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At least 703 records · Page 39Linked to original sources
USGS1991

Landforms of the conterminous United States — A digital shaded relief portrayal

Our map was made by digital image-processing, a technical specialty related to the broader fields of computer graphics and machine vision (Dawson, 1987; Kennie and McLaren, 1988). The technology includes the many spacially based operations first brought together and developed systematically to manipulate Ranger, Mariner, Landsat, and other images that are reassembled from spacecraft telemetry in a raster or scan-line arrangement of square-grid elements (Nathan, 1966; Castleman, 1979; Sheldon, 1987). These computer procedures have been successfully transferred to landform analysis from remote-sensing applications by substituting terrain heights or sea-floor depths for the customary values of electromagnetic radiation obtained from satellites an stored in digital arrays of pixels (Batson and others, 1975).

IMAP↗
USGS2002

Geologic map of the Stillwater Complex, Montana: A digital database

This report provides a digital version of the Geologic map of the Stillwater Complex, Montana by Page and Nokleberg (1974). Paper copies of the four geologic map sheets from the original report were scanned and initially attributed by Optronics Specialty Co., Inc. (Northridge, CA) and remitted to the U.S. Geological Survey for further attribution and publication of the geospatial digital files. The resulting digital geologic dataset can be queried in a geographic information system (GIS) in many ways to produce a variety of geological maps.

Montana↗
USGS2002

Geologic map of the Lassen Peak, Chaos Crags, and Upper Hat Creek area, California

This digital publication contains all the information used to publish U.S. Geological Survey Geologic Investigations Series I-2723 (Christiansen and others, 2002). The map shows the distribution and relationships of volcanic and surficial-sedimentary deposits in an area of Lassen Volcanic National Park and vicinity. Emphasis is on products of the 1914-1917 eruptions of Lassen Peak and the approximately 1000-year-old eruptions of Chaos Crags. ArcInfo grids were prepared from scanned composite images of four U.S. Geological Survey 7.5' topographic quadrangle maps and were georeferenced and reprojected.

IMAP↗
USGS1980

Maps showing geology and shallow structure of eastern Rhode Island Sound and Vineyard Sound, Massachusetts

This report presents results of marine studies conducted by the U.S. Geological Survey (USGS) during the summers of 1975 and 1976 in eastern Rhode Island Sound and Vineyard Sound (fig. 1) located off the southeastern coast of Massachusetts. The study was made in cooperation with the Massachusetts Department of Public Works and the New England Division of the U.S. Army Corps of Engineers. It covered an area of the Atlantic Inner Continental Shelf between latitude 41 deg 12' and 41 deg 33'N, and between longitude 70 deg 37' and 71 deg 15'W (see index map). Major objectives included assessment of sand and gravel resources, environmental impact evaluation both of offshore mining of these resources and of offshore disposal of solid waste and dredge spoil material, identification and mapping of the offshore geology, and determination of the geologic history of this part of the Inner Shelf. A total of 670 kilometers (km) of closely spaced high-resolution seismic-reflection profiles, 224 km of side-scan sonar data, and 16 cores totaling 90 meters (m) of recovered sediment, were collected during the investigation. This report is companion to geologic maps published for Cape Cod Bay (Oldale and O'Hara, 1975) and Buzzards Bay, Mass. (Robb and Oldale, 1977).

