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At least 91 records · Page 5Linked to original sources
USGS1997

Digital shaded-relief image of Alaska

One of the most spectacular physiographic images of the conterminous United States, and the first to have been produced digitally, is that by Thelin and Pike ( USGS I-2206, 1991 ). The image is remarkable for its crispness of detail and for the natural appearance of the artificial land surface. Our goal has been to produce a shaded-relief image of Alaska that has the same look and feel as the Thelin and Pike image. The Alaskan image could have been produced at the same scale as its lower 48 counterpart (1:3,500,000). But by insetting the Aleutian Islands into the Gulf of Alaska, we were able to print the Alaska map at a larger scale (1:2,500,000) and about the same physical size as the Thelin and Pike image. Benefits of the 1:2,500,000 scale are (1) greater resolution of topographic features and (2) ease of reference to the U.S. Geological Survey (USGS) (1987) Alaska Map E and the statewide geologic map (Beikman, 1980), which are both 1:2,500,000 scale. Manually drawn, shaded-relief images of Alaska's land surface have long been available (for example, Department of the Interior, 1909; Raisz, 1948). The topography depicted on these early maps is mainly schematic. Maps showing topographic contours were first available for the entire State in 1953 (USGS, 1:250,000) (J.H. Wittmann, USGS, written commun., 1996). The Alaska Map E was initially released in 1954 in both planimetric (revised in 1973 and 1987) and shaded-relief versions (revised in 1973, 1987, and 1996); topography depicted on the shaded-relief version is based on the 1:250,000-scale USGS topographic maps. Alaska Map E was later modified to include hypsometric tinting by Raven Maps and Images (1989, revised 1993) as copyrighted versions. Other shaded-relief images were produced for The National Geographic Magazine (LaGorce, 1956; 1:3,000,000) or drawn by Harrison (1970; 1:7,500,000) for The National Atlas of the United States. Recently, the State of Alaska digitally produced a shaded-relief image of Alaska at 1:2,500,000 scale (Alaska Department of Natural Resources, 1994), using the 1,000-m digital elevation data set referred to below. An important difference between our image and these previous ones is the method of reproduction: like the Thelin and Pike (1991) image, our image is a composite of halftone images that yields sharp resolution and preserves contrast. Indeed, the first impression of many viewers is that the Alaskan image and the Thelin and Pike image are composites of satellite-generated photographs rather than an artificial rendering of a digital elevation model. A shaded-relief image represents landforms in a natural fashion; that is, a viewer perceives the image as a rendering of reality. Thus a shaded-relief image is intrinsically appealing, especially in areas of spectacular relief. In addition, even subtle physiographic features that reflect geologic structures or the type of bedrock are visible. To our knowledge, some of these Alaskan features have not been depicted before and so the image should provide earth scientists with a new "look" at fundamental geologic features of Alaska.

Alaska↗
USGS2000

Operational guidelines (version 1.0) for geological fieldwork in areas endemic for Coccidioidomycosis (Valley Fever)

Coccidioidomycosis (Valley Fever) is a disease caused by the inhalation of the arthroconidia (spores) of Coccidioides immitis, a fungus that lives in the soils of southwestern United States. Although large numbers of people are exposed to the arthroconidia and are consequently infected, very few individuals contract the more serious forms of the disease. Earth scientists working in field areas where Coccidioides immitis is endemic have an increased risk of becoming infected. Because field operations often disturb the upper surface of the ground, they may inhale large numbers of arthroconidia. This also increases their risk of developing more severe forms of the disease. Any other occupations or activities that create dusty conditions in endemic areas also have increased risk of infection. Risk management strategies can lower the incidence of infection and also reduce the numbers of arthroconidia inhaled thereby decreasing the chances of developing more serious disease. Dust control, by utilizing dust masks, and dust prevention, by limiting ground disturbing activities, are the primary weapons against infection. However, infection risk can also be lowered by conducting fields studies in the winter months; avoiding sites favorable for Coccidioides immitis growth; seeking prompt medical treatment if flu-like or respiratory illness occur during, or within a few weeks following, fieldwork; getting a coccidioidin skin test to determine susceptibility to the disease; and by educating all members of the field party about the possibilities and consequences of infection.

