A modified version of the Bertaut-Warren-Averbach (BWA) technique (Bertaut 1949, 1950; Warren and Averbach 1950) has been developed to measure coherent scattering domain (CSD) sizes and strains in minerals by analysis of X-ray diffraction (XRD) data. This method is used to measure CSD thickness distributions for calculated and experimental XRD patterns of illites and illite-smectites (I-S). The method almost exactly recovers CSD thickness distributions for calculated illite XRD patterns. Natural I-S samples contain swelling layers that lead to nonperiodic structures in the c* direction and to XRD peaks that are broadened and made asymmetric by mixed layering. Therefore, these peaks cannot be analyzed by the BWA method. These difficulties are overcome by K-saturation and heating prior to X-ray analysis in order to form 10-Å periodic structures. BWA analysis yields the thickness distribution of mixed-layer crystals (coherently diffracting stacks of fundamental illite particles). For most I-S samples, CSD thickness distributions can be approximated by lognormal functions. Mixed-layer crystal mean thickness and expandability then can be used to calculate fundamental illite particle mean thickness. Analyses of the dehydrated, K-saturated samples indicate that basal XRD reflections are broadened by symmetrical strain that may be related to local variations in smectite interlayers caused by dehydration, and that the standard deviation of the strain increases regularly with expandability. The 001 and 002 reflections are affected only slightly by this strain and therefore are suited for CSD thickness analysis. Mean mixed-layer crystal thicknesses for dehydrated I-S measured by the BWA method are very close to those measured by an integral peak width method.
","language":"English","publisher":"The Clay Minerals Society","doi":"10.1346/CCMN.1998.0460105","usgsCitation":"Drits, V.A., Eberl, D.D., and Srodon, J., 1998, XRD measurement of mean thickness, thickness distribution and strain for illite and illite-smectite crystallites by the Bertaut-Warren-Averbach technique: Clays and Clay Minerals, v. 46, no. 1, p. 38-50, https://doi.org/10.1346/CCMN.1998.0460105.","productDescription":"13 p.","startPage":"38","endPage":"50","costCenters":[],"links":[{"id":230901,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"46","issue":"1","noUsgsAuthors":false,"publicationDate":"2024-02-28","publicationStatus":"PW","scienceBaseUri":"505bd1fae4b08c986b32f611","contributors":{"authors":[{"text":"Drits, Victor A.","contributorId":65616,"corporation":false,"usgs":false,"family":"Drits","given":"Victor","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":386268,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Eberl, Dennis D.","contributorId":68388,"corporation":false,"usgs":true,"family":"Eberl","given":"Dennis","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":386269,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Srodon, Jan","contributorId":50780,"corporation":false,"usgs":false,"family":"Srodon","given":"Jan","email":"","affiliations":[],"preferred":false,"id":386270,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70020463,"text":"70020463 - 1998 - Caribou distribution during the post-calving period in relation to infrastructure in the Prudhoe Bay oil field, Alaska","interactions":[],"lastModifiedDate":"2019-11-10T11:38:13","indexId":"70020463","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":894,"text":"Arctic","active":true,"publicationSubtype":{"id":10}},"title":"Caribou distribution during the post-calving period in relation to infrastructure in the Prudhoe Bay oil field, Alaska","docAbstract":"There is concern that caribou (Rangifer tarandus) may avoid roads and facilities (i.e., infrastructure) in the Prudhoe Bay oil field (PBOF) in northern Alaska, and that this avoidance can have negative effects on the animals. We quantified the relationship between caribou distribution and PBOF infrastructure during the post-calving period (mid-June to mid-August) with aerial surveys from 1990 to 1995. We conducted four to eight surveys per year with complete coverage of the PBOF. We identified active oil field infrastructure and used a geographic information system (GIS) to construct ten 1 km wide concentric intervals surrounding the infrastructure. We tested whether caribou distribution is related to distance from infrastructure with a chi-squared habitat utilization-availability analysis and log-linear regression. We considered bulls, calves, and total caribou of all sex/age classes separately. The habitat utilization-availability analysis indicated there was no consistent trend of attraction to or avoidance of infrastructure. Caribou frequently were more abundant than expected in the intervals close to infrastructure, and this trend was more pronounced for bulls and for total caribou of all sex/age classes than for calves. Log-linear regression (with Poisson error structure) of numbers of caribou and distance from infrastructure were also done, with and without combining data into the 1 km distance intervals. The analysis without intervals revealed no relationship between caribou distribution and distance from oil field infrastructure, or between caribou distribution and Julian date, year, or distance from the Beaufort Sea coast. The log-linear regression with caribou combined into distance intervals showed the density of bulls and total caribou of all sex/age classes declined with distance from infrastructure. Our results indicate that during the post-calving period: 1) caribou distribution is largely unrelated to distance from infrastructure; 2) caribou regularly use habitats in the PBOF; 3) caribou often occur close to infrastructure; and 4) caribou do not appear to avoid oil field infrastructure.
","language":"English","publisher":"Arctic Institute of North America","publisherLocation":"Calgary, AB","doi":"10.14430/arctic1050","issn":"00040843","usgsCitation":"Cronin, M.A., Amstrup, S.C., Durner, G.M., Noel, L.E., McDonald, T.L., and Ballard, W.B., 1998, Caribou distribution during the post-calving period in relation to infrastructure in the Prudhoe Bay oil field, Alaska: Arctic, v. 51, no. 2, p. 85-93, https://doi.org/10.14430/arctic1050.","productDescription":"9 p.","startPage":"85","endPage":"93","costCenters":[{"id":114,"text":"Alaska Science Center","active":true,"usgs":true}],"links":[{"id":479851,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.14430/arctic1050","text":"Publisher Index Page"},{"id":231060,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Alaska","otherGeospatial":"Prudhoe Bay Oil Field","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -148.96362304687497,\n 69.93406993820341\n ],\n [\n -147.227783203125,\n 69.93406993820341\n ],\n [\n -147.227783203125,\n 70.63448406630856\n ],\n [\n -148.96362304687497,\n 70.63448406630856\n ],\n [\n -148.96362304687497,\n 69.93406993820341\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"51","issue":"2","noUsgsAuthors":false,"publicationDate":"1998-01-01","publicationStatus":"PW","scienceBaseUri":"5059f37ce4b0c8380cd4b837","contributors":{"authors":[{"text":"Cronin, Matthew A.","contributorId":57307,"corporation":false,"usgs":false,"family":"Cronin","given":"Matthew","email":"","middleInitial":"A.","affiliations":[{"id":28157,"text":"LGL Alaska Research Associates, Anchorage, AK","active":true,"usgs":false},{"id":7211,"text":"University of Alaska, Fairbanks","active":true,"usgs":false}],"preferred":false,"id":386309,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Amstrup, Steven C.","contributorId":67034,"corporation":false,"usgs":false,"family":"Amstrup","given":"Steven","email":"","middleInitial":"C.","affiliations":[{"id":13182,"text":"Polar Bears International","active":true,"usgs":false}],"preferred":false,"id":386308,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Durner, George M. 0000-0002-3370-1191 gdurner@usgs.gov","orcid":"https://orcid.org/0000-0002-3370-1191","contributorId":3576,"corporation":false,"usgs":true,"family":"Durner","given":"George","email":"gdurner@usgs.gov","middleInitial":"M.","affiliations":[{"id":114,"text":"Alaska Science Center","active":true,"usgs":true},{"id":116,"text":"Alaska Science Center Biology MFEB","active":true,"usgs":true}],"preferred":true,"id":386307,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Noel, Lynn E.","contributorId":179096,"corporation":false,"usgs":false,"family":"Noel","given":"Lynn","email":"","middleInitial":"E.","affiliations":[{"id":28157,"text":"LGL Alaska Research Associates, Anchorage, AK","active":true,"usgs":false}],"preferred":false,"id":386306,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"McDonald, Trent L.","contributorId":92193,"corporation":false,"usgs":false,"family":"McDonald","given":"Trent","email":"","middleInitial":"L.","affiliations":[{"id":6660,"text":"Western EcoSystems Technology, Inc","active":true,"usgs":false}],"preferred":false,"id":386310,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Ballard, Warren B.","contributorId":172887,"corporation":false,"usgs":false,"family":"Ballard","given":"Warren","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":386311,"contributorType":{"id":1,"text":"Authors"},"rank":6}]}} ,{"id":70020465,"text":"70020465 - 1998 - Dating previously balanced rocks in seismically active parts of California and Nevada","interactions":[],"lastModifiedDate":"2024-01-17T00:38:00.828447","indexId":"70020465","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1796,"text":"Geology","active":true,"publicationSubtype":{"id":10}},"title":"Dating previously balanced rocks in seismically active parts of California and Nevada","docAbstract":"Precariously balanced boulders that could be knocked down by strong earthquake ground motion are found in some seismically active areas of southern California and Nevada. In this study we used two independent surface-exposure dating techniques—rock-varnish microlamination and cosmogenic 36Cl dating methodologies—to estimate minimum- and maximum-limiting ages, respectively, of the precarious boulders and by inference the elapsed time since the sites were shaken down. The results of the exposure dating indicate that all of the precarious rocks are >10.5 ka and that some may be significantly older. At Victorville and Jacumba, California, these results show that the precarious rocks have not been knocked down for at least 10.5 k.y., a conclusion in apparent conflict with some commonly used probabilistic seismic hazard maps. At Yucca Mountain, Nevada, the ages of the precarious rocks are >10.5 to >27.0 ka, providing an independent measure of the minimum time elapsed since faulting occurred on the Solitario Canyon fault.