Massachusetts, Rhode Island↗
USGS2001

Geologic map of the Chewelah 30' x 60' Quadrangle, Washington and Idaho

This data set maps and describes the geology of the Chewelah 30' X 60' quadrangle, Washington and Idaho. Created using Environmental Systems Research Institute's ARC/INFO software, the data base consists of the following items: (1) a map coverage containing geologic contacts and units, (2) a point coverage containing site-specific geologic structural data, (3) two coverages derived from 1:100,000 Digital Line Graphs (DLG); one of which represents topographic data, and the other, cultural data, (4) two line coverages that contain cross-section lines and unit-label leaders, respectively, and (5) attribute tables for geologic units (polygons), contacts (arcs), and site-specific data (points). In addition, the data set includes the following graphic and text products: (1) A PostScript graphic plot-file containing the geologic map, topography, cultural data, and two cross sections, and on a separate sheet, a Correlation of Map Units (CMU) diagram, an abbreviated Description of Map Units (DMU), modal diagrams for granitic rocks, an index map, a regional geologic and structure map, and a key for point and line symbols; (2) PDF files of the Readme text-file and expanded Description of Map Units (DMU), and (3) this metadata file. The geologic map database contains original U.S. Geological Survey data generated by detailed field observation and by interpretation of aerial photographs. The map was compiled from geologic maps of eight 1:48,000 15' quadrangle blocks, each of which was made by mosaicing and reducing the four constituent 7.5' quadrangles. These 15' quadrangle blocks were mapped chiefly at 1:24,000 scale, but the detail of the mapping was governed by the intention that it was to be compiled at 1:48,000 scale. The compilation at 1:100,000 scale entailed necessary simplification in some areas and combining of some geologic units. Overall, however, despite a greater than two times reduction in scale, most geologic detail found on the 1:48,000 maps is retained on the 1:100,000 map. Geologic contacts across boundaries of the eight constituent quadrangles required minor adjustments, but none significant at the final 1:100,000 scale. The geologic map was compiled on a base-stable cronoflex copy of the Chewelah 30' X 60' topographic base and then scribed. The scribe guide was used to make a 0.007 mil-thick blackline clear-film, which was scanned at 1200 DPI by Optronics Specialty Company, Northridge, California. This image was converted to vector and polygon GIS layers and minimally attributed by Optronics Specialty Company. Minor hand-digitized additions were made at the USGS. Lines, points, and polygons were subsequently edited at the USGS by using standard ARC/INFO commands. Digitizing and editing artifacts significant enough to display at a scale of 1:100,000 were corrected. Within the database, geologic contacts are represented as lines (arcs), geologic units as polygons, and site-specific data as points. Polygon, arc, and point attribute tables (.pat, .aat, and .pat, respectively) uniquely identify each geologic datum.

Miscellaneous Field Studies Map↗
USGS2000

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory-Processing, taxonomy, and quality control of benthic macroinvertebrate samples

Qualitative and quantitative methods to process benthic macroinvertebrate (BMI) samples have been developed and tested by the U.S. Geological Survey?s National Water Quality Laboratory Biological Group. The qualitative processing method is based on visually sorting a sample for up to 2 hours. Sorting focuses on attaining organisms that are likely to result in taxonomic identifications to lower taxonomic levels (for example, Genus or Species). Immature and damaged organisms are also sorted when they are likely to result in unique determinations. The sorted sample remnant is scanned briefly by a second person to determine if obvious taxa were missed. The quantitative processing method is based on a fixed-count approach that targets some minimum count, such as 100 or 300 organisms. Organisms are sorted from randomly selected 5.1- by 5.1-centimeter parts of a gridded subsampling frame. The sorted remnant from each sample is resorted by a second individual for at least 10 percent of the original sort time. A large-rare organism search is performed on the unsorted remnant to sort BMI taxa that were not likely represented in the sorted grids. After either qualitatively or quantitatively sorting the sample, BMIs are identified by using one of three different types of taxonomic assessment. The Standard Taxonomic Assessment is comparable to the U.S. Environmental Protection Agency Rapid Bioassessment Protocol III and typically provides Genus- or Species-level taxonomic resolution. The Rapid Taxonomic Assessment is comparable to the U.S. Environmental Protection Agency Rapid Bioassessment Protocol II and provides Familylevel and higher taxonomic resolution. The Custom Taxonomic Assessment provides Species-level resolution whenever possible for groups identified to higher taxonomic levels by using the Standard Taxonomic Assessment. The consistent use of standardized designations and notes facilitates the interpretation of BMI data within and among water-quality studies. Taxonomic identifications are quality assured by verifying all referenced taxa and randomly reviewing 10 percent of the taxonomic identifications performed weekly by Biological Group taxonomists. Taxonomic errors discovered during this review are corrected. BMI data are reviewed for accuracy and completeness prior to release. BMI data are released phylogenetically in spreadsheet format and unprocessed abundances are corrected for laboratory and field subsampling when necessary.

