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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 55 records · Page 3Linked to original sources
USGS2011

New strategy needed in earthquake, volcano monitoring

Recent advances in space geodesy provide unprecedented opportunities for measuring and understanding processes related to earthquake occurrence and volcanic eruptions in the United States and elsewhere. The Global Positioning System (GPS) uses Earth-orbiting satellites to obtain relative movements of ground points accurate to a few millimeters, either through periodically repeated surveys or by continuous measurements at permanent sites [ Segall and Davis , 1997]. Satellite interferometric synthetic aperture radar (InSAR) uses repeat-pass radar backscatter images of Earth's surface to obtain complete spatial mappings of surface deformation over 100 km × 100 km scenes to centimeter precision [ Massonnet and Feigl , 1998]. During the past 5 years GPS and InSAR increasingly have been applied to local studies of active fault zones and volcanic systems, imaging the sources of deformation buried in Earth's crust and quantifying the hazards they pose to society. The potential now exists to deploy these tools to map and monitor all of the actively deforming western United States, and a new scientific initiative with these goals is under active discussion [ Silver et al , 1998].

Eos Science News↗
USGS2011

Standardization of gravimeter calibrations in the geological survey

The calibration of gravimeters has long been primarily the concern of geodesists involved in measuring large gravity differences, but recent developments suggest that the precision and stability of gravimeter calibrations may have greater geologic importance in the future. First, the use of high-speed computers and an increasing variety of supplemental data now make possible the geologic interpretation of gravity anomalies so small that they would not have been noticed in surveys made ten years ago. The kind of gravity interpretation that identifies small reefs and local accumulations of petroleum [ McCulloh , 1967] often requires local increases in station density and the assurance that the calibration of meters used in all parts of a survey are compatible. Second, temporal changes of gravity have already been measured in connection with earthquakes [ Barnes , 1966], volcanic eruptions [ Iida et al , 1952], and the movement of ice caps [ Behrendt , 1967]; they are now being considered for several other types of geologic processes.

Alaska, Arizona, California, Colorado, Oregon, Was↗
USGS2011

The U.S. Geological Survey's gravity program in California

Since the 1963 gravity symposium, the U.S. Geological Survey has entered into a cooperative program with the California Division of Mines and Geology, the Army Map Service, and several universities for the purpose of completing a 5-mgal Bouguer gravity map of the entire State of California at a scale of 1:250,000 by 1970. The areal division of responsibility within the program is shown on a map of California by Chapman (p. 542). It is evident from a plot of existing stations that considerably more data are required in the eastern Mojave Desert located in the southeastern corner of the state, and in the Sierra Nevada north of Lake Tahoe. Additional fill-in work is needed in nearly all parts of the state. The data requirements vary for a 5-mgal contour map depending on the local complexity of the gravity field; but in general, we are obtaining gravity stations at an interval of about 3 km along roads, trails, and rivers, and 5 to 8 km between these access routes by cross-country jeep, horseback, or helicopter if necessary. About 6000 new stations were obtained in California by the Geological Survey during 1968 and we expect to obtain about 3000 more in 1969.

California↗
USGS2011

Progress on a gravity map of Alaska

The U.S. Geological Survey began gravity surveys in Alaska ten years ago with local surveys in the Copper River and Tanana Basins. Shortly before the 1963 AGU gravity symposium [ Barnes , 1965], the emphasis shifted from local surveys to the preparation of a reconnaissance gravity map of the whole state with a 10-mgal contour interval on a scale of 1:2,500,000, which would be similar to the gravity map of the United States [ Woollard and Joesting , 1964]. Data have now been obtained in approximately three-fourths of the state, but there are large variations in both station density and geologic usefulness of the coverage. The amount of coverage is primarily influenced by the distribution of water bodies because more than three-fourths of the stations have been obtained by riverboats, small skiffs, and floatplanes.

Alaska↗
USGS2011

International geophysics: Symposium on the hydrology of deltas

A Symposium on the Hydrology of Deltas was held in Bucharest, Romania, on May 6–9; it was followed by a field trip to the delta of the Danube River on May 10–14. The Symposium was organized by Unesco, with the collaboration of the Romanian Government and the support of the International Association of Scientific Hydrology (IASH). The Romanian Government did an excellent job of arranging for airport reception, hotels in Bucharest, a meeting hall for the technical sessions, hospitality sessions, a full side program for wives of delegates, and hotels, meals, and transportation (bus, train, and boat) on the field trip. The Institute of Hydrotechnical Research of the Romanian Government provided most of the support.