This paper examines the linkages between the carbon cycle and sedimentary processes on land. Available data suggest that sedimentation on land can bury vast quantities of organic carbon, roughly 1015 g C yr−1. To evaluate the relative roles of various classes of processes in the burial of carbon on land, terrestrial sedimentation was modeled as a series of 864 scenarios. Each scenario represents a unique choice of intensities for seven classes of processes and two different global wetland distributions. Comparison was made with presumed preagricultural conditions. The classes of processes were divided into two major component parts: clastic sedimentation of soil-derived carbon and organic sedimentation of autochthonous carbon. For clastic sedimentation, masses of sediment were considered for burial as reservoir sediment, lake sediment, and combined colluvium, alluvium, and aeolian deposits. When the ensemble of models is examined, the human-induced burial of 0.6-1.5·1015 g yr−1 of carbon on land is entirely plausible. This sink reaches its maximum strength between 30° and 50° N. Paddy lands stand out as a type of land use that warrants future study, but the many faces of rice agriculture limit generalization. In an extreme scenario, paddy lands alone could be made to bury about 1·1015 g C yr−1. Arguing that terrestrial sedimentation processes could be much of the sink for the so called “missing carbon” is reasonable. Such a hypothesis, however, requires major redesign of how the carbon cycle is modeled. Unlike ecosystem processes that are amenable to satellite monitoring and parallel modeling, many aspects of terrestrial sedimentation are hidden from space.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98GB00741","usgsCitation":"Stallard, R.F., 1998, Terrestrial sedimentation and the carbon cycle: Coupling weathering and erosion to carbon burial: Global Biogeochemical Cycles, v. 12, no. 2, p. 231-257, https://doi.org/10.1029/98GB00741.","productDescription":"27 p.","startPage":"231","endPage":"257","numberOfPages":"27","costCenters":[{"id":5044,"text":"National Research Program - Central Branch","active":true,"usgs":true}],"links":[{"id":479885,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/98gb00741","text":"Publisher Index Page"},{"id":231099,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"12","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505ba562e4b08c986b3209f0","contributors":{"authors":[{"text":"Stallard, Robert F. 0000-0001-8209-7608 stallard@usgs.gov","orcid":"https://orcid.org/0000-0001-8209-7608","contributorId":1924,"corporation":false,"usgs":true,"family":"Stallard","given":"Robert","email":"stallard@usgs.gov","middleInitial":"F.","affiliations":[{"id":5044,"text":"National Research Program - Central Branch","active":true,"usgs":true}],"preferred":true,"id":386325,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70020474,"text":"70020474 - 1998 - Late Quaternary slip on the Santa Cruz Island fault, California","interactions":[],"lastModifiedDate":"2023-12-20T23:55:27.860354","indexId":"70020474","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1786,"text":"Geological Society of America Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Late Quaternary slip on the Santa Cruz Island fault, California","docAbstract":"The style, timing, and pattern of slip on the Santa Cruz Island fault were investigated by trenching the fault and by analysis of offset late Quaternary landforms. A trench excavated across the fault at Christi Beach, on the western coast of the island, exposed deformation of latest Pleistocene to Holocene sediments and pre-Quaternary rocks, recording repeated large-magnitude rupture events. The most recent earthquake at this site occurred ca. 5 ka. Coastal terraces preserved on western Santa Cruz Island have been dated using the uranium-series technique and by extrapolation using terrace elevations and the eustatic record. Offset of terraces and other landforms indicates that the Santa Cruz Island fault is predominantly left lateral, having a horizontal slip rate of not more than 1.1 mm/yr and probably about 0.8 mm/yr. The fault also has a smaller reverse component, slipping at a rate of between 0.1 and 0.2 mm/yr. Combined with measurements of slip per event, this information suggests a long-term average recurrence interval of at least 2.7 k.y. and probably 4–5 k.y., and average earthquake magnitudes of Mw 7.2–7.5. Sense of slip, recurrence interval, and earthquake magnitudes calculated here for the Santa Cruz Island fault are very similar to recent results for other faults along the southern margin of the western Transverse Range, including the Malibu Coast fault, the Santa Monica fault, the Hollywood fault, and the Raymond fault, supporting the contention that these faults constitute a continuous and linked fault system, which is characterized by large but relatively infrequent earthquakes.
Describes the preflight and inflight calibration approaches used for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The system is a multispectral, high-spatial resolution sensor on the Earth Observing System's EOS-AM1 platform. Preflight calibration of ASTER uses well-characterized sources to provide calibration and preflight round-robin exercises to understand biases between the calibration sources of ASTER and other EOS sensors. These round-robins rely on well-characterized, ultra-stable radiometers. An experiment field in Yokohama, Japan, showed that the output from the source used for the visible and near-infrared (VNIR) subsystem of ASTER may be underestimated by 1.5%, but this is still within the 4% specification for the absolute, radiometric calibration of these bands. Inflight calibration will rely on vicarious techniques and onboard blackbodies and lamps. Vicarious techniques include ground-reference methods using desert and water sites. A recent joint field campaign gives confidence that these methods currently provide absolute calibration to better than 5%, and indications are that uncertainties less than the required 4% should be achievable at launch. The EOS-AM1 platform will also provide a spacecraft maneuver that will allow ASTER to see the Moon, allowing further characterization of the sensor. A method for combining the results of these independent calibration results is presented. The paper also describes the plans for validating the Level 2 data products from ASTER. These plans rely heavily upon field campaigns using methods similar to those used for the ground-reference, vicarious calibration methods.
","language":"English","publisher":"IEEE","doi":"10.1109/36.701023","issn":"01962892","usgsCitation":"Thome, K., Aral, K., Hook, S., Kieffer, H., Lang, H., Matsunaga, T., Ono, A., Palluconi, F., Sakuma, H., Slater, P., Takashima, T., Tonooka, H., Tsuchida, S., Welch, R., and Zalewski, E., 1998, ASTER preflight and inflight calibration and the validation of level 2 products: IEEE Transactions on Geoscience and Remote Sensing, v. 36, no. 4, p. 1161-1172, https://doi.org/10.1109/36.701023.","productDescription":"12 p.","startPage":"1161","endPage":"1172","numberOfPages":"12","costCenters":[],"links":[{"id":231334,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"36","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e638e4b0c8380cd47271","contributors":{"authors":[{"text":"Thome, K.","contributorId":45078,"corporation":false,"usgs":true,"family":"Thome","given":"K.","affiliations":[],"preferred":false,"id":386392,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Aral, K.","contributorId":39157,"corporation":false,"usgs":true,"family":"Aral","given":"K.","email":"","affiliations":[],"preferred":false,"id":386390,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Hook, S.","contributorId":52360,"corporation":false,"usgs":true,"family":"Hook","given":"S.","email":"","affiliations":[],"preferred":false,"id":386393,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kieffer, H.","contributorId":60405,"corporation":false,"usgs":true,"family":"Kieffer","given":"H.","affiliations":[],"preferred":false,"id":386394,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Lang, H.","contributorId":14601,"corporation":false,"usgs":true,"family":"Lang","given":"H.","email":"","affiliations":[],"preferred":false,"id":386386,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Matsunaga, T.","contributorId":29157,"corporation":false,"usgs":true,"family":"Matsunaga","given":"T.","email":"","affiliations":[],"preferred":false,"id":386388,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Ono, A.","contributorId":21710,"corporation":false,"usgs":true,"family":"Ono","given":"A.","email":"","affiliations":[],"preferred":false,"id":386387,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Palluconi, F. D.","contributorId":80854,"corporation":false,"usgs":true,"family":"Palluconi","given":"F. D.","affiliations":[],"preferred":false,"id":386397,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Sakuma, H.","contributorId":80855,"corporation":false,"usgs":true,"family":"Sakuma","given":"H.","email":"","affiliations":[],"preferred":false,"id":386398,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Slater, P.","contributorId":86521,"corporation":false,"usgs":true,"family":"Slater","given":"P.","email":"","affiliations":[],"preferred":false,"id":386400,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Takashima, T.","contributorId":43527,"corporation":false,"usgs":true,"family":"Takashima","given":"T.","email":"","affiliations":[],"preferred":false,"id":386391,"contributorType":{"id":1,"text":"Authors"},"rank":11},{"text":"Tonooka, H.","contributorId":33486,"corporation":false,"usgs":true,"family":"Tonooka","given":"H.","email":"","affiliations":[],"preferred":false,"id":386389,"contributorType":{"id":1,"text":"Authors"},"rank":12},{"text":"Tsuchida, S.","contributorId":63564,"corporation":false,"usgs":true,"family":"Tsuchida","given":"S.","email":"","affiliations":[],"preferred":false,"id":386395,"contributorType":{"id":1,"text":"Authors"},"rank":13},{"text":"Welch, R.M.","contributorId":73776,"corporation":false,"usgs":true,"family":"Welch","given":"R.M.","email":"","affiliations":[],"preferred":false,"id":386396,"contributorType":{"id":1,"text":"Authors"},"rank":14},{"text":"Zalewski, E.","contributorId":84946,"corporation":false,"usgs":true,"family":"Zalewski","given":"E.","email":"","affiliations":[],"preferred":false,"id":386399,"contributorType":{"id":1,"text":"Authors"},"rank":15}]}} ,{"id":70020485,"text":"70020485 - 1998 - Singularity and Nonnormality in the Classification of Compositional Data","interactions":[],"lastModifiedDate":"2013-03-01T15:16:31","indexId":"70020485","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2700,"text":"Mathematical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Singularity and Nonnormality in the Classification of Compositional Data","docAbstract":"Geologists may want to classify compositional data and express the classification as a map. Regionalized classification is a tool that can be used for this purpose, but it incorporates discriminant analysis, which requires the computation and inversion of a covariance matrix. Covariance matrices of compositional data always will be singular (noninvertible) because of the unit-sum constraint. Fortunately, discriminant analyses can be calculated using a pseudo-inverse of the singular covariance matrix; this is done automatically by some statistical packages such as SAS. Granulometric data from the Darss Sill region of the Baltic Sea is used to explore how the pseudo-inversion procedure influences discriminant analysis results, comparing the algorithm used by SAS to the more conventional Moore-Penrose algorithm. Logratio transforms have been recommended to overcome problems associated with analysis of compositional data, including singularity. A regionalized classification of the Darss Sill data after logratio transformation is different only slightly from one based on raw granulometric data, suggesting that closure problems do not influence severely regionalized classification of compositional data.