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At least 631 records · Page 35Linked to original sources

Analysis of a spatial point pattern: Examining the damage to pavement and pipes in Santa Clara Valley resulting from the Loma Prieta earthquake

This report describes some simple spatial statistical methods to explore the relationships of scattered points to geologic or other features, represented by points, lines, or areas. It also describes statistical methods to search for linear trends and clustered patterns within the scattered point data. Scattered points are often contained within irregularly shaped study areas, necessitating the use of methods largely unexplored in the point pattern literature. The methods take advantage of the power of modern GIS toolkits to numerically approximate the null hypothesis of randomly located data within an irregular study area. Observed distributions can then be compared with the null distribution of a set of randomly located points. The methods are non-parametric and are applicable to irregularly shaped study areas. Patterns within the point data are examined by comparing the distribution of the orientation of the set of vectors defined by each pair of points within the data with the equivalent distribution for a random set of points within the study area. A simple model is proposed to describe linear or clustered structure within scattered data. A scattered data set of damage to pavement and pipes, recorded after the 1989 Loma Prieta earthquake, is used as an example to demonstrate the analytical techniques. The damage is found to be preferentially located nearer a set of mapped lineaments than randomly scattered damage, suggesting range-front faulting along the base of the Santa Cruz Mountains is related to both the earthquake damage and the mapped lineaments. The damage also exhibit two non-random patterns: a single cluster of damage centered in the town of Los Gatos, California, and a linear alignment of damage along the range front of the Santa Cruz Mountains, California. The linear alignment of damage is strongest between 45° and 50° northwest. This agrees well with the mean trend of the mapped lineaments, measured as 49? northwest.

California↗

Geomorphology and depositional subenvironments of Gulf Islands National Seashore, Mississippi

The U.S. Geological Survey (USGS) is studying coastal hazards and coastal change to improve our understanding of coastal ecosystems and to develop better capabilities of predicting future coastal change. One approach to understanding the dynamics of coastal systems is to monitor changes in barrier-island subenvironments through time. This involves examining morphological and topographic change at temporal scales ranging from millennia to years and spatial scales ranging from tens of kilometers to meters. Of particular interest are the processes that produce those changes and the determination of whether or not those processes are likely to persist into the future. In these analyses of hazards and change, both natural and anthropogenic influences are considered. Quantifying past magnitudes and rates of coastal change and knowing the principal factors that govern those changes are critical to predicting what changes are likely to occur under different scenarios, such as short-term impacts of extreme storms or long-term impacts of sea-level rise. Gulf Islands National Seashore was selected for detailed mapping of barrier-island morphology and topography because the islands offer a diversity of depositional subenvironments and the islands' areas and positions have changed substantially in historical time. The geomorphologic and subenvironmental maps emphasize the processes that formed the surficial features and also serve as a basis for documenting which subenvironments are relatively stable, such as the beach ridge complex, and those which are highly dynamic, such as the beach and active overwash zones. The primary mapping procedures used supervised functions within a Geographic Information System (GIS) that classified depositional subenvironments and features (map units) and delineated boundaries of the features (shapefiles). The GIS classified units on the basis of tonal patterns of a feature in contrast to adjacent features observed on georeferenced aerial photographs. Land elevations from recent lidar surveys served as supplementary data to assist in delineating the map-unit boundaries.

Mississippi↗

Geomorphology and depositional subenvironments of Gulf Islands National Seashore, Perdido Key and Santa Rosa Island, Florida

The U.S. Geological Survey (USGS) is studying coastal hazards and coastal change to improve our understanding of coastal ecosystems and to develop better capabilities of predicting future coastal change. One approach to understanding the dynamics of coastal systems is to monitor changes in barrier-island subenvironments through time. This involves examining morphologic and topographic change at temporal scales ranging from millennia to years and spatial scales ranging from tens of kilometers to meters. Of particular interest are the processes that produce those changes and the determination of whether or not those processes are likely to persist into the future. In these analyses of hazards and change, both natural and anthropogenic influences are considered. Quantifying past magnitudes and rates of coastal change and knowing the principal factors that govern those changes are critical to predicting what changes are likely to occur under different scenarios, such as short-term impacts of extreme storms or long-term impacts of sea-level rise. Gulf Islands National Seashore was selected for detailed mapping of barrier-island morphology and topography because the islands offer a diversity of depositional subenvironments and because island areas and positions have changed substantially in historical time. The geomorphologic and subenvironmental maps emphasize the processes that formed the surficial features and also serve as a basis for documenting which subenvironments are relatively stable, such as the vegetated barrier core, and those which are highly dynamic, such as the beach and inactive overwash zones. The primary mapping procedures were supervised functions within a Geographic Information System (GIS) that were applied to delineate and classify depositional subenvironments and features, collectively referred to as map units. The delineated boundaries of the map units were exported to create one shapefile, and are differentiated by the field "Type" in the associated attribute table. Map units were delineated and classified based on differences in tonal patterns of features in contrast to adjacent features observed on orthophotography. Land elevations from recent lidar surveys served as supplementary data to assist in delineating the map unit boundaries.

