Excitation−emission matrix (EEM) fluorescence spectroscopy has been widely used to characterize dissolved organic matter (DOM) in water and soil. However, interpreting the >10,000 wavelength-dependent fluorescence intensity data points represented in EEMs has posed a significant challenge. Fluorescence regional integration, a quantitative technique that integrates the volume beneath an EEM, was developed to analyze EEMs. EEMs were delineated into five excitation−emission regions based on fluorescence of model compounds, DOM fractions, and marine waters or freshwaters. Volumetric integration under the EEM within each region, normalized to the projected excitation−emission area within that region and dissolved organic carbon concentration, resulted in a normalized region-specific EEM volume (Φi,n). Solid-state carbon nuclear magnetic resonance (13C NMR), Fourier transform infrared (FTIR) analysis, ultraviolet−visible absorption spectra, and EEMs were obtained for standard Suwannee River fulvic acid and 15 hydrophobic or hydrophilic acid, neutral, and base DOM fractions plus nonfractionated DOM from wastewater effluents and rivers in the southwestern United States. DOM fractions fluoresced in one or more EEM regions. The highest cumulative EEM volume (ΦT,n = ΣΦi,n) was observed for hydrophobic neutral DOM fractions, followed by lower ΦT,n values for hydrophobic acid, base, and hydrophilic acid DOM fractions, respectively. An extracted wastewater biomass DOM sample contained aromatic protein- and humic-like material and was characteristic of bacterial-soluble microbial products. Aromatic carbon and the presence of specific aromatic compounds (as indicated by solid-state 13C NMR and FTIR data) resulted in EEMs that aided in differentiating wastewater effluent DOM from drinking water DOM.
The southern rim of the Isidis basin contains one of the highest densities of valley networks, several restricted paleolake basins, and the stratigraphically lowest (oldest) terrain on Mars. Geologic mapping in Viking, MGS/MOC, and MOLA data, Odyssey/THEMIS data, and other multispectral data products supports the presence of extensive fans of debris and sediments deposited along the inner rim of the Isidis basin where large valleys enter the lowlands. Additional processes subsequent to the period of intense fluvial activity, including mass flow analogous to some glacial processes, have contributed to the materials accumulated on the margins of the Isidis basin. These have occurred along preexisting channels and valleys at the termini of major channels where they enter the plains along the highland-lowland boundary. If the abundant valley networks in highland terrains are the result of runoff accompanied by saturated groundwater flow, as has been suggested in previous studies of ancient fluvial highland terrains, then the extreme age and abundance of early valley networks in the Libya Montes highland rocks should have resulted in deposition of materials that record evidence for the long-term presence of water in the form of aqueous alteration of polycrystalline constituents. The material deposited along the basin margin is likely to consist of ancient altered highland rocks in several physical states (weathered, rounded, and angular) exposing both weathered and altered surfaces, and exposures of alteration profiles in fractured faces and unweathered material from rock interiors. Debris fans shed off the southern rim of Isidis Planitia should contain materials that have experienced possible saturated groundwater flow, residence within paleolake basins, and derivative materials deposited during the most fluvially intensive part of Martian geologic history. Many of these materials have also been reworked by ice-related processes. In situ measurements of the ancient crustal materials, in the form of rocks within the debris fans, and the weathered condition of the rocky material are potential sources for mineralogical evidence of climatic conditions in earliest Martian geologic history. The absence of alteration within rocks would, on the other hand, support the hypothesis that fluvial runoff during the earliest history of Mars was geologically brief rather than long-term and that long-term saturated groundwater flow was not present. Determination of the presence or absence of alteration would have corresponding implications for hypotheses requiring the long-term presence of aqueous solutions (i.e., complex organic compounds and life). A proposed MER site along the margin addresses realistic field science objectives of the Mars Exploration Rover mission and the current goals of the Mars Exploration Program. In situ measurements may be important in deriving estimates of the longevity and intensity of past wetter climates.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/2002je002040","issn":"01480227","usgsCitation":"Crumpler, L., and Tanaka, K.L., 2003, Geology and MER target site characteristics along the southern rim of Isidis Planitia, Mars: Journal of Geophysical Research E: Planets, v. 108, no. 12, 42 p., https://doi.org/10.1029/2002je002040.","productDescription":"42 p.","costCenters":[],"links":[{"id":388269,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"108","issue":"12","noUsgsAuthors":false,"publicationDate":"2003-12-12","publicationStatus":"PW","scienceBaseUri":"505a2290e4b0c8380cd57168","contributors":{"authors":[{"text":"Crumpler, L.S.","contributorId":81575,"corporation":false,"usgs":true,"family":"Crumpler","given":"L.S.","email":"","affiliations":[],"preferred":false,"id":403533,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Tanaka, K. L.","contributorId":31394,"corporation":false,"usgs":false,"family":"Tanaka","given":"K.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":403532,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70025059,"text":"70025059 - 2003 - Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems","interactions":[],"lastModifiedDate":"2018-05-03T16:20:38","indexId":"70025059","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2317,"text":"Journal of Geophysical Research E: Planets","active":true,"publicationSubtype":{"id":10}},"title":"Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems","docAbstract":"Imaging spectroscopy is a tool that can be used to spectrally identify and spatially map materials based on their specific chemical bonds. Spectroscopic analysis requires significantly more sophistication than has been employed in conventional broadband remote sensing analysis. We describe a new system that is effective at material identification and mapping: a set of algorithms within an expert system decision‐making framework that we call Tetracorder. The expertise in the system has been derived from scientific knowledge of spectral identification. The expert system rules are implemented in a decision tree where multiple algorithms are applied to spectral analysis, additional expert rules and algorithms can be applied based on initial results, and more decisions are made until spectral analysis is complete. Because certain spectral features are indicative of specific chemical bonds in materials, the system can accurately identify and map those materials. In this paper we describe the framework of the decision making process used for spectral identification, describe specific spectral feature analysis algorithms, and give examples of what analyses and types of maps are possible with imaging spectroscopy data. We also present the expert system rules that describe which diagnostic spectral features are used in the decision making process for a set of spectra of minerals and other common materials. We demonstrate the applications of Tetracorder to identify and map surface minerals, to detect sources of acid rock drainage, and to map vegetation species, ice, melting snow, water, and water pollution, all with one set of expert system rules. Mineral mapping can aid in geologic mapping and fault detection and can provide a better understanding of weathering, mineralization, hydrothermal alteration, and other geologic processes. Environmental site assessment, such as mapping source areas of acid mine drainage, has resulted in the acceleration of site cleanup, saving millions of dollars and years in cleanup time. Imaging spectroscopy data and Tetracorder analysis can be used to study both terrestrial and planetary science problems. Imaging spectroscopy can be used to probe planetary systems, including their atmospheres, oceans, and land surfaces.
