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At least 235 records · Page 13Linked to original sources
USGS2008

Seasonal survival of radiomarked emperor geese in western Alaska

The population of emperor geese ( Chen canagica ) in western Alaska, USA, declined by >50% from the 1960s to the mid‐1980s and has increased only slightly since. Rates of population increase among arctic geese are especially sensitive to changes in adult survival. Improving adult survival in seasons or geographic areas where survival is low may be the best means of increasing the emperor goose population. We monitored fates of 133 adult female emperor geese that were radiomarked with surgically implanted very high frequency or satellite radiotransmitters from 1999 to 2004 to assess whether monthly survival varied among years, seasons, or geographic areas. Because of uncertainties in determining whether a bird had died based on the radio signal, we analyzed 2 versions of the data. One version used conservative criteria to identify which birds had died based on radio signals and the other used more liberal criteria. In the conservative version of the data we detected 12 mortalities of emperor geese, whereas in the liberal interpretation there were 18 mortalities. In both versions, the models with greatest support indicated that monthly survival varied seasonally and that compared to most seasons estimated monthly survival was lower (φ = 0.95–0.98) in May and August when emperor geese were mainly on the Yukon‐Kuskokwim Delta. From 44% to 47% of annual mortality occurred in those months. Estimated monthly survival was higher (φ = 0.98–1.0) from September through March when emperor geese were at autumn staging or wintering areas and in June and July when birds were nesting, rearing broods, or molting. Estimated annual survival was 0.85 (95% CI = 0.77–0.92) in the best‐supported model when we used conservative criteria to identify mortalities and 0.79 (95% CI = 0.74–0.85) under the best model using liberal mortality criteria. Lower survival in August and May corresponded to periods when subsistence harvest of emperor geese was likely highest. Managers may be able to most effectively influence population growth rate of emperor geese by reducing subsistence harvest on the Yukon‐Kuskokwim Delta in May and August.

Alaska↗
USGS2002

U.S. Geological Survey Activities Related to American Indians and Alaska Natives Fiscal Year 2002

Information is a resource for Native American governments, communities, organizations, and people. The U.S. Geological Survey (USGS) provides technical expertise, reports, and other impartial information sources that benefit Native Americans interested in subsistence issues, water, land use, and the health of many parts of the environment. Native self-sufficiency, economic development, and conservation are cultivated through Native decisions informed with USGS data and analyses. The USGS works in cooperation with American Indian and Alaska Native governments, conducting research on water and mineral resources, animals and plants of environmental, economic, or subsistence importance, natural hazards, and geologic resources. Digital data on cartography, mineral resources, streamflow, biota, and other topics are available to American Indian and Alaska Native individuals and institutions. The USGS recognizes the need to learn from and share knowledge with Native peoples. This report describes most of the activities that the USGS conducted with American Indian and Alaska Native governments, educational institutions, and individuals during Federal Fiscal Year 2002. Some of these USGS activities were carried out in concert with the Bureau of Indian Affairs (BIA). Others were conducted by Tribes, Tribal organizations, professional societies, and the USGS. A growing number of Tribal governments, educational institutions, and other Tribal organizations have begun using geographic information systems and other digital technologies in recent years. As Tribes become more interested in and more adept at managing digital information, they are seeking relevant data from the USGS more frequently. Using digital technologies provides Tribal governments with additional means of managing lands and resources for the benefit of current and future generations. The USGS recognizes the need to make its information available to Tribal governments, and to work with those governments and other institutions to advance data management capabilities. The USGS also recognizes that Tribal institutions have varying needs, interests, and capacities. The USGS strives to be sensitive to the unique circumstances of each of these institutions while supporting their self-driven evolution. The USGS is responding to these needs by increasing the transfer of scientific information to American Indian and Alaska Native governments and by training employees of those governments to conduct scientific studies and improve scientific data management. The USGS is also encouraging American Indians and Alaska Natives to pursue careers in science and seeking ways to hire Indian and Native students. By identifying, improving, and disseminating information about available hiring mechanisms, the USGS is working to make hiring such students easier, and, therefore, more likely, for USGS managers. The U.S. Geological Survey is the Federal science bureau within the Department of the Interior (DoI). The USGS is non-regulatory and is not a significant manager of Federal or Trust lands or assets. However, as described in this report, there are several types of USGS activities that involve American Indians, Alaska Natives, and their lands. One type of activity is the course of formal studies, conducted through existing USGS programs, that involves collection of specific types of data as well as investigative and research projects. These projects typically last 2 or 3 years, although a few are parts of longer-term activities. Some projects are funded through cooperative agreements, from monies provided to the USGS by individual Tribal governments, or by the BIA. The USGS provides matching funds for cooperative projects. These formal projects may also receive funding from the U.S. Environmental Protection Agency, the Indian Health Service (part of the Department of Health and Human Services), or other Federal agencies. The USGS routinely works with its sister bureaus in the Department of the Interior to provide the scientific information and expertise needed to meet the Department's science priorities. Within this context, the USGS and the BIA are cooperating to use USGS information resources to benefit American Indian and Alaska Native peoples and their lands. The second type of USGS activity is less formal, based on initiatives designed and conducted by USGS employees. Frequently involving educational activities, these endeavors are prompted by employee interests, often as collateral issues, that result from one or more USGS employees identifying and responding to an observed need. In these activities, USGS employees help fulfill a mission of the USGS--to prove scientific relevance--while helping their fellow citizens. Increasingly, some of the educational activities are becoming parts of formal USGS projects. USGS employees have also taken the initiative in assisting American Indians and Alaska Natives through participation in several organizations that were created to foster awareness of science among Native peoples and to help build support and communication networks. One such group is the American Indian Science and Engineering Society (AISES). This group sponsors an annual national meeting in which USGS employees participate. USGS employees join this organization on a voluntary basis, bringing the benefits of this expanded network to the USGS, as many employees do with other professional organizations. Each part of the USGS has identified an American Indian/Alaska Native liaison. The USGS has a regional organizational structure, with Western, Central, and Eastern Regions. The regions work in concert with specific scientific disciplines to conduct the scientific mission of the USGS. The regional structure is intended to bring us closer to our customers; we hope that Native Americans and Alaska Natives will use the contacts listed at the end of this report.

