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Results for “Eos, Transactions, American Geophysical Union”

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 217 records · Page 12Linked to original sources
USGS2012

Probing the Earth's strength: Can we measure small stress at high pressure?

Simulating the conditions and processes that occur in the Earth's deep interior has been a major goal of experimental geophysics since the 1920s. In particular, pioneers such as P. W. Bridgman, David Griggs, Hugh Heard, Mervyn Paterson, William Brace, and their colleagues sought to establish the basic relations between differential stresses and rock and mineral deformation under pressure-temperature conditions that favor such inelastic processes as brittle fracture, frictional sliding, plastic deformation, and dynamic metamorphism. This work has been applied to diverse problems in the Earth sciences, including the physical nature of earth quake sources, the forces that drive and resist plate movement, deformation under partial-melting conditions at the tops of mantle plumes, the flexure of the lithosphere, post-glacial rebound, and the origin of the preferred orientation of minerals and the resultant seismic anisotropy and metamorphic textures.

Eos, Transactions, American Geophysical Union↗
USGS2011

Comment on “Sea level rise shown to drive coastal erosion”

In a recent article ( Eos, Trans., AGU , February 8, 2000, p.55), Leatherman et al. [2000] state that they have confirmed an association between sea-level rise and coastal erosion. Applying their results to the New Jersey, Delaware, and Maryland coasts and using a projected sea-level rise, the authors predict that by 2050 the shoreline will recede 60 m, about two times the average beach width. However, Leatherman et al. [2000] have not convincingly quantified a relationship between sea-level rise and shoreline erosion.We do not agree with their rationale for subsetting their data, and they have not considered other explanations for a background erosion along the U.S. east coast. Furthermore, their future projections are not supported by their analyses.

Eos, Transactions, American Geophysical Union↗
USGS2012

Ancient blue oaks reveal human impact on San Francisco Bay salinity

San Francisco Bay is one of the most important estuaries on the west coast of the Americas. Its water quality is controlled primarily by streamflow from the Sacramento and San Joaquin rivers. In fact, freshwater inflow from the Sacramento-San Joaquin Delta explains 86% of the salinity variability at the mouth of the San Francisco Bay estuary [ Peterson et al ., 1989]. The massive diversion of streamflow by the California State Water Project and the Central Valley Project, part of the largest manmade water control system on Earth [ Reisner , 1988], has raised salinity in the estuary on daily, seasonal, and annual timescales [ Nichols et al., 1986; Peterson et al., 1989].

California↗
USGS2014

The volcanic history of the San Juan Mountains, Colorado

The San Juan Mountains, which are made up chiefly of volcanic rocks, are located in southwestern Colorado and occupy a rudely circular area of over 10,000 square miles, or larger than the state of Massachusetts. They have been studied and mapped geologically by the United States Geological Survey, chiefly by field parties under Whitman Cross and Esper S. Larsen.

Colorado↗
USGS2014

Investigations relating to the absorption of precipitation and its penetration to the zone of saturation

This paper deals briefly with the methods and results from three separate investigations that are in progress as to the quantity of rain‐water that percolates downward to the water‐table in the localities where it falls. 1. Workers in the Department of Agriculture, under the direction of W. W. McLaughlin and in cooperation with the California State Department of Public Works, have used several related methods to intercept and measure the rainfall‐penetration. H. F. Blaney and C. A. Taylor have conducted these tests near Los Angeles. A report covering this work, with H. F. Blaney, C. A. Taylor, and A. A. Young as co‐authors, will be published in the near future as a bulletin by the State of California, Department of Public Works, Division of Water Resources. Rough sketches of some of the apparatus used are shown in Figures 1 and 2.

California↗
USGS2014

Some recent studies in evaporation

During the past few years several important contributions to the study of evaporation from open water‐surfaces have been made. Each has applications to which it is peculiarly adapted, and each has its limitations.

Eos, Transactions, American Geophysical Union↗
USGS2014

Investigations of underground water problems in Arizona, California, New Mexico, and Oregon

This report is a summary of investigations in progress in 1932 in the southwestern portion of the United States. It covers only those investigations that deal with water in the zone of saturation, and excludes those that deal primarily with water in the zone of aeration. Arizona H. C. Schwalen, Irrigation Engineer, Agricultural Experiment‐Station, Tucson, Arizona, has proposed to undertake a study of the effect of pumping from wells, and of the capacity of water‐bearing strata, but no report of progress is available. Several other hydrologic investigations are now being made by the Agricultural Experiment‐ Station, but relate primarily to infiltration and transpiration.