","language":"English","publisher":"AGU","doi":"10.1029/2002JE001847","issn":"01480227","usgsCitation":"Clark, R.N., Swayze, G.A., Livo, K., Kokaly, R.F., Sutley, S.J., Dalton, J.B., McDougal, R.R., and Gent, C.A., 2003, Imaging spectroscopy: Earth and planetary remote sensing with the USGS Tetracorder and expert systems: Journal of Geophysical Research E: Planets, v. 108, no. 12, p. 1-44, https://doi.org/10.1029/2002JE001847.","productDescription":"Article 5; 44 p.","startPage":"1","endPage":"44","costCenters":[{"id":35995,"text":"Geology, Geophysics, and Geochemistry Science Center","active":true,"usgs":true}],"links":[{"id":236133,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"108","issue":"12","noUsgsAuthors":false,"publicationDate":"2003-12-06","publicationStatus":"PW","scienceBaseUri":"505a3884e4b0c8380cd615cf","contributors":{"authors":[{"text":"Clark, Roger N. 0000-0002-7021-1220 rclark@usgs.gov","orcid":"https://orcid.org/0000-0002-7021-1220","contributorId":515,"corporation":false,"usgs":true,"family":"Clark","given":"Roger","email":"rclark@usgs.gov","middleInitial":"N.","affiliations":[{"id":211,"text":"Crustal Geophysics and Geochemistry Science Center","active":true,"usgs":true}],"preferred":true,"id":403639,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Swayze, Gregg A. 0000-0002-1814-7823 gswayze@usgs.gov","orcid":"https://orcid.org/0000-0002-1814-7823","contributorId":518,"corporation":false,"usgs":true,"family":"Swayze","given":"Gregg","email":"gswayze@usgs.gov","middleInitial":"A.","affiliations":[{"id":309,"text":"Geology and Geophysics Science Center","active":true,"usgs":true},{"id":211,"text":"Crustal Geophysics and Geochemistry Science Center","active":true,"usgs":true}],"preferred":true,"id":403641,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Livo, K. Eric 0000-0001-7331-8130","orcid":"https://orcid.org/0000-0001-7331-8130","contributorId":17886,"corporation":false,"usgs":true,"family":"Livo","given":"K. Eric","affiliations":[],"preferred":false,"id":403644,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kokaly, Raymond F. 0000-0003-0276-7101 raymond@usgs.gov","orcid":"https://orcid.org/0000-0003-0276-7101","contributorId":150717,"corporation":false,"usgs":true,"family":"Kokaly","given":"Raymond","email":"raymond@usgs.gov","middleInitial":"F.","affiliations":[{"id":211,"text":"Crustal Geophysics and Geochemistry Science Center","active":true,"usgs":true},{"id":171,"text":"Central Mineral and Environmental Resources Science Center","active":true,"usgs":true}],"preferred":false,"id":403643,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Sutley, Steve J.","contributorId":33774,"corporation":false,"usgs":true,"family":"Sutley","given":"Steve","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":403646,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Dalton, J. Brad","contributorId":90831,"corporation":false,"usgs":true,"family":"Dalton","given":"J.","email":"","middleInitial":"Brad","affiliations":[],"preferred":false,"id":403645,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"McDougal, Robert R. rmcdouga@usgs.gov","contributorId":1812,"corporation":false,"usgs":true,"family":"McDougal","given":"Robert","email":"rmcdouga@usgs.gov","middleInitial":"R.","affiliations":[],"preferred":false,"id":403642,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Gent, Carol A.","contributorId":40646,"corporation":false,"usgs":true,"family":"Gent","given":"Carol","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":403640,"contributorType":{"id":1,"text":"Authors"},"rank":8}]}} ,{"id":70025068,"text":"70025068 - 2003 - Application of two hydrologic models with different runoff mechanisms to a hillslope dominated watershed in the northeastern US: A comparison of HSPF and SMR","interactions":[],"lastModifiedDate":"2012-03-12T17:20:27","indexId":"70025068","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2342,"text":"Journal of Hydrology","active":true,"publicationSubtype":{"id":10}},"title":"Application of two hydrologic models with different runoff mechanisms to a hillslope dominated watershed in the northeastern US: A comparison of HSPF and SMR","docAbstract":"Differences in the simulation of hydrologic processes by watershed models directly affect the accuracy of results. Surface runoff generation can be simulated as either: (1) infiltration-excess (or Hortonian) overland flow, or (2) saturation-excess overland flow. This study compared the Hydrological Simulation Program - FORTRAN (HSPF) and the Soil Moisture Routing (SMR) models, each representing one of these mechanisms. These two models were applied to a 102 km2 watershed in the upper part of the Irondequoit Creek basin in central New York State over a seven-year simulation period. The models differed in both the complexity of simulating snowmelt and baseflow processes as well as the detail in which the geographic information was preserved by each model. Despite their differences in structure and representation of hydrologic processes, the two models simulated streamflow with almost equal accuracy. Since streamflow is an integral response and depends mainly on the watershed water balance, this was not unexpected. Model efficiency values for the seven-year simulation period were 0.67 and 0.65 for SMR and HSPF, respectively. HSPF simulated winter streamflow slightly better than SMR as a result of its complex snowmelt routine, whereas SMR simulated summer flows better than HSPF as a result of its runoff and baseflow processes. An important difference between model results was the ability to predict the spatial distribution of soil moisture content. HSPF aggregates soil moisture content, which is generally related to a specific pervious land unit across the entire watershed, whereas SMR predictions of moisture content distribution are geographically specific and matched field observations reasonably well. Important is that the saturated area was predicted well by SMR and confirmed the validity of using saturation-excess mechanisms for this hillslope dominated watershed. ?? 2003 Elsevier B.V. All rights reserved.