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USGS2012

Synoptic water-level measurements of the Upper Floridan aquifer in Florida and parts of Georgia, South Carolina, and Alabama, May-June 2010

Water levels for the Upper Floridan aquifer were measured throughout Florida and in parts of Georgia, South Carolina, and Alabama in May-June 2010. These measurements were compiled for the U.S. Geological Survey (USGS) Floridan Aquifer System Groundwater Availability Study and conducted as part of the USGS Groundwater Resources Program. Data were collected by personnel from the USGS Florida Water Science Center, Georgia Water Science Center, South Carolina Water Science Center and several state and county agencies in Florida, Georgia, South Carolina, and Alabama using standard techniques. Data collected by USGS personnel are stored in the USGS National Water Information System (NWIS), Groundwater Site-Inventory System (GWSI). Furnished records from cooperators are stored in NWIS/GWSI when possible, but are available from the source agency.

Alabama, Florida, Georgia, South Carolina↗

USGS2018

Integrated observations and informatics improve understanding of changing marine ecosystems

Marine ecosystems have numerous benefits for human societies around the world and many policy initiatives now seek to maintain the health of these ecosystems. To enable wise decisions, up to date and accurate information on marine species and the state of the environment they live in is required. Moreover, this information needs to be openly accessible to build indicators and conduct timely assessments that decision makers can use. The questions and problems being addressed demand global-scale investigations, transdisciplinary science, and mechanisms to integrate and distribute data that otherwise would appear to be disparate. Essential Ocean Variables (EOVs) and marine Essential Biodiversity Variables (EBVs), conceptualized by the Global Ocean Observing System (GOOS) and the Marine Biodiversity Observation Network (MBON), respectively, guide observation of the ocean. Additionally, significant progress has been made to coordinate efforts between existing programs, such as the GOOS, MBON, and Ocean Biogeographic Information System collaboration agreement. Globally and nationally relevant indicators and assessments require increased sharing of data and analytical methods, sustained long-term and large-scale observations, and resources to dedicated to these tasks. We propose a vision and key tenets as a guiding framework for building a global integrated system for understanding marine biological diversity and processes to address policy and resource management needs. This framework includes: using EOVs and EBVs and implementing the guiding principles of Findable, Accessible, Interoperable, Reusable (FAIR) data and action ecology. In doing so, we can encourage relevant, rapid, and integrative scientific advancement that can be implemented by decision makers to maintain marine ecosystem health.

Frontiers in Marine Science↗

USGS2014

Proceedings of the U.S. Geological Survey Eighth Biennial Geographic Information Science Workshop and first The National Map Users Conference, Denver, Colorado, May 10-13, 2011