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Mathematical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Springer","doi":"10.1023/A:1021705120065","issn":"08828121","usgsCitation":"Bohling, G.C., Davis, J., Olea, R., and Harff, J., 1998, Singularity and Nonnormality in the Classification of Compositional Data: Mathematical Geology, v. 30, no. 1, p. 5-20, https://doi.org/10.1023/A:1021705120065.","startPage":"5","endPage":"20","numberOfPages":"16","costCenters":[],"links":[{"id":231335,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":268639,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1023/A:1021705120065"}],"volume":"30","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b90e4e4b08c986b3196c5","contributors":{"authors":[{"text":"Bohling, Geoffrey C.","contributorId":43109,"corporation":false,"usgs":false,"family":"Bohling","given":"Geoffrey","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":386402,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Davis, J.C.","contributorId":72121,"corporation":false,"usgs":true,"family":"Davis","given":"J.C.","email":"","affiliations":[],"preferred":false,"id":386404,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Olea, Ricardo A. 0000-0003-4308-0808","orcid":"https://orcid.org/0000-0003-4308-0808","contributorId":26436,"corporation":false,"usgs":true,"family":"Olea","given":"Ricardo A.","affiliations":[{"id":241,"text":"Eastern Energy Resources Science Center","active":true,"usgs":true}],"preferred":false,"id":386401,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Harff, Jan","contributorId":63957,"corporation":false,"usgs":false,"family":"Harff","given":"Jan","email":"","affiliations":[],"preferred":false,"id":386403,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70020487,"text":"70020487 - 1998 - Flow of river water into a Karstic limestone aquifer. 1. Tracing the young fraction in groundwater mixtures in the Upper Floridan Aquifer near Valdosta, Georgia","interactions":[],"lastModifiedDate":"2020-01-06T06:29:09","indexId":"70020487","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":835,"text":"Applied Geochemistry","active":true,"publicationSubtype":{"id":10}},"title":"Flow of river water into a Karstic limestone aquifer. 1. Tracing the young fraction in groundwater mixtures in the Upper Floridan Aquifer near Valdosta, Georgia","docAbstract":"The quality of water in the Upper Floridan aquifer near Valdosta, Georgia is affected locally by discharge of Withlacoochee River water through sinkholes in the river bed. Data on transient tracers and other dissolved substances, including Cl−, 3H, tritiogenic helium-3 (3He), chlorofluorocarbons (CFC-11, CFC-12, CFC-113), organic C (DOC), O2 (DO), H2S, CH4, δ18O, δD, and 14C were investigated as tracers of Withlacoochee River water in the Upper Floridan aquifer. The concentrations of all tracers were affected by dilution and mixing. Dissolved Cl−, δ18O, δD, CFC-12, and the quantity (3H+3He) are stable in water from the Upper Floridan aquifer, whereas DOC, DO, H2S, CH4, 14C, CFC-11, and CFC-113 are affected by microbial degradation and other geochemical processes occurring within the aquifer. Groundwater mixing fractions were determined by using dissolved Cl− and δ18O data, recognizing 3 end-member water types in the groundwater mixtures: (1) Withlacoochee River water (δ18O=−2.5±0.3‰, Cl−=12.2±2 mg/l), (2) regional infiltration water (δ18O=−4.2±0.1‰, Cl−=2.3±0.1 mg/l), and (3) regional paleowater resident in the Upper Floridan aquifer (δ18O=−3.4±0.1‰, Cl−=2.6±0.1 mg/l) (uncertainties are ±1σ). Error simulation procedures were used to define uncertainties in mixing fractions. Fractions of river water in groundwater range from 0 to 72% and average 10%. The influence of river-water discharge on the quality of water in the Upper Floridan aquifer was traced from the sinkhole area on the Withlacoochee River 25 km SE in the direction of regional groundwater flow. Infiltration of water is most significant to the N and NW of Valdosta, but becomes negligible to the S and SE in the direction of general thickening of post-Eocene confining beds overlying the Upper Floridan aquifer.
Recent global travel time tomography studies by Zhou [1996] and van der Hilst et al. [1997] have been performed with cell parameterizations of the order of those frequently used in regional tomography studies (i.e., with cell sizes of 1°–2°). These new global models constitute a considerable improvement over previous results that were obtained with rather coarse parameterizations (5° cells). The inferred structures are, however, of larger scale than is usually obtained in regional models, and it is not clear where and if individual cells are actually resolved. This study aims at resolving lateral heterogeneity on scales as small as 0.6° in the upper mantle and 1.2°–3° in the lower mantle. This allows for the adequate mapping of expected small-scale structures induced by, for example, lithosphere subduction, deep mantle upwellings, and mid-ocean ridges. There are three major contributions that allow for this advancement. First, we employ an irregular grid of nonoverlapping cells adapted to the heterogeneous sampling of the Earth's mantle by seismic waves [Spakman and Bijwaard, 1998]. Second, we exploit the global data set of Engdahl et al. [1998], which is a reprocessed version of the global data set of the International Seismological Centre. Their reprocessing included hypocenter redetermination and phase reidentification. Finally, we combine all data used (P, pP, and pwP phases) into nearly 5 million ray bundles with a limited spatial extent such that averaging over large mantle volumes is prevented while the signal-to-noise ratio is improved. In the approximate solution of the huge inverse problem we obtain a variance reduction of 57.1%. Synthetic sensitivity tests indicate horizontal resolution on the scale of the smallest cells (0.6° or 1.2°) in the shallow parts of subduction zones decreasing to approximately 2°–3° resolution in well-sampled regions in the lower mantle. Vertical resolution can be worse (up to several hundreds of kilometers) in subduction zones with rays predominantly pointing along dip. Important features of the solution are as follows: 100–200 km thick high-velocity slabs beneath all major subduction zones, sometimes flattening in the transition zone and sometimes directly penetrating into the lower mantle; large high-velocity anomalies in the lower mantle that have been attributed to subduction of the Tethys ocean and the Farallon plate; and low-velocity anomalies continuing across the 660 km discontinuity to hotspots at the surface under Iceland, east Africa, the Canary Islands, Yellowstone, and the Society Islands. Our findings corroborate that the 660 km boundary may resist but not prevent (present day) large-scale mass transfer from upper to lower mantle or vice versa. This observation confirms the results of previous, global mantle studies that employed coarser parameterizations.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98JB02467","issn":"01480227","usgsCitation":"Bijwaard, H., Spakman, W., and Engdahl, E., 1998, Closing the gap between regional and global travel time tomography: Journal of Geophysical Research B: Solid Earth, v. 103, no. B12, p. 30055-30078, https://doi.org/10.1029/98JB02467.","productDescription":"24 p.","startPage":"30055","endPage":"30078","numberOfPages":"24","costCenters":[],"links":[{"id":231451,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"103","issue":"B12","noUsgsAuthors":false,"publicationDate":"1998-12-10","publicationStatus":"PW","scienceBaseUri":"5059f674e4b0c8380cd4c78c","contributors":{"authors":[{"text":"Bijwaard, H.","contributorId":16187,"corporation":false,"usgs":true,"family":"Bijwaard","given":"H.","email":"","affiliations":[],"preferred":false,"id":386423,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Spakman, W.","contributorId":92428,"corporation":false,"usgs":true,"family":"Spakman","given":"W.","email":"","affiliations":[],"preferred":false,"id":386425,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Engdahl, E.R.","contributorId":22906,"corporation":false,"usgs":true,"family":"Engdahl","given":"E.R.","email":"","affiliations":[],"preferred":false,"id":386424,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70020495,"text":"70020495 - 1998 - Estimation of the depth to the fresh-water/salt-water interface from vertical head gradients in wells in coastal and island aquifers","interactions":[],"lastModifiedDate":"2024-03-05T01:36:31.073353","indexId":"70020495","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1923,"text":"Hydrogeology Journal","active":true,"publicationSubtype":{"id":10}},"title":"Estimation of the depth to the fresh-water/salt-water interface from vertical head gradients in wells in coastal and island aquifers","docAbstract":"An accurate estimate of the depth to the theoretical interface between fresh, water and salt water is critical to estimates of well yields in coastal and island aquifers. The Ghyben–Herzberg relation, which is commonly used to estimate interface depth, can greatly underestimate or overestimate the fresh-water thickness, because it assumes no vertical head gradients and no vertical flow. Estimation of the interface depth needs to consider the vertical head gradients and aquifer anisotropy that may be present. This paper presents a method to calculate vertical head gradients using water-level measurements made during drilling of a partially penetrating well; the gradient is then used to estimate interface depth. Application of the method to a numerically simulated fresh-water/salt-water system shows that the method is most accurate when the gradient is measured in a deeply penetrating well. Even using a shallow well, the method more accurately estimates the interface position than does the Ghyben–Herzberg relation where substantial vertical head gradients exist. Application of the method to field data shows that drilling, collection methods of water-level data, and aquifer inhomogeneities can cause difficulties, but the effects of these difficulties can be minimized.