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Hydrology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/j.jhydrol.2003.07.005","issn":"00221694","usgsCitation":"Johnson, M., Coon, W., Mehta, V., Steenhuis, T., Brooks, E., and Boll, J., 2003, Application of two hydrologic models with different runoff mechanisms to a hillslope dominated watershed in the northeastern US: A comparison of HSPF and SMR: Journal of Hydrology, v. 284, no. 1-4, p. 57-76, https://doi.org/10.1016/j.jhydrol.2003.07.005.","startPage":"57","endPage":"76","numberOfPages":"20","costCenters":[],"links":[{"id":209352,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/j.jhydrol.2003.07.005"},{"id":235681,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"284","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059ecbfe4b0c8380cd49468","contributors":{"authors":[{"text":"Johnson, M.S.","contributorId":49382,"corporation":false,"usgs":true,"family":"Johnson","given":"M.S.","email":"","affiliations":[],"preferred":false,"id":403687,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Coon, W.F.","contributorId":102524,"corporation":false,"usgs":true,"family":"Coon","given":"W.F.","email":"","affiliations":[],"preferred":false,"id":403689,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Mehta, V.K.","contributorId":31183,"corporation":false,"usgs":true,"family":"Mehta","given":"V.K.","email":"","affiliations":[],"preferred":false,"id":403686,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Steenhuis, T.S.","contributorId":66041,"corporation":false,"usgs":true,"family":"Steenhuis","given":"T.S.","affiliations":[],"preferred":false,"id":403688,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Brooks, E.S.","contributorId":22547,"corporation":false,"usgs":true,"family":"Brooks","given":"E.S.","email":"","affiliations":[],"preferred":false,"id":403685,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Boll, J.","contributorId":15812,"corporation":false,"usgs":true,"family":"Boll","given":"J.","email":"","affiliations":[],"preferred":false,"id":403684,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70025133,"text":"70025133 - 2003 - The interactive effects of UV-B and insecticide exposure on tadpole survival, growth and development","interactions":[],"lastModifiedDate":"2017-02-01T11:24:59","indexId":"70025133","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1015,"text":"Biological Conservation","active":true,"publicationSubtype":{"id":10}},"title":"The interactive effects of UV-B and insecticide exposure on tadpole survival, growth and development","docAbstract":"Because declines within amphibian populations can seldom be attributed to a single cause, it is important to focus on multiple stressors, both natural and anthropogenic. Variables such as UV-B radiation and chemical contamination can interact with one another in ways that might not be predicted from single-factor studies. We exposed southern leopard frog (Rana sphenocephala) tadpoles to the insecticide carbaryl and varying intensities of UV-B radiation in artificial ponds and examined their effects on survival, size at metamorphosis, and the duration of the larval period. Tadpole survival to metamorphosis was positively influenced by UV-B intensity. Tadpoles in ponds exposed to carbaryl contained over three times more algae and yielded larger metamorphs than control ponds. Although previous laboratory studies have indicated carbaryl becomes more toxic in the presence of UV-B, we did not find such an effect, perhaps because of the protection afforded by dissolved organic carbon within the ponds. Our research emphasizes the importance of conducting field studies to more accurately predict what occurs under a natural setting. Published by Elsevier Science Ltd.","language":"English","publisher":"Elsevier","doi":"10.1016/S0006-3207(02)00348-8","issn":"00063207","usgsCitation":"Bridges, C.M., and Boone, M.D., 2003, The interactive effects of UV-B and insecticide exposure on tadpole survival, growth and development: Biological Conservation, v. 113, no. 1, p. 49-54, https://doi.org/10.1016/S0006-3207(02)00348-8.","productDescription":"6 p.","startPage":"49","endPage":"54","numberOfPages":"6","costCenters":[{"id":192,"text":"Columbia Environmental Research Center","active":true,"usgs":true}],"links":[{"id":235987,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":209484,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0006-3207(02)00348-8"}],"volume":"113","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bad4fe4b08c986b323b19","contributors":{"authors":[{"text":"Bridges, Christine M.","contributorId":173847,"corporation":false,"usgs":false,"family":"Bridges","given":"Christine","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":403950,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Boone, Michelle D.","contributorId":55361,"corporation":false,"usgs":true,"family":"Boone","given":"Michelle","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":403949,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70025138,"text":"70025138 - 2003 - Stratigraphy and palaeoclimatic significance of Late Quaternary loess-palaeosol sequences of the Last Interglacial-Glacial cycle in central Alaska","interactions":[],"lastModifiedDate":"2012-03-12T17:20:56","indexId":"70025138","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3219,"text":"Quaternary Science Reviews","active":true,"publicationSubtype":{"id":10}},"title":"Stratigraphy and palaeoclimatic significance of Late Quaternary loess-palaeosol sequences of the Last Interglacial-Glacial cycle in central Alaska","docAbstract":"Loess is one of the most widespread subaerial deposits in Alaska and adjacent Yukon Territory and may have a history that goes back 3 Ma. Based on mineralogy and major and trace element chemistry, central Alaskan loess has a composition that is distinctive from other loess bodies of the world, although it is quartz-dominated. Central Alaskan loess was probably derived from a variety of rock types, including granites, metabasalts and schists. Detailed stratigraphic data and pedologic criteria indicate that, contrary to early studies, many palaeosols are present in central Alaskan loess sections. The buried soils indicate that loess sedimentation was episodic, or at least rates of deposition decreased to the point where pedogenesis