The U.S. Geological Survey (USGS) is sponsoring the first The National Map Users Conference in conjunction with the eighth biennial Geographic Information Science (GIS) Workshop on May 10-13, 2011, in Lakewood, Colorado. The GIS Workshop will be held at the USGS National Training Center, located on the Denver Federal Center, Lakewood, Colorado, May 10-11. The National Map Users Conference will be held directly after the GIS Workshop at the Denver Marriott West, a convention hotel in the Lakewood, Colorado area, May 12-13. The National Map is designed to serve the Nation by providing geographic data and knowledge for government, industry, and public uses. The goal of The National Map Users Conference is to enhance communications and collaboration among the communities of users of and contributors to The National Map, including USGS, Department of the Interior, and other government GIS specialists and scientists, as well as the broader geospatial community. The USGS National Geospatial Program intends the conference to serve as a forum to engage users and more fully discover and meet their needs for the products and services of The National Map. The goal of the GIS Workshop is to promote advancement of GIS and related technologies and concepts as well as the sharing of GIS knowledge within the USGS GIS community. This collaborative opportunity for multi-disciplinary GIS and associated professionals will allow attendees to present and discuss a wide variety of geospatial-related topics. The Users Conference and Workshop collaboration will bring together scientists, managers, and data users who, through presentations, posters, seminars, workshops, and informal gatherings, will share accomplishments and progress on a variety of geospatial topics. During this joint event, attendees will have the opportunity to present or demonstrate their work; to develop their knowledge by attending hands-on workshops, seminars, and presentations given by professionals from USGS and other Federal Agencies, GIS related companies, and academia; and to network with other professionals to develop collaborative opportunities. Specific conference topics include scientific and modeling applications using The National Map, opportunities for partnerships, and advances in geospatial technologies. The first part of the week will be the GIS Workshop, offered as a pre-conference seminar. It will focus on hands-on GIS training and seminars concerning current topics of geospatial interest. The focus of the USGS GIS Workshop is to showcase specific techniques and concepts for using GIS in support of science. The presentations will be educational and not a marketing endeavor. To promote awareness of and interaction with selected USGS corporate and local science center data products, as well as promoting collaboration, a “GIS Olympics” event will be held Tuesday evening during the GIS Workshop. The second part of the week will feature interactive briefings and discussions on issues and opportunities of The National Map. The focus of the Users Conference will be on the role of The National Map in supporting science initiatives, emergency response, land and wildlife management, and other activities. All presentations at the Users Conference include use or innovations related to a The National Map data theme or application. On Wednesday evening, a poster session is being held as a combined event for all attendees and as a juncture between the events. On Thursday evening, the Henry Gannett Award will be presented. Additionally, poster awards will be presented. Several prominent speakers are featured at plenary sessions at The National Map Users Conference, including Deanna A. Archuleta, Deputy Assistant Secretary for Water and Science, Department of the Interior; Dr. Barbara P. Buttenfield, Professor of Geography at the University of Colorado in Boulder; best-selling author Frederick Reuss; and Dr. Joel Scheraga, Senior Advisor for Climate Adaptation, U.S. Environmental Protection Agency. Additionally, panel discussions have attracted participation from notable experts from government, academia, and the private sector. This Proceedings volume will serve as an activity reference for workshop attendees, as well as an archive of technical abstracts presented at the workshop. Author, co-author, and presenter names, affiliations, and contact information are listed with presentation titles with the abstracts. Some hands-on sessions are offered twice; in these instances, abstracts submitted for publication are presented in the proceedings on both days on which they are offered.

Scientific Investigations Report↗

USGS2013

Geodatabase compilation of hydrogeologic, remote sensing, and water-budget-component data for the High Plains aquifer, 2011

The High Plains aquifer underlies almost 112 million acres in the central United States. It is one of the largest aquifers in the Nation in terms of annual groundwater withdrawals and provides drinking water for 2.3 million people. The High Plains aquifer has gained national and international attention as a highly stressed groundwater supply primarily because it has been appreciably depleted in some areas. The U.S. Geological Survey has an active program to monitor the changes in groundwater levels for the High Plains aquifer and has documented substantial water-level changes since predevelopment: the High Plains Groundwater Availability Study is part of a series of regional groundwater availability studies conducted to evaluate the availability and sustainability of major aquifers across the Nation. The goals of the regional groundwater studies are to quantify current groundwater resources in an aquifer system, evaluate how these resources have changed over time, and provide tools to better understand a systems response to future demands and environmental stresses. The purpose of this report is to present selected data developed and synthesized for the High Plains aquifer as part of the High Plains Groundwater Availability Study. The High Plains Groundwater Availability Study includes the development of a water-budget-component analysis for the High Plains completed in 2011 and development of a groundwater-flow model for the northern High Plains aquifer. Both of these tasks require large amounts of data about the High Plains aquifer. Data pertaining to the High Plains aquifer were collected, synthesized, and then organized into digital data containers called geodatabases. There are 8 geodatabases, 1 file geodatabase and 7 personal geodatabases, that have been grouped in three categories: hydrogeologic data, remote sensing data, and water-budget-component data. The hydrogeologic data pertaining to the northern High Plains aquifer is included in three separate geodatabases: (1) base data from a groundwater-flow model; (2) hydrogeology and hydraulic properties data; and (3) groundwater-flow model data to be used as calibration targets. The remote sensing data for this study were developed by the U. S. Geological Survey Earth Resources Observation and Science Center and include historical and predicted land-use/land-cover data and actual evapotranspiration data by using remotely sensed temperature data. The water-budget-component data contains selected raster data from maps in the “Selected Approaches to Estimate Water-Budget Components of the High Plains, 1940 Through 1949 and 2000 Through 2009” report completed in 2011 ( http://pubs.usgs.gov/sir/2011/5183/ ). Federal Geographic Data Committee compliant metadata were created for each spatial and tabular data layer in the geodatabases.