Arizona, California, New Mexico, Oregon↗
USGS2014

Recent investigations of Thiem's method for determining permeability of water‐bearing materials

This paper presents results obtained in an investigation of the ground-water resources of the Platte River Valley that is being conducted in cooperation between the Conservation and Survey Department of the University of Nebraska and the United States Geological Survey. Most quantitative ground-water studies are concerned with the amount of water that percolates into the discharge-area of an investigated region from the recharge-area in order to determine the amount of water that can be safely withdrawn from the discharge-area without an excessive lowering of the ground-water level. D'Arcy found that the quantity of water discharged through a column of water-bearing material was proportional t o the hydraulic gradient, the cross-sectional area, and a constant which depends upon the material. If these three factors are known, the discharge through any cross section of a water-bearing formation may be computed.

Eos, Transactions, American Geophysical Union↗
USGS2014

Investigations of the fluctuations of water‐levels in observation‐wells in Virginia

An automatic water ‐stage recorder has been maintained on an observation ‐ well in Arlington County, Virginia , about 1‐½ miles from the United States Weather Bureau, in Washington, D.C., since June, 1928, but there are a few interruptions in the record. This is a dug well , about 28 feet deep and extends through terrace deposits of gravelly silt or loam. It has not been used for water ‐supply during the period of record. The recorder was installed by the United States Geological Survey and the record has been given considerable study by O. E. Meinzer, W. N. White, and L. K. Wensel, all of the Geological Survey. In July, 1931, the study of this well was made a part of a more comprehensive investigation of the ground‐ water resources of Virginia in cooperation with the State Geological Survey, which was assigned to the writer. The well is essentially of the water ‐table type, and its hydrograph shows approximately the periods of rainfall‐penetration and the relative amounts of recharge in each of these periods. The record is especially instructive because of certain unusual climatic conditions that have existed in the last four years.

Virginia↗
USGS2014

Some relations between ground‐water hydrology and oceanography

In many areas along the sea-coasts of the world the water-supply for human use is derived largely, and in some areas wholly, from underground sources. Because of the proximity to the ocean in these areas, in some respects the geologic and hydrologic conditions that govern the occurrence and movement of ground-water are quite different from those in inland areas, and to properly interpret them the ground-water hydrologist must avail himself of facts developed by the oceanographer. These conditions are encountered in a marginal zone that in different localities may extend only a few feet or many miles inland from the coast, and presumably for greater or less distances out beneath the ocean. These special conditions have been recognized and extensively studied for many years, for example, in the lowland-area of Holland that lies between the Zuider Zee and the North Sea, and on Long Island, New York. Within recent years more or less attention has been given to these conditions in many of the coastal states of the United States, and in the Hawaiian Islands and Cuba. It is the purpose of this statement to indicate some of the problems of groundwater hydrology that are related to oceanography.

Eos, Transactions, American Geophysical Union↗
USGS2014

Geophysical interpretation of ground‐water levels

The theory of rock‐pressure as a cause of artesian‐head dates back at least to early Grecian times. Thus the philosopher Thales, about 600 B.C., taught that the springs derive their water from the ocean through subterranean channels and that the water is lifted to the springs by rook‐pressure. The theory of rock‐pressure has had a number of recent advocates, chief among whom was the British geologist, J. W. Gregory, but apparently no effective attempt was made by any of them to apply critical data to the problem. In general, geologists and hydrologists have rejected rock‐pressure as a vague heresy and have assumed that the artesian formations function as perfectly rigid and inert containers, not recognizing the fact that the data in regard to the performance of wells appear to conflict with such an interpretation .

Eos, Transactions, American Geophysical Union↗
USGS2014

Further remarks on the Cripple Creek Volcano, Colorado

Structural evidence, particularly in the deeper mine‐workings, indicates that the volcano , which is of Tertiary age, was developed by explosive eruptions at a number of points along intersecting fissure‐systems that had been formed in pre‐Cambrian granite by east‐west compression, probably during the Laramide revolution. The volcanic breccia, which consists principally of phonolitic material, appears to fill several elongate or elliptical funnel‐shaped openings that coalesce upward and taper downward into roots. Local adjustments that followed the principal explosive eruptions developed fissure‐systems in the breccia parallel and transverse to the older fissure‐systems and permitted the intrusion of dikes and irregular masses of latite‐phonolite and syenite within the breccia mass. Mild regional readjustment, caused by compression in a nearly north‐south direction, ensued and reopened these fissure‐systems within and around the breccia mass. It was followed by the relatively widespread intrusion of dikes and irregular masses of phonolite. Local readjustment then recurred repeatedly, mainly along the master fissure‐systems, and was followed by three successive intrusions of alkaline basaltic dikes and finally by the formation of mineral veins.