Bucharest↗
USGS2012

Groundwater Recharge Conference Reading, England September 21-24, 1970

An international Conference on Artificial Groundwater Recharge was held at the University of Reading, Whiteknights Park, Reading, Berkshire, England, sponsored by the Water Research Association, Medmenham, Marlow, Buckinghamshire. One hundred sixty-one delegates, representing 20 countries, registered. Five excellent tours were made available for them, to such installations as: the Hydraulics Research Station and Institute of Hydrology, Weilingford, Berkshire; the Metropolitan Water Board, Ashford Common Works, Sunbury-on-Thames; the Water Pollution Research Laboratory, Stevenage; and the Water Research Association, Medmenham, and Water Resources Board, Reading, Berkshire.

Eos Science News↗
USGS2012

Man-made earthquakes and earthquake prediction

Convincing evidence that man can trigger earthquakes has been developed since the 1963–1967 report. The fact that man can start earthquakes has increased our understanding of earthquake mechanisms and reinforced our judgment that we are approaching the possibility of earthquake prediction. Traditionally, seismologists have avoided the subject of earthquake prediction because of its distasteful association with people who claim to be able to predict earthquakes by mystical nonscientific methods. Research on prediction has been intensified since the reports of the Panel on Earthquake Prediction [ Press , 1965] and the Interagency Working Group for Earthquake Research [ Pecora , 1968],. however, and it is appropriate to assess our progress toward that goal. Pakiser et al . [1969] and Oliver [1970] have also summarized recent U.S. progress toward earthquake prediction.

Eos Science News↗
USGS2012

Magnetic anomalies over the continents

By far most of the magnetic coverage over continents has been made via aircraft. The obvious advantages of the airborne method over ground measurements are the speed and economy of the survey, the coverage of areas that are inaccessible on the ground, and the nature of the data, which are displayed continuously rather than as discrete points along a profile. Much aeromagnetic work both in the United States and abroad has been conducted by private companies exploring for ore and petroleum. Unfortunately almost none of the data have been published, nor have they been made available to the public.

Eos Science News↗
USGS2012

Erosion and sedimentation

Research activities in erosion and sedimentation processes have expanded broadly during the past several years and have kept pace with generally accelerated developments in all phases of hydrology and water resources investigations.

Eos Science News↗
USGS2012

Third International Seminar for Hydrology Professors

The Third International Seminar for Hydrology Professors was held at Purdue University in Lafayette, Indiana. There were 72 U.S. participants from 25 States and 19 participants from 15 other countries as follows: three from Canada; two each from Costa Rica and Peru; and one each from The Republic of China, Colombia, El Salvador, France, India, Republic of Korea, Mexico, New Zealand, Portugal, Romania, Turkey, and the United Arab Republic. Seventy-eight of the participants were college or university professors and 13 represented various state and national research and technical agencies.

Indiana↗
USGS2011

Radioactive waste storage in the arid zone

By the turn of the century, nuclear power may generate more than one-half of the electric energy, and about one-third of the total energy consumed in the United States [ Thompson , 1971; Chapman et al ., 1972]. By 2020, the total quantity of high-level radioactive wastes (HLW) generated as a byproduct of nuclear fuel reprocessing for such power generation may total about 900,000 m 3 as liquid or 70,000 m 3 as solid [ Gera and Jacobs , 1972]; the radioactivity of long-lived nuclides in the HLW will total about 8.7×10 10 Ci [ Gera and Jacobs , 1972]. (High-level wastes are defined as wastes containing at least 1 Ci of radioactivity per liter of liquid, or 70 Ci/kg of solid [American Institute of Chemical Engineering, ANSI Standard N5.8-1967]. Wastes from chemical processing of irradiated nuclear fuels typically contain several hundred to several thousand curies per gallon [ Fox , 1969].)

Eos Science News↗
USGS2012

Group takes a fresh look at the lithosphere underneath southern Kenya

Since the turn of the century the well-developed Kenya rift has been a crucial location for studying the interrelationships between extension, uplift, and magmatism. In 1989–1990, an experiment conducted by the Kenya Rift International Seismic Project (KRISP) focused on the central and northern portions of Kenya (Figure 1) and provided a rich base of information regarding the structure and evolution of the rift, which answered many key questions and raised others. Does the crust thin to the south of the Kenya dome as it does to the north?, and if it does, which crustal layer would be mainly affected? How is the Chyulu Hills Quaternary volcanism related to the rifting process? What is the relationship between the crust and lithospheric mantle during extension?