Open-File Report↗
USGS2000

Method of analysis and quality-assurance practices for determination of pesticides in water by solid-phase extraction and capillary-column gas chromatography/mass spectrometry at the U.S. Geological Survey California District Organic Chemistry Laboratory, 1996-99

A method of analysis and quality-assurance practices were developed to study the fate and transport of pesticides in the San Francisco Bay-Estuary by the U.S. Geological Survey. Water samples were filtered to remove suspended-particulate matter and pumped through C-8 solid-phase extraction cartridges to extract the pesticides. The cartridges were dried with carbon dioxide and the pesticides were eluted with three cartridge volumes of hexane:diethyl ether (1:1) solution. The eluants were analyzed using capillary-column gas chromatography/mass spectrometry in full-scan mode. Method detection limits for pesticides ranged from 0.002 to 0.025 microgram per liter for 1-liter samples. Recoveries ranged from 44 to 140 percent for 25 pesticides in samples of organic-free reagent water and Sacramento-San Joaquin Delta and Suisun Bay water fortified at 0.05 and 0.50 microgram per liter. The estimated holding time for pesticides after extraction on C-8 solid-phase extraction cartridges ranged from 10 to 257 days.

California↗
USGS2001

Spatial digital database for the geologic map of the east part of the Pullman 1° x 2° quadrangle, Idaho

The paper geologic map of the east part of the Pullman 1° x 2° degree quadrangle, Idaho (Rember and Bennett, 1979) was scanned and initially attributed by Optronics Specialty Co., Inc. (Northridge, CA) and remitted to the U.S. Geological Survey for further attribution and publication of the geospatial digital files. The resulting digital geologic map GIS can be queried in many ways to produce a variety of geologic maps. This digital geospatial database is one of many being created by the U.S. Geological Survey as an ongoing effort to provide geologic information in a geographic information system (GIS) for use in spatial analysis. Digital base map data files (topography, roads, towns, rivers and lakes, and others.) are not included: they may be obtained from a variety of commercial and government sources. This database is not meant to be used or displayed at any scale larger than 1:250,000 (for example, 1:100,000 or 1:24,000). The digital geologic map graphics and plot files (pull250k.gra/.hp /.eps) that are provided in the digital package are representations of the digital database.

Idaho↗
USGS2001

Petrography and physical properties of selected rock types associated with the Hayward Fault, California

This report provides brief petrographic descriptions of rock samples collected from the vicinity of the Hayward Fault, Northern California. Two groups of rock samples are represented here: A set of six samples that were used for laboratory measurements of P- and S-wave velocity , strength, density, and porosity. This group was examined using standard petrographic microscope, scanning electron microscope (SEM) and electron microprobe techniques on polished thin sections. A larger group of samples, most of them 1"-diameter cores, on which density and magnetic susceptibility measurements were made as part of gravity and magnetic surveys of the Hayward Fault. Because this second group of samples received less extensive laboratory study, examination of them was limited to standard petrographic microscope examination of covered thin sections. The density and susceptibility measurements of this second group of samples are included in this report.

California↗
USGS2001

Geologic map and digital database of the Porcupine Wash 7.5 minute Quadrangle, Riverside County, southern California