could keep ahead of aeolian input. As in China, loess deposition and pedogenesis are likely competing processes and neither stops completely during either phase of the loess/soil formation cycle. Loess deposition in central Alaska took place before, and probably during the last interglacial period, during stadials of the mid-Wisconsin period, during the last glacial period and during the Holocene. An unexpected result of our geochronological studies is that only moderate loess deposition took place during the last glacial period. Our studies lead us to conclude that vegetation plays a key role in loess accumulation in Alaska. Factors favouring loess production are enhanced during glacial periods but factors that favour loess accumulation are diminished during glacial periods. The most important of these is vegetation; boreal forest serves as an effective loess trap, but sparsely distributed herb tundra does not. Thus, thick accumulations of loess should not be expected where tundra vegetation was dominant and this is borne out by modern studies near the treeline in central Alaska. Much of the stratigraphic diversity of North American loess, including that found in the Central Lowlands, the Great Plains, and Alaska is explained by a new model that emphasizes the relative importance of loess production factors versus loess accumulation factors.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Quaternary Science Reviews","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/S0277-3791(03)00167-7","issn":"02773791","usgsCitation":"Muhs, D., Ager, T.A., Bettis, E., McGeehin, J., Been, J., Beget, J.E., Pavich, M., Stafford, T.W., and Stevens, D., 2003, Stratigraphy and palaeoclimatic significance of Late Quaternary loess-palaeosol sequences of the Last Interglacial-Glacial cycle in central Alaska: Quaternary Science Reviews, v. 22, no. 18-19, p. 1947-1986, https://doi.org/10.1016/S0277-3791(03)00167-7.","startPage":"1947","endPage":"1986","numberOfPages":"40","costCenters":[],"links":[{"id":209514,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0277-3791(03)00167-7"},{"id":236060,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"22","issue":"18-19","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b99ace4b08c986b31c542","contributors":{"authors":[{"text":"Muhs, D.R. 0000-0001-7449-251X","orcid":"https://orcid.org/0000-0001-7449-251X","contributorId":61460,"corporation":false,"usgs":true,"family":"Muhs","given":"D.R.","affiliations":[],"preferred":false,"id":403968,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ager, T. A.","contributorId":88386,"corporation":false,"usgs":true,"family":"Ager","given":"T.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":403972,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bettis, E. Arthur III","contributorId":72822,"corporation":false,"usgs":true,"family":"Bettis","given":"E. Arthur","suffix":"III","affiliations":[],"preferred":false,"id":403971,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"McGeehin, J.","contributorId":49554,"corporation":false,"usgs":true,"family":"McGeehin","given":"J.","email":"","affiliations":[],"preferred":false,"id":403967,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Been, J.M.","contributorId":26685,"corporation":false,"usgs":true,"family":"Been","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":403966,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Beget, J. E.","contributorId":63392,"corporation":false,"usgs":true,"family":"Beget","given":"J.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":403969,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Pavich, M.J.","contributorId":70788,"corporation":false,"usgs":true,"family":"Pavich","given":"M.J.","email":"","affiliations":[],"preferred":false,"id":403970,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Stafford, Thomas W. Jr.","contributorId":21283,"corporation":false,"usgs":true,"family":"Stafford","given":"Thomas","suffix":"Jr.","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":403964,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Stevens, D.A.S.P.","contributorId":21330,"corporation":false,"usgs":true,"family":"Stevens","given":"D.A.S.P.","email":"","affiliations":[],"preferred":false,"id":403965,"contributorType":{"id":1,"text":"Authors"},"rank":9}]}} ,{"id":70025143,"text":"70025143 - 2003 - Performance of the radial semblance method for the location of very long period volcanic signals","interactions":[],"lastModifiedDate":"2021-07-26T16:53:09.609395","indexId":"70025143","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1135,"text":"Bulletin of the Seismological Society of America","onlineIssn":"1943-3573","printIssn":"0037-1106","active":true,"publicationSubtype":{"id":10}},"title":"Performance of the radial semblance method for the location of very long period volcanic signals","docAbstract":"We investigate the performance of a source location method that combines multichannel semblance and particle motions and is being increasingly used to obtain estimates of the source locations of very long period (VLP) seismic signals recorded on volcanoes. The method makes use of the radial particle motions and large wavelengths that characterize the VLP events. To assess the capabilities of this radial semblance method, and to better understand its limitations, we quantify the effects of window length, noise contents of the signal, inaccurate velocity models, receiver coverage, and orientation errors in the horizontal components of the receivers. Our results show that the semblance method performs best when (1) the noise level is low enough to allow a good characterization of the waveforms, (2) the sources are located at distances between one half of the average receiver spacing and about two times the network aperture, and (3) the orientations of the horizontal components of the seismometers are known with relative accuracy. When these requirements are met, the radial semblance method constitutes an adequate tool to obtain preliminary locations of VLP volcanic signals recorded by broadband networks. Moreover, we provide a formula to determine the radial semblance level that should be used to define error regions associated to the estimated source locations.
