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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 199 records · Page 11Linked to original sources
USGS2011

The U.S. Geological Survey's gravity program in the Rocky Mountain and Basin Range areas

Most of the gravity surveys of the U.S. Geological Survey have been support programs in connection with regional geologic structural studies, ground-water investigations, and heavy-metals exploration. Many of the studies were undertaken in conjunction with geological mapping and mineral investigations by the Survey's project geologists. Gravity data often complement aeromagnetic surveys to identify the sources of potential-field anomalies; other gravity data have been used to supplement high-resolution seismic and electrical investigations [ Mattick , 1967]. Geochemical follow-up has been fruitful in western Montana [ Mudge et al, 1967].

Arizona, Colorado, Idaho, Montana, Nevada, New Mex↗
USGS2011

IASH Commission of Snow and Ice meeting: Paris, France, September 3-5, 1969

The IASH Commission of Snow and Ice met jointly with the Working Group on Glaciology of the Special Committee on Antarctic Research (SCAR). Five technical guides have been prepared by the Commission of Snow and Ice for major IHD projects and have been in press at Unesco for more than a year and a half. They should be published by December 1969. A sixth guide, on Sea, Lake and River Ice, was approved for publication, and two other guides (Avalanche Classification and Part 2 of Combined Heat, Ice, and Water Balances) have been distributed in first or second draft form. They should be ready for approval by the next meeting of the officers of the Commission. Even though these guides have not yet been officially published, they have served as instruction and coordination media for a large number of glacier and seasonal snow cover projects in many nations during the first part of the International Hydrological Decade.

Eos, Transactions, American Geophysical Union↗
USGS2011

A progress report: Water conservation by removal of phreatophytes

Evapotranspiration from the flood plain of a major river depletes the water contributed from upstream areas of the watershed. This depletion can be significant in arid regions where water supplies are inadequate. Phreatophyte control offers a method of reducing the evapotranspiration and thus increases the water available to downstream users. This control is achieved by removing the woody phreatophytes and replacing them with grasses having a lower consumptive use.

Arizona↗
USGS2011

International symposium on hydrometry

Approximately 520 engineers and scientists from 55 countries attended the International Symposium on Hydrometry held at Koblenz, Federal Republic of Germany, from September 13 through 22, 1970. The symposium was convened by Unesco and organized in cooperation with the World Meteorological Organizations (WMO), Unesco, the National Committee for the International Hydrological Decade of the Federal Republic of Germany, and the International Association of Scientific Hydrology (IASH). The symposium was organized within the framework of the International Hydrological Decade (IHD). After a welcoming speech by J. Wallner, Chairman of the Organizing Committee, the opening address was presented by S. Dumitrescu, the representative of Unesco. Introductory statements were then delivered by T. Palas, the representative of WMO; by L.J. Tison, the representative of IASH; and by K. Wittock, the representative of the Government of the Federal Republic of Germany.

Eos, Transactions, American Geophysical Union↗
USGS2012

Geochemistry of water

The quadrennium 1967–1970 has been a productive period in the field of water geochemistry. Field studies, laboratory investigations, and theoretical considerations have led to significant advances in our knowledge of the chemical behavior of natural waters and of the solid earth materials that contain them. A symposium on trace inorganics in water, sponsored by the American Chemical Society, was held in Miami, Florida, in 1967. The proceedings of this conference were published in 1968 in the Advances in Chemistry Series 73. This volume deals with the occurrence, behavior, and analysis of inorganic constituents in natural waters.

Eos, Transactions, American Geophysical Union↗
USGS2011

Water projects design with inadequate data: Madrid, Spain June 4-9, 1973

The Symposium on the Design of Water Resources Projects with Inadequate Data drew 300 participants, representing more than 60 countries. The symposium was planned within the framework of the International Hydrological Decade and was convened by Unesco and WMO. Organization of the symposium was carried out by Unesco and the Spanish National Committee for the IHD in cooperation with WMO and the IAHS. These organizations are to be commended for their efforts toward ensuring the success of the symposium. The efforts of the Spanish National Committee, which handled the many local arrangements, are especially appreciated.

Madrid↗
USGS2011

Earthquake mechanism and displacement fields close to fault zones: Report on the Sixth GEOP Research Conference

The Sixth Geodesy/Solid Earth and Ocean Physics (GEOP) Research Conwas held on February 4–5, 1974, at the Institute of Geophysics and Planetary Physics, University of California, San Diego, in La Jolla, California. It was attended by about 100 persons. James N. Brune, program chairman, opened the conference and delivered the introductory address, a somewhat extended version of which is printed elsewhere in this issue. Brune's paper and the following summaries of the sessions constitute a report of the conference.

