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16 recordsLinked to original sources
USGS2014

A sub-national scale geospatial analysis of diamond deposit lootability: the case of the Central African Republic

The Central African Republic (CAR), a country with rich diamond deposits and a tumultuous political history, experienced a government takeover by the Seleka rebel coalition in 2013. It is within this context that we developed and implemented a geospatial approach for assessing the lootability of high value-to-weight resource deposits, using the case of diamonds in CAR as an example. According to current definitions of lootability, or the vulnerability of deposits to exploitation, CAR's two major diamond deposits are similarly lootable. However, using this geospatial approach, we demonstrate that the deposits experience differing political geographic, spatial location, and cultural geographic contexts, rendering the eastern deposits more lootable than the western deposits. The patterns identified through this detailed analysis highlight the geographic complexities surrounding the issue of conflict resources and lootability, and speak to the importance of examining these topics at the sub-national scale, rather than relying on national-scale statistics.

The Extractive Industries and Society↗
USGS1983

Human interactions with ground-water

Ground-Water could be considered as an immense reservoir, from which only a certain amount of water can be withdrawn without affecting the quantity and quality of water. This amount is determined by the characteristics of the environment in which ground-water occurs and by the interactions of ground-water with precipitation, surface water, and people. It should be recognized that quantity and quality of ground-water are intimately related and should be considered accordingly. Quantity refers to usable water and water is usable for any specific purpose only so long as its quality has not deteriorated beyond acceptable limits. Thus an overall quantitative and qualitative management of ground water is inevitable, and its should also involve the uses of ground-water reservoirs for purposes other than water supply. The main objective of ground-water management is to ensure that ground-water resources will be available in appropriate time and in appropriate quantity and quality to meet the most important demands of our society. Traditional, and obvious uses of ground-water are the extraction of water for water supplies (domestic, municipal, agricultural, and industrial) and the natural discharge feeding lakes and maintaining base flow of streams. Not so obvious are the uses of ground-water reservoirs, the very framework within which ground-water occurs and moves, and in which other fluids or materials can be stored. In the last two decades, ground-water reservoirs have been intensively considered for many other purposes than water supplies. Diversified and very often conflicting uses need to be evaluated and dealt with in the most efficient way in order to determine the importance of each possible use, and to assign priorities of these uses. With rising competition for the use of ground-water reservoirs, we will also need to increase the potential for effective planning of ground-water development and protection. Man's development and use of ground-water necessarily modifies the natural conditions and the total natural system must be successfully blended with the unnatural stresses placed upon it. This can be accomplished by introducing new methods (such as ground-water zoning) in and by developing alternative strategies for ground-water management and protection. ?? 1983 D. Reidel Publishing Company.

GeoJournal↗
USGS2011

The United Nations framework classification for fossil energy and mineral reserves and resources 2009

Effective resource management in a globalizing economy requires accurate assessments of fossil energy and minerals resources. The recoverable quantities must be described and categorized in a manner that is consistent with scientific and social/economic information describing the economy as well as with the information describing the projects to recover them. A number of different standards have evolved over time in response to various professional needs Under a mandate given by the United Nations Economic and Social Council, the United Nations Economic Commission for Europe (UNECE) has cooperated with Governments, regulatory agencies, industry, international organizations, and professional organizations (including Committee for Mineral Reserves International Reporting Standards (CRIRSCO), the Society of Petroleum Engineers (SPE), the American Association of Petroleum Geologists (AAPG), and the Society of Petroleum Evaluation Engineers (SPEE)), as well as with outstanding experts, to define a global classification for extractive activities (including oil, gas, heavy oil and bitumen extraction) that reflects the principal concerns of existing petroleum and mineral classifications. The United Nations Framework Classification for Fossil Energy and Mineral Reserves and Resources-2009 (UNFC-2009) aims to serve the following four principal needs: 1. The needs in international energy and mineral studies to formulate robust and long-sighted policies. 2. The needs of governments in managing their resources accordingly, allowing market prices to be transferred to the wellhead with as little loss as possible. 3. The industries' needs for information while deploying technology, management and finance to secure energy supplies and capture value efficiently within the established frameworks to serve its host countries, shareholders and stakeholders. 4. The financial community's need for information to allocate capital appropriately, providing reduced costs and improved long-sightedness through the application of lower risk-compensated discount factors. The projects are categorised with respect to economic and social viability, project feasibility and maturity and uncertainty with respect to the quantities addressed. The categorisation of projects rather than of accumulations provides coherence with other critical management information such as production, cash flows, value and demand for various input factors. This key aspect of UNFC-2009 reflects the critical relationship between the quantities that can be recovered economically and the recovery processes (projects) that must be implemented to achieve those recoveries. It facilitates the recognition of potential wastage of resources through flaring or inefficient recovery processes and therefore also the potential for improvement. Copyright 2011, Society of Petroleum Engineers.