","language":"English","publisher":"Seismological Society of America","doi":"10.1785/0120020143","issn":"00371106","usgsCitation":"Almendros, J., and Chouet, B., 2003, Performance of the radial semblance method for the location of very long period volcanic signals: Bulletin of the Seismological Society of America, v. 93, no. 5, p. 1890-1903, https://doi.org/10.1785/0120020143.","productDescription":"14 p.","startPage":"1890","endPage":"1903","costCenters":[],"links":[{"id":387429,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a7690e4b0c8380cd781ad","contributors":{"authors":[{"text":"Almendros, J.","contributorId":73369,"corporation":false,"usgs":true,"family":"Almendros","given":"J.","affiliations":[],"preferred":false,"id":403990,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Chouet, B.","contributorId":68465,"corporation":false,"usgs":true,"family":"Chouet","given":"B.","affiliations":[],"preferred":false,"id":403989,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70025151,"text":"70025151 - 2003 - Comparison of heat and bromide as ground-water tracers near streams","interactions":[],"lastModifiedDate":"2018-11-16T10:37:37","indexId":"70025151","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1861,"text":"Ground Water","active":true,"publicationSubtype":{"id":10}},"title":"Comparison of heat and bromide as ground-water tracers near streams","docAbstract":"Heat and bromide were compared as tracers for examining stream/ground water exchanges along the middle reaches of the Santa Clara River, California, during a 10-hour surface water sodium bromide injection test. Three cross sections that comprise six shallow (<1 m) piezometers were installed at the upper, middle, and lower sections of a 17 km long study reach, to monitor temperatures and bromide concentrations in the shallow ground water beneath the stream. A heat and ground water transport simulation model and a closely related solute and ground water transport simulation model were matched up for comparison of simulated and observed temperatures and bromide concentrations in the streambed. Vertical, one-dimensional simulations of sediment temperature were fitted to observed temperature results, to yield apparent streambed hydraulic conductivities in each cross section. The temperature-based hydraulic conductivities were assigned to a solute and ground water transport model to predict sediment bromide concentrations, during the sodium bromide injection test. Vertical, one-dimensional simulations of bromide concentrations in the sediments yielded a good match to the observed bromide concentrations, without adjustment of any model parameters except solute dispersivities. This indicates that, for the spatial and temporal scales examined on the Santa Clara River, the use of heat and bromide as tracers provide comparable information with respect to apparent hydraulic conductivities and fluxes for sediments near streams. In other settings, caution should be used due to differences in the nature of conservative (bromide) versus nonconservative (heat) tracers, particularly when preferential flowpaths are present.","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.2003.tb02403.x","issn":"0017467X","usgsCitation":"Constantz, J., Cox, M., and Su, G., 2003, Comparison of heat and bromide as ground-water tracers near streams: Ground Water, v. 41, no. 5, p. 647-656, https://doi.org/10.1111/j.1745-6584.2003.tb02403.x.","productDescription":"10 p.","startPage":"647","endPage":"656","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":235685,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":209354,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1111/j.1745-6584.2003.tb02403.x"}],"country":"United States","state":"California","otherGeospatial":"Santa Clara River","volume":"41","issue":"5","noUsgsAuthors":false,"publicationDate":"2005-12-13","publicationStatus":"PW","scienceBaseUri":"5059f842e4b0c8380cd4cf9a","contributors":{"authors":[{"text":"Constantz, J.","contributorId":29953,"corporation":false,"usgs":true,"family":"Constantz","given":"J.","email":"","affiliations":[],"preferred":false,"id":404013,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cox, M.H.","contributorId":34306,"corporation":false,"usgs":true,"family":"Cox","given":"M.H.","email":"","affiliations":[],"preferred":false,"id":404014,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Su, G.W.","contributorId":23314,"corporation":false,"usgs":true,"family":"Su","given":"G.W.","email":"","affiliations":[],"preferred":false,"id":404012,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70025162,"text":"70025162 - 2003 - Paleoseismic evidence of characteristic slip on the Western segment of the North Anatolian fault, Turkey","interactions":[],"lastModifiedDate":"2023-10-18T00:21:56.343301","indexId":"70025162","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1135,"text":"Bulletin of the Seismological Society of America","onlineIssn":"1943-3573","printIssn":"0037-1106","active":true,"publicationSubtype":{"id":10}},"title":"Paleoseismic evidence of characteristic slip on the Western segment of the North Anatolian fault, Turkey","docAbstract":"We have conducted a paleoseismic investigation of serial fault rupture at one site along the 110-km rupture of the North Anatolian fault that produced the Mw 7.4 earthquake of 17 August 1999. The benefit of using a recent rupture to compare serial ruptures lies in the fact that the location, magnitude, and slip vector of the most recent event are all very well documented. We wished to determine whether or not the previous few ruptures of the fault were similar to the recent one. We chose a site at a step-over between two major strike-slip traces, where the principal fault is a normal fault. Our two excavations across the 1999 rupture reveal fluvial sands and gravels with two colluvial wedges related to previous earthquakes. Each wedge is about 0.8 m thick. Considering the processes of collapse and subsequent diffusion that are responsible for the formation of a colluvial wedge, we suggest that the two paleoscarps were similar in height to the 1999 scarp. This similarity supports the concept of characteristic slip, at least for this location along the fault. Accelerator mass spectrometry (AMS) radiocarbon dates of 16 charcoal samples are consistent with the interpretation that these two paleoscarps formed during large historical events in 1509 and 1719. If this is correct, the most recent three ruptures at the site have occurred at 210- and 280-year intervals.