Report↗
USGS1991

A comparison of aerial and boat-based surveys for marbled murrelets in southeast Alaska, July 23-28, 1991

Aerial and boat-based surveys for Marbled Murrelets ( Brachyramphus marmoratus ) were conducted simultaneously over short transect distances (ca. 2 km) in three different areas of the Alexander Archipelago to assess the accuracy and variability of aerial counts compared to boat-based counts. Additional aerial surveys were conducted over a wider geographic area to assess temporal and spatial variability of murrelet aggregations.

Alaska↗
USGS1993

Reconnaissance guidelines for gold exploration in Central Alaska

Distribution of more than 300 gold-bearing samples from the Livengood (Tolovana) and parts of the Fairbanks and Rampart mining districts in central Alaska, USA, indicate that the concentration of gold in placers is spatially related both to structural features and to Late Cretaceous and (or) Tertiary felsic plutons. The regional consistency of these spatial relationships is demonstrated by proximity analysis using a Geographic Information System (GIS), and suggests a genetic association between faults, felsic plutons, and gold occurrences. The local presence of gold within several of the plutons indicates that these are the source of some of the gold. In addition, some gold occurs proximal to faults where plutons are not present, suggesting that some of the gold was also derived from the country rock. We envision a model whereby weakly mineralized solutions, thermally driven by latent plutonic heat, were enriched by circulation through clastic units that may have had a naturally elevated gold background. The resultant enriched solutions were channeled and reconcentrated along or adjacent to large-scale fault systems. Future exploration to define individual target areas should be directed toward areas where Late Cretaceous and (or) Tertiary felsic plutons occur near major faults. ?? 1993.