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, ↗

USGS2018

U.S. Landsat Analysis Ready Data

U.S. Landsat Analysis Ready Data (ARD) are a revolutionary new U.S. Geological Survey science product that allows the Landsat archive to be more accessible and easier to analyze and reduces the amount of time users spend on data processing for monitoring and assessing landscape change. U.S. Landsat ARD are Level-2 products derived from Landsat Collections Level-1 precision and terrain-corrected scenes that are processed and arranged in spatially consistent tiles and dense temporal stacks for immediate use in monitoring and assessing landscape change.

Fact Sheet↗

USGS2006

Water resources data, Puerto Rico and the U.S. Virgin Islands, water year 2004

The Caribbean Water Science Center of the U.S. Geological Survey (USGS), in cooperation with local and Federal agencies obtains a large amount of data pertaining to the water resources of the Commonwealth of Puerto Rico and the Territory of the U.S. Virgin Islands each water year. These data, accumulated during many water years, constitute a valuable data base for developing an improved understanding of the water resources of the area. To make these data readily available to interested parties outside the U.S. Geological Survey, the data are published annually in this report series entitled 'Water Resources Data for Puerto Rico and the U.S. Virgin Islands.' This report includes records on both surface and ground water. Specifically, it contains: (1) discharge records for 89 streamflow-gaging stations, daily sediment records for 13 sediment stations, stage records for 18 reservoirs, and (2) water-quality records for 20 streamflow-gaging stations, and for 38 ungaged stream sites, 13 lake sites, 2 lagoons, and 1 bay, and (3) water-level records for 72 observation wells. Water-resources data for Puerto Rico for calendar years 1958-67 were released in a series of reports entitled 'Water Records of Puerto Rico.' Water-resources data for the U.S. Virgin Islands for the calendar years 1962-69 were released in a report entitled 'Water Records of U.S. Virgin Islands.' Included were records of streamflow, ground-water levels, and water-quality data for both surface and ground water. Beginning with the 1968 calendar year, surface-water records for Puerto Rico were released separately on an annual basis. Ground-water level records and water-quality data for surface and ground water were released in companion reports covering periods of several years. Data for the 1973-74 reports were published under separate covers. Water-resources data reports for 1975 to 2003 water years consist of one volume each and contain data for streamflow, water quality, and ground water.

Water Data Report↗

USGS2000

Preliminary report on the 16 October 1999 M 7.1 Hector mine, California, earthquake