Florida↗

A multitemporal (1979-2009) land-use/land-cover dataset of the binational Santa Cruz Watershed

Trends derived from multitemporal land-cover data can be used to make informed land management decisions and to help managers model future change scenarios. We developed a multitemporal land-use/land-cover dataset for the binational Santa Cruz watershed of southern Arizona, United States, and northern Sonora, Mexico by creating a series of land-cover maps at decadal intervals (1979, 1989, 1999, and 2009) using Landsat Multispectral Scanner and Thematic Mapper data and a classification and regression tree classifier. The classification model exploited phenological changes of different land-cover spectral signatures through the use of biseasonal imagery collected during the (dry) early summer and (wet) late summer following rains from the North American monsoon. Landsat images were corrected to remove atmospheric influences, and the data were converted from raw digital numbers to surface reflectance values. The 14-class land-cover classification scheme is based on the 2001 National Land Cover Database with a focus on "Developed" land-use classes and riverine "Forest" and "Wetlands" cover classes required for specific watershed models. The classification procedure included the creation of several image-derived and topographic variables, including digital elevation model derivatives, image variance, and multitemporal Kauth-Thomas transformations. The accuracy of the land-cover maps was assessed using a random-stratified sampling design, reference aerial photography, and digital imagery. This showed high accuracy results, with kappa values (the statistical measure of agreement between map and reference data) ranging from 0.80 to 0.85.

Arizona↗

Results of time-domain electromagnetic soundings in Miami-Dade and southern Broward Counties, Florida

Time-domain electromagnetic (TEM) soundings were made in Miami-Dade and southern Broward Counties to aid in mapping the landward extent of saltwater in the Biscayne aquifer. A total of 79 soundings were collected in settings ranging from urban to undeveloped land, with some of the former posing problems of land access and interference from anthropogenic features. TEM soundings combined with monitoring-well data were used to determine if the saltwater front had moved since the last time it was mapped, to provide additional spatial coverage where existing monitoring wells were insufficient, and to help interpret a previously collected helicopter electromagnetic (HEM) survey flown in the southernmost portion of the study area. TEM soundings were interpreted as layered resistivity-depth models. Using information from well logs and water-quality data, the resistivity of the freshwater saturated Biscayne aquifer is expected to be above 30 ohm-meters, and the saltwater-saturated aquifer will have resistivities of less than 10 ohm-meters allowing determination of water quality from the TEM interpretations. TEM models from 29 soundings were compared to electromagnetic induction logs collected in nearby monitoring wells. In general, the agreement of these results was very good, giving confidence in the use of the TEM data for mapping saltwater encroachment.

Florida↗

Sharing our data—An overview of current (2016) USGS policies and practices for publishing data on ScienceBase and an example interactive mapping application

This report provides an overview of current (2016) U.S. Geological Survey policies and practices related to publishing data on ScienceBase, and an example interactive mapping application to display those data. ScienceBase is an integrated data sharing platform managed by the U.S. Geological Survey. This report describes resources that U.S. Geological Survey Scientists can use for writing data management plans, formatting data, and creating metadata, as well as for data and metadata review, uploading data and metadata to ScienceBase, and sharing metadata through the U.S. Geological Survey Science Data Catalog. Because data publishing policies and practices are evolving, scientists should consult the resources cited in this paper for definitive policy information. An example is provided where, using the content of a published ScienceBase data release that is associated with an interpretive product, a simple user interface is constructed to demonstrate how the open source capabilities of the R programming language and environment can interact with the properties and objects of the ScienceBase item and be used to generate interactive maps.