Conference Paper↗
USGS2008

Sensitivity of the Colorado Plateau to change: Climate, ecosystems, and society

The Colorado Plateau is located in the interior, dry end of two moisture trajectories coming from opposite directions, which have made this region a target for unusual climate fluctuations. A multidecadal drought event some 850 years ago may have eliminated maize cultivation by the first human settlers of the Colorado Plateau, the Fremont and Anasazi people, and contributed to the abandonment of their settlements. Even today, ranching and farming are vulnerable to drought and struggle to persist. The recent use of the Colorado Plateau primarily as rangeland has made this region less tolerant to drought due to unprecedented levels of surface disturbances that destroy biological crusts, reduce soil carbon and nitrogen stocks, and increase rates of soil erosion. The most recent drought of 2002 demonstrated the vulnerability of the Colorado Plateau in its currently depleted state and the associated costs to the local economies. New climate predictions for the southwestern United States include the possibility of a long-term shift to warmer, more arid conditions, punctuated by megadroughts not seen since medieval times. It remains to be seen whether the present-day extractive industries, aided by external subsidies, can persist in a climate regime that apparently exceeded the adaptive capacities of the Colorado Plateau's prehistoric agriculturalists.

Ecology and Society↗
USGS1998

Instream sand and gravel mining: Environmental issues and regulatory process in the United States

Sand and gravel are widely used throughout the U.S. construction industry, but their extraction can significantly affect the physical, chemical, and biological characteristics of mined streams. Fisheries biologists often find themselves involved in the complex environmental and regulatory issues related to instream sand and gravel mining. This paper provides an overview of information presented in a symposium held at the 1997 midyear meeting of the Southern Division of the American Fisheries Society in San Antonio, Texas, to discuss environmental issues and regulatory procedures related to instream mining. Conclusions from the symposium suggest that complex physicochemical and biotic responses to disturbance such as channel incision and alteration of riparian vegetation ultimately determine the effects of instream mining. An understanding of geomorphic processes can provide insight into the effects of mining operations on stream function, and multidisciplinary empirical studies are needed to determine the relative effects of mining versus other natural and human-induced stream alterations. Mining regulations often result in a confusing regulatory process complicated, for example, by the role of the U.S. Army Corps of Engineers, which has undergone numerous changes and remains unclear. Dialogue among scientists, miners, and regulators can provide an important first step toward developing a plan that integrates biology and politics to protect aquatic resources.

Fisheries↗
USGS1993

Economic analysis of critical habitat designation for the desert tortoise (Mojave population)