The M w 7.1 Hector Mine, California, earthquake occurred at 9:46 GMT on 16 October 1999. The event caused minimal damage because it was located in a remote, sparsely populated part of the Mojave Desert, approximately 47 miles east-southeast of Barstow, with epicentral coordinates 34.59°N 116.27°W and a hypocentral depth of 5 ± 3 km. Twelve foreshocks, M 1.9-3.8, preceded the mainshock during the previous twelve hours. All of these events were located close to the hypocenter of the mainshock. The Hector Mine earthquake occurred within the Eastern California Shear Zone (ECSZ). By virtue of its remote location, the societal impact of the Hector Mine earthquake was, fortunately, minimal in spite of the event's appreciable size. The ECSZ is characterized by high seismicity, a high tectonic strain rate, and a broad, distributed zone of north-northwest-trending faults (ECSZ; Figure 1 ; Dokka and Travis, 1990 ; Sauber et al., 1986 ; Sauber et al., 1994 ; Sieh et al., 1993 ). Data regarding the slip rates of faults within the ECSZ suggest that on the order of 15% of the Pacific-North American plate motion occurs along this zone ( Sauber et al., 1986 ; Wesnousky, 1986 ). Most of the faults in the ECSZ have low slip rates and long repeat times for major earthquakes, on the order of several thousands to tens of thousands of years. The occurrence of the Hector Mine earthquake within seven years and only about 30 km east of the 1992 M w 7.3 Landers earthquake suggests that the closely spaced surface faults in the ECSZ are mechanically related. The Hector Mine event involved rupture on two previously mapped fault zones—the Bullion Fault and an unnamed, more northerly-trending fault that is informally referred to in this paper as the Lavic Lake Fault (Dibblee, 1966 , 1967a , b ). Traces of the Bullion Fault exhibit evidence of Holocene displacement and were zoned as active in 1988 under California's Mquist-Priolo Earthquake Fault Zoning Act ( Hart and Bryant, 1997 ). The pattern of rupture along more than one named fault was also observed from the 1992 Landers earthquake ( Hauksson et al., 1993 ; Sieh et al., 1994). Much of the fault zone that produced the Hector Mine earthquake had been buried by relatively young stream deposits, and the fault scarps in bedrock have a subdued morphology. It appears that these faults have not experienced significant offset for perhaps 10,000 years or more ( Hart, 1987 ). Planned future investigations will refine the age of the last event on these faults. The portion of the Lavic Lake Fault that ruptured between the northern end of the Bullion Mountains and Lavic Lake had not previously been mapped. However, our field investigations have identified ancient, subdued fault scarps along portions of the 1999 rupture zone in this area. It thus appears that the entire segment of the Lavic Lake Fault that was involved in the 1999 event had ruptured in the past. As is typical for most faults within the Eastern California Shear Zone, the rate of movement along the Lavic Lake Fault may be quite slow (<1 mm/yr) and should produce earthquakes only infrequently. This event is a reminder that faults that have ruptured in late Quaternary time, but that lack evidence of Holocene displacement, can still produce earthquakes in this low-slip-rate tectonic setting. Additionally, the Hector Mine earthquake is noteworthy for a couple of other reasons. First, it clearly produced triggered seismicity over much of southern California, from the rupture zone toward the south-southwest in particular. Second, as we will discuss, the event may provide new data and insight into recently developed paradigms concerning earthquake interactions and the role of static stress changes. Questions such as these will, of course, be the subject of extensive detailed analyses in years to come. Fortunately, the Hector Mine sequence will provide one of the best data sets obtained to date for a significant earthquake in the United States. Because it occurred when major upgrades to both the regional seismic network (TriNet) and the regional geodetic network (SCIGN) were well underway, the Earth science community will have abundant high-quality data with which to explore the important and interesting questions that have been raised. In this paper, we present and discuss the basic data and preliminary results from the Hector Mine earthquake.

California↗

USGS1997

GSLIB-style programs for discriminant analysis and regionalized classification

Discriminant analysis is a statistical technique used to predict the group membership of a set of multivariate observations, each of which is assumed to arise from one of a set of distinct classes or groups. Each group is characterized by a certain distribution in multivariate space, and group allocations are based on the similarity of each sample to each group. Assuming multivariate normality, generalized distance measures based on the squared Mahalanobis distance from each sample to each group centroid arise as the natural measure of similarity. One can allocate samples to groups either on the basis of minimum generalized distance or, equivalently, maximum posterior probability of group membership. In earth science applications samples are often associated with geographic locations. In this situation regionalized classification can be used to produce a map representing group membership throughout the sampled domain. This can be accomplished by interpolating either generalized distances or membership probabilities from sample locations to regularly spaced grid nodes and comparing resulting grids to produce a classification map. This paper presents a set of GSLIB-style FORTRAN programs for performing discriminant analysis and regionalized classification. The program disco performs discriminant analysis and the programs xmd2cls and prb2cls combine interpolated distances and probabilities, respectively, to create a grid of predicted classifications. In addition, the utility program colbind allows the user to combine selected columns from different GSLIB-style data files into one file. ?? 1997 Elsevier Science Ltd.