Open-File Report↗

Water resources of the English River, Old Mans Creek, and Clear Creek basins in Iowa

The surface and ground water resources of a 991 square mile area comprising the drainage basins of English River, Old Mans Creek and Clear Creek are presented. These basins lie to the west and southwest of Iowa City, Iowa, and all three streams are tributary to the Iowa River. The area is comprised of rolling uplands with relatively broad valleys and is devoted mainly to agriculture and livestock farming. In general, the surface water use is adversely affected by the high variability of flows and particularly by the critically small minimum flows. Augmentation of the minimum flows by means of storage reservoirs is possible but may be uneconomical in the broad valleys which require a high area to volume ratio. The surface water supply is presented in the form of tables and graphs which show information on maximum and minimum flows, mean flow, duration of flow, frequency of low flow and flood flow and storage requirements. Low-flow discharge. profiles for the English River and South Fork English River derived from measurements at partial record and supplementary sites are also shown. Ground water is available from shallow wells in nearly all of the area; however, the wells vary widely in productivity and reliability during a drouth. Potentially excellent aquifers may be found in the alluvium which underlies the valleys since similar areas along the lower Iowa River basin have produced yield up to 100 gallons per minute. However, the best and most reliable source of good ground water is the Jordan Sandstone. This aquifer varies from 1,375 feet below ground level in the eastern part of the area to 2,200 feet below ground level at the western end of the area. It is capable of supplying as much as 1,000 gallons per minute to individual wells. Its location is shown in the report by means of map contours referenced to mean sea level.

Iowa↗

Geology of the Juazohn Quadrangle, Liberia

As part of a program undertaken cooperatively by the Liberian Geological Survey (LGS) and the U. S. Geological Survey (USGS), under the sponsorship of the Government of Liberia and the Agency for International Development, U. S. Department of State, Liberia was mapped by geologic and geophysical methods during the period 1965 to 1972. The resulting geologic and geophysical maps are published in ten folios, each covering one quadrangle (see index map). The Juazohn quadrangle was systematically mapped by the author from December 1970 to June 1972. Field data provided by private companies and other members of the LGS-USGS project were used in map compilation, and are hereby acknowledged.

Juazohn Quadrangle↗

Selected hydrologic data, Yampa River basin and parts of the White River basin, northwestern Colorado and south-central Wyoming

Selected hydrologic data are presented from four energy-related projects conducted by the U.S. Geological Survey in the Yampa River basin and parts of the White River basin in northwestern Colorado and south-central Wyoming. Water-quality data during 1974 and 1975 and parts of 1976 for 129 ground-water sites and 119 surface-water sites are tabulated. For most samples, major cations, anions, and trace metals were analyzed. For the same time period, field measurements of specific conductance, temperature, and pH were made on 252 springs and wells. These samplings sites, as well as the locations of 20 climatological stations, 18 snow-course sites, and 43 surface-water gaging stations, are shown on maps. Geologic units that contain coal deposits or supply much of the water used for stock and domestic purposes in the area also are shown on a map. (Woodard-USGS)

Open-File Report↗

Approximate water-level changes in wells in the Chicot and Evangeline aquifers in the Houston-Galveston region, Texas, 1977-80 and 1979-80

This report, which was prepared in cooperation with the cities of Houston and Galveston, the Harris Galveston Coastal Subsidence Distract, and the Texas Department of Water Resources, presents data on water-level changes during 1977-80 and 1979-80 in the Chicot and Evangelina aquifers (figs. 1-4). During these periods, ground water pumping decreased in Galveston County and southern Harris County and increased in northern and western Harris County (Gabrysch, 1979). Water levels in about 550 wells were used to construct the maps showing water level changes.

Open-File Report↗

Ground-water pumpage in Nassau County, Long Island, New York, 1920-77: Introduction and user's guide to the data compilation

Pumpage data from about 2,100 wells used for public and nonpublic water-supply in Nassau County from 1920-77 have been collected and are available for public inspection at the U.S. Geological Survey office in Syosset, Nassau County. Except for wells in use before 1920, these data constitute the entire record available through 1977. The data are divided into two categories--pumpage from wells used for public supply, and pumpage from wells used mainly for industrial and commercial uses, designated as nonpublic water supply. Pumpage is tabulated by well or well field and is given by month or year with an annual total. The report serves as an introduction and user 's manual to the data, which are available for inspection but are not included in the report because they fill several hundred pages. The report describes the method of reporting pumpage on Long Island and how pumpage values were derived from the records. It also includes well-completion data and two maps showing the location of all wells.

New York↗

Progress report to the Arkansas State Highway and Transportation Department, year ending September 30, 1981

The objectives of the cooperative program with the Arkansas State Highway and Transportation Department are described. Accomplishments within the program are summarized and reports are listed. The accomplishments include operation of a crest-stage station network, modeling of rainfall-runoff station data, publication of drainage-area reports for all major river basins in Arkansas, floodflow-characteristics reports at proposed bridge sites, furnishing peak-flow and stage information at many sites, and furnishing technical advice and field training to Highway and Transportation Department personnel. Program plans for the 1982 fiscal year are listed and discussed. Other water-resources programs and publications that may be of interest are discussed and all available flood-prone-area maps for Arkansas are listed.