Eos, Transactions, American Geophysical Union↗
USGS2011

IASPEI workshop: Seismic modeling of laterally varying structures

During the past 10 years, significant progress has been made in the methods of collection and analysis of seismic reflection and refraction data. This progress has led to the development of new models for the structure and composition of the earth's crust, based on sophisticated analysis of numerous profiles in many areas of geologic importance. The third triannual meeting of the IASPEI (International Association of Seismology and Physics of the Earth's Interior) Commission of Controlled Source Seismology was convened in Park City, Utah, on August 11–17, 1980, to bring together seismologists and geologists to explore and assess the progress of controlled source techniques (controlled sources include explosions, air guns, and Vibroseis‐type sources), and to evaluate its significance in terms of current models of the seismic velocity structure and composition of the crust and upper mantle. Particular attention was paid to the progress and problems in the modeling of two‐ and three‐dimensional structures.

Eos, Transactions, American Geophysical Union↗
USGS2011

Geomagnetic Workshop

A workshop on geomagnetism, sponsored by the Geologic Division of the U.S. Geological Survey, was held in the Denver West Office Complex in Golden, Colorado, April 13–15, 1982. There were 90 registered participants from government agencies, academic institutions, and industry. This effort stemmed from the realization that geomagnetism, once a small but coherent discipline, has now expanded into numerous areas of the geosciences, yet those doing research in these specialties seldom make contact outside their area of immediate interest. The impetus for this event came from the members of a committee formed to review the geomagnetic activities within the U.S. Geological Survey. They observed that the level of communication between the various elements of this now diverse discipline was inadequate, not only within their organization but also between federal agencies, academia, and the private sector. While the desire was to cover as much of geomagnetism as possible, it was necessary for a workshop of reasonable size and length to exclude some important areas of the subject: magnetic reversal chronology, studies of the externally produced variations, and most aspects of internal induction. The plan was to give emphasis to some of the newer areas: those which have recently seen a high level of activity and those with increasing activity abroad compared to that in the United States. The purpose was to evaluate the status and problems in selected areas with an eye to those whose emphasis might produce fruitful results in the next decade.

Eos, Transactions, American Geophysical Union↗
USGS2011

Coastal ocean dynamics

The main objective of the Coastal Ocean Dynamics Experiment (CODE) is to observe and describe the response of continental shelf waters to strong atmospheric forcing in a relatively simple geomorphological setting. In order to achieve this goal, CODE has been designed (1) to define the different space and time scales of the physical parameters important to the shelf flow field and (2) to identify and describe the essential kinematical and dynamical processes governing wind‐driven circulation on the continental shelf. A variety of models exist for the wind‐forced response of continental shelf waters. The salient differences among these models lies in the assumed balances between terms in the governing equations. For example, Gill and Schumann [1974] in a barotropic model assume a geostrophic cross‐shelf momentum balance but include the time‐dependent and surface and bottom stress terms in the along‐shelf momentum balance. Csanady [1978] in his arrested topographic wave model involving bottom friction assumes a quasisteady alongshelf response neglecting advective terms and retaining the geostrophic cross‐shelf balance. Various shelf wave models assume inviscid dynamics and other models assume a simple balance between surface and bottom stress in shallow water. To test the different assumptions behind these models, all terms in the governing equations need to be accurately estimated.

California↗
USGS2011

GLORIA II sonograph mosaic of the western U.S. Exclusive Economic Zone

In 1983 the United States declared sovereign rights and jurisdiction over living and nonliving resources in an area extending 200 nautical miles (370 km) seaward from its shores. In response to the establishment of this Exclusive Economic Zone (EEZ), the U.S. Geological Survey (USGS) has implemented a program, called EEZ‐Scan, to systematically map the EEZ, using the Geological Long‐ Range Inclined ASDIC (GLORIA) II longrange side scan sonar system developed by the Institute of Oceanographic Sciences (IOS) of Great Britain [Somers et al, 1978]. The first part of the EEZ‐Scan field program was completed in the summer of 1984, when USGS and IOS scientists surveyed the EEZ off the western conterminous United States aboard the British research vessel Farnella (Figure 1). The west coast survey, requiring 96 days of ship time and four separate legs, has resulted in virtually total sonograph coverage of the sea floor from the continental shelf break to the 200‐nautical mile limit between the Mexican and Canadian borders, an area of about 850,000 km 2 . Other data collected on the cruises included two‐channel digital seismic reflection and 3.5‐kHz highresolution and 10‐kHz bathymetric profiles, as well as towed magnetometer data along approximately 20,000 km of trackline spaced nominally at 30‐km intervals.

Western U.S. Exclusive Economic Zone↗
USGS2011

World slope map

A colored slope map (scale 1:80,000,000) was generated from digital land and sea floor elevations at 5‐min spacings from data tapes from the National Geophysical Data Center. Slope analysis is facilitated by examining the average slope in 250‐m altitude‐depth intervals both globally and in each of eight tectonic plates. The most striking feature of the map is the multiple parallel bands of steep slope at subduction zones. Submarine volcanic chains produce zones of steep slope that show little degradation at the scale of the map since the Cretaceous. The average slope, or roughness, of spreading ridges decreases exponentially with increasing spreading rate. The passive continental margins generate a steep zone at 1–2 km depth. The lowest average global slope (0.2°) occurs at sea level and reflects the base level that the sea provides for subaerial erosion and the upper limit for marine sedimentation. Slope minima also are caused by the abyssal plains at 4–6 km depth and by glacial ice caps at 3 km elevation.