The U.S. Fish and Wildlife Service emergency 1isted the Mojave population of the desert tortoise as endangered on August 4, 1989. The Mojave population formally was listed as threatened on April 2, 1990. The Endangered Species Act of 1973, as amended, requires that the economic benefits and costs and other relevant effects of critical habitat designation be considered. The Secretary of the Interior may exclude from designation areas where the costs of designation are greater than the benefits, unless the exclusion would result in extinction of the species. Desert tortoises are threatened by an accumulation of human-and disease-related mortality accompanied by habitat destruction, degradation, and fragmentation. Many desert tortoises are illegally collected for pets, food, and commercial trade. Others are accidentally struck and killed by vehicles on roads and highways or are killed by gunshot or vehicles traveling off-highway. Raven predation on hatchling desert tortoises has increased as raven populations in the desert have risen. An upper respiratory tract disease is suspected to be a major cause of mortality in the western Mojave Desert. This presumably incurable affliction presumably is thought to be spread through the release of infected tortoises into the desert. The Service has proposed designating critical habitat in nine counties within four states. The 12 critical habitat units encompass 6.4 million acres of land, more than 80% federally owned. This region is economically and demographically diverse. Most of the land is sparsely settled and characterized as a hot desert ecosystem. Major industries in the region include entertainment and lodging (primarily in Las Vegas), property development to accommodate the rapid population growth, and services. Millions of rural acres in the region are leased by the federal government for livestock grazing and used for mining. Overall economic benefits to the affected states derived from cattle and sheep grazing in the hot desert areas are minimal and, according to a recent U.S. General Accounting Office study (1991), local economies do not depend on the grazing of public lands for economic survival. The economic analysis describes the economy in 1990, prior to designation, and estimates the effects of designation. The report estimates those incremental effects attributable to critical habitat designation. Impacts attributable to listing the species were not considered in this analysis. Although critical habitat units have been designated in nine counties, two counties are omitted from the economic analysis because of the small proportion of critical habitat acreage they include. Three key activities (cattle grazing, mineral extraction, and off-road vehicle use) were studied in detail. Even if livestock grazing and commercial off-road racing events were eliminated in the proposed critical habitat units, the potential incremental regional economic impacts would be extremely small. The findings in the report do not include the assumption that mining would be eliminated from critical habitat units, but rather that consultation may result in added mitigation and/or relocation of features. Studies show that society will realize benefits from preservation of species and ecosystems. Survey-based studies confirm that benefits exist and are substantial in size, although these benefits often are not measured in traditional economic markets. The total benefit to society of desert tortoise preservation includes several components. Biodiversity in the Mojave and Colorado Deserts will be improved, some recreation values may increase, and gains in intrinsic value will be realized. Critical habitat designation should result in the loss of fewer than 425 total jobs in the seven counties. These include 340 direct ranching jobs and 85 indirect jobs in other industries. This estimated employment loss will not be permanent for most laborers, it is anticipated that over 85% will be reemployed within two years. The economic consequences of designating critical habitat includes reduced ranch profits in the seven counties of $4,470,000 [the estimated permanent decrease in ranch profits, capitalized at 10% for a 50-year period, in accordance with the methodology of River, et al. (1978)]. Second, the federal government will compensate allottees with a one-time payment estimated at $376,000 for the loss of permanent improvements to grazing lands (pending BLM administrative decisions of partially affected allotments). Finally, discontinuing grazing fees will result in an annual reduction of $170,000 in collected grazing fees that are divided among range improvements, the Federal Treasury, and local governments.