Computers & Geosciences↗

USGS1990

Catalog of US GeoData

The development of geographic information systems (GIS) is a rapidly growing industry that supports natural resources, studies, land management, environmental analysis, and urban and transporation planning. The increasing use of computers for storing and analyzing earth science information has greatly expanded the demand for digital cartographic and geographic data. Digital cartography involves the collection, storage, processing, analysis, and display of map data with the aid of computers. The U.S. Geological Survey (USGS), the Nation's largest earth science research agency, through its National Mapping Program, has expanded digital cartography operations to include the collection of elevation, planimetric, land use and land cover, and geographic names information in digital form. This digital information is available on 9-track magnetic tapes and, in the case of 1:2,000,000-scale planimetric digital line graph data, in Compact Disc Read Only Memory (CD-ROM) format. Digital information can be used with all types of geographic and land information systems.

General Information Product↗

USGS2021

Alaska landbird montoring survey: Alaska regional protocol framework for monitoring landbirds using point counts

Alaska provides habitat for 143 species of landbirds that occur regularly in the state, about half of which breed predominantly north of the border between the contiguous United States and Canada. The road-based North American Breeding Bird Survey (BBS) provides some data on population trends in Alaska, but most northern populations are inadequately monitored by this program because of a paucity of roads. To remedy this deficiency, Boreal Partners in Flight developed the Alaska Landbird Monitoring Survey (ALMS) to monitor breeding populations of landbirds in off-road areas of Alaska in tandem with data collected from the roadside BBS. The primary objective of ALMS is to monitor long-term population trends of landbirds and other species that can be monitored by diurnal point counts during the breeding season, including many shorebirds and aquatic birds. A secondary objective is to estimate landbird densities by habitat, which can be used to model avian distribution and abundance across Alaska. ALMS is a collaborative program whereby agencies and other entities conduct standardized surveys of breeding birds and their habitats on the lands they manage and then contribute the data to the U.S. Geological Survey Alaska Science Center for storage and analysis. The short-term implementation goal of ALMS is to monitor birds systematically within each of 100 randomly selected survey blocks, thereby matching the number of BBS surveys conducted in each of Alaska's five Bird Conservation Regions (BCRs). Each block has a mini-grid of 15−25 points that are surveyed biennially, with half of the blocks surveyed in alternating years. Survey blocks are stratified by accessibility and cost-effectiveness. Refuges may opt to limit sites to those accessible by foot, vehicle, boat, or fixed-wing aircraft, as these can be surveyed more inexpensively and reliably over time. Observers survey each point within a survey block for birds using a 10-min point count once per summer on a biennial basis. They collect corresponding habitat data during the first visit and at subsequent 10-year intervals or whenever a disturbance (e.g., fire, wind) has caused a significant change. USGS analyzes ALMS data jointly with BBS data to test for differences between off-road and roadside areas and to increase power to detect statewide trends. Additional blocks can be surveyed in areas that are more difficult and expensive to access as resources become available in the future. Long-term monitoring enables detection of change in bird populations in relation to fire, disease and insect damage, resource development, climate-related change, and other landscape-level disturbances across Alaska. Results from ALMS can also help prioritize conservation and research towards species before they become endangered and require expensive recovery programs.

Alaska↗

USGS2012

EarthExplorer

The EarthExplorer trifold provides basic information for on-line access to remotely-sensed data from the U.S. Geological Survey Earth Resources Observation and Science (EROS) Center archive. The EarthExplorer (http://earthexplorer.usgs.gov/) client/server interface allows users to search and download aerial photography, satellite data, elevation data, land-cover products, and digitized maps. Minimum computer system requirements and customer service contact information also are included in the brochure.