Open-File Report↗
USGS2000

Research, methodology, and applications of probabilistic seismic-hazard mapping of the Central and Eastern United States; minutes of a workshop on June 13-14, 2000, at Saint Louis University

The U.S. Geological Survey (USGS) is updating and revising its 1996 national seismic-hazard maps for release in 2001. Part of this process is the convening of four regional workshops with earth scientists and other users of the maps. The second of these workshops was sponsored by the USGS and the Mid-America Earthquake Center, and was hosted by Saint Louis University on June 13-14, 2000. The workshop concentrated on the central and eastern U.S. (CEUS) east of the Rocky Mountains. The tasks of the workshop were to (1) evaluate new research findings that are relevant to seismic hazard mapping, (2) discuss modifications in the inputs and methodology used in the national maps, (3) discuss concerns by engineers and other users about the scientific input to the maps and the use of the hazard maps in building codes, and (4) identify needed research in the CEUS that can improve the seismic hazard maps and reduce their uncertainties. These minutes summarize the workshop discussions. This is not a transcript; some individual remarks and short discussions of side issues and logistics were omitted. Named speakers were sent a draft of the minutes with a request for corrections of any errors in remarks attributed to them. Nine people returned corrections, amplifications, or approvals of their remarks as reported. The rest of this document consists of the meeting agenda, discussion summaries, and a list of the 60 attendees.

Open-File Report↗
USGS2002

Rationale and operational plan to upgrade the U.S. gravity database

A concerted effort is underway to prepare a substantially upgraded digital gravity anomaly database for the United States and to make this data set and associated usage tools available on the internet. This joint effort, spearheaded by the geophysics groups at the National Imagery and Mapping Agency (NIMA), University of Texas at El Paso (UTEP), U.S. Geological Survey (USGS), and National Oceanic and Atmospheric Administration (NOAA), is an outgrowth of the new geoscientific community initiative called Geoinformatics (www.geoinformaticsnetwork.org). This dominantly geospatial initiative reflects the realization by Earth scientists that existing information systems and techniques are inadequate to address the many complex scientific and societal issues. Currently, inadequate standardization and chaotic distribution of geoscience data, inadequate accompanying documentation, and the lack of easy-to-use access tools and computer codes for analysis are major obstacles for scientists, government agencies, and educators. An example of the type of activities envisioned, within the context of Geoinformatics, is the construction, maintenance, and growth of a public domain gravity database and development of the software tools needed to access, implement, and expand it. This product is far more than a high quality database; it is a complete data system for a specific type of geophysical measurement that includes, for example, tools to manipulate the data and tutorials to understand and properly utilize the data. On August 9, 2002, twenty-one scientists from the federal, private and academic sectors met at a workshop to discuss the rationale for upgrading both the United States and North American gravity databases (including offshore regions) and, more importantly, to begin developing an operational plan to effectively create a new gravity data system. We encourage anyone interested in contributing data or participating in this effort to contact G.R. Keller or T.G. Hildenbrand. This workshop was the first step in building a web-based data system for sharing quality gravity data and methodology, and it builds on existing collaborative efforts. This compilation effort will result in significant additions to and major refinement of the U.S. database that is currently released publicly by NOAA’s National Geophysical Data Center and will also include an additional objective to substantially upgrade the North American database, released over 15 years ago (Committee for the Gravity Anomaly Map of North America, 1987).

Open-File Report↗
USGS2005

Preliminary geologic map of the Los Angeles 30' x 60' quadrangle, Southern California