Journal of Geochemical Exploration↗
USGS2016

Biogeography of boreal passerine range dynamics in western North America: past, present, and future

Many of the Neotropical migrant bird species that breed throughout the Canadian boreal region are not found in the Alaskan boreal region, separated by the northwestern cordilleran mountains, despite the presence of climatically suitable habitat. We asked whether biological or climatic factors constrain certain species from crossing this geographic barrier. Analyzing a comprehensive dataset for 80 boreal passerine species, we used phylogenetic logistic regression to evaluate the relative importance of physical, migratory and competition metrics versus current and paleoclimatic suitability factors. Controlling for current climatic suitability within boreal Alaska, we found that species with the greatest climatic suitability across the northwestern cordillera, presently and also during the mid-Holocene period, were most likely to be regular breeders in the Alaskan boreal region. Migratory strategy also played a role, but could not be disentangled from its strong phylogenetic basis. Our analysis suggests that the perceived barrier of the northwestern cordillera may be easily weakened as climate change improves conditions there for many forest species. The weakening of this barrier may lead to relatively rapid range expansions and the reshuffling of species communities. Species’ realized distributional shifts will be a function of the interplay between a changing climate and static topographic features.

Ecography: Pattern and Diversity in Ecology↗
USGS2008

NOAA/West Coast and Alaska Tsunami Warning Center Pacific Ocean response criteria

New West Coast/Alaska Tsunami Warning Center (WCATWC) response criteria for earthquakes occurring in the Pacific basin are presented. Initial warning decisions are based on earthquake location, magnitude, depth, and - dependent on magnitude - either distance from source or precomputed threat estimates generated from tsunami models. The new criteria will help limit the geographical extent of warnings and advisories to threatened regions, and complement the new operational tsunami product suite. Changes to the previous criteria include: adding hypocentral depth dependence, reducing geographical warning extent for the lower magnitude ranges, setting special criteria for areas not well-connected to the open ocean, basing warning extent on pre-computed threat levels versus tsunami travel time for very large events, including the new advisory product, using the advisory product for far-offshore events in the lower magnitude ranges, and specifying distances from the coast for on-shore events which may be tsunamigenic. This report sets a baseline for response criteria used by the WCATWC considering its processing and observational data capabilities as well as its organizational requirements. Criteria are set for tsunamis generated by earthquakes, which are by far the main cause of tsunami generation (either directly through sea floor displacement or indirectly by triggering of slumps). As further research and development provides better tsunami source definition, observational data streams, and improved analysis tools, the criteria will continue to adjust. Future lines of research and development capable of providing operational tsunami warning centers with better tools are discussed.

Science of Tsunami Hazards↗
USGS1979

New host and geographical records for the leech Acanthobdella peledina Grube 1851 (Hirudinea, Acanthobdellidae)

A total of four leeches (Acanthobdella peledina), parasitizing four specimens of the least cisco (Coregonus sardinella), were found during July and August 1977. The hosts and parasites were collected during a fishery survey by the U.S. Fish and Wildlife Service in the North Slope waters of Naval Petroleum Reserve, Alaska. Two host fishes were collected from the Chipp River (70035' latitude, 155012' longitude) and two from an unnamed, landlocked lake (69054' latitude, 153o23' longitude). The Chipp River collection site is about 130 km southeast of Barrow, and the unnamed lake about 200 km southeast of Barrow. The leeches, which were fixed in situ with neutral formalin, appeared to have penetrated the integument and were embedded in subcutaneous tissues and white muscle at the base of the pelvic fins. The specimens were cylindrical and about 23 mm long and 2-3 mm wide. Color before fixation was olive-green. The five anterior segments each had four pairs of hooked setae at the ventral surface. Our identification was based on a description in Bykhovskaya-Pavlovskaya et al., 1962, Key to parasites of freshwater fish of the USSR (Transl. from Russian), NTIS TT-64-11040.