This data set maps and describes the geology of the Porcupine Wash 7.5 minute quadrangle, Riverside County, southern California. The quadrangle, situated in Joshua Tree National Park in the eastern Transverse Ranges physiographic and structural province, encompasses parts of the Hexie Mountains, Cottonwood Mountains, northern Eagle Mountains, and south flank of Pinto Basin. It is underlain by a basement terrane comprising Proterozoic metamorphic rocks, Mesozoic plutonic rocks, and Mesozoic and Mesozoic or Cenozoic hypabyssal dikes. The basement terrane is capped by a widespread Tertiary erosion surface preserved in remnants in the Eagle and Cottonwood Mountains and buried beneath Cenozoic deposits in Pinto Basin. Locally, Miocene basalt overlies the erosion surface. A sequence of at least three Quaternary pediments is planed into the north piedmont of the Eagle and Hexie Mountains, each in turn overlain by successively younger residual and alluvial deposits. The Tertiary erosion surface is deformed and broken by north-northwest-trending, high-angle, dip-slip faults and an east-west trending system of high-angle dip- and left-slip faults. East-west trending faults are younger than and perhaps in part coeval with faults of the northwest-trending set. The Porcupine Wash database was created using ARCVIEW and ARC/INFO, which are geographical information system (GIS) software products of Envronmental Systems Research Institute (ESRI). The database consists of the following items: (1) a map coverage showing faults and geologic contacts and units, (2) a separate coverage showing dikes, (3) a coverage showing structural data, (4) a scanned topographic base at a scale of 1:24,000, and (5) attribute tables for geologic units (polygons and regions), contacts (arcs), and site-specific data (points). The database, accompanied by a pamphlet file and this metadata file, also includes the following graphic and text products: (1) A portable document file (.pdf) containing a navigable graphic of the geologic map on a 1:24,000 topographic base. The map is accompanied by a marginal explanation consisting of a Description of Map and Database Units (DMU), a Correlation of Map and Database Units (CMU), and a key to point-and line-symbols. (2) Separate .pdf files of the DMU and CMU, individually. (3) A PostScript graphic-file containing the geologic map on a 1:24,000 topographic base accompanied by the marginal explanation. (4) A pamphlet that describes the database and how to access it. Within the database, geologic contacts , faults, and dikes are represented as lines (arcs), geologic units as polygons and regions, and site-specific data as points. Polygon, arc, and point attribute tables (.pat, .aat, and .pat, respectively) uniquely identify each geologic datum and link it to other tables (.rel) that provide more detailed geologic information.

California↗
USGS2001

Geologic map and digital database of the Conejo Well 7.5 minute quadrangle, Riverside County, southern California

This data set maps and describes the geology of the Conejo Well 7.5 minute quadrangle, Riverside County, southern California. The quadrangle, situated in Joshua Tree National Park in the eastern Transverse Ranges physiographic and structural province, encompasses part of the northern Eagle Mountains and part of the south flank of Pinto Basin. It is underlain by a basement terrane comprising Proterozoic metamorphic rocks, Mesozoic plutonic rocks, and Mesozoic and Mesozoic or Cenozoic hypabyssal dikes. The basement terrane is capped by a widespread Tertiary erosion surface preserved in remnants in the Eagle Mountains and buried beneath Cenozoic deposits in Pinto Basin. Locally, Miocene basalt overlies the erosion surface. A sequence of at least three Quaternary pediments is planed into the north piedmont of the Eagle Mountains, each in turn overlain by successively younger residual and alluvial deposits. The Tertiary erosion surface is deformed and broken by north-northwest-trending, high-angle, dip-slip faults in the Eagle Mountains and an east-west trending system of high-angle dip- and left-slip faults. In and adjacent to the Conejo Well quadrangle, faults of the northwest-trending set displace Miocene sedimentary rocks and basalt deposited on the Tertiary erosion surface and Pliocene and (or) Pleistocene deposits that accumulated on the oldest pediment. Faults of this system appear to be overlain by Pleistocene deposits that accumulated on younger pediments. East-west trending faults are younger than and perhaps in part coeval with faults of the northwest-trending set. The Conejo Well database was created using ARCVIEW and ARC/INFO, which are geographical information system (GIS) software products of Envronmental Systems Research Institute (ESRI). The database consists of the following items: (1) a map coverage showing faults and geologic contacts and units, (2) a separate coverage showing dikes, (3) a coverage showing structural data, (4) a point coverage containing line ornamentation, and (5) a scanned topographic base at a scale of 1:24,000. The coverages include attribute tables for geologic units (polygons and regions), contacts (arcs), and site-specific data (points). The database, accompanied by a pamphlet file and this metadata file, also includes the following graphic and text products: (1) A portable document file (.pdf) containing a navigable graphic of the geologic map on a 1:24,000 topographic base. The map is accompanied by a marginal explanation consisting of a Description of Map and Database Units (DMU), a Correlation of Map and Database Units (CMU), and a key to point-and line-symbols. (2) Separate .pdf files of the DMU and CMU, individually. (3) A PostScript graphic-file containing the geologic map on a 1:24,000 topographic base accompanied by the marginal explanation. (4) A pamphlet that describes the database and how to access it. Within the database, geologic contacts , faults, and dikes are represented as lines (arcs), geologic units as polygons and regions, and site-specific data as points. Polygon, arc, and point attribute tables (.pat, .aat, and .pat, respectively) uniquely identify each geologic datum and link it to other tables (.rel) that provide more detailed geologic information.