Eos, Transactions, American Geophysical Union↗
USGS2011

High-energy nearshore processes

The problem of shoreline erosion has become a matter of much interest in the recent press. To some extent this interest has been driven by the slow rise in sea level that has lent an air of inevitabilty to matters. However, the discussions certainly become more focused by the approach of a major storm or hurricane: for instance, the 1985 scare associated with Hurricane Gloria. In fact, it is these major events that dominate the episodic erosion history of an area, and so it is on the basis of knowledge of these events that decisions are made on the development and management of our shorelines. Unfortunately, both our understanding of the fundamental processes and the extent to which our knowledge is transmitted to coastal planners is less than we might hope.

Eos, Transactions, American Geophysical Union↗
USGS2011

Hawaii Volcano Observatory 75th anniversary

The 75th anniversary of the founding of the U.S. Geological Survey (USGS) Hawaiian Volcano Observatory (HVO) was celebrated during January 1987. The festivities began on January 9 with the opening in Hilo of a major exhibit at the Wailoa Center on the current work of HVO, its history, and its special relationship to Hawaii Volcanoes National Park. In addition to spectacular photographs of volcanic activity and HVO field work, the exhibit featured continuous showings of underwater footage taken during the recent eruptive activity (December 1986) and a computer monitor that displayed the activity of HVO seismic net in real time. The exhibit, which was coordinated by HVO librarian/photo archivist Taeko Jane Takahashi and which featured the professional work of HVO photographer J . D. Griggs, was well received and will probably form the core of a future traveling exhibit.

Hawaii↗
USGS2011

The periodic structure of the natural record, and nonlinear dynamics

Concepts of cyclicity in geology have involved many famous protagonists in the history of Earth sciences. Early in this century, sophisticated theories of terrestrial rhythms had been formulated by such pioneers as T. C. Chamberlin [1909], R. T. , Chamberlin [1914], Barrell [1917], Stille [1924], Joly [1925, 1930], Holmes [1926], Lull [1929], Schuchert [1932], Grabau [1940], and Umbgrove [1939 a,b, 1947] (see the review by Williams [1981]). The physical chemist S. Arrhenius [1908] had also formulated a general hypothesis for cosmological origins of terrestrial phenomena. Khain [1964] later proposed resonances between terrestrial and cosmological rhythms, and McCrea [1975] and Williams [1975] summarized evidence of galactic correlations with glaciation.

Eos, Transactions, American Geophysical Union↗
USGS2011

Geomorphic and hydrologic dynamics of zero-order basins

The 1987 International Symposium on Erosion and Sedimentation in the Pacific Rim, held August 3–7, 1987, in Corvallis, Oreg., included a special session on the geomorphic and hydrologic dynamics of zero-order drainage basins. “Zero-order basin” is one of several terms used to describe unchanneled swales or hollows that may occupy considerable areas of higher-order drainage basins. These basins serve as important accumulation sites for water, sediment, and accompanying contaminants that subsequently may enter streams. Moreover, in many terrains along the Pacific rim, zero-order basins are significant geologic hazard sites in which rapid landslides and debris flows commonly begin. Widespread recognition o f the importance of zero-order basins has occurred only within the last 15 years, and this special session was aimed at collecting and assessing some of the pertinent knowledge that has been gained to date.

Oregon↗
USGS2011

Doctorate time rising sharply: How long should it take?

The period 1967–1987 saw a 20% increase in the time it takes to complete the doctorate. That figure is based on data provided by the National Research Council from 11 scientific and engineering fields, including the Earth, atmospheric and marine sciences. The median time spent earning the degree rose from 5.4 years in 1967 to 6.1 years in 1977 to 6.9 years in 1987—an increase of 1.5 years in a single generation. Completion time still seems to be rising! All graduating doctoral students in 1987 had a median age of 33.6 years; chemistry students were youngest at 29, and education students were the oldsters at 39.8 years.

Eos, Transactions, American Geophysical Union↗
USGS2011

Geophysics at Katmai: Geophysical expedition to Novarupta Volcano, Katmai National Park, Alaska

The great eruption of 1912 in the Aleutian Range of Alaska (Figure 1) is exceptional for both its size and relative simplicity. It was the largest eruption of this century and the largest rhyolitic outburst in almost 20 centuries. The 60-hour, 30-km 3 (ejecta volume) eruption produced extensive fallout deposits, an ash-flow sheet that gave rise to the Valley of Ten Thousand Smokes, and the 3-km-diameter Mt. Katmai caldera. Because magma reached the surface through uniform nonvolcanic basement and the vent underwent little or no collapse (unusual for such a large event), the site provides an ideal target for surface geophysical and subsurface coring exploration of structures and conditions produced by explosive volcanism [Panel on Volcanic Studies at Katmai, 1989]. A project to investigate upper crustal magmatic processes at Katmai is part of the U.S. Continental Scientific Drilling Program [Eichelberger and Hildreth, 1986]. The surface studies phase of this project was undertaken last summer and preliminary results are now emerging.

Alaska↗