General Information Product↗

USGS2019

Identifying characteristics of actionable science for drought planning and adaptation: Final report to the North Central Climate Adaptation Science Center

Changing climate conditions can make water management planning and drought preparedness decisions more complicated than ever before. Resource managers can no longer rely solely on historical data and trends to base their actions, and are in need of science that is relevant to their specific needs and can directly inform important planning decisions. Questions remain, however, regarding the most effective and efficient methods for extending scientific knowledge and products into management and decision-making. This study analyzed two unique cases of water management to better understand how science can be translated into resource management actions and decision-making. In particular, this project sought to understand 1) the characteristics that make science actionable and useful for water resource management and drought preparedness, and 2) the ideal types of scientific knowledge or science products that facilitate the use of science in management and decision-making. The first case study focused on beaver mimicry, an emerging nature-based solution that increases the presence of wood and woody debris in rivers and streams to mimic the actions of beavers. This technique has been rapidly adopted by natural resource managers as a way to restore riparian areas, increase groundwater infiltration, and slow surface water flow so that more water is available later in the year during hotter and dryer months. The second case study focused on an established research program, Colorado Dust on Snow, that provides water managers with scientific information explaining how the movement of dust particles from the Colorado Plateau influences hydrology and the timing and intensity of snow melt and water runoff into critical water sources. This program has support from and is being used by several water conservation districts in the state. Understanding how scientific knowledge translates into action and decision-making in these cases is expected to strengthen our knowledge of actionable science in the context of drought and its impacts on ecosystems. The project team gathered qualitative data through stakeholder interviews and will conduct an extensive literature review. Findings from these efforts will also be incorporated into a broader Intermountain West synthesis effort to determine and assess commonalities and differences among socio-ecological aspects of drought adaptation and planning.

Colorado, Kansas, Montana, Nebraska, North Dakota,↗

USGS2011

The U.S. Geological Survey cartographic and geographic information science research activities 2006-2010

The U.S. Geological Survey (USGS) produces geospatial databases and topographic maps for the United States of America. A part of that mission includes conducting research in geographic information science (GIScience) and cartography to support mapping and improve the design, quality, delivery, and use of geospatial data and topographic maps. The Center of Excellence for Geospatial Information Science (CEGIS) was established by the USGS in January 2006 as a part of the National Geospatial Program Office. CEGIS (http://cegis.usgs.gov) evolved from a team of cartographic researchers at the Mid-Continent Mapping Center. The team became known as the Cartographic Research group and was supported by the Cooperative Topographic Mapping, Geographic Analysis and Monitoring, and Land Remote Sensing programs of the Geography Discipline of the USGS from 1999-2005. In 2006, the Cartographic Research group and its projects (http://carto-research.er.usgs.gov/) became the core of CEGIS staff and research. In 2006, CEGIS research became focused on The National Map (http://nationalmap.gov).

Cartography and Geographic Information Science↗

USGS2000

Acoustic Doppler Current Profiler Data Processing System manual [ADCP]

This open-file report describes the data processing software currently in use by the U.S. Geological Survey (USGS), Woods Hole Coastal and Marine Science Center (WHCMSC), to process time series of acoustic Doppler current data obtained by Teledyne RD Instruments Workhorse model ADCPs. The Sediment Transport Instrumentation Group (STG) at the WHCMSC has a long-standing commitment to providing scientists high quality oceanographic data published in a timely manner. To meet this commitment, STG has created this software to aid personnel in processing and reviewing data as well as evaluating hardware for signs of instrument malfunction. The output data format for the data is network Common Data Form (netCDF), which meets USGS publication standards. Typically, ADCP data are recorded in beam coordinates. This conforms to the USGS philosophy to post-process rather than internally process data. By preserving the original data quality indicators as well as the initial data set, data can be evaluated and reprocessed for different types of analyses. Beam coordinate data are desirable for internal and surface wave experiments, for example. All the code in this software package is intended to run using the MATLAB program available from The Mathworks, Inc. As such, it is platform independent and can be adapted by the USGS and others for specialized experiments with non-standard requirements. The software is continuously being updated and revised as improvements are required. The most recent revision may be downloaded from: http://woodshole.er.usgs.gov/operations/stg/Pubs/ADCPtools/adcp_index.htm The USGS makes this software available at the user?s discretion and responsibility.