Journal of Parasitology↗
USGS2017

Assessing the risk of non-native marine species in the Bering Sea

Invasive species are one of the leading global conservation concerns, which can have strong, negative impacts on ecosystems, vulnerable species, and valuable natural resources. Arctic regions have experienced a relatively low number of biological introductions to date. Their geographical remoteness, cold waters, and presence of sea ice present challenging conditions for both non-native organisms and the vessels that transport them, presumably leading to low rates of introduction and establishment. However, observed increases in water temperatures reductions in sea ice, and projected increases in shipping traffic are expected to render arctic marine regions more susceptible to the arrival and colonization of marine invasives. Risk assessments for these Arctic regions are important to inform management and monitoring priorities by determining which species pose the greatest risk. To this end, we developed a ranking system for non-native marine species and used this system to assess the risk of non-native species to the Bering Sea. Using species’ published physiological tolerances, we mapped habitat suitability under current and future climate scenarios to identify geographic areas of current and future concern. In addition, we described shipping traffic from commercial and fishing vessels to identify ports of entry for non-native species. Collectively, these analyses identify which marine species have the greatest risk for invasion, where in the Bering Sea invasion risk and species establishment is greatest, and which ports are most likely to serve as an entry point for marine invasives into Alaska’s Bering Sea. The ranking system we developed for non-native marine species consists of 33 questions grouped into five categories. The first four categories evaluate a species’ ability to arrive and establish in the Bering Sea, its reliance on humans for introductions, its biology, and its impacts on ecological and human systems. The fifth category is not included in the total ranking score, but provides information on management considerations. The ranking system has methods to account for data deficiencies and calculates these deficiencies to allow readers to weigh the lack of knowledge with the ranking score. We prioritized non-native species for ranking based on their geographic proximity to the Bering Sea. We evaluated 46 species and ranking scores ranged from 29.1 to 74.3 (out of a possible 100), with highest scores indicating greatest risk. Taxonomy at the level of phylum did not explain variation in ranking values, likely due to the substantial biological variation relative to our ranking criteria among members of the same phylum. To investigate where non-native species may survive and persist in the Bering Sea, we compared species’ temperature and salinity thresholds to environmental conditions of the Bering Sea. Environmental conditions were obtained from three Regional Ocean Modeling Systems (ROMS) and investigated under two time periods: current (2003-2012) and mid-century (2030-2039). We identified potential habitat for survival for 42 species, and potential habitat for reproduction for 29 species. Under current conditions, all species had temperature and salinity thresholds that would allow survival in the Bering Sea for at least part of the year, and most species (79% to 83%) had thresholds that would allow for survival year-round. For species with temperature and salinity thresholds unsuitable for survival in the Bering Sea, winter temperatures appear to be the limiting factor. Most species had six to nine weeks of suitable conditions for reproduction. Future increases in water temperatures are expected to open more habitat for marine invasives. Two of the three ROMs project an increase in the number of non-native species that would be able to survive year-round by mid-century. Moreover, models project between 37% and 60% of the Bering Sea shelf habitat to become more suitable under mid-century climate condition.

Alaska↗
USGS2002

U.S. Geological Survey 2002 petroleum resource assessment of the National Petroleum Reserve in Alaska (NPRA): play maps and technically recoverable resource estimates

This report provides a summary of the estimated volume of technically recoverable undiscovered oil and nonassociated gas resources for each of the 24 plays evaluated in the U.S. Geological Survey 2002 petroleum resource assessment of the NPRA (Bird and Houseknecht, 2002). It also provides a set of illustrations showing the stratigraphic and geographic location of each play. Additional details of this assessment will follow in later publications.

Alaska↗
USGS1995

Increasing frequency of plastic particles ingested by seabirds in the subarctic North Pacific

We examined gut contents of 1799 seabirds comprising 24 species collected in 1988-1990 to assess the types and quantities of plastic particles ingested by seabirds in the subarctic waters of Alaska. Of the 15 species found to ingest plastic, most were surface-feeders (shearwaters, petrels, gulls) or plankton-feeding divers (auklets, puffins). Of 4417 plastic particles examined, 76% were industrial pellets and 21% were fragments of ‘user’ plastic. Ingestion rates varied geographically, but no trends were evident and rates of plastic ingestion varied far more among species within areas than within species among areas. Comparison with similar data from 1968 seabirds comprising 37 species collected in 1969-1977 revealed that plastic ingestion by seabirds has increased significantly during the 10–15-year interval between studies. This was demonstrated by: (i) an increase in the total number of species ingesting plastic; (ii) an increase in the frequency of occurrence of plastic particles within species that ingested plastic; and, (iii) an increase in the mean number of plastic particles ingested by individuals of those species.