We use data from broadband seismometers deployed around the summit of Kilauea Volcano to quantify the mechanism associated with a transient in the flow of magma feeding the east rift eruption of the volcano. The transient is marked by rapid inflation of the Kilauea summit peaking at 22 μrad 4.5 hours after the event onset, followed by slow deflation over a period of 3 days. Superimposed on the summit inflation is a series of sawtooth displacement pulses, each characterized by a sudden drop in amplitude lasting 5–10 s followed by an exponential recovery lasting 1–3 min. The sawtooth waveforms display almost identical shapes, suggesting a process involving the repeated activation of a fixed source. The particle motion associated with each sawtooth is almost linear, and its major swing shows compressional motion at all stations. Analyses of semblance and particle motion are consistent with a point source located 1 km beneath the northeast edge of the Halemaumau pit crater. To estimate the source mechanism, we apply a moment tensor inversion to the waveform data, assuming a point source embedded in a homogeneous half-space with compressional and shear wave velocities representative of the average medium properties at shallow depth under Kilauea. Synthetic waveforms are constructed by a superposition of impulse responses for six moment tensor components and three single force components. The origin times of individual impulses are distributed along the time axis at appropriately small, equal intervals, and their amplitudes are determined by least squares. In this inversion, the source time functions of the six tensor and three force components are determined simultaneously. We confirm the accuracy of the inversion method through a series of numerical tests. The results from the inversion show that the waveform data are well explained by a pulsating transport mechanism operating on a subhorizontal crack linking the summit reservoir to the east rift of Kilauea. The crack acts like a buffer in which a batch of fluid (magma and/or gas) accumulates over a period of 1–3 min before being rapidly injected into a larger reservoir (possibly the east rift) over a timescale of 5–10 s. The seismic moment and volume change associated with a typical batch of fluid are approximately 1014 N m and 3000 m3, respectively. Our results also point to the existence of a single force component with amplitude of 109 N, which may be explained as the drag force generated by the flow of viscous magma through a narrow constriction in the flow path. The total volume of magma associated with the 4.5-hour-long activation of the pulsating source is roughly 500,000 m3 in good agreement with the integrated volume flow rate of magma estimated near the eruptive site.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98JB01122","issn":"01480227","usgsCitation":"Ohminato, T., Chouet, B., Dawson, P., and Kedar, S., 1998, Waveform inversion of very long period impulsive signals associated with magmatic injection beneath Kilauea Volcano, Hawaii: Journal of Geophysical Research B: Solid Earth, v. 103, no. 10, p. 23839-23862, https://doi.org/10.1029/98JB01122.","productDescription":"24 p.","startPage":"23839","endPage":"23862","numberOfPages":"24","costCenters":[],"links":[{"id":488098,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/98jb01122","text":"Publisher Index Page"},{"id":231264,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"103","issue":"10","noUsgsAuthors":false,"publicationDate":"1998-10-10","publicationStatus":"PW","scienceBaseUri":"505bcf9fe4b08c986b32e9e8","contributors":{"authors":[{"text":"Ohminato, T.","contributorId":53021,"corporation":false,"usgs":true,"family":"Ohminato","given":"T.","email":"","affiliations":[],"preferred":false,"id":386519,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Chouet, B. A.","contributorId":31813,"corporation":false,"usgs":true,"family":"Chouet","given":"B. A.","affiliations":[],"preferred":false,"id":386517,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Dawson, P. 0000-0003-4065-0588","orcid":"https://orcid.org/0000-0003-4065-0588","contributorId":49529,"corporation":false,"usgs":true,"family":"Dawson","given":"P.","affiliations":[],"preferred":false,"id":386518,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kedar, S.","contributorId":64931,"corporation":false,"usgs":true,"family":"Kedar","given":"S.","affiliations":[],"preferred":false,"id":386520,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70020519,"text":"70020519 - 1998 - The National Water Data Exchange-capabilities and trends in the dissemination and exchange of water data","interactions":[],"lastModifiedDate":"2012-03-12T17:20:17","indexId":"70020519","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1934,"text":"IAHS-AISH Publication","active":true,"publicationSubtype":{"id":10}},"title":"The National Water Data Exchange-capabilities and trends in the dissemination and exchange of water data","docAbstract":"This paper discusses the programmes of the National Water Data Exchange (NAWDEX) in providing access to US Geological Survey (USGS) water data and water-related information. NAWDEX dissseminates water data and water-related information by working cooperatively through a network of 68 Assistance Centers to more than 430 member organizations. In addition, NAWDEX provides access to the USGS Water Data Storage System (WATSTORE) and the US Environmental Protection Agency's Storage and Retrieval System (STORET). Recently, the trend has been to make water resources data available over the World Wide Web on the Internet. The NAWDEX homepage, located at Uniform Resource Locator http://h2o.er.usgs.gov/public/nawdex/nawdex.html, provides links to (a) Selected Water Resources Abstracts; (b) National Water Conditions Report; (c) historical streamflow data: and (d) real-time streamflow conditions. NAWDEX also transfers data to users over the Internet through the file transfer protocol (FTP).","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"IAHS-AISH Publication","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"IAHS","publisherLocation":"Wallingford, United Kingdom","issn":"01447815","usgsCitation":"Burton, J., 1998, The National Water Data Exchange-capabilities and trends in the dissemination and exchange of water data: IAHS-AISH Publication, no. 253, p. 237-248.","startPage":"237","endPage":"248","numberOfPages":"12","costCenters":[],"links":[{"id":231303,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"issue":"253","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505ba841e4b08c986b321ae4","contributors":{"authors":[{"text":"Burton, J.S.","contributorId":36549,"corporation":false,"usgs":true,"family":"Burton","given":"J.S.","email":"","affiliations":[],"preferred":false,"id":386524,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70020531,"text":"70020531 - 1998 - An improved technique for modeling initial reservoir hydrocarbon saturation distributions: Applications in Illinois (USA) aux vases oil reservoirs","interactions":[],"lastModifiedDate":"2012-03-12T17:20:16","indexId":"70020531","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2419,"text":"Journal of Petroleum Science and Engineering","active":true,"publicationSubtype":{"id":10}},"title":"An improved technique for modeling initial reservoir hydrocarbon saturation distributions: Applications in Illinois (USA) aux vases oil reservoirs","docAbstract":"An improved technique for modeling the initial reservoir hydrocarbon saturation distributions is presented. In contrast to the Leverett J-function approach, this methodology (hereby termed flow-unit-derived initial oil saturation or FUSOI) determines the distributions of the initial oil saturations from a measure of the mean hydraulic radius, referred to as the flow zone indicator (FZI). FZI is derived from porosity and permeability data. In the FUSOI approach, capillary pressure parameters, S(wir), P(d), and ??, derived from the Brooks and Corey (1966) model [Brooks, R.H., Corey, A.T., 1966. Hydraulic properties of porous media, Hydrology Papers, Colorado State Univ., Ft. Collins, No. 3, March.], are correlated to the FZI. Subsequent applications of these parameters then permit the computation of improved hydrocarbon saturations as functions of FZI and height above the free water level (FWL). This technique has been successfully applied in the Mississippian Aux Vases Sandstone reservoirs of the Illinois Basin (USA). The Aux Vases Zeigler field (Franklin County, IL, USA) was selected for a field-wide validation of this FUSOI approach because of the availability of published studies. With the initial oil saturations determined on a depth-by-depth basis in cored wells, it was possible to geostatistically determine the three-dimensional (3-D) distributions of initial oil saturations in the Zeigler field. The original oil-in-place (OOIP), computed from the detailed initialization of the 3-D reservoir simulation model of the Zeigler field, was found to be within 5.6% of the result from a rigorous material balance method.An improved technique for modeling the initial reservoir hydrocarbon saturation distributions is presented. In contrast to the Leverett J-function approach, this methodology (hereby termed flow-unit-derived initial oil saturation or FUSOI) determines the distributions of the initial oil saturations from a measure of the mean hydraulic radius, referred to as the flow zone indicator (FZI). FZI is derived from porosity and permeability data. In the FUSOI approach, capillary pressure parameters, Swir, Pd, and ??, derived from the Brooks and Corey (1966) model, are correlated to the FZI. Subsequent applications of these parameters then permit the computation of improved hydrocarbon saturations as functions of FZI and height above the free water level (FWL). This technique has been successfully applied in the Mississippian Aux Vases Sandstone reservoirs of the Illinois Basin (USA). The Aux Vases Zeigler field (Franklin County, IL, USA) was selected for a field-wide validation of this FUSOI approach because of the availability of published studies. With the initial oil saturations determined on a depth-by-depth basis in cored wells, it was possible to geostatistically determine the three-dimensional (3-D) distributions of initial oil saturations in the Zeigler field. The original oil-in-place (OOIP), computed from the detailed initialization of the 3-D reservoir simulation model of the Zeigler field, was found to be within 5.6% of the result from a rigorous material balance method.