California, Nevada↗
USGS2006

Apparent Consumption vs. Total Consumption--A Lead-Acid Battery Case Study

Introduction: This report compares estimates of U.S. apparent consumption of lead with estimates of total U.S. consumption of this mineral commodity from a materials flow perspective. The difference, attributed to the amount of lead contained in imported and exported products, was found to be significant for this sector. The study also assesses the effects of including mineral commodities incorporated in manufactured products on the interpretation of observed trends in minerals consumption and trade. Materials flow is a systems approach to understanding what happens to the materials we use from the time a material is extracted, through its processing and manufacturing, to its ultimate disposition. The U.S. Geological Survey (USGS) provides accurate and detailed mineral production and mineral commodity consumption statistics that are essential for government, nongovernment organizations, and the public to gain a better understanding of how and where materials are used and their effect on the environment and society. Published statistics on mineral apparent consumption are limited to estimates of consumption of raw material forms (ore, concentrate, and [or] refined metal). For this study, apparent consumption is defined as mine production + secondary refined production + imports (concentrates and refined metal) ? exports (concentrates and refined metal) + adjustments for government and industry stock changes. These estimates do not account for the amount of mineral commodities contained in manufactured products that are imported to the United States, nor do they deduct the amount of these mineral commodities contained in manufactured products that are exported from the United States. When imports or exports of manufactured products contribute significantly to the total use of a particular raw material, an estimate of consumption that does not consider the incorporated forms of these mineral commodities within imported or exported manufactured products can be either under- or overreported (depending on the net trade flow). Factors that influence consumption and trade patterns include variations in industry structure, labor or financial markets, legislation, and technology. As U.S. trade patterns of manufactured products change, omitting mineral commodities incorporated into these goods as part of U.S. mineral commodity consumption estimates may affect the interpretation of observed trends in minerals consumption and trade. Although it may be desirable to include minerals contained in manufactured products as part of consumption estimates, collection and estimation of these data are sometimes difficult. Consumption and trade data for every traded product may not be readily available. Compiling comprehensive consumption statistics for mineral commodities, which have many end uses, each including multiple products, may be time consuming. For these reasons, studies of all mineral commodities are not feasible. Mineral commodity selection for this study is based on data accessibility considerations and the relative importance of lead contained in imported and exported products when considered part of total U.S. lead consumption. Lead was selected for this initial evaluation of total mineral consumption because of the need to understand the consumption pattern of this potentially toxic metal and its compounds, the relative simplicity of this sector?s end-use structure, and the availability of trade data. This study draws upon the findings of an earlier lead consumption study (Biviano and others, 1999) conducted by the USGS for the period 1984 to 1993, but uses a different study methodology for an industry whose structure has changed from that considered in the earlier study. Figure 1 shows the quantity of material contributing to U.S. total consumption of lead metal from domestic and foreign industrial sectors in 2004, based upon trade data reported by the USGS and the U.S. International Trade Commission (USITC). For

Scientific Investigations Report↗
USGS2009

Copper: a metal for the ages

Copper was one of the first metals ever extracted and used by humans, and it has made vital contributions to sustaining and improving society since the dawn of civilization. Copper was first used in coins and ornaments starting about 8000 B.C., and at about 5500 B.C., copper tools helped civilization emerge from the Stone Age. The discovery that copper alloyed with tin produces bronze marked the beginning of the Bronze Age at about 3000 B.C. Copper is easily stretched, molded, and shaped; is resistant to corrosion; and conducts heat and electricity efficiently. As a result, copper was important to early humans and continues to be a material of choice for a variety of domestic, industrial, and high-technology applications today.

Fact Sheet↗
USGS1985

U. S. PHOSPHATE INDUSTRY: REVISED PROSPECTS AND POTENTIAL.

Although the United States is the world's largest producer and exporter of phosphates, serious doubts have arisen in recent years that U. S. deposits could sustain this important role. The development of borehole mining; i. e. , extracting the phosphate matrix as a slurry through a drill hole, however, is cause for optimism. Commercial borehole mining is still years away, but the potential advantages are numerous and important. Recent surveys also suggest that offshore deposits and deeply buried onshore deposits much exceed previous estimates. On the basis of the new technology and revised resource estimates, one can easily see the potential for increased production from U. S. deposits.

Marine Technology Society Journal↗
USGS2008

Development of a standard reference material for Cr(vi) in contaminated soil

Over the last several decades, considerable contamination by hexavalent chromium has resulted from the land disposal of Chromite Ore Processing Residue (COPR). COPR contains a number of hexavalent chromium-bearing compounds that were produced in high temperature industrial processes. Concern over the carcinogenic potential of this chromium species, and its environmental mobility, has resulted in efforts to remediate these waste sites. To provide support to analytical measurements of hexavalent chromium, a candidate National Institute of Standards and Technology (NIST) Standard Reference Material?? (SRM 2701), having a hexavalent chromium content of approximately 500 mg kg -1, has been developed using material collected from a waste site in Hudson County, New Jersey, USA. The collection, processing, preparation and preliminary physico-chemical characterization of the material are discussed. A two-phase multi-laboratory testing study was carried out to provide data on material homogeneity and to assess the stability of the material over the duration of the study. The study was designed to incorporate several United States Environmental Protection Agency (USEPA) determinative methods for hexavalent chromium, including Method 6800 which is based on speciated isotope dilution mass spectrometry (SIDMS), an approach which can account for chromium species inter-conversion during the extraction and measurement sequence. This journal is ?? The Royal Society of Chemistry 2008.