Marine Pollution Bulletin↗
USGS2012

High shrew diversity on Alaska's Seward Peninsula: Community assembly and environmental change

In September 2010, 6 species of shrews (genus: Sorex ) were collected at a single locality on the Seward Peninsula of Alaska. Such high sympatric diversity within a single mammalian genus is seldom realized. This phenomenon at high latitudes highlights complex Arctic community dynamics that reflect significant turnover through time as a consequence of environmental change. Each of these shrew species occupies a broad geographic distribution collectively spanning the entire Holarctic, although the study site lies within Eastern Beringia, near the periphery of all individual ranges. A review of published genetic evidence reflects a depauperate shrew community within ice-free Beringia through the last glaciation, and recent assembly of current diversity during the Holocene.

Alaska↗
USGS1993

Catalog of earthquake hypocenters at Redoubt Volcano and Mt. Spurr, Alaska: October 12, 1989 - December 31, 1990

The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute of the University of Alaska, Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, began a program of seismic monitoring at potentially active volcanoes in the Cook Inlet region in 1988. Seismic monitoring of this area was previously accomplished by two independent seismic networks operated by the U.S. Geological Survey (Northern Cook Inlet) and the Geophysical Institute (Southern Cook Inlet). In 1989 the AVO seismic program consisted of three small-aperture networks of six, five, and six stations on Mt. Spurr, Redoubt Volcano, and Augustine Volcano respectively. Thirty-five other stations were operated in the Cook Inlet region as part of the AVO program. During 1990 six additional stations were added to the Redoubt network in response to eruptive activity, and three stations were installed at Iliamna Volcano. The principal objectives of the AVO program have been the seismic surveillance of the Cook Inlet volcanoes and the investigation of seismic processes associated with active volcanism. The locations of seismograph stations operated by AVO between 1988 and 1990 are shown in Figure 1. Geographic coordinates, elevations, and the installation date of each of the stations are contained in Appendix A. Signals from each of the stations are telemetered to Fairbanks, where recording and analysis take place. Data is recorded digitally in event-detection mode on a PC/AT system and continuously and in event-detection mode on a Masscomp system (Alaska Volcano Observatory Staff, 1990). The two event-detection systems employ different triggering parameters, with the PC/AT system having greater sensitivity for events in close proximity to the volcanoes. Data is also recorded on Helicorders, a Real-time Seismic Amplitude Measurement (RSAM) system (Murray and Endo, 1989; Endo and Murray, 1991), and a Seismic Spectral Amplitude Measurement (SSAM) system (Stephens and others, in press). A description of the various components of the computer systems, their networking, and associated software is given by March and Power (1990). Following a 23 year period of quiescence, Redoubt Volcano erupted between December 14,1989 and April 21,1990. The eruption was accompanied by thousands of earthquakes (Alaska Volcano Observatory Staff, 1990). Throughout the eruption sequence, data from the PC/AT system provided the primary means of determining earthquake hypocenters. This report catalogs the earthquake hypocenters and magnitudes calculated from data collected between October 12, 1989 and December 31, 1990 on the PC/AT acquisition system, provides station locations, statistics, and calibrations, and outlines which stations were recorded and used in triggering the PC/AT system.

Alaska↗
USGS2000

U.S. Geological Survey Activities Related to American Indians and Alaska Natives Fiscal Year 2000