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Journal of Petroleum Science and Engineering","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier Sci B.V.","publisherLocation":"Amsterdam, Netherlands","doi":"10.1016/S0920-4105(98)00075-8","issn":"09204105","usgsCitation":"Udegbunam, E., and Amaefule, J., 1998, An improved technique for modeling initial reservoir hydrocarbon saturation distributions: Applications in Illinois (USA) aux vases oil reservoirs: Journal of Petroleum Science and Engineering, v. 21, no. 3-4, p. 143-152, https://doi.org/10.1016/S0920-4105(98)00075-8.","startPage":"143","endPage":"152","numberOfPages":"10","costCenters":[],"links":[{"id":206987,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0920-4105(98)00075-8"},{"id":231493,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"21","issue":"3-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059ea73e4b0c8380cd48884","contributors":{"authors":[{"text":"Udegbunam, E.","contributorId":98072,"corporation":false,"usgs":true,"family":"Udegbunam","given":"E.","email":"","affiliations":[],"preferred":false,"id":386568,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Amaefule, J.O.","contributorId":60407,"corporation":false,"usgs":true,"family":"Amaefule","given":"J.O.","email":"","affiliations":[],"preferred":false,"id":386567,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70020535,"text":"70020535 - 1998 - Rocky 7 prototype Mars rover field geology experiments: 1. Lavic Lake and Sunshine volcanic field, California","interactions":[],"lastModifiedDate":"2024-07-31T15:36:14.65038","indexId":"70020535","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","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":"Rocky 7 prototype Mars rover field geology experiments: 1. Lavic Lake and Sunshine volcanic field, California","docAbstract":"Experiments with the Rocky 7 rover were performed in the Mojave Desert to better understand how to conduct rover-based, long-distance (kilometers) geological traverses on Mars. The rover was equipped with stereo imaging systems for remote sensing science and hazard avoidance and 57Fe Mössbauer and nuclear magnetic resonance spectrometers for in situ determination of mineralogy of unprepared rock and soil surfaces. Laboratory data were also obtained using the spectrometers and an X ray diffraction (XRD)/XRF instrument for unprepared samples collected from the rover sites. Simulated orbital and descent image data assembled for the test sites were found to be critical for assessing the geologic setting, formulating hypotheses to be tested with rover observations, planning traverses, locating the rover, and providing a regional context for interpretation of rover-based observations. Analyses of remote sensing and in situ observations acquired by the rover confirmed inferences made from orbital and simulated descent images that the Sunshine Volcanic Field is composed of basalt flows. Rover data confirmed the idea that Lavic Lake is a recharge playa and that an alluvial fan composed of sediments with felsic compositions has prograded onto the playa. Rover-based discoveries include the inference that the basalt flows are mantled with aeolian sediment and covered with a dense pavement of varnished basalt cobbles. Results demonstrate that the combination of rover remote sensing and in situ analytical observations will significantly increase our understanding of Mars and provide key connecting links between orbital and descent data and analyses of returned samples.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98JE01768","issn":"01480227","usgsCitation":"Arvidson, R., Acton, C., Blaney, D., Bowman, J., Kim, S., Klingelhofer, G., Marshall, J., Niebur, C., Plescia, J., Saunders, R., and Ulmer, C., 1998, Rocky 7 prototype Mars rover field geology experiments: 1. Lavic Lake and Sunshine volcanic field, California: Journal of Geophysical Research E: Planets, v. 103, no. E10, p. 22671-22688, https://doi.org/10.1029/98JE01768.","productDescription":"18 p.","startPage":"22671","endPage":"22688","numberOfPages":"18","costCenters":[],"links":[{"id":479797,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/98je01768","text":"Publisher Index Page"},{"id":230949,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"103","issue":"E10","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505aae1ce4b0c8380cd8701c","contributors":{"authors":[{"text":"Arvidson, R. E.","contributorId":46666,"corporation":false,"usgs":true,"family":"Arvidson","given":"R. E.","affiliations":[],"preferred":false,"id":386585,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Acton, C.","contributorId":24521,"corporation":false,"usgs":true,"family":"Acton","given":"C.","affiliations":[],"preferred":false,"id":386583,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Blaney, D.","contributorId":72513,"corporation":false,"usgs":true,"family":"Blaney","given":"D.","email":"","affiliations":[],"preferred":false,"id":386590,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Bowman, J.","contributorId":58046,"corporation":false,"usgs":true,"family":"Bowman","given":"J.","affiliations":[],"preferred":false,"id":386589,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Kim, S.","contributorId":53120,"corporation":false,"usgs":true,"family":"Kim","given":"S.","email":"","affiliations":[],"preferred":false,"id":386587,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Klingelhofer, G.","contributorId":57195,"corporation":false,"usgs":true,"family":"Klingelhofer","given":"G.","email":"","affiliations":[],"preferred":false,"id":386588,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Marshall, J.","contributorId":45243,"corporation":false,"usgs":true,"family":"Marshall","given":"J.","email":"","affiliations":[],"preferred":false,"id":386584,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Niebur, C.","contributorId":51050,"corporation":false,"usgs":true,"family":"Niebur","given":"C.","affiliations":[],"preferred":false,"id":386586,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Plescia, J.","contributorId":20500,"corporation":false,"usgs":true,"family":"Plescia","given":"J.","affiliations":[],"preferred":false,"id":386582,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Saunders, R.S.","contributorId":14437,"corporation":false,"usgs":true,"family":"Saunders","given":"R.S.","email":"","affiliations":[],"preferred":false,"id":386581,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Ulmer, C.T.","contributorId":7035,"corporation":false,"usgs":true,"family":"Ulmer","given":"C.T.","email":"","affiliations":[],"preferred":false,"id":386580,"contributorType":{"id":1,"text":"Authors"},"rank":11}]}} ,{"id":70020555,"text":"70020555 - 1998 - Development and testing of a contamination potential mapping system for a portion of the General Separations Area, Savannah River Site, South Carolina","interactions":[],"lastModifiedDate":"2017-01-18T12:48:56","indexId":"70020555","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1539,"text":"Environmental Geology","active":true,"publicationSubtype":{"id":10}},"title":"Development and testing of a contamination potential mapping system for a portion of the General Separations Area, Savannah River Site, South Carolina","docAbstract":"A methodology was developed to evaluate and map the contamination potential or aquifer sensitivity of the upper groundwater flow system of a portion of the General Separations Area (GSA) at the Department of Energy's Savannah River Site (SRS) in South Carolina. A Geographic Information System (GIS) was used to integrate diverse subsurface geologic data, soils data, and hydrology utilizing a stack-unit mapping approach to construct mapping layers. This is the first time that such an approach has been used to delineate the hydrogeology of a coastal plain environment. Unit surface elevation maps were constructed for the tops of six Tertiary units derived from over 200 boring logs. Thickness or isopach maps were created for five hydrogeologic units by differencing top and basal surface elevations. The geologic stack-unit map was created by stacking the five isopach maps and adding codes for each stack-unit polygon. Stacked-units were rated according to their hydrogeologic properties and ranked using a logarithmic approach (utility theory) to establish a contamination potential index. Colors were assigned to help display relative importance of stacked-units in preventing or promoting transport of contaminants. The sensitivity assessment included the effects of surface soils on contaminants which are particularly important for evaluating potential effects from surface spills. Hydrogeologic/hydrologic factors did not exhibit sufficient spatial variation to warrant incorporation into contamination potential assessment. Development of this contamination potential mapping system provides a useful tool for site planners, environmental scientists, and regulatory agencies.A methodology was developed to evaluate and map the contamination potential or aquifer sensitivity of the upper groundwater flow system of a portion of the General Separations Area (GSA) at the Department of Energy's Savannah River Site (SRS) in South Carolina. A Geographic Information System (GIS) was used to integrate diverse subsurface geologic data, soils data, and hydrology utilizing a stack-unit mapping approach to construct mapping layers. This is the first time that such an approach has been used to delineate the hydrogeology of a coastal plain environment. Unit surface elevation maps were constructed for the tops of six Tertiary units derived from over 200 boring logs. Thickness or isopach maps were created for five hydrogeologic units by differencing top and basal surface elevations. The geologic stack-unit map was created by stacking the five isopach maps and adding codes for each stack-unit polygon. Stacked-units were rated according to their hydrogeologic properties and ranked using a logarithmic approach (utility theory) to establish a contamination potential index. Colors were assigned to help display relative importance of stacked-units in preventing or promoting transport of contaminants. The sensitivity assessment included the effects of surface soils on contaminants which are particularly important for evaluating potential effects from surface spills. Hydrogeologic/hydrologic factors did not exhibit sufficient spatial variation to warrant incorporation into contamination potential assessment. Development of this contamination potential mapping system provides a useful tool for site planners, environmental scientists, and regulatory agencies.