Okmok Volcano, in the eastern Aleutian Islands, erupted in February and March of 1997 producing a 6-km-long lava flow and low-level ash plumes. This caldera is one of the most active in the Aleutian Arc, and is now the focus of international multidisciplinary studies. A synthesis of remotely sensed data (AirSAR, derived DEMs, Landsat MSS and ETM+ data, AVHRR, ERS, JERS, Radarsat) has given a sequence of events for the virtually unobserved 1997 eruption. Elevation data from the AirSAR sensor acquired in October 2000 over Okmok were used to create a 5-m resolution DEM mosaic of Okmok Volcano. AVHRR nighttime imagery has been analyzed between February 13 and April 11, 1997. Landsat imagery and SAR data recorded prior to and after the eruption allowed us to accurately determine the extent of the new flow. The flow was first observed on February 13 without precursory thermal anomalies. At this time, the flow was a large single lobe flowing north. According to AVHRR Band 3 and 4 radiance data and ground observations, the first lobe continued growing until mid to late March, while a second, smaller lobe began to form sometime between March 11 and 12. This is based on a jump in the thermal and volumetric flux determined from the imagery, and the physical size of the thermal anomalies. Total radiance values waned after March 26, indicating lava effusion had ended and a cooling crust was growing. The total area (8.9 km2), thickness (up to 50 m) and volume (1.54×108 m3) of the new lava flow were determined by combining observations from SAR, Landsat ETM+, and AirSAR DEM data. While the first lobe of the flow ponded in a pre-eruption depression, our data suggest the second lobe was volume-limited. Remote sensing has become an integral part of the Alaska Volcano Observatory’s monitoring and hazard mitigation efforts. Studies like this allow access to remote volcanoes, and provide methods to monitor potentially dangerous ones.
","language":"English","publisher":"Elsevier","doi":"10.1016/S0377-0273(03)00180-X","issn":"03770273","usgsCitation":"Patrick, M., Dehn, J., Papp, K., Lu, Z., Dean, K., Moxey, L., Izbekov, P., and Guritz, R., 2003, The 1997 eruption of Okmok Volcano, Alaska: A synthesis of remotely sensed imagery: Journal of Volcanology and Geothermal Research, v. 127, no. 1-2, p. 87-105, https://doi.org/10.1016/S0377-0273(03)00180-X.","productDescription":"19 p.","startPage":"87","endPage":"105","numberOfPages":"19","costCenters":[{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"links":[{"id":478528,"rank":10000,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.725.4123","text":"External Repository"},{"id":235920,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":209455,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0377-0273(03)00180-X"}],"volume":"127","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505ba63de4b08c986b320fb2","contributors":{"authors":[{"text":"Patrick, M.R.","contributorId":96059,"corporation":false,"usgs":true,"family":"Patrick","given":"M.R.","email":"","affiliations":[],"preferred":false,"id":404073,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Dehn, J.","contributorId":36731,"corporation":false,"usgs":true,"family":"Dehn","given":"J.","email":"","affiliations":[],"preferred":false,"id":404069,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Papp, K.R.","contributorId":107907,"corporation":false,"usgs":true,"family":"Papp","given":"K.R.","email":"","affiliations":[],"preferred":false,"id":404076,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Lu, Z.","contributorId":106241,"corporation":false,"usgs":true,"family":"Lu","given":"Z.","affiliations":[],"preferred":false,"id":404075,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Dean, K.","contributorId":42767,"corporation":false,"usgs":false,"family":"Dean","given":"K.","email":"","affiliations":[{"id":13097,"text":"Geophysical Institute, University of Alaska Fairbanks","active":true,"usgs":false}],"preferred":false,"id":404070,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Moxey, L.","contributorId":104263,"corporation":false,"usgs":true,"family":"Moxey","given":"L.","email":"","affiliations":[],"preferred":false,"id":404074,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Izbekov, P.","contributorId":46748,"corporation":false,"usgs":true,"family":"Izbekov","given":"P.","affiliations":[],"preferred":false,"id":404071,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Guritz, R.","contributorId":56428,"corporation":false,"usgs":true,"family":"Guritz","given":"R.","email":"","affiliations":[],"preferred":false,"id":404072,"contributorType":{"id":1,"text":"Authors"},"rank":8}]}} ,{"id":70025173,"text":"70025173 - 2003 - Nuclear transfer of synchronized African wild cat somatic cells into enucleated domestic cat oocytes","interactions":[],"lastModifiedDate":"2012-03-12T17:20:57","indexId":"70025173","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1033,"text":"Biology of Reproduction","active":true,"publicationSubtype":{"id":10}},"title":"Nuclear transfer of synchronized African wild cat somatic cells into enucleated domestic cat oocytes","docAbstract":"The African wild cat is one of the smallest wild cats and its future is threatened by hybridization with domestic cats. Nuclear transfer, a valuable tool for retaining genetic variability, offers the possibility of species continuation rather than extinction. The aim of this study was to investigate the ability of somatic cell nuclei of the African wild cat (AWC) to dedifferentiate within domestic cat (DSH) cytoplasts and to support early development after nuclear transplantation. In experiment 1, distributions of AWC and DSH fibroblasts in each cell-cycle phase were assessed by flow cytometry using cells cultured to confluency and disaggregated with pronase, trypsin, or mechanical separation. Trypsin (89.0%) and pronase (93.0%) yielded higher proportions of AWC nuclei in the G0/G1 phase than mechanical separation (82.0%). In contrast, mechanical separation yielded higher percentages of DSH nuclei in the G0/G1 phase (86.6%) than pronase (79.7%) or trypsin (74.2%) treatments. In both species, pronase induced less DNA damage than trypsin. In experiment 2, the effects of serum starvation, culture to confluency, and exposure to roscovitine on the distribution of AWC and DSH fibroblasts in various phases of the cell cycle were determined. Flow cytometry analyses revealed