnetic anomalies.

California↗
USGS2013

Public-policy issues associated with the SAFRR Tsunami Scenario

The SAFRR (Science Application for Risk Reduction) tsunami scenario simulates a tsunami generated by a hypothetical magnitude 9.1 earthquake that occurs offshore of the Alaska Peninsula (Kirby and others, 2013). In addition to the work performed by the authors on public-policy issues associated with the SAFRR tsunami scenario, this section of the scenario also reflects the policy discussions of the State of California’s Tsunami Policy Work Group, a voluntary advisory body formed in October 2011, which operates under the California Natural Resources Agency (CNRA), Department of Conservation, and is charged with identifying, evaluating, and making recommendations to resolve issues that are preventing full and effective implementation of tsunami hazard mitigation and risk reduction throughout California’s coastal communities. It also presents the analyses of plans and hazard policies of California’s coastal counties, incorporated cities, and major ports performed by the staff of the California Geological Survey (CGS) and Lauren Prehoda, Office of Environmental and Government Affairs, California Department of Conservation. It also draws on the policy framework and assessment prepared for the ARkStorm Pacific Coast winter storm and catastrophic flooding (Topping and others, 2010).

Open-File Report↗