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Environmental Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Springer-Verlag GmbH & Company KG","publisherLocation":"Berlin, Germany","doi":"10.1007/s002540050313","issn":"09430105","usgsCitation":"Rine, J., Berg, R.C., Shafer, J., Covington, E., Reed, J., Bennett, C., and Trudnak, J., 1998, Development and testing of a contamination potential mapping system for a portion of the General Separations Area, Savannah River Site, South Carolina: Environmental Geology, v. 35, no. 4, p. 263-277, https://doi.org/10.1007/s002540050313.","startPage":"263","endPage":"277","numberOfPages":"15","costCenters":[{"id":13634,"text":"South Atlantic Water Science Center","active":true,"usgs":true}],"links":[{"id":231305,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206942,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/s002540050313"}],"country":"United States","state":"South Carolina","otherGeospatial":"Savannah River Site","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -81.9854736328125,\n 32.87382044499353\n ],\n [\n -81.9854736328125,\n 33.42341844641943\n ],\n [\n -81.26174926757812,\n 33.42341844641943\n ],\n [\n -81.26174926757812,\n 32.87382044499353\n ],\n [\n -81.9854736328125,\n 32.87382044499353\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"35","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0027e4b0c8380cd4f5fc","contributors":{"authors":[{"text":"Rine, J.M.","contributorId":53145,"corporation":false,"usgs":true,"family":"Rine","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":386682,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Berg, R. C.","contributorId":11673,"corporation":false,"usgs":true,"family":"Berg","given":"R.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":386680,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Shafer, J.M.","contributorId":72995,"corporation":false,"usgs":true,"family":"Shafer","given":"J.M.","email":"","affiliations":[],"preferred":false,"id":386686,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Covington, E.R.","contributorId":58157,"corporation":false,"usgs":true,"family":"Covington","given":"E.R.","email":"","affiliations":[],"preferred":false,"id":386684,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Reed, J.K.","contributorId":38031,"corporation":false,"usgs":true,"family":"Reed","given":"J.K.","email":"","affiliations":[],"preferred":false,"id":386681,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Bennett, C.B.","contributorId":61308,"corporation":false,"usgs":true,"family":"Bennett","given":"C.B.","email":"","affiliations":[],"preferred":false,"id":386685,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Trudnak, J.E.","contributorId":56938,"corporation":false,"usgs":true,"family":"Trudnak","given":"J.E.","email":"","affiliations":[],"preferred":false,"id":386683,"contributorType":{"id":1,"text":"Authors"},"rank":7}]}} ,{"id":70020573,"text":"70020573 - 1998 - Erosional valleys in the Thaumasia region of Mars: Hydrothermal and seismic origins","interactions":[],"lastModifiedDate":"2024-07-31T15:34:12.740793","indexId":"70020573","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","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":"Erosional valleys in the Thaumasia region of Mars: Hydrothermal and seismic origins","docAbstract":"Analysis of erosional valleys, geologic materials and features, and topography through time in the Thaumasia region of Mars using co-registered digital spatial data sets reveals significant associations that relate to valley origin. Valleys tend to originate (1) on Noachian to Early Hesperian (stages 1 and 2) large volcanoes, (2) within 50–100 km of stages 1 and 2 rift systems, and (3) within 100 km of Noachian (stage 1) impact craters >50 km in diameter. These geologic preferences explain observations of higher valley-source densities (VSDs) in areas of higher elevations and regional slopes (>1°) because the volcanoes, rifts, and craters form high, steep topography or occur in terrain of high relief. Other stage 1 and stage 2 high, steep terrains, however, do not show high VSDs. The tendency for valleys to concentrate near geologic features and the overall low drainage densities in Thaumasia compared to terrestrial surfaces rule out widespread precipitation as a major factor in valley formation (as is proposed in wann, wet climate scenarios) except perhaps during the Early Noachian, for which much of the geologic record has been obliterated. Instead, volcanoes and rifts may indicate the presence of shallow crustal intrusions that could lead to local hydrothermal circulation, melting of ground ice and snow, and groundwater sapping. However, impact-crater melt would provide a heat source at the surface that might drive away water, fonning valleys in the process. Post-stage 1 craters mostly have low nearby VSDs, which, for valleys incised in older rocks, suggests burial by ejecta and, for younger valleys, may indicate desiccation of near-surface water and deepening of the cryosphere. Later Hesperian and Amazonian (stages 3 and 4) valleys originate within 100–200 km of three young, large impact craters and near rifts systems at Warrego Valles and the southern part of Coprates rise. These valleys likely developed when the cryosphere was a couple kilometers or more thick, inhibiting valley development by hydrothermal circulation. However, eruption of groundwater may have occurred from impact-induced fracturing and lateral and perhaps minor upward transport of water due to seismic pumping. The two smaller craters formed along the plateau margin where the highest potential hydraulic head would occur in aquifers beneath the plateau. In the case of the larger crater (Lowell, 200 km in diameter), potential aquifers would likely be at depths of kilometers below the cryosphere. Seismic energy generated by the Lowell impactor would have been much greater, pumping both groundwater and perhaps fluidized slurry to the surface from beneath the cryosphere to form the young valleys and flow deposit. Along the margin of Thaumasia, tectonic pressurization of groundwater also may have contributed to valley formation. Dissection of rim materials of the Argyre impact may relate to tectonic activity and the unconsolidated state of basin ejecta.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98JE01599","issn":"01480227","usgsCitation":"Tanaka, K.L., Dohm, J.M., Lias, J., and Hare, T., 1998, Erosional valleys in the Thaumasia region of Mars: Hydrothermal and seismic origins: Journal of Geophysical Research E: Planets, v. 103, no. E13, p. 31407-31419, https://doi.org/10.1029/98JE01599.","productDescription":"13 p.","startPage":"31407","endPage":"31419","numberOfPages":"13","costCenters":[],"links":[{"id":487326,"rank":2,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/98je01599","text":"Publisher Index Page"},{"id":230951,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"otherGeospatial":"Mars","volume":"103","issue":"E13","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0a46e4b0c8380cd5229e","contributors":{"authors":[{"text":"Tanaka, K. L.","contributorId":31394,"corporation":false,"usgs":false,"family":"Tanaka","given":"K.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":386733,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Dohm, J. M.","contributorId":102150,"corporation":false,"usgs":true,"family":"Dohm","given":"J.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":386736,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lias, J.H.","contributorId":46714,"corporation":false,"usgs":true,"family":"Lias","given":"J.H.","email":"","affiliations":[],"preferred":false,"id":386735,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Hare, T.M. 0000-0001-8842-389X","orcid":"https://orcid.org/0000-0001-8842-389X","contributorId":43828,"corporation":false,"usgs":true,"family":"Hare","given":"T.M.","affiliations":[],"preferred":false,"id":386734,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70020575,"text":"70020575 - 1998 - Meteoric sphaerosiderite lines and their use for paleohydrology and paleoclimatology","interactions":[],"lastModifiedDate":"2024-01-12T14:51:43.001013","indexId":"70020575","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1796,"text":"Geology","active":true,"publicationSubtype":{"id":10}},"title":"Meteoric sphaerosiderite lines and their use for paleohydrology and paleoclimatology","docAbstract":"Sphaerosiderite, a morphologically distinct millimeter-scale spherulitic siderite (FeCO3), forms predominantly in wetland soils and sediments, and is common in the geologic record. Ancient sphaerosiderites are found in paleosol horizons within coal-bearing stratigraphic intervals and, like their modern counterparts, are interpreted as having formed in water-saturated environments. Here we report on sphaerosiderites from four different stratigraphic units, each of which has highly variable 13C and relatively stable 18C compositions. The unique isotopic trends are analogous to well-documented meteoric calcite lines, which we define here as meteoric sphaerosiderite lines. Meteoric sphaerosiderite lines provide a new means of constraining ground-water δ18O and thus allow evaluation of paleohydrology and paleoclimate in humid continental settings.