California↗
USGS2001

Environmental studies of the World Trade Center area after the September 11, 2001 attack

This web site describes the results of an interdisciplinary environmental characterization of the World Trade Center (WTC) area after September 11, 2001. Information presented in this site was first made available to the World Trade Center emergency response teams on September 18, 2001 (Thermal hot spot information), and September 27, 2001 (maps and compositional results). The Airborne Visible / Infrared Imaging Spectrometer (AVIRIS), a hyperspectral remote sensing instrument, was flown by JPL/NASA over the World Trade Center (WTC) area on September 16, 18, 22, and 23, 2001 ( Link to the AVIRIS JPL data facility) . A 2-person USGS crew collected samples of dusts and airfall debris from more than 35 localities within a 1-km radius of the World trade Center site on the evenings of September 17 and 18, 2001. Two samples were collected of indoor locations that were presumably not affected by rainfall (there was a rainstorm on September 14). Two samples of material coating a steel beam in the WTC debris were also collected. The USGS ground crew also carried out on-the-ground reflectance spectroscopy measurements during daylight hours to field calibrate AVIRIS remote sensing data. Radiance calibration and rectification of the AVIRIS data were done at JPL/NASA. Surface reflectance calibration, spectral mapping, and interpretation were done at the USGS Imaging Spectroscopy Lab in Denver. The dust/debris and beam-insulation samples were analyzed for a variety of mineralogical and chemical parameters using Reflectance Spectroscopy (RS), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), chemical analysis, and chemical leach test techniques in U.S. Geological Survey laboratories in Denver, Colorado.

New York↗
USGS2001

Borehole P- and S-wave velocity at thirteen stations in Southern California

The U.S. Geological Survey (USGS), as part of a program to acquire seismic velocity data at locations of strong-ground motion in earthquakes (e.g., Gibbs et al., 2000), has investigated thirteen additional sites in the Southern California region. Of the thirteen sites, twelve are in the vicinity of Whittier, California, and one is located in San Bernardino, California. Several deployments of temporary seismographs were made after the Whittier Narrows, California earthquake of 1 October 1987 (Mueller et al., 1988). A deployment, between 2 October and 9 November 1987, was the motivation for selection of six of the drill sites. Temporary portable seismographs at Hoover School (HOO), Lincoln School (LIN), Corps of Engineers Station (NAR), Olive Junior High School (OLV), Santa Anita Golf Course (SAG), and Southwestern Academy (SWA) recorded significant aftershock data. These portable sites, with the exception of Santa Anita Golf Course, were co-sited with strong-motion recorders. Stations at HOO, Lincoln School Whittier (WLB), Saint Paul High School (STP), Alisos Adult School (EXC), Cerritos College Gymnasium (CGM), Cerritos College Physical Science Building (CPS), and Cerritos College Police Building (CPB) were part of an array of digital strong-motion stations deployed from "bedrock" in Whittier to near the deepest part of the Los Angeles basin in Norwalk. Although development and siting of this new array (partially installed at the time of this writing) was generally motivated by the Whittier Narrows earthquake, these new sites (with the exception of HOO) were not part of any Whittier Narrows aftershock deployments. A similar new digital strong-motion site was installed at the San Bernardino Fire Station during the same time frame. Velocity data were obtained to depths of about 90 meters at two sites, 30 meters at seven sites, and 18 to 25 meters at four sites. Lithology data from the analysis of cuttings and samples was obtained from the two 90-meter deep holes and from five of the shallower holes to supplement the velocity interpretation. The two 90-meter boreholes (SB1, CPB) have been instrumented with borehole seismometers for continuous monitoring of earthquake activity (Rogers et al., 1998). No drill samples or cuttings were obtained from the other six sites, but driller's logs were scanned for major changes noted there. The velocity models at those sites were interpreted using only the measured data and major changes in the driller's log as noted above. The sites are shown in Figure 1 and listed in Table 1, which gives references to information regarding the strong-motion data. Several hundred strong-motion records of the main-shock were written by this moderate size earthquake (ML = 5.9), making it important from a scientific and engineering prospective (Brady et al., 1988; Shakal et al., 1988).