Open-File Report↗

USGS2005

Quality-assurance plan for ground-water activities, U.S. Geological Survey, Washington Water Science Center

This quality-assurance plan documents the standards, policies, and procedures used by the U.S. Geological Survey's Washington Water Science Center, for activities related to the collection, processing, storage, analysis, and publication of ground-water data. This plan serves as a guide to all Washington Water Science Center personnel involved in ground-water activities, and changes as the needs and requirements of the Washington Water Science Center and Discipline change. Regular updates to this plan represent an integral part of the quality-assurance process.

Open-File Report↗

USGS2012

Inflation of Long Valley Caldera from one year of continuous GPS observations

A permanent Global Positioning System receiver at Casa Diablo Hot Springs, Long Valley Caldera, California was installed in January, 1993, and has operated almost continuously since then. The data have been transmitted daily to the Jet Propulsion Laboratory for routine analysis with data from the Fiducial Laboratories for an International Natural sciences Network (FLINN) by the JPL FLINN analysis center. Results from these analyses have been used to interpret the on going deformation at Long Valley, with data excluded from periods when the antenna was covered under 2.5 meters of snow and from some periods when Anti Spoofing was enforced on the GPS signal. The remaining time series suggests that uplift of the resurgent dome of Long Valley Caldera during 1993 has been 2.5±1.1 cm/yr and horizontal motion has been 3.0±0.7 cm/yr at S53W in a no-net-rotation global reference frame, or 1.5±0.7 cm/yr at S14W relative to the Sierra Nevada block. These rates are consistent with uplift predicted from frequent horizontal strain measurements. Spectral analysis of the observations suggests that tidal forcing of the magma chamber is not a source of the variability in the 3 dimensional station location. These results suggest that remotely operated, continuously recording GPS receivers could prove to be a reliable tool for volcano monitoring throughout the world.

California↗

USGS2011

Documentation of methods and inventory of irrigation data collected for the 2000 and 2005 U.S. Geological Survey Estimated use of water in the United States, comparison of USGS-compiled irrigation data to other sources, and recommendations for future compilations

Every five years since 1950, the U.S. Geological Survey (USGS) National Water Use Information Program (NWUIP) has compiled water-use information in the United States and published a circular report titled "Estimated use of water in the United States," which includes estimates of water withdrawals by State, sources of water withdrawals (groundwater or surface water), and water-use category (irrigation, public supply, industrial, thermoelectric, and so forth). This report discusses the impact of important considerations when estimating irrigated acreage and irrigation withdrawals, including estimates of conveyance loss, irrigation-system efficiencies, pasture, horticulture, golf courses, and double cropping. This report also documents the methods and data sources used by the USGS Water Science Centers (WSCs) for estimating irrigated acreage and irrigation withdrawals reported in the 2000 and 2005 USGS 5-year water-use compilations. For the 2005 USGS water-use compilation, the most common sources used by WSCs for obtaining irrigated crop acreage were the 2002 Census of Agriculture, 2003 Farm and Ranch Irrigation Survey (FRIS), National Agricultural Statistics Service (NASS), universities, and local and State agencies. In this report, the authors compare USGS-compiled irrigated acreage to Census of Agriculture- and FRIS- reported irrigated acreage. Nationwide irrigated acreage increased from the 1997 to 2007 Census of Agriculture estimates by about 1 percent and from the 1998 to 2008 FRIS estimates by about 9 percent. Conversely, total irrigated acreage decreased from the 2000 to 2005 USGS water-use compilations by about 2 percent. An indirect method for estimating irrigation withdrawals is presented and results are compared to the 2005 USGS-reported irrigation withdrawals for selected States. This method is meant to demonstrate a way to check data reported or received from a third party, if metered data are unavailable. Of the 11 States where this method was applied, 8 States had estimated irrigation withdrawals that were within 15 percent of what was reported in the 2005 water-use compilation, and 3 States had estimated irrigation withdrawals that were more than 20 percent of what was reported in 2005. Recommendations for improving estimates of irrigated acreage and irrigation withdrawals also are presented in this report. Conveyance losses and irrigation-system efficiencies should be considered in order to achieve a more accurate representation of irrigation withdrawals. Better documentation of data sources and methods used can help lead to more consistent information in future irrigation water-use compilations. Finally, a summary of data sources and methods used to estimate irrigated acreage and irrigation withdrawals for the 2000 and 2005 compilations for each WSC is presented in appendix 1.