This data set maps and describes the geology of the Los Angeles 30? x 60? quadrangle, southern California. Compilation of the Los Angeles quadrangle is based upon published mapping at scales of 1:12,000 and smaller, unpublished mapping at scales of 1:12,000 and smaller, with reconnaissance mapping by the compilers to resolve some edge-matching problems. The Los Angeles 30' x 60' quadrangle covers approximately 5,000 km2 including some of the most densely populated urban and suburban areas of the southern California megalopolis. It extends about 90 km E-W and about 55 km N-S, from Fillmore and Thousand Oaks in the west to Vincent in the northeast and Montebello in the southeast, and includes urban San Gabriel Valley and San Gabriel Mountain foothill communities from Monrovia to Pasadena, as well as Glendale, downtown Los Angeles, Hollywood, Santa Monica, Malibu, in addition to all the communities in the San Fernando Valley, Simi Valley, and the upper Santa Clara River Valley. From the 2000 Census, the population of these urban and suburban areas totals approximately 5.6 million, and estimates of property value total hundreds of billions of dollars. Residents and transient visitors are subject to potential hazards from earthquakes, debris flows and other landslides, floods, wildfires, subsidence from ground water and petroleum withdrawal, and swelling soils; and coastal areas are exposed to flooding and erosion by storm and tsunami waves. Topographic relief ranges from about one hundred meters sub sea (in Santa Monica Bay) to more than 2,000 meters above sea level at Pacifico Mountain in the high San Gabriel Mountains. In addition to the populated area, the quadrangle includes significant areas of wilderness in the Angeles and Los Padres National Forests, in the Santa Monica Mountains National Recreation Area, and the Sespe Condor Sanctuary. The geologic map illustrates the general distribution of the rocks and surficial deposits in the area and their structural and stratigraphic relations to one another. The principal characteristics of the map units are described and are part of the database. The map provides a regional geologic framework as an aid to better evaluations of the potential for hazard from active earth processes. It synthesizes and combines studies by many earth scientists. Most of the source maps are at more detailed scales than 1:100,000, and we utilized the most detailed source materials available. We have not attempted to resolve all problems of stratigraphic correlation and nomenclature. In most areas we have retained the unit designations of source-map authors, but in some areas, particularly in the igneous-metamorphic complex of the San Gabriel Mountains, some unit designations have been changed. Hopefully, this map will stimulate further work to describe and correlate the many units within the scope of a more coherent, more accurate geologic history.

California↗
USGS1974

First EROS/AID International Course on remote sensing

The First International Training Course on Remote Sensing held at the Earth Resources Observations Systems (EROS) Data Center in Sioux Falls, South Dakota, was sponsored by the Agency for International Development (AID), U.S. Department of State, from June 4 to 27, 1973. This course was conducted by the U.S. Geological Survey (USGS) under Participating Agency Services Agreement (PASA) TA (IC) 2-72, 931-11-995-902-72-3138905, as part of the AID program to provide training in remote sensing technology for earth scientists in the less developed countries.

South Dakota↗
USGS1995

Multichannel seismic-reflection profiling on the R/V Maurice Ewing during the Los Angeles Region Seismic Experiment (LARSE), California

This report describes the acquisition of deep-crustal multichannel seismic-reflection data in the Inner California Borderland aboard the R/V Maurice Ewing, conducted in October 1994 as part of the Los Angeles Regional Seismic Experiment (LARSE). LARSE is a cooperative study of the crustal structure of southern California involving earth scientists from the U.S. Geological Survey, Caltech, the University of Southern California, the University of California Los Angeles, and the Southern California Earthquake Center (SCEC). During LARSE, the R/V Ewing's 20- element air gun array, totaling 137.7 liters (8470 cu. in.), was used as the primary seismic source for wide-angle recording along three main onshore-offshore lines centered on the Los Angeles basin and the epicenters of the 1933 Long Beach and 1994 Northridge earthquakes. The LARSE onshore-offshore lines were each 200-250 km long, with the offshore portions being between 90 and 150 km long. The nearly 24,000 air gun signals generated by the Ewing were recorded by an array of 170 PASSCAL REFTEK recorders deployed at 2 km intervals along all three of the onshore lines and 9 ocean bottom seismometers (OBSs) deployed along two of the lines. Separate passes over the OBS-deployment lines were performed with a long air gun repetition rate (60 and 90 seconds) to minimize acoustic-wave interference from previous shots in the OBS data. The Ewing's 4.2-km, 160-channel, digital streamer was also used to record approximately 1250 km of 40-fold multichannel seismic-reflection data. To enhance the fold of the wide-angle data recorded onshore, mitigating against cultural and wind noise in the Los Angeles basin, the entire ship track was repeated at least once resulting in fewer than about 660 km of unique trackline coverage in the Inner Borderland. Portions of the seismic-reflection lines were repeated up to 6 times. A variety of other geophysical data were also continuously recorded, including 3.5 kHz bathymetry, multi-beam swath Hydrosweep bathymetry, magnetics, and gravity data. In this report, we describe the equipment and procedures used to acquire multichannel seismic-reflection and other geophysical data aboard the Ewing, provide a detailed cruise narrative, discuss the reduction of the data, and present near-trace constant offset seismic sections of the acquired profiles.