Journal of Analytical Atomic Spectrometry↗
USGS2020

Gas hydrates in sustainable chemistry

Gas hydrates have received considerable attention due to their important role in flow assurance for the oil and gas industry, their extensive natural occurrence on Earth and extraterrestrial planets, and their significant applications in sustainable technologies including but not limited to gas and energy storage, gas separation, and water desalination. Given not only their inherent structural flexibility depending on the type of guest gas molecules and formation conditions, but also the synthetic effects of a wide range of chemical additives on their properties, these variabilities could be exploited to optimise the role of gas hydrates. This includes increasing their industrial applications, understanding and utilising their role in Nature, identifying potential methods for safely extracting natural gases stored in naturally occurring hydrates within the Earth, and for developing green technologies. This review summarizes the different properties of gas hydrates as well as their formation and dissociation kinetics and then reviews the fast-growing literature reporting their role and applications in the aforementioned fields, mainly concentrating on advances during the last decade. Challenges, limitations, and future perspectives of each field are briefly discussed. The overall objective of this review is to provide readers with an extensive overview of gas hydrates that we hope will stimulate further work on this riveting field.

Chemical Society Reviews↗
USGS2017

Selenium

Selenium (Se) was discovered in 1817 in pyrite from copper mines in Sweden. It is a trace element in Earth’s crust, with an abundance of three to seven orders of magnitude less than the major rock-forming elements. Commercial use of selenium began in the United States in 1910, when it was used as a pigment for paints, ceramic glazes, and red glass. Since that time, it has had many other economic uses—notably, in the 1930s and 1940s, when it was used in rectifiers (which change alternating current to direct current), and in the 1960s, when it began to be used in the liner of photocopier drums. In the 21st century, other compounds have replaced selenium in these older products; modern uses for selenium include energy-efficient windows that limit heat transfer and thin-film photovoltaic cells that convert solar energy into electricity. In Earth’s crust, selenium is found as selenide minerals, selenate and selenite salts, and as substitution for sulfur in sulfide minerals. It is the sulfide minerals, most commonly those in porphyry copper deposits, that provide the bulk of the selenium produced for the international commodity market. Selenium is obtained as a byproduct of copper refining and recovered from the anode slimes generated in electrolytic production of copper. Because of this, the countries that have the largest resources and (or) reserves of copper also have the largest resources and (or) reserves of selenium. Because selenium occurs naturally in Earth’s crust, its presence in air, water, and soil results from both geologic reactions and human activity. Selenium is found concentrated naturally in soils that overlie bedrock with high selenium concentrations. Selenium mining, processing, use in industrial and agricultural applications, and disposal may all contribute selenium to the environment. A well-known case of selenium contamination from agricultural practices was discovered in 1983 in the Kesterson National Wildlife Refuge in California. There, waters draining from agricultural fields created wetlands with high concentrations of dissolved selenium in the water. The selenium was taken up by aquatic wildlife and caused massive numbers of embryonic deformities and deaths. Regulatory agencies have since worked to safeguard ecological and human health by creating environmental exposure guidelines based upon selenium concentrations in water and in fish tissue. Any attempt to regulate selenium concentrations requires a delicate balance because selenium occurs naturally and is also a vital nutrient for the health of wildlife, domestic stock, and humans. Selenium is commonly added as a vitamin to animal feed, and in some regions of the United States and the world, it is added as an amendment to soils for uptake by agricultural crops. The important role of selenium in economic products, energy supply, agriculture, and health will continue for well into the future. The challenge to society is to balance the benefits of selenium use with the environmental consequences of its extraction. Increased understanding of the elemental cycle of selenium in the earth may lead to new (or unconventional) sources of selenium, the discovery of new methods of extraction, and new technologies for minimizing the transfer of selenium from rock to biota, so to protect environmental and human health.