Paleoclimatic interpretations of the Upper Triassic Chinle Formation (Colorado Plateau) based on plants conflict with those based on the sedimentary rocks. The plants are suggestive of a humid, equable climate, whereas the rocks are more consistent with deposition under highly seasonal precipitation and ground-water conditions. Fossil plant assemblages are limited to the lower members of the Chinle Formation, which were deposited within incised valleys that were cut into underlying Lower to Middle Triassic and older rocks. In contrast, the upper members of the formation, which were deposited across the fluvial plain after the incised valleys were filled, have few preserved fossil plants. The taphonomic characteristics of the plant fossil assemblages, within the stratigraphic and hydrologic context of the incised valley-fill sequence, explain the vertical and lateral distribution of these assemblages. The depositional, hydrological, and near-surface geochemical conditions were more conducive to preservation of the plants. Fossil plant assemblages in fully terrestrial incised-valley fills should be taphonomically biased toward riparian wetland environments. If those assemblages are used to interpret paleoclimate, the paleoclimatic interpretations will also be biased. The bias may be particularly strong in climates such as those during deposition of the Chinle Formation, when the riparian wetlands may reflect local hydrologic conditions rather than regional climate, and should be taken into account when using these types of plant assemblages in paleoclimatic interpretations.
We map the shaking intensity suffered in Los Angeles County during the 17 January 1994, Northridge earthquake using municipal safety inspection data. The intensity is estimated from the number of buildings given red, yellow, or green tags, aggregated by census tract. Census tracts contain from 200 to 4000 residential buildings and have an average area of 6 km2 but are as small as 2 and 1 km2 in the most densely populated areas of the San Fernando Valley and downtown Los Angeles, respectively. In comparison, the zip code areas on which standard MMI intensity estimates are based are six times larger, on average, than the census tracts. We group the buildings by age (before and after 1940 and 1976), by number of housing units (one, two to four, and five or more), and by construction type, and we normalize the tags by the total number of similar buildings in each census tract. We analyze the seven most abundant building categories. The fragilities (the fraction of buildings in each category tagged within each intensity level) for these seven building categories are adjusted so that the intensity estimates agree. We calibrate the shaking intensity to correspond with the modified Mercalli intensities (MMI) estimated and compiled by Dewey et al. (1995); the shapes of the resulting isoseismals are similar, although we underestimate the extent of the MMI = 6 and 7 areas. The fragility varies significantly between different building categories (by factors of 10 to 20) and building ages (by factors of 2 to 6). The post-1940 wood-frame multi-family (≧5 units) dwellings make up the most fragile building category, and the post-1940 woodframe single-family dwellings make up the most resistant building category.
Tritium/helium-3 (3H/3He) and chlorofluorocarbon (CFCs, CFC–11, CFC–12, CFC–113) data are used to date the young fraction in groundwater mixtures from a karstic limestone aquifer near Valdosta, Georgia, where regional paleowater in the Upper Floridan aquifer receives recharge from two young sources—the flow of Withlacoochee River water through sinkholes in the river bed, and leakage of infiltration water through post-Eocene semi-confining beds above the Upper Floridan aquifer. In dating the young fraction of mixtures using CFCs, it is necessary to reconstruct the CFC concentration that was in the young fraction prior to mixing. The 3H/3He age is independent of the extent of dilution with older (3H-free and 3Hetrit-free) water. The groundwater mixtures are designated as Type-1 for mixtures of regional paleowater and regional infiltration water and Type-2 for mixtures containing more than approximately 4% of river water. The fractions of regional paleowater, regional infiltration water, and Withlacoochee River water in the groundwater mixtures were determined from Cl− and δ18O data for water from the Upper Floridan aquifer at Valdosta, Georgia.
The chlorofluorocarbons CFC–11 and CFC–113 are removed by microbial degradation and/or sorption processes in most anaerobic (Type-2) groundwater at Valdosta, but are present in some aerobic Type-1 water. CFC–12 persists in both SO4-reducing and methanogenic water. The very low detection limits for CFCs (approximately 0.3 pg kg−1) permitted CFC–11 and CFC–12 dating of the fraction of regional infiltration water in Type-1 mixtures, and CFC-12 dating of the river-water fraction in Type-2 mixtures. Overall, approximately 50% of the 85 water samples obtained from the Upper Floridan aquifer have CFC–12-based ages of the young fraction that are consistent with the 3H concentration of the groundwater. Because of uncertainties associated with very low 3H and 3He content in dilute mixtures, 3H/3He dating is limited to the river-water fraction in Type-2 mixtures containing more than about 10% river water. Of the 41 water samples measured for 3H/3He dating, dilution of 3H and low 3He concentration limited 3H/3He dating to 16 mixtures in which 3H/3He ages are defined with errors ranging from ±2 to ±7.5 a (1 σ). After correction for dilution with (assumed) CFC-free regional infiltration water and regional paleowater in the Upper Floridan aquifer, adjusted CFC–12 ages agree with 3H/3He ages within 5 a or less in 7 of the 9 co-dated Type-2 mixtures.
Tritium data and dating based on both CFC–11 and CFC–12 in Type-1 mixtures indicate that travel times of infiltration water through the overlying Post-Eocene semi-confining beds exceed 35 a. The CFC and 3H/3He dating indicate that the river fraction in most groundwater entered the groundwater reservoir in the past 20 to 30 a. Few domestic and municipal supply wells sampled intercept water younger than 5 a. Calculated velocities of river water in the Upper Floridan aquifer downgradient of the sinkhole area range from 0.4 to 8.2 m/d. Radiocarbon data indicate that ages of the regional paleowater are on the 10 000-a time scale. An average lag time of approximately 10 to 25 a is determined for discharge of groundwater from the surficial and intermediate aquifers above the Upper Floridan aquifer to the Withlacoochee River.
","language":"English","publisher":"Elsevier","doi":"10.1016/S0883-2927(98)00032-8","issn":"08832927","usgsCitation":"Plummer, N., Busenberg, E., Drenkard, S., Schlosser, P., Ekwurzel, B., Weppernig, R., McConnell, J.B., and Michel, R.L., 1998, Flow of river water into a karstic limestone aquifer: 2. Dating the young fraction in groundwater mixtures in the Upper Floridan aquifer near Valdosta, Georgia: Applied Geochemistry, v. 13, no. 8, p. 1017-1043, https://doi.org/10.1016/S0883-2927(98)00032-8.","productDescription":"27 p.","startPage":"1017","endPage":"1043","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":487347,"rank":10000,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1016/s0883-2927(98)00032-8","text":"Publisher Index Page"},{"id":231269,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":206928,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/S0883-2927(98)00032-8"}],"country":"United States","state":"Georgia","county":"Lowndes County 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P.","contributorId":106656,"corporation":false,"usgs":true,"family":"Schlosser","given":"P.","email":"","affiliations":[],"preferred":false,"id":386800,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Ekwurzel, B.","contributorId":27223,"corporation":false,"usgs":true,"family":"Ekwurzel","given":"B.","affiliations":[],"preferred":false,"id":386794,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Weppernig, R.","contributorId":57616,"corporation":false,"usgs":true,"family":"Weppernig","given":"R.","affiliations":[],"preferred":false,"id":386796,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"McConnell, J. B.","contributorId":25577,"corporation":false,"usgs":true,"family":"McConnell","given":"J.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":386793,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Michel, R. L.","contributorId":86375,"corporation":false,"usgs":true,"family":"Michel","given":"R.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":386798,"contributorType":{"id":1,"text":"Authors"},"rank":8}]}} ,{"id":70020598,"text":"70020598 - 1998 - Proxy of monsoon seasonality in carbon isotopes from paleosols of the southern Chinese Loess Plateau","interactions":[],"lastModifiedDate":"2024-01-12T14:47:48.017904","indexId":"70020598","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1796,"text":"Geology","active":true,"publicationSubtype":{"id":10}},"title":"Proxy of monsoon seasonality in carbon isotopes from paleosols of the southern Chinese Loess Plateau","docAbstract":"Soil organic matter (SOM) and soil carbonate (SC) are common constituents in soils and are directly related to plant growth. SOM accumulates gradually from the decomposition of plant material over time, whereas SC formation is biased to dry-season soil-dissolved CO2 that derives from plant respiration during a drying phase of the growing season. In some mixed C3-C4 environments, the peak of C3 and C4 plant metabolism differs seasonally, and the carbon source that contributes to the SOM and SC can be different. Consequently, δ13SOM values reflect an annual average of the floral biomass, but δ13SC values reflect a seasonal aspect of the plant community. The relationship between δ13CSC and δ13CSOM is mainly controlled by how different the seasonal conditions are. Our results suggest that the relationship is a seasonal proxy that can be used to differentiate the seasonality effects of Indian, East Asian, and Siberian monsoons on the Chinese Loess Plateau during the last interglacial-glacial cycle.