Colorado↗
USGS2014

Volcanic history of the Magdalena District, New Mexico

The Magdalena District in central New Mexico comprises the Magdalena Range and Granite Mountain which are block mountains of the Basin Range type. They consist of Carboniferous sedimentary formations on a pre-Cambrian basement and are covered by Tertiary volcanic rocks. Volcanism in the District was preceded by considerable faulting, tilting, and uplifting very probably in early Tertiary time. The initial volcanic extrusion consisted of latite flows and tuffs now resting unconformably on the Granite Mountain fault-block in the northern part of the District. Subsequent extrusions consisted of alternations of andesites, rhyolites, and latites, and have a minimum thickness of approximately 4,000 feet. Graben faulting, probably in compensation for the effusion of the large volumes of lava, followed and some of the major faults were subsequently the sites of the intrusion of monzonitic and granitic stocks. Late lamprophyre and white rhyolite dikes in large numbers intruded the intrusive as well as earlier extrusive and sedimentary rocks.

New Mexico↗
USGS2014

Fluctuations of water‐surface in observation‐wells and at stream gaging‐stations in the Mokelumne Area, California, during the earthquake of December 20, 1932

On December 20, 1932, much of the western United States felt a pronounced earthquake‐shock which caused noticeable fluctuations of the water‐surface in several observation‐wells and at two stream gaging‐stations in the Mokelumne Area, central California. These effects of the earthquake are reported briefly in this paper. According to Dr. Byerly (personal communication, February 9, 1933), in charge of the seismograph‐station of the University of California at Berkeley, the earthquake‐ vibrations at that place began at 10 h 11 m 00 s p.m., Pacific Standard Time, December 20, 1932, and continued three hours on the records of his most sensitive instruments. He reports further that the maximum double amplitude of the Earth‐motion at Berkeley was of the order of two mm and that the north‐south and east‐west components of the amplitude were approximately equal. In the Mokelumne Area, which centers about the City of Lodi, 57 miles north 70° east from the seismograph‐station at Berkeley, the pronounced initial Earth‐shock caused chandeliers to sway, upset some bric‐a‐brac, and in at least one building opened a few cracks in the interior plastering. At Stockton, 15 miles south of Lodi, the glass of at least one display‐window in a shop was cracked.

California↗
USGS2014

Deep‐well salinity‐exploration

One of the outstanding accomplishments of recent years in connection with the study of the geologic source of groundwater and the quality of water yielded by different formations has been the development of methods and equipment for the exploration of wells. The description and use of the deep ‐ well current‐meter on well ‐ exploration work in Hawaii and New Mexico has already appeared in published literature (John McCombs and A. G. Fiedler, Methods of exploring and repairing leaky artesian wells, U.S. Geol. Sur. Water‐Supply Paper 596, pp. 1–32, 1928) on hydrology but recent developments in the application of electrical conductivity‐measurements for determining the salinity of water in wells have not heretofore been presented. In addition to being of considerable scientific importance in connection with problems of ground‐water hydrology, the practical value of locating the place at which salt water is entering a well and contaminating a potable water‐supply is great. Such information may be the means of preventing the loss of large investments in industries, irrigation‐projects, and cities that are dependent upon well ‐water supplies that may at some time become contaminated by salty or other highly mineralized water.

Nevada, Hawaii↗
USGS2014

Rare chemical constituents of amelia (Virginia) pegmatite dikes, and their mineral sources

Students of Igneous phenomena have long since become familiar with the occurrence of rare minerals in pegmatitic bodies. The great local concentration of rare elements in pegmatite minerals provides a remarkably good opportunity for the Investigation of deep-seated rock constituents, for it is reasonable to suppose that these same elements are widely distributed in minute amounts through the parent rocks to which they are genetically related; but their concentration in pegmatite bodies affords a record of their presence that is lacking in other rocks. The unusual number of rare minerals of the Amelia, Virginia, pegmatites has long attracted attention, and the rare elements of the more abundant minerals which have been investigated in the laboratories of the United States Geological Survey afford an unusual opportunity to study the rare constituents of a pegmatite. This famous locality for rare minerals is situated 38 miles southwest of Richmond, just south of Appomattox River, on the Piedmont plateau.

Eos, Transactions, American Geophysical Union↗
USGS2014

Field evidence about the viscosity of lavas

There appears to be surprisingly little definite information on the viscosity of lavas. With few exceptions writers content themselves with such general and indefinite terms as “mobile”, “viscous”, or “highly viscous”. Apparently the only attempts to actually calculate viscosity have been made on Hawaiian lavas.

Hawaii↗