Professional Paper↗
USGS2016

Geometric quality assessment of lidar data based on swath overlap

This paper provides guidelines on quantifying the relative horizontal and vertical errors observed between conjugate features in the overlapping regions of lidar data. The quantification of these errors is important because their presence quantifies the geometric quality of the data. A data set can be said to have good geometric quality if measurements of identical features, regardless of their position or orientation, yield identical results. Good geometric quality indicates that the data are produced using sensor models that are working as they are mathematically designed, and data acquisition processes are not introducing any unforeseen distortion in the data. High geometric quality also leads to high geolocation accuracy of the data when the data acquisition process includes coupling the sensor with geopositioning systems. Current specifications (e.g. Heidemann 2014) do not provide adequate means to quantitatively measure these errors, even though they are required to be reported. Current accuracy measurement and reporting practices followed in the industry and as recommended by data specification documents also potentially underestimate the inter-swath errors, including the presence of systematic errors in lidar data. Hence they pose a risk to the user in terms of data acceptance (i.e. a higher potential for Type II error indicating risk of accepting potentially unsuitable data). For example, if the overlap area is too small or if the sampled locations are close to the center of overlap, or if the errors are sampled in flat regions when there are residual pitch errors in the data, the resultant Root Mean Square Differences (RMSD) can still be small. To avoid this, the following are suggested to be used as criteria for defining the inter-swath quality of data: a) Median Discrepancy Angle b) Mean and RMSD of Horizontal Errors using DQM measured on sloping surfaces c) RMSD for sampled locations from flat areas (defined as areas with less than 5 degrees of slope) It is suggested that 4000-5000 points are uniformly sampled in the overlapping regions of the point cloud, and depending on the surface roughness, to measure the discrepancy between swaths. Care must be taken to sample only areas of single return points only. Point-to-Plane distance based data quality measures are determined for each sample point. These measurements are used to determine the above mentioned parameters. This paper details the measurements and analysis of measurements required to determine these metrics, i.e. Discrepancy Angle, Mean and RMSD of errors in flat regions and horizontal errors obtained using measurements extracted from sloping regions (slope greater than 10 degrees). The research is a result of an ad-hoc joint working group of the US Geological Survey and the American Society for Photogrammetry and Remote Sensing (ASPRS) Airborne Lidar Committee.

Conference Paper↗
USGS1996

An examination of organic/carbonate-bound metals in bottom sediments of Bayou Trepagnier, Louisiana

To assess potential impact of metals on the biosphere in bottom sediments, forms were determined for selected metals in a southeastern Louisiana bayou, Bayou (B.) Trepagnier, which has been impacted by industrial activity at its head by a manufacturing complex (MC). Ten pairs of cores along the length of the bayou allowed variation with distance to be studied. Sequential extractions provided data on five chemical partitioning phases for subsamples from each of the cores. Results show that, beyond the mineral residue phase (phase 6 of the extractions) the organic/carbonate phase (phase 4 of the extractions) generally contains the highest concentrations of metals. This paper focuses on phase 4. In addition, metals in phase 4 show significant downstream gradients, though concentrations towards the mouth do not generally appear to differ significantly from those at a control site outside of the bayou. Data were also examined for interrelationships, and high correlation coefficients were the impetus for moving to a multivariate statistical method, polytopic vector analysis (PVA). Six end-members (EMs) were produced. EMs 2, 5, and 6 have high relative proportions of anthropogenic metals and are observed in highest proportions upstream, near the MC. These EMs may reflect industrial input from the MC. EM 3 contains significant calcium, magnesium, and manganese, with minor amounts of lead and barium, and is related to input from nearby Lake Ponchartrain since it increases in weight downstream. EMs 1 and 4 are composed of components commonly found in detrital minerals (e.g., iron, aluminum, magnesium, manganese, and silicon) and are probably not the product of anthropogenic influence. For anthropogenically-weighted end-members (EMs 2, 5, and 6) there appears to be little difference between weights at the mouth of the bayou and weights at the control site outside the bayou.