California↗
USGS1998

Geology, geochemistry, geophysics, mineral occurrences, and mineral resource assessment for the Commonwealth of Puerto Rico

The Commonwealth of Puerto Rico has been investigated over a very long period of time by earth scientists from many disciplines and with diverse objectives in the studies. This publication attempts to apply much of the geologic, geochemical, geophysical, and mineral occurrence information to a single objective focused on producing a mineral resource assessment for the Commonwealth of Puerto Rico. However, the value of this publication lies not within the results of the mineral resource assessment nor within the interactive PDF files which can be viewed on the screen, but within the geologic, geochemical, geophysical, and mineral occurrence digital map coverages and databases which can be used for their own unique applications. The mineral resource assessment of Puerto Rico represents compilation of several decades of mineral investigations and studies. These investigations have been the joint efforts of the U.S. Geological Survey, the Puerto Rico Department of Natural Resources, and the University of Puerto Rico. This report contains not only the mineral-resource assessment, but also much of the scientific evidence upon which the assessment was based.

Puerto Rico↗
USGS2021

Geologic map of the State of Hawaii

This geologic map and its digital databases present the geology of the eight major islands of the State of Hawaiʻi. The map should serve as a useful guide to anyone studying the geologic setting and history of Hawai‘i, including ground- and surface-water resources, economic deposits, and landslide or volcanic hazards. Its presentation in digital format allows the rapid application of geologic knowledge when conducting field work; analyzing land-use or engineering problems; studying onshore or nearshore biologic communities; or simply understanding the relation between the geology, scenery, and cultural history of the Hawaiian paradise. The map includes a Description of Map Units, which describes the lithologic characteristics and distribution of the geologic deposits. A Correlation of Map Units shows how the different geologic formations are related to each other stratigraphically. A fairly complete geospatial database of the radiometric ages and geochemical analyses has been compiled from findings published over the past 100 years by numerous Earth scientists working across the island chain.

Hawaii↗
USGS2020

Seismicity of the Earth 1900–2018

This map illustrates 119 years of global seismicity in the context of global plate tectonics and the Earth’s physiography. Primarily designed for use by earth scientists, engineers, and educators, this map provides a comprehensive overview of strong (magnitude [ M ] 5.5 and larger) earthquakes since 1900. The map clearly identifies the locations of the “great” earthquakes ( M 8.0 and larger) and the aftershock or rupture area (green fill), if known, of the M 8.3 or larger earthquakes. The circular earthquake symbols are scaled to be proportional to the moment magnitude and therefore to the area of faulting, thus providing a better understanding of the relative sizes and distribution of earthquakes in the magnitude range 5.5 to 9.5. Plotting the known rupture or aftershock areas (which are closely related) of the largest earthquakes also provides a better appreciation of the faulting extent of some of the most famous and damaging instrumentally recorded earthquakes in modern history.

Scientific Investigations Map↗
USGS1987

Selected hydrologic and physical properties of Mesozoic formations in the Upper Colorado River Basin in Arizona, Colorado, Utah, and Wyoming: Excluding the San Juan Basin

Data for hydrologic and physical properties of Mesozoic formations in the Upper Colorado River Basin, excluding the San Juan Basin, have been collected by government agencies, private industry, property owners, and other sources. These data were compiled and analyzed so that they would be available for use by hydrologists, earth scientists, planners, and others. Five methods of data analysis are discussed. The results of these five methods are not directly comparable because of differences in the volume of an aquifer represented by each method. Aquifer tests represent the largest volume of an aquifer, specific capacity and drill-stem tests represent a smaller volume, slug-injection tests represent a still smaller volume, and laboratory tests represent the smallest volume. Because they represent large volumes of an aquifer, aquifer tests were considered to give the best estimates of hydrologic characteristics. Laboratory data for permeability to air and hydraulic conductivity were determined to be related by a simple power function.

Arizona, Colorado, Utah, Wyoming↗
USGS2014

Land cover characterization and mapping of South America for the year 2010 using Landsat 30 m satellite data

Detailed and accurate land cover and land cover change information is needed for South America because the continent is in constant flux, experiencing some of the highest rates of land cover change and forest loss in the world. The land cover data available for the entire continent are too coarse (250 m to 1 km) for resource managers, government and non-government organizations, and Earth scientists to develop conservation strategies, formulate resource management options, and monitor land cover dynamics. We used Landsat 30 m satellite data of 2010 and prepared the land cover database of South America using state-of-the-science remote sensing techniques. We produced regionally consistent and locally relevant land cover information by processing a large volume of data covering the entire continent. Our analysis revealed that in 2010, 50% of South America was covered by forests, 2.5% was covered by water, and 0.02% was covered by snow and ice. The percent forest area of South America varies from 9.5% in Uruguay to 96.5% in French Guiana. We used very high resolution (<5 m) satellite data to validate the land cover product. The overall accuracy of the 2010 South American 30-m land cover map is 89% with a Kappa coefficient of 79%. Accuracy of barren areas needs to improve possibly using multi-temporal Landsat data. An update of land cover and change database of South America with additional land cover classes is needed. The results from this study are useful for developing resource management strategies, formulating biodiversity conservation strategies, and regular land cover monitoring and forecasting.