that the dynamics of the cell cycle varied as culture conditions were modified. Specifically, a higher percentage of AWC and DSH nuclei were in the G0/G1 phase after cells were serum starved (83% vs. 96%) than were present in cycling cells (50% vs. 64%), after contact inhibition (61% vs. 88%), or after roscovitine (56% vs. 84%) treatment, respectively. In experiment 3, we evaluated the effects of cell synchronization and oocyte maturation (in vivo vs. in vitro) on the reconstruction and development of AWC-DSH- and DSH-DSH-cloned embryos. The method of cell synchronization did not affect the fusion and cleavage rate because only a slightly higher percentage of fused couplets cleaved when donor nuclei were synchronized by serum starvation (83.0%) than after roscovitine (80.0%) or contact-inhibition (80.0%). The fusion efficiency of in vivo and in vitro matured oocytes used as recipient cytoplasts of AWC donor nuclei (86.6% vs. 85.2%) was similar to the rates obtained with DSH donor nuclei, 83.7% vs. 73.0%, respectively. The only significant effect of source of donor nucleus (AWC vs. DSH) was on the rate of blastocyst formation in vitro. A higher percentage of the embryos derived from AWC nuclei developed to the blastocyst stage than did embryos produced from DSH nuclei, 24.2% vs. 3.3%, respectively (P < 0.05). In experiment 4, the effect of calcium in the fusion medium on induction of oocyte activation and development of AWC-DSH-cloned embryos was determined. The presence of calcium in the fusion medium induced a high incidence of cleavage of DSH oocytes (54.3%), while oocyte cleavage frequency was much lower in the absence of calcium (16.6%). The presence or absence of calcium in the fusion medium did not affect the fusion, cleavage, and blastocyst development of AWC-DSH-cloned embryos. In experiment 5, AWC-DSH-cloned embryos were transferred to the uteri of 11 synchronized domestic cat recipients on Day 6 or 7 after oocyte aspiration. Recipients were assessed by ultrasonography on Day 21 postovulation, but no pregnancies were observed. In the present study, after NT, AWC donor nuclei were able to dedifferentiate in DSH cytoplasts and support high rates of blastocyst development in vitro. Incomplete reprogramming of the differentiated nucleus may be a major constraint to the in vivo developmental potential of the embryos.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Biology of Reproduction","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1095/biolreprod.102.014449","issn":"00063363","usgsCitation":"Gomez, M., Jenkins, J., Giraldo, A., Harris, R., King, A., Dresser, B., and Pope, C., 2003, Nuclear transfer of synchronized African wild cat somatic cells into enucleated domestic cat oocytes: Biology of Reproduction, v. 69, no. 3, p. 1032-1041, https://doi.org/10.1095/biolreprod.102.014449.","startPage":"1032","endPage":"1041","numberOfPages":"10","costCenters":[],"links":[{"id":487503,"rank":10000,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1095/biolreprod.102.014449","text":"Publisher Index Page"},{"id":209516,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1095/biolreprod.102.014449"},{"id":236062,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"69","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a68d3e4b0c8380cd739fc","contributors":{"authors":[{"text":"Gomez, M.C.","contributorId":67704,"corporation":false,"usgs":true,"family":"Gomez","given":"M.C.","email":"","affiliations":[],"preferred":false,"id":404105,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Jenkins, J.A. 0000-0002-5087-0894","orcid":"https://orcid.org/0000-0002-5087-0894","contributorId":51703,"corporation":false,"usgs":true,"family":"Jenkins","given":"J.A.","affiliations":[{"id":17705,"text":"Wetland and Aquatic Research Center","active":true,"usgs":true}],"preferred":false,"id":404101,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Giraldo, A.","contributorId":58826,"corporation":false,"usgs":true,"family":"Giraldo","given":"A.","email":"","affiliations":[],"preferred":false,"id":404103,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Harris, R.F.","contributorId":66044,"corporation":false,"usgs":true,"family":"Harris","given":"R.F.","email":"","affiliations":[],"preferred":false,"id":404104,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"King, A.","contributorId":68521,"corporation":false,"usgs":true,"family":"King","given":"A.","email":"","affiliations":[],"preferred":false,"id":404106,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Dresser, B.L.","contributorId":56841,"corporation":false,"usgs":true,"family":"Dresser","given":"B.L.","email":"","affiliations":[],"preferred":false,"id":404102,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Pope, C.E.","contributorId":96064,"corporation":false,"usgs":true,"family":"Pope","given":"C.E.","email":"","affiliations":[],"preferred":false,"id":404107,"contributorType":{"id":1,"text":"Authors"},"rank":7}]}} ,{"id":70025174,"text":"70025174 - 2003 - Why earthquakes correlate weakly with the solid Earth tides: Effects of periodic stress on the rate and probability of earthquake occurrence","interactions":[],"lastModifiedDate":"2012-03-12T17:20:56","indexId":"70025174","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2314,"text":"Journal of Geophysical Research B: Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Why earthquakes correlate weakly with the solid Earth tides: Effects of periodic stress on the rate and probability of earthquake occurrence","docAbstract":"We provide an explanation why earthquake occurrence does not correlate well with the daily solid Earth tides. The explanation is derived from analysis of laboratory experiments in which faults are loaded to quasiperiodic failure by the combined action of a constant stressing rate, intended to simulate tectonic loading, and a small sinusoidal stress, analogous to the Earth tides. Event populations whose failure times correlate with the oscillating stress show two modes of response; the response mode depends on the stressing frequency. Correlation that is consistent with stress threshold failure models, e.g., Coulomb failure, results when the period of stress oscillation exceeds a characteristic time tn; the degree of correlation between failure time and the phase of the driving stress depends on the amplitude and frequency of the stress oscillation and on the stressing rate. When the period of the