Scientific Investigations Report↗

USGS2011

Ground motion attenuation during M 7.1 Darfield and M 6.2 Christchurch, New Zealand, earthquakes and performance of global predictive models

The M 7.1 Darfield earthquake occurred 40 km west of Christchurch (New Zealand) on 4 September 2010. Six months after, the city was struck again with an M 6.2 event on 22 February local time (21 February UTC). These events resulted in significant damage to infrastructure in the city and its suburbs. The purpose of this study is to evaluate the performance of global predictive models (GMPEs) using the strong motion data obtained from these two events to improve future seismic hazard assessment and building code provisions for the Canterbury region. The Canterbury region is located on the boundary between the Pacific and Australian plates; its surface expression is the active right lateral Alpine fault (Berryman et al. 1993). Beneath the North Island and the north South Island, the Pacific plate subducts obliquely under the Australian plate, while at the southwestern part of the South Island, a reverse process takes place. Although New Zealand has experienced several major earthquakes in the past as a result of its complex seismotectonic environment ( e.g. , M 7.1 1888 North Canterbury, M 7.0 1929 Arthur's Pass, and M 6.2 1995 Cass), there was no evidence of prior seismic activity in Christchurch and its surroundings before the September event. The Darfield and Christchurch earthquakes occurred along the previously unmapped Greendale fault in the Canterbury basin, which is covered by Quaternary alluvial deposits (Forsyth et al. 2008). In Figure 1, site conditions of the Canterbury epicentral area are depicted on a V S 30 map. This map was determined on the basis of topographic slope calculated from a 1-km grid using the method of Allen and Wald (2007). Also shown are the locations of strong motion stations. The Darfield event was generated as a result of a complex rupture mechanism; the recordings and geodetic data reveal that earthquake consists of three sub-events (Barnhart et al. 201 1 , page 815 of this issue). The first event was due to rupturing of a blind reverse fault with M 6.2, followed by a second event (M 6.9), releasing the largest portion of the energy on the right-lateral Greendale fault. The third sub-event (M 5.7) is due to a reverse fault with a right-lateral component (Holden et al. 2011). The Christchurch earthquake occurred on an oblique thrust fault. The comparison of spectral acceleration values at stations near Christchurch reveals that the second event produced much larger amplitudes of shaking than the Darfield event due to its proximity to the epicenter. Both events resulted in noticeably large amplitudes of the vertical motion, often exceeding horizontal motion in the near-fault area. The vertical motions, showing asymmetric acceleration traces and pulses, reached 1.26 g during the Darfield earthquake and 2.2 g during the Christchurch event. These events were recorded by more than 100 strong motion stations operated by the Institute of Geological and Nuclear Sciences (http://www.geonet.org.nz/). Using the processed data from these stations, peak ground acceleration (PGA) and 5%-damped spectral acceleration values at 0.3, 1, and 3 s are used for performance evaluation of the global ground motion predictive equations (GMPEs). The selected GMPEs are the Next Generation Attenuation (NGA) models of Abrahamson and Silva (2008), Boore and Atkinson (2008), Campbell and Bozorgnia (2008), and Chiou and Youngs (2008). The Graizer and Kalkan (2007, 2009) model, which is based on the NGA project database, is also included. These GMPEs are abbreviated respectively as AS08, BA08, CB08, CY08, and GK07. Because they have been used widely for seismic hazard analysis for crustal earthquakes, their performance assessment becomes a critical issue especially for immediate response and recovery planning after major events. The occurrence of aftershocks similar to the Christchurch event will most probably control seismic hazard in the broader area, as confirmed by the recent M 6.0 event on June 13, 2011.

Christchurch, Darfield↗