California↗
USGS2002

Evaluation of airborne thermal-infrared image data for monitoring aquatic habitats and cultural resources within the Grand Canyon

This study examined thermal-infrared (TIR) image data acquired using the airborne Advanced Thematic Mapper (ATM) sensor in the afternoon of July 25th, 2000 over a portion of the Colorado River corridor to determine the capability of these 100-cm resolution data to address some biologic and cultural resource requirements for GCMRC. The requirements investigated included the mapping of warm backwaters that may serve as fish habitats and the detection (and monitoring) of archaeological structures and natural springs that occur on land. This report reviews the procedure for calibration of the airborne TIR data to obtain surface water temperatures and shows the results for various river reaches within the acquired river corridor. With respect to mapping warm backwater areas, our results show that TIR data need to be acquired with a gain setting that optimizes the range of temperatures found within the water to increase sensitivity of the resulting data to a level of 0.1 °C and to reduce scan-line noise. Data acquired within a two-hour window around maximum solar heating (1:30 PM) is recommended to provide maximum solar heating of the water and to minimize cooling effects of late-afternoon shadows. Ground-truth data within the temperature range of the warm backwaters are necessary for calibration of the TIR data. The ground-truth data need to be collected with good locational accuracy. The derived water-temperature data provide the capability for rapid, wide-area mapping of warm-water fish habitats using a threshold temperature for such habitats. The collected daytime TIR data were ineffective in mapping (detecting) both archaeological structures and natural springs (seeps). The inability of the daytime TIR data to detect archaeological structures is attributed to the low thermal sensitivity (0.3 °C) of the collected data. The detection of subtle thermal differences between geologic materials requires sensitivities of at least 0.1 °C, which can be obtained by most TIR sensors using an appropriate gain setting. Simultaneous data collection for both land and water purposes can be achieved using sensors that collect TIR data in two separate channels, each channel using a gain setting most appropriate for land or water. The detection of archaeological structures and natural water seeps would also be improved by collection of data after sunset, which would require a separate data acquisition from that providing surface water temperature data and therefore additional cost. At this point, the cost for acquiring TIR data is quite high ($620/river-km) compared to the potential benefits of the data, unless reflected-wavelength data are also collected that can satisfy other GCMRC protocol requirements (such as mapping riparian vegetation). This is especially true if multiple data acquisitions are required during the year for temporal analyses of backwater areas. The cost for these data cannot be totally mitigated by its ability to partly replace the need for ground surveys of backwaters because calibration of the TIR data will require some ground-truth data from warm backwater areas (in addition to low-temperature main-stem data). However, the airborne data can provide a product that cannot be approached by ground surveys, that being an instantaneous (2 hour) map of surface water temperature over a 160-km stretch of the Grand Canyon.

Arizona↗
USGS2002

Digital mapping techniques '02, workshop proceedings : May 19-22, 2002, Salt Lake City, Utah