oscillating stress is less than tn, the correlation is not consistent with threshold failure models, and much higher stress amplitudes are required to induce detectable correlation with the oscillating stress. The physical interpretation of tn is the duration of failure nucleation. Behavior at the higher frequencies is consistent with a second-order dependence of the fault strength on sliding rate which determines the duration of nucleation and damps the response to stress change at frequencies greater than 1/tn. Simple extrapolation of these results to the Earth suggests a very weak correlation of earthquakes with the daily Earth tides, one that would require >13,000 earthquakes to detect. On the basis of our experiments and analysis, the absence of definitive daily triggering of earthquakes by the Earth tides requires that for earthquakes, tn exceeds the daily tidal period. The experiments suggest that the minimum typical duration of earthquake nucleation on the San Andreas fault system is ???1 year.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Geophysical Research B: Solid Earth","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"01480227","usgsCitation":"Beeler, N., and Lockner, D., 2003, Why earthquakes correlate weakly with the solid Earth tides: Effects of periodic stress on the rate and probability of earthquake occurrence: Journal of Geophysical Research B: Solid Earth, v. 108, no. 8.","costCenters":[],"links":[{"id":236099,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"108","issue":"8","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bd0a1e4b08c986b32ef8b","contributors":{"authors":[{"text":"Beeler, N.M. 0000-0002-3397-8481","orcid":"https://orcid.org/0000-0002-3397-8481","contributorId":68894,"corporation":false,"usgs":true,"family":"Beeler","given":"N.M.","affiliations":[],"preferred":false,"id":404108,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lockner, D.A. 0000-0001-8630-6833","orcid":"https://orcid.org/0000-0001-8630-6833","contributorId":85603,"corporation":false,"usgs":true,"family":"Lockner","given":"D.A.","affiliations":[],"preferred":false,"id":404109,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70025180,"text":"70025180 - 2003 - Geochronology and eruptive history of the Katmai volcanic cluster, Alaska Peninsula","interactions":[],"lastModifiedDate":"2016-10-26T12:40:32","indexId":"70025180","displayToPublicDate":"2003-01-01T00:00:00","publicationYear":"2003","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1427,"text":"Earth and Planetary Science Letters","active":true,"publicationSubtype":{"id":10}},"title":"Geochronology and eruptive history of the Katmai volcanic cluster, Alaska Peninsula","docAbstract":"In the Katmai district of the Alaska Peninsula, K–Ar and 40Ar/39Ar ages have been determined for a dozen andesite–dacite stratocones on the arc front and for 11 rear-arc volcanoes, 10 of which are monogenetic. Tied to mapping and stratigraphic studies, our dating emphasized proximal basal lavas that rest on basement rocks, in order to estimate ages of inception of each polygenetic cone. Oldest among arc-front cones is Alagogshak Volcano (690–43 ka), succeeded in the Holocene by the active Mount Martin cone. Mount Mageik consists of four overlapping subedifices, basal lavas of which give ages of 93, 71, and 59 ka, and Holocene. The three small prehistoric cones of Trident Volcano yield ages of 143, 101–58, and 44 ka. Falling Mountain and Mount Cerberus, dacite domes near the 1912 Novarupta vent, are related compositionally to the Trident group and give ages of 70 ka and 114 ka. Mount Katmai, which underwent caldera collapse in 1912, consists of two subedifices that overlapped in space and time, and is the only arc-front center here to include basalt and rhyolite; one cone began by 90 ka, the other by 47 ka. Snowy Mountain also consists of two contiguous cones, which started around 200 and 171 ka, respectively, the younger remaining active into the Holocene. Devils Desk, the only mafic cone on the arc front, was short-lived at about 245 ka. In the rear-arc, (1) Mount Griggs produced mafic-to-silicic andesite in several episodes between 292 ka and the Holocene; (2) the Savonoski River cluster includes a Pliocene dacite dome and five small mafic cones (390–88 ka); (3) Gertrude Creek cone (49.8% SiO2) yields an age of 500 ka; and (4) the Saddlehorn Creek cluster includes five Pliocene basalt-to-andesite remnants. Eruptive volumes were reconstructed, permitting estimates of average eruption rates for edifice lifetimes. Since the mid Pleistocene, total volume erupted along the arc front here is 210±47 km3 and in the rear-arc 39±6 km3, of which Mount Griggs alone accounts for 35±5 km3. Most productive has been Mount Katmai at 70±18 km3, yielding a rate of ∼1 km3/kyr, followed by Mount Mageik (0.33 km3/kyr) and Mount Griggs (0.3 km3/kyr since 50 ka).
\n\n
Persistent human disturbance is a major cause for the decline in populations of many cave-dwelling bats and other sensitive cave-obligate organisms. Cave gating has been used to eliminate human disturbance, but few studies have assessed directly the impact of such management activities on resident bats. In northeastern Oklahoma, USA, 25 entrances of caves inhabited by two endangered species and one endangered subspecies of bats are protected from human entry with internal gates. Because cave gates may impede ingress and egress of bats at caves, we evaluated the impacts of internal gates before and after their construction at six colonies of endangered gray bats (Myotis grisescens) from 1981 to 2001. No caves were abandoned by gray bats after the construction of internal gates; in fact, total numbers of gray bats using the six caves increased from 60,130 in 1981 to 70,640 in 2001. Two caves harbored more gray bats after gating, and three caves had no change in gray bat numbers after gating. We also compared initiations of emergences at three gated and three open-passage caves in June and July 1999–2000. No differences in timing of initiation of emergence were found between colonies in gated versus open-passage caves. Our results support the use of internal gates to protect and thereby enhance recovery of colonies of endangered gray bats. Additional research is encouraged to confirm that our observations on gray bats are generally applicable to other species of cave-dwelling bats.
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