The U.S. Geological Survey (USGS) is an impartial scientific organization that strives to produce scientific results that are relevant to the people of the United States and their land and resource managers. USGS does not improve the quality of its customers' lives; it provides the informational tools for American Indians, Alaska Natives, and other customers to understand and improve their own lives. In cooperation with American Indian and Alaska Native governments, the USGS conducts research on water and mineral resources, animals and plants of environmental, economic, or subsistence importance, natural hazards, and geologic resources. Digital data on cartography, mineral resources, stream flows, biota, and other data sets are available to American Indian and Alaska Native institutions. The USGS recognizes the need to learn from and share knowledge with Native peoples. This report describes most of the activities that the USGS conducted with American Indian and Alaska Native governments, educational institutions, and individuals during Federal Fiscal Year 2000. Some of these USGS activities were conducted in concert with the Bureau of Indian Affairs. Others were conducted by Tribes and the USGS. In the year 2000, the USGS began examining its activities related to American Indians and Native Alaskans to determine how it can better serve these customers within its mandates. More Tribal governments, educational institutions, and other Tribal organizations are using geographic information systems and other digital technologies in recent years. As Tribes become more interested and more adept at managing digital information, they are seeking such data from the USGS with greater frequency. The increasing use of such technologies allows Tribal governments additional means of managing lands and resources for the benefit of current and future generations. The USGS recognizes the need to make its information available to Tribal governments, and to work with those governments and other institutions to advance data management capabilities. The USGS is responding to this need by increasing the transfer of scientific information to American Indian and Alaska Native governments and by training employees of these governments to conduct and improve scientific studies. The USGS is also encouraging American Indians and Alaska Natives to pursue careers in science, and seeking ways to hire Indian and Native students. By identifying, improving, and disseminating information about available hiring mechanisms, the USGS is working to make hiring such students easier, and therefore more likely, for USGS managers. The U.S. Geological Survey is the Federal science bureau within the Department of the Interior (DoI). The USGS is non-regulatory and is not a significant manager of Federal or Trust lands or assets. However, there are two types of USGS activities that do involve American Indians, Alaska Natives, and their lands. The first type of activity is the course of formal studies, conducted through existing USGS programs, that involve collection of specific types of data as well as investigative and research projects. These projects have a duration of two or three years, although a few are parts of longer-term activities. Some are funded through cooperative agreements or reimbursable accounts, from monies provided to the USGS by individual Tribal governments or by the Bureau of Indian Affairs (BIA). The USGS provides matching funds for cooperative projects. These formal projects may also receive funding from the U.S. Environmental Protection Agency, the Indian Health Service (part of the Department of Health and Human Services), or other Federal agencies. The USGS routinely works with its sister bureaus in the Department of the Interior to provide the scientific information and expertise needed to meet the Department's science priorities. Within this context, the USGS and the Bureau of Indian Affairs are cooperating to use USGS knowledge for the benefit of American Indian and Native peoples and their lands. The second type of USGS activity is less formal, based on initiatives designed and conducted by USGS employees. Frequently involving educational activities, these endeavors are prompted by employee interests, often as collateral issues, that result from an individual or group of USGS employees identifying and responding to an observed need. In these activities, USGS employees help us fulfill a mission of the USGS, to make science relevant, while helping their fellow citizens. USGS employees have also taken the initiative to assist American Indians and Alaska Natives through participation in several organizations that were created to foster knowledge of science among Native peoples and to help build support and communication networks. One such group is the American Indian Science and Engineering Society (AISES). This group sponsors an annual national meeting in which USGS employees participate. USGS employees join this organization on a voluntary basis, paying the costs themselves, yet bringing the benefits of this expanded network to the USGS, as many employees do with other professional organizations. Each part of the USGS has identified an American Indian/Alaska Native liaison. As USGS moves to a more regional organizational structure, it will establish contacts in the Western, Central, and Eastern Regions. Within the USGS, this report will help in developing outreach, educational, and program documents for use in future years. It is hoped that USGS employees, American Indians, and Alaska Natives will adapt these activities in new areas and will use the USGS contacts to expand the relevance of the USGS to more Americans.

Report↗
USGS2005

Argon geochronology of late Pleistocene to Holocene Westdahl volcano, Unimak Island, Alaska

High-precision 40Ar/39Ar geochronology of selected lavas from Westdahl Volcano places time constraints on several key prehistoric eruptive phases of this large active volcano. A dike cutting old pyroclastic-flow and associated lahar deposits from a precursor volcano yields an age of 1,654+/-11 k.y., dating this precursor volcano as older than early Pleistocene. A total of 11 geographically distributed lavas with ages ranging from 47+/-14 to 127+/-2 k.y. date construction of the Westdahl volcanic center. Lava flows cut by an apparent caldera-rim structure yielded ages of 81+/-5 and 121+/-8 k.y., placing a maximum date of 81 ka on caldera formation. Late Pleistocene and Holocene lavas fill the caldera, but most of them are obscured by the large summit icecap.