The Digital Mapping Techniques '02 (DMT'02) workshop was attended by 101 technical experts from 43 agencies, universities, and private companies, including representatives from 25 state geological surveys (see Appendix A). This workshop was similar in nature to the previous five meetings, held in Lawrence, Kansas (Soller, 1997), in Champaign, Illinois (Soller, 1998a), in Madison, Wisconsin (Soller, 1999), in Lexington, Kentucky (Soller, 2000), and in Tuscaloosa, Alabama (Soller, 2001). This year's meeting was hosted by the Utah Geological Survey, from May 19 to 22, 2002, on the University of Utah campus in Salt Lake City. As in the previous meetings, the objective was to foster informal discussion and exchange of technical information. When an attendee adopts or modifies a newly learned technique on the basis of discussions at the workshop, the workshop clearly has met that objective. Evidence of learning and cooperation among participating agencies continued to be a highlight of the DMT workshops (see example in Soller, 1998b, and various papers in this volume). All the DMT workshops have been coordinated by the Association of American State Geologists (AASG) and the U.S. Geological Survey (USGS) Data Capture Working Group, which was formed in August 1996 to support the AASG and the USGS in their effort to build a National Geologic Map Database (see Soller and Berg, this volume, and http://ncgmp.usgs.gov/ngmdbproject/standards/datacapt/ ). The Working Group was formed because increased production efficiencies, standardization, and quality of digital map products were needed for the database--and the State and Federal geological surveys--to provide more high-quality digital maps to the public. At the 2002 meeting, oral and poster presentations and special discussion sessions emphasized (1) methods for creating and publishing map products (here, "publishing" includes Web-based release); (2) techniques for scanning already published maps and managing and delivering them on the Web; (3) continued development of the National Geologic Map Database; and (4) progress toward building a standard geologic map data model. In addition, special presentations were provided on building a statewide GIS council, incorporating geology as a NSDI Framework layer, and resolving the roles of surveyors and GIS professionals.

Open-File Report↗
USGS2002

Spatial digital database for the geology of the San Pedro River Basin in Cochise, Gila, Graham, Pima, and Pinal Counties, Arizona

This spatial digital database for the geology of the San Pedro River Basin in southeastern Arizona was compiled from three maps by Dickinson (1993, 1998, 2000). Mylar originals of the map sheets were scanned, and the resultant images were rectified to a mathematically-generated set of latitude and longitude registration points. Geologic linework was digitized from the rectified images on screen using ArcView (ver. 3.2), and the resultant shapefiles were converted to ArcInfo (ver. 7.2) coverages. Lines and polygons were then attributed; and the files were merged omtp a single ArcInfo database (quib24k). This digital spatial database is one of many being created by the U.S. Geological Survey as an ongoing effort to provide geologic information in a geographic information system (GIS) for use in spatial analysis. This database can be queried in many ways to produce a variety of geologic maps. Digital base map data files (topography, roads, towns, rivers and lakes, etc.) are not included: they may be obtained from a variety of commercial and government sources. This database is not meant to be used or displayed at any scale larger than 1:24,000 (for example, 1:12,000). The map area is located in southeastern Arizona. This report describes the map units, the methods used to convert the geologic map data into a digital format, and the ArcInfo GIS file structures and relationships; and it explains how to download the digital files from the U.S. Geological Survey public access World Wide Web site on the Internet. See figures 2 and 3 for page-size versions of the map compilation.

Arizona↗
USGS2002

A new method for GPS-based wind speed determinations during airborne volcanic plume measurements

Begun nearly thirty years ago, the measurement of gases in volcanic plumes is today an accepted technique in volcano research. Volcanic plume measurements, whether baseline gas emissions from quiescent volcanoes or more substantial emissions from volcanoes undergoing unrest, provide important information on the amount of gaseous output of a volcano to the atmosphere. Measuring changes in gas emission rates also allows insight into eruptive behavior. Some of the earliest volcanic plume measurements of sulfur dioxide were made using a correlation spectrometer (COSPEC). The COSPEC, developed originally for industrial pollution studies, is an upward-looking optical spectrometer tuned to the ultraviolet absorption wavelength of sulfur dioxide (Millán and Hoff, 1978). In airborne mode, the COSPEC is mounted in a fixed-wing aircraft and flown back and forth just underneath a volcanic plume, perpendicular to the direction of plume travel (Casadevall and others, 1981; Stoiber and others, 1983). Similarly, for plumes close to the ground, the COSPEC can be mounted in an automobile and driven underneath a plume if a suitable road system is available (Elias and others, 1998). The COSPEC can also be mounted on a tripod and used to scan a volcanic plume from a fixed location on the ground, although the effectiveness of this configuration declines with distance from the plume (Kyle and others, 1990). In the 1990’s, newer airborne techniques involving direct sampling of volcanic plumes with infrared spectrometers and electrochemical sensors were developed in order to measure additional gases such as CO2 and H2S (Gerlach and others, 1997; Gerlach and others, 1999; McGee and others, 2001). These methods involve constructing a plume cross-section from several measurement traverses through the plume in a vertical plane. Newer instruments such as open-path Fourier transform infrared (FTIR) spectrometers are now being used to measure the gases in volcanic plumes mostly from fixed locations on the ground. Most FTIR studies to date measure only gas compositions or ratios of gas species (Love and others, 1998; Francis and others, 1998; Horrocks and others, 1999). What all of these methods have in common, however, is the necessity to know plume velocities if accurate gas emission rates are to be calculated. Even open-path FTIR studies done in tandem with a COSPEC require knowledge of plume velocity in order to compute emission rates.