Observational evidence for both static and transient near-field and far-field triggered seismicity are explained in terms of a frictional instability model, based on a single degree of freedom spring-slider system and rate- and state-dependent frictional constitutive equations. In this study a triggered earthquake is one whose failure time has been advanced by Δt (clock advance) due to a stress perturbation. Triggering stress perturbations considered include square-wave transients and step functions, analogous to seismic waves and coseismic static stress changes, respectively. Perturbations are superimposed on a constant background stressing rate which represents the tectonic stressing rate. The normal stress is assumed to be constant. Approximate, closed-form solutions of the rate-and-state equations are derived for these triggering and background loads, building on the work of Dieterich [1992, 1994]. These solutions can be used to simulate the effects of static and transient stresses as a function of amplitude, onset time t0, and in the case of square waves, duration. The accuracies of the approximate closed-form solutions are also evaluated with respect to the full numerical solution and t0. The approximate solutions underpredict the full solutions, although the difference decreases as t0 approaches the end of the earthquake cycle. The relationship between Δt and t0 differs for transient and static loads: a static stress step imposed late in the cycle causes less clock advance than an equal step imposed earlier, whereas a later applied transient causes greater clock advance than an equal one imposed earlier. For equal Δt, transient amplitudes must be greater than static loads by factors of several tens to hundreds depending on t0. We show that the rate-and-state model requires that the total slip at failure is a constant, regardless of the loading history. Thus a static load applied early in the cycle, or a transient applied at any time, reduces the stress at the initiation of failure, whereas static loads that are applied sufficiently late raise it. Rate-and-state friction predictions differ markedly from those based on Coulomb failure stress changes (ΔCFS) in which Δt equals the amplitude of the static stress change divided by the background stressing rate. The ΔCFS model assumes a stress failure threshold, while the rate-and-state equations require a slip failure threshold. The complete rate-and-state equations predict larger Δt than the ΔCFS model does for static stress steps at small t0, and smaller Δt than the ΔCFS model for stress steps at large t0. The ΔCFS model predicts nonzero Δt only for transient loads that raise the stress to failure stress levels during the transient. In contrast, the rate-and-state model predicts nonzero Δt for smaller loads, and triggered failure may occur well after the transient is finished. We consider heuristically the effects of triggering on a population of faults, as these effects might be evident in seismicity data. Triggering is manifest as an initial increase in seismicity rate that may be followed by a quiescence or by a return to the background rate. Available seismicity data are insufficient to discriminate whether triggered earthquakes are “new” or clock advanced. However, if triggering indeed results from advancing the failure time of inevitable earthquakes, then our modeling suggests that a quiescence always follows transient triggering and that the duration of increased seismicity also cannot exceed the duration of a triggering transient load. Quiescence follows static triggering only if the population of available faults is finite.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/98JB01125","issn":"01480227","usgsCitation":"Gomberg, J., Beeler, N., Blanpied, M., and Bodin, P., 1998, Earthquake triggering by transient and static deformations: Journal of Geophysical Research B: Solid Earth, v. 103, no. 10, p. 24411-24426, https://doi.org/10.1029/98JB01125.","productDescription":"16 p.","startPage":"24411","endPage":"24426","numberOfPages":"16","costCenters":[],"links":[{"id":230953,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"103","issue":"10","noUsgsAuthors":false,"publicationDate":"1998-10-10","publicationStatus":"PW","scienceBaseUri":"505a0507e4b0c8380cd50c19","contributors":{"authors":[{"text":"Gomberg, J.","contributorId":95994,"corporation":false,"usgs":true,"family":"Gomberg","given":"J.","email":"","affiliations":[],"preferred":false,"id":386851,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"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":386850,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Blanpied, M.L.","contributorId":61961,"corporation":false,"usgs":true,"family":"Blanpied","given":"M.L.","email":"","affiliations":[],"preferred":false,"id":386849,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Bodin, P.","contributorId":29554,"corporation":false,"usgs":true,"family":"Bodin","given":"P.","email":"","affiliations":[],"preferred":false,"id":386848,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70020610,"text":"70020610 - 1998 - Tidally oriented vertical migration and position maintenance of zooplankton in a temperate estuary","interactions":[],"lastModifiedDate":"2016-07-27T11:46:46","indexId":"70020610","displayToPublicDate":"1998-01-01T00:00:00","publicationYear":"1998","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2620,"text":"Limnology and Oceanography","active":true,"publicationSubtype":{"id":10}},"title":"Tidally oriented vertical migration and position maintenance of zooplankton in a temperate estuary","docAbstract":"In many estuaries, maxima in turbidity and abundance of several common species of zooplankton occur in the low salinity zone (LSZ) in the range of 0.5-6 practical salinity units (psu). Analysis of zooplankton abundance from monitoring in 1972-1987 revealed that historical maxima in abundance of the copepod Eurytemora affinis and the mysid Neomysis mercedis, and in turbidity as determined from Secchi disk data, were close to the estimated position of 2 psu bottom salinity. The copepod Sinocalanus doerrii had a maximum slightly landward of that of E. affinis. After 1987 these maxima decreased and shifted to a lower salinity, presumably because of the effects of grazing by the introduced clam Potamocorbula amurensis. At the same time, the copepod Pseudodiaptomus forbesi, the mysid Acanthomysis sp., and amphipods became abundant with peaks at salinity around 0.2-0.5 psu. Plausible mechanisms for maintenance of these persistent abundance peaks include interactions between variation in flow and abundance, either in the vertical or horizontal plane, or higher net population growth rate in the peaks than seaward of the peaks. In spring of 1994, a dry year, we sampled in and near the LSZ using a Lagrangian sampling scheme to follow selected isohalines while sampling over several complete tidal cycles. Acoustic Doppler current profilers were used to provide detailed velocity distributions to enable us to estimate longitudinal fluxes of organisms. Stratification was weak and gravitational circulation nearly absent in the LSZ. All of the common species of zooplankton migrated vertically in response to the tides, with abundance higher in the water column on the flood than on the ebb. Migration of mysids and amphipods was sufficient to override net seaward flow to produce a net landward flux of organisms. Migration of copepods, however, was insufficient to reverse or even greatly diminish the net seaward flux of organisms, implying alternative mechanisms of position maintenance.
","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Limnology and Oceanography","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00243590","usgsCitation":"Kimmerer, W., Burau, J., and Bennett, W., 1998, Tidally oriented vertical migration and position maintenance of zooplankton in a temperate estuary: Limnology and Oceanography, v. 43, no. 7, p. 1697-1709.","startPage":"1697","endPage":"1709","numberOfPages":"13","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":552,"text":"San Francisco Bay-Delta","active":false,"usgs":true},{"id":5079,"text":"Pacific Regional Director's Office","active":true,"usgs":true}],"links":[{"id":230993,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"43","issue":"7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bb383e4b08c986b325e2b","contributors":{"authors":[{"text":"Kimmerer, W.J.","contributorId":23305,"corporation":false,"usgs":true,"family":"Kimmerer","given":"W.J.","email":"","affiliations":[],"preferred":false,"id":386859,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Burau, J.R. 0000-0002-5196-5035","orcid":"https://orcid.org/0000-0002-5196-5035","contributorId":7307,"corporation":false,"usgs":true,"family":"Burau","given":"J.R.","affiliations":[],"preferred":false,"id":386858,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bennett, W.A.","contributorId":100572,"corporation":false,"usgs":true,"family":"Bennett","given":"W.A.","email":"","affiliations":[],"preferred":false,"id":386860,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ]}