Alaska↗
USGS2009

NOAA/West coast and Alaska Tsunami warning center Atlantic Ocean response criteria

West Coast/Alaska Tsunami Warning Center (WCATWC) response criteria for earthquakesoccurring in the Atlantic and Caribbean basins are presented. Initial warning center decisions are based on an earthquake's location, magnitude, depth, distance from coastal locations, and precomputed threat estimates based on tsunami models computed from similar events. The new criteria will help limit the geographical extent of warnings and advisories to threatened regions, and complement the new operational tsunami product suite. Criteria are set for tsunamis generated by earthquakes, which are by far the main cause of tsunami generation (either directly through sea floor displacement or indirectly by triggering of sub-sea landslides).The new criteria require development of a threat data base which sets warning or advisory zones based on location, magnitude, and pre-computed tsunami models. The models determine coastal tsunami amplitudes based on likely tsunami source parameters for a given event. Based on the computed amplitude, warning and advisory zones are pre-set.

Science of Tsunami Hazards↗
USGS1990

Procedures and rationale for marking sea otters captured and treated during the T/V Exxon Valdez oil spill

Four methods were used for marking sea otters ( Enhydra lutris ) captured and treated during the response to the T/V Exxon Valdez oil spill. Colored and numbered flipper tags were placed on each sea otter that was brought to the otter treatment centers. These tags allowed individual recognition and permitted the tracking of individuals through the treatment and holding processes. Recovery of tagged carcasses may provide a crude measure of the fates of rehabilitated otters. Seven sea otters were instrumented with radio transmitters attached to flipper tags as part of a pilot release program. The results of that study were inconclusive. Forty-five sea otters were implanted with radio transmitters as part of a study to assess the fate of rehabilitated sea otters. Specific objectives of the study include estimating survived rates and monitoring the reproductive success of the sample of rehabilitated sea otters and comparing the results with similar variables in a control population. Transponder chips were injected in the perianal region of all but seven of the instrumented sea otters, and all were tagged with red flipper tags. The advantages and disadvantages of each type of tag are discussed.

Alaska↗
USGS2011

U.S. Geological Survey circum-arctic resource appraisal

Among the greatest uncertainties in future energy supply is the amount of oil and gas yet to be found in the Arctic. Using a probabilistic geology-based methodology, the U.S. Geological Survey has assessed the area north of the Arctic Circle. The Circum-Arctic Resource Appraisal (CARA) consists of three parts: (1) Mapping the sedimentary sequences of the Arctic (Grantz and others 2009), (2) Geologically based estimation of undiscovered technically recoverable petroleum (Gautier and others 2009, discussed in this presentation) and (3) Economic appraisal of the cost of delivering the undiscovered resources to major markets (also reported at this conference by White and others). We estimate that about 30% of the world's undiscovered gas and about 13% of the world's undiscovered oil may be present in the Arctic, mostly offshore under less than 500m of water. Billion BOE-plus accumulations of gas and oil are predicted at a 50% probability in the Kara Sea, Barents Sea, offshore East and West Greenland, Canada, and Alaska. On a BOE basis, undiscovered natural gas is three times more abundant than oil in the Arctic and is concentrated in Russian territory. Oil resources, while critically important to the interests of Arctic countries, are probably not sufficient to significantly shift the current geographic patterns of world oil production. Copyright 2011, Offshore Technology Conference.

Conference Paper↗
USGS2012

Database for volcanic processes and geology of Augustine Volcano, Alaska

Augustine Island (volcano) in lower Cook Inlet, Alaska, has erupted repeatedly in late-Holocene and historical times. Eruptions typically beget high-energy volcanic processes. Most notable are bouldery debris avalanches containing immense angular clasts shed from summit domes. Coarse deposits of these avalanches form much of Augustine's lower flanks. This geologic map at 1:25,000 scale depicts these deposits, these processes. This digital release contains information used to produce the geologic map published as Plate 1 in U.S. Geological Survey Professional Paper 1762 (Waitt and Begét, 2009). The main component of this digital release is a geologic map database prepared using geographic information systems (GIS) applications. This release also contains links to files to view or print the map plate, accompanying measured sections, and main report text from Professional Paper 1762. It should be noted that Augustine Volcano erupted in 2006, after the completion of the geologic mapping shown in Professional Paper 1762 and presented in this database. Information on the 2006 eruption can be found in U.S. Geological Survey Professional Paper 1769. For the most up to date information on the status of Alaska volcanoes, please refer to the U.S. Geological Survey Volcano Hazards Program website.

Alaska↗