Remote Sensing↗
USGS2009

USGS: Science at the intersection of land and ocean

The US Geological Survey (USGS) conducts an ongoing national assessment of coastal change hazards in order to help protect lives and support management of coastal infrastructure and resources. The research group rapidly gathers to investigate coastal changes along the Gulf Coast's sandy beaches after each hurricane to examine the magnitude and variability of impacts. This investigation helps to protect the environment and the American people by preparing maps that show the extreme coastal change. It also posts online video and still photography and LIDAR (light detection and ranging) survey data after each storm, to provide a clear picture of the devastated area. The USGS provides data to understand changing coastal vulnerabilities so that informed decisions can be made to protect disaster affected areas and its resources. Earth scientists in the USGS are learning more about coastal dynamics, determining changes, and improving the ability to forecast how coastal environments will respond to the next storm.

Sea Technology↗
USGS2014

Response and recovery lessons from the 2010-2011 earthquake sequence in Canterbury, New Zealand

The impacts and opportunities that result when low-probability moderate earthquakes strike an urban area similar to many throughout the US were vividly conveyed in a one-day workshop in which social and Earth scientists, public officials, engineers, and an emergency manager shared their experiences of the earthquake sequence that struck the city of Christchurch and surrounding Canterbury region of New Zealand in 2010-2011. Without question, the earthquake sequence has had unprecedented impacts in all spheres on New Zealand society, locally to nationally--10% of the country's population was directly impacted and losses total 8-10% of their GDP. The following paragraphs present a few lessons from Christchurch.

Canterbury↗
USGS1990

Earth sciences and emergency management

As understanding of California's earthquake risk had increased over the past decade, there has been a concurrent expansion of interactions between emergency management professionals and earth scientists. The effort have resulted not from a formal plan-though the U.S National Earthquake Hazards Reduction Program has provided much of the support for scientific advances since 1977-but from interactions focused on specific projects. three examples stand out, perhaps suggesting how mutually beneficial exchanges can simultaneously enhance science and public safety.

Earthquakes & Volcanoes (USGS)↗
USGS2016

Crustal permeability

Permeability is the primary control on fluid flow in the Earth’s crust and is key to a surprisingly wide range of geological processes, because it controls the advection of heat and solutes and the generation of anomalous pore pressures. The practical importance of permeability – and the potential for large, dynamic changes in permeability – is highlighted by ongoing issues associated with hydraulic fracturing for hydrocarbon production (“fracking”), enhanced geothermal systems, and geologic carbon sequestration. Although there are thousands of research papers on crustal permeability, this is the first book-length treatment. This book bridges the historical dichotomy between the hydrogeologic perspective of permeability as a static material property and the perspective of other Earth scientists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions.

Book↗
USGS2010

It's not just about climate change - What about soils?

Vladimir Vernadsky was one of the giants of geochemistry. Considered the founder of the fi eld of biogeochemistry and a true pioneer in “whole Earth” studies, he realized by 1945 that “Man under our very eyes is becoming a mighty and ever-growing geological force.” In the intervening 65 years, his “ever-growing force” has become a tidal wave. The global population has been increasing exponentially since the beginning of the industrial revolution, and as a result has increased by nearly a factor of three between 1945, when his observation was published, and today (see fi gure). Current projections anticipate a population exceeding 9 billion by 2050. This explosive human population growth has been fueled by ancient hydrocarbons and has come with high costs. Most Earth scientists are concerned with the implications of the rapid accumulation of greenhouse gases in the atmosphere. The consequences include a climate state without polar ice, acidifying oceans, and increasingly variable water fl uxes. The rate and extent of these and many other negative climate-related impacts, and how to mitigate them, have caused a vigorous discussion on climate change that is in the news on a nearly daily basis.

Elements↗