Louisiana↗
USGS2010

Western Mineral and Environmental Resources Science Center--providing comprehensive earth science for complex societal issues

Minerals in the environment and products manufactured from mineral materials are all around us and we use and come into contact with them every day. They impact our way of life and the health of all that lives. Minerals are critical to the Nation's economy and knowing where future mineral resources will come from is important for sustaining the Nation's economy and national security. The U.S. Geological Survey (USGS) Mineral Resources Program (MRP) provides scientific information for objective resource assessments and unbiased research results on mineral resource potential, production and consumption statistics, as well as environmental consequences of mining. The MRP conducts this research to provide information needed for land planners and decisionmakers about where mineral commodities are known and suspected in the earth's crust and about the environmental consequences of extracting those commodities. As part of the MRP scientists of the Western Mineral and Environmental Resources Science Center (WMERSC or 'Center' herein) coordinate the development of national, geologic, geochemical, geophysical, and mineral-resource databases and the migration of existing databases to standard models and formats that are available to both internal and external users. The unique expertise developed by Center scientists over many decades in response to mineral-resource-related issues is now in great demand to support applications such as public health research and remediation of environmental hazards that result from mining and mining-related activities. Western Mineral and Environmental Resources Science Center Results of WMERSC research provide timely and unbiased analyses of minerals and inorganic materials to (1) improve stewardship of public lands and resources; (2) support national and international economic and security policies; (3) sustain prosperity and improve our quality of life; and (4) protect and improve public health, safety, and environmental quality. The MRP supports approximately 40 USGS research specialists who utilize cooperative agreements with universities, industry, and other governmental agencies to support their collaborative research and information exchange. Scientists of the WMERSC study how and where non-fuel mineral resources form and are concentrated in the earth's crust, where mineral resources might be found in the future, and how mineral materials interact with the environment to affect human and ecosystem health. Natural systems (ecosystems) are complex - our understanding of how ecosystems operate requires collecting and synthesizing large amounts of geologic, geochemical, biologic, hydrologic, and meteorological information. Scientists in the Center strive to understand the interplay of various processes and how they affect the structure, composition, and health of ecosystems. Such understanding, which is then summarized in publicly available reports, is used to address and solve a wide variety of issues that are important to society and the economy. WMERSC scientists have extensive national and international experience in these scientific specialties and capabilities - they have collaborated with many Federal, State, and local agencies; with various private sector organizations; as well as with foreign countries and organizations. Nearly every scientific and societal challenge requires a different combination of scientific skills and capabilities. With their breadth of scientific specialties and capabilities, the scientists of the WMERSC can provide scientifically sound approaches to a wide range of societal challenges and issues. The following sections describe examples of important issues that have been addressed by scientists in the Center, the methods employed, and the relevant conclusions. New directions are inevitable as societal needs change over time. Scientists of the WMERSC have a diverse set of skills and capabilities and are proficient in the collection and integration of