Open-File Report↗
USGS2002

Abstracts of the annual Planetary Geologic Mappers Meeting, June 18-19, 2001, Albuquerque, New Mexico

The annual Planetary Geologic Mappers Meeting serves two purposes. In addition to giving mappers the opportunity to exchange ideas, experiences, victories, and problems with others, presentations are reviewed by the Geologic Mapping Subcommittee (GeMS) to provide input to the Planetary Geology and Geophysics Mapping Program review panel’s consideration of new proposals and progress reports that include mapping tasks. Funded mappers bring both oral presentation materials (slides or viewgraphs) and map products to post for review by GeMS and fellow mappers. Additionally, the annual meetings typically feature optional field trips offering earth analogs and parallels to planetary mapping problems. The 2001 Mappers Meeting, June 18-19, was convened by Tim Parker, Dave Senske, and Ken Tanaka and was hosted by Larry Crumpler and Jayne Aubele of the New Mexico Museum of Natural History and Science in Albuquerque, New Mexico. Oral presentations were given in the Museum’s Honeywell Auditorium, and maps were posted in the Sandia Room. In addition to active mappers, guests included local science teachers who had successfully competed for the right to attend and listen to the reports. It was a unique pleasure for mappers to have the opportunity to interact with and provide information to teachers responding so enthusiastically to the meeting presentation. On Sunday, June 17, Larry and Jayne conducted an optional pre-meeting field trip. The flanks of Rio Grande Rift, east and west of Albuquerque and Valles Caldera north of town presented tectonic, volcanic, and sedimentary examples of the Rift and adjoining areas analogous to observed features on Mars and Venus. The arid but volcanically and tectonically active environment of New Mexico’s rift valley enables focus on features that appear morphologically young and spectacular in satellite images and digital relief models. The theme of the trip was to see what, at orbiter resolution, "obvious" geologic features look like at lander (outcrop) scales. Trips to the top of the rift-flanking mountains (Sandia Peak, 10,600 ft) and the Valles Caldera, as well as various active spring deposits highlighted the day. After welcoming remarks from the host, Larry Crumpler, opening remarks by Tim Parker and Dave Senske and a report on mapping program status by Ken Tanaka, the mappers’ oral presentations began the morning of June 18, with a session on Venus Geologic Mapping. The afternoon continued with an exciting USGS Planetary GIS on the Web (PIGWAD) demonstration and ended with an open discussion of issues in planetary mapping. Posted maps of Venus quadrangles were viewed during the morning break. Tuesday’s Mars Geologic Mapping session began with a pep talk from Tim Parker encouraging mapping community input to the MER landing site selection committee and continued with Steve Saunders describing the potential contribution of Odyssey Mission data to the geologic mapping of Mars. A Mars map poster session was held during the morning break, and the meeting was adjourned mid-afternoon. After the mappers meeting on Tuesday, attendants were treated to a "Field trip to Mars." The Institute of Meteoritics at the University of New Mexico houses an outstanding collection of meteorites, including those that have been identified as originating from Mars. The Institute tour featured examples of most of the different lithologies exhibited by martian meteorites identified to date, as well as some of the analytical tests (scanning electron microscope) they are conducting on specimens from ALH84001. Wednesday, June 20, featured an optional post-meeting field trip to see a travertine quarry and nearby sites of travertine deposition, the Very Large Array near Socorro, and other volcanic features within the Rio Grande Rift.

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