Open-File Report↗

Selected ground-water data in parts of Gilliam, Morrow, and Umatilla counties, Oregon

Over the last 20 years there has been a shift from dryland to irrigated agriculture in parts of Gilliam, Morrow, and Umatilla Counties in northeastern Oregon. Some irrigation water used in this area obtained from surface sources, but a significant amount is obtained from wells. The principal aquifer in the area is the Columbia River Basalt Group. Wells in the basalt are commonly drilled to depths of 500 to 1,200 ft and many produce more than 1,000 gal/min. A cooperative ground-water modeling study by the U.S. Geological Survey and Oregon Water Resources Department has resulted in the compilation of data from drillers logs and well inspections for wells completed in the basalt aquifer. Water-level measurements have been made in some wells in the area since the 1950's. The wells with longest periods of record are those that are part of a Statewide network of observation wells measured by the U. S. Geological Survey and Oregon Water Resources Department. This report includes a table of well information, representative hydrographs, and well location maps. (USGS)

Open-File Report↗

Statistical summaries of selected Iowa streamflow data through September 30, 1988

Statistical summaries of streamflow data collected at 144 active and discontinued stream-gaging stations in Iowa through water year 1988 are presented in the report. The summaries for each streamgaging station include: 1) station description, 2) the most recent stage-discharge rating table, 3) statistics of monthly and annual mean discharges, 4) boxplots of monthly and annual mean discharges, 5) monthly and annual flow durations, 6) probabilities of annual high discharges, 7) probabilities of annual low discharges, and 8) probabilities of seasonal low discharges. The minimum period of record at stations included in the report is 10 years. The location of each station is shown on a map of Iowa.

Iowa↗

Earthquake damage in greater Los Angeles

Generalized regions of highest damage from three Los Angeles area earthquakes of the 20th century. The area of highest damage from the 1971 San Fernando earthquake, not shown, lay mostly within the area that experience high damage in 19947. The map illustrates that moderate magnitude earthquakes can produce series effects over large areas. The map is not intended to depict future damage patterns.

California↗

Selected U.S. Bureau of Mines reports on Alaska indexed by quadrangle

Most U.S. Bureau of Mines reports on the geology and mineral resources of Alaska that were published or placed in open files through April 30, 1974, are listed by the quadrangles (scale 1:250,000) into which Alaska has been divided for topographic mapping (p. 2). References to reports that deal with Alaska as a whole and cannot be readily assigned to individual quadrangles or deal with many scattered parts of the state are listed under ALASKA - GENERAL, which appears before the alphabetically arranged quadrangle listings. References to the Minerals Yearbook, published annually, are not included as this periodical contains mainly statistical data. Also omitted are reports on mining, milling, and metallurgical practices; compilations of coal, oil, and gas analyses unless data on geological occurrences are also given; and reports on permissible explosives, health, and safety. This index is the second in a planned series of specialized lists, arranged by quadrangle, that will facilitate library research on the geology and mineral resources of Alaska. The first in the series is "Geological Survey open-file reports on Alaska indexed by quadrangle," by Edward H. Cobb, which was released as open-file report 74-7 on May 16, 1974.

Alaska↗

Geochemical maps showing the distribution and abundance of molybdenum in the Tanacross Quadrangle, Alaska

This series of geochemical maps shows the distribution of molybdenum in four sample media: (A) the oxide residue (the oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh stream sediment, (C) the ash of streambank sod (mixed organic and inorganic material) collected beneath the water level, and (D) the ash of aquatic bryophytes (mosses). The molybdenum data are plotted on base maps showing generalized geology and the drainage pattern. The map symbols show the sample sites and ranges of values in the following manner: (1) open symbols denote background, (2) small black symbols represent weakly anomalous values, and (3) large black symbols denotes strongly anomalous values. Because the small black symbols represent weakly anomalous values, they are considered to be significant only where they are closely associated with strongly anomalous metal values either in the same sample medium or with anomalous values in other sample media. The ranges of values represented by the symbols are shown on the histograms which accompany the geochemical maps. An explanation of sampling, preparation, and analytical procedures is given in Circular 734, which accompanies this folio. Complete analytical data for geochemical samples collected by the U.S. Geological Survey in the Tanacross quadrangle are available in a U.S. Geological Survey open-file report (O'Leary and others, 1976).

Alaska↗