East African Rift, Great Rift Valley, Gregory Rift↗
USGS2011

Urban seismic experiments investigate Seattle fault and basin

In the past decade, Earth scientists have recognized the seismic hazards that crustal faults and sedimentary basins pose to Seattle, Washington (Figure 1). In 1998, the US. Geological Survey and its collaborators initiated a series of urban seismic studies of the upper crust to better map seismogenic structures and sedimentary basins in the Puget Lowland. These studies are called the Seismic Hazard Investigations of Puget Sound (SHIPS). In March 1998, we conducted our first SHIPS study, an investigation of the upper crustal structure of the Puget Lowland, using marine airgun sources and land recorders [ Fisher et al. , 1999].The study was nicknamed Wet SHIPS. In September 1999, we obtained a seismic refraction line to study the upper crustal structure in the Seattle area in a land-based study nicknamed Dry SHIPS [ Brocher et al. , 2000] (Figure 1). In March 2000, we recorded the demolition of the Seattle Kingdome sports stadium using a dense array of seismic recorders for a detailed site response study; this study was nicknamed Kingdome SHIPS (Figure 1).

Washington↗
USGS2011

Buckets of ash track tephra flux from Halema'uma'u Crater, Hawai'i

The 2008–2009 eruption at Kīlauea Volcano's summit made news because of its eight small discrete explosive eruptions and noxious volcanic smog (vog) created from outgassing sulfur dioxide. Less appreciated is the ongoing, weak, but continuous output of tephra, primarily ash, from the new open vent in Halema'uma'u Crater. This tephra holds clues to processes causing the eruption and forming the new crater-in-a-crater, and its flux is important to hazard evaluations. The setting of the vent–easily accessible from the Hawaiian Volcano Observatory (HVO)—is unusually favorable for neardaily tracking of tephra mass flux during this small prolonged basaltic eruption. Recognizing this, scientists from HVO are collecting ash and documenting how ejection masses, components, and chemical compositions vary through time.

Hawai'i↗
USGS2013

Working with strainmeter data

The Plate Boundary Observatory (PBO), the geodetic component of the U.S. National Science Foundation–funded Earthscope program, includes 75 borehole and 6 laser strainmeters ( http://pbo.unavco.org ). The strainmeters are installed at several locations: on the Cascadia forearc in Washington state and on Vancouver Island, Canada; in arrays of two to nine instruments along the North American–Pacific plate boundary in California; at Mount St. Helens; and in Yellowstone National Park. For deformation signals seconds to weeks in duration, strainmeters have a resolution and a signal-to-noise ratio superior to those of seismometers and GPS. However, this high sensitivity can introduce nontectonic signals into strain data, presenting data interpretation challenges, especially for borehole strainmeters.

Eos, Earth and Space Science News↗
USGS2014

Science is the first step to siting nuclear waste repositories

As Shaw [2014] notes, U.S. research on shale as a repository host was halted before expending anything close to the effort devoted to studying crystalline rock, salt, and - most notably - tuff at Yucca Mountain. The new political reality regarding Yucca Mountain may allow reconsideration of the decision to abandon research on shale as a repository host.

Eos, Earth and Space Science News↗
USGS2014

Geophysical advances triggered by 1964 Great Alaska Earthquake

A little more than 50 years ago, on 27 March 1964, the Great Alaska earthquake and tsunami struck. At moment magnitude 9.2, this earthquake is notable as the largest in U.S. written history and as the second-largest ever recorded by instruments worldwide. But what resonates today are its impacts on the understanding of plate tectonics, tsunami generation, and earthquake history as well as on the development of national programs to reduce risk from earthquakes and tsunamis.

Alaska↗
USGS2014

Magnetic storms and induction hazards

Magnetic storms are potentially hazardous to the activities and technological infrastructure of modern civilization. This reality was dramatically demonstrated during the great magnetic storm of March 1989, when surface geoelectric fields, produced by the interaction of the time-varying geomagnetic field with the Earth's electrically conducting interior, coupled onto the overlying Hydro-Québec electric power grid in Canada. Protective relays were tripped, the grid collapsed, and about 9 million people were temporarily left without electricity [ Bolduc , 2002].

Eos, Earth and Space Science News↗