Circular↗
USGS1999

Seismic and tsunami hazard in Puerto Rico and the Virgin Islands

Executive Summary Puerto Rico and the Virgin Islands are located at an active plate boundary between the North American plate and the northeast corner of the Caribbean plate. The region was subject in historical times to large magnitude earthquakes and devastating tsunamis. A major downward tilt of the sea floor north of Puerto Rico and the Virgin Islands, large submarine rockslides, and an unusually large negative gravity anomaly are also indicative of a tectonically active region. Scientists have so far failed to explain the deformation of this region in a coherent and predictable picture, such as in California, and this has hampered their ability to assess seismic and tsunami hazards in the region. The NE corner of the Caribbean is unique among the seismically-active regions of the United States in that it is mostly covered by water. This fact presents an additional challenge for seismic and tsunami hazard assessment and mitigation. The workshop, convened in San Juan on March 23-24, 1999, was "historic" in that it brought together for the first time a broad spectrum of scientists, engineers, and public and private sector officials who deal with such diverse questions as tectonic models, probabilistic assessment of seismic hazard, prediction of tsunami runup, strong ground motion, building codes, stability of man-made structures, and the public’s preparedness for natural disasters. It was an opportunity for all the participants to find out how their own activity fit into the broad picture of science and how it aids society in hazard assessment and mitigation. In addition, the workshop was offered as a continuing education course at the Colegio de Ingenieros y Agrimensores de Puerto Rico, which assured a rapid dissemination of the results to the local community. A news conference which took place during the workshop alerted the public to the efforts of the USGS, other Federal agencies, the Commonwealth of Puerto Rico, universities and the private sector. During the first day of the workshop, participants from universities, federal institutions, and consulting firms in Puerto Rico, the Virgin Islands, the continental U.S., Dominican Republic, and Europe reviewed the present state of knowledge including a review and discussion of present plate models, recent GPS and seismic reflection data, seismicity, paleoseismology, and tsunamis. The state of earthquake/tsunami studies in Puerto Rico was presented by several faculty members from the University of Puerto Rico at Mayaguez. A preliminary seismic hazard map was presented by the USGS and previous hazard maps and economic loss assessments were considered. During the second day, the participants divided into working groups and prepared specific recommendations for future activities in the region along the six following topics below. Highlights of these recommended activities are: Marine geology and geophysics – Acquire deep-penetration seismic reflection and refraction data, deploy temporary ocean bottom seismometer arrays to record earthquakes, collect high-resolution multibeam bathymetry and side scan sonar data of the region, and in particular, the near shore region, and conduct focussed high-resolution seismic studies around faults. Determine slip rates of specific offshore faults. Assemble a GIS database for available marine geological and geophysical data. Paleoseismology and active faults - Field reconnaissance aimed at identifying Quaternary faults and determining their paleoseismic chronology and slip rates, as well as identifying and dating paleoliquefaction features from large earthquakes. Quaternary mapping of marine terraces, fluvial terraces and basins, beach ridges, etc., to establish framework for understanding neotectonic deformation of the island. Interpretation of aerial photography to identify possible Quaternary faults. Earthquake seismology – Determine an empirical seismic attenuation function using observations from local seismic networks and recently-installed broad-band stations. Evaluate existing earthquake catalogs from local networks and regional stations, complete the catalogs. Transcribe the pre-1991 network data from 9-track tape onto more stable archival media. Calibrate instruments of local networks. Use GPS measurement to constrain deformation rates used in seismic-hazard maps. Engineering – Prepare liquefaction susceptibility maps for the urban areas. Update and improve databases for types of site conditions. Collect site effect observations and near-surface geophysical measurements for future local (urban-area) hazard maps. Expand the number of instruments in the strong motion program. Develop fragility curves for Puerto Rico construction types and details, and carry out laboratory testing on selected types of mass-produced construction. Consider tsunami design in shoreline construction projects. Tsunami hazard - Extract tsunami observations from archives and develop a Caribbean historical tsunami database. Analyze prehistoric tsunami deposits. Collect accurate, up-to-date, near-shore topography and bathymetry for accurate inundation models. Prepare tsunami flooding and evacuation maps. Establish a Caribbean Tsunami Warning System for Puerto Rico and the Virgin Islands. Evaluate local, regional, national, and global seismic networks and equipment, and their role in a tsunami warning system. Societal concerns – Prepare warning messages, protocols, and evacuation routes for earthquake, tsunami, and landslide hazards for Puerto Rico and the U.S. Virgin Islands. Advocate enforcement of existing building codes. Prepare non-technical hazard assessment maps for political and educational uses. Raise the awareness of potentially affected populations by presentations at elementary schools, by the production of a tsunami video, and by distribution of earthquake preparedness manuals in newspaper supplements. Promote partnerships at state and federal level for long-term earthquake and tsunami hazard mitigation. This partnership should also include the private sector such as the insurance industry, telecommunication companies, and the engineering community. The following reports of the various working groups are the cumulative recommendations of the community of scientists, engineers, and public officials, who participated in the workshop. The list of participants and the workshop’s agenda are given in the appendix. Marine and Geology and Geophysics Working Group Paleoseismology and Active Faults Working Group Joint Working Group for Earthquake Seismology and Engineering Tsunami Working Group Societal Concerns Working Group

Puerto Rico and the Virgin Islands↗