We use three-dimensional elastic models to help guide the kinematic interpretation of crustal deformation associated with strike-slip faults. Deformation of the brittle upper crust in the vicinity of strike-slip fault systems is modeled with the assumption that upper crustal deformation is driven by the relative plate motion in the upper mantle. The driving motion is represented by displacement that is specified on the bottom of a 15-km-thick elastic upper crust everywhere except in a zone of finite width in the vicinity of the faults, which we term the “shear zone.” Stress-free basal boundary conditions are specified within the shear zone. The basal driving displacement is either pure strike slip or strike slip with a small oblique component, and the geometry of the fault system includes a single fault, several parallel faults, and overlapping en echelon faults. We examine the variations in deformation due to changes in the width of the shear zone and due to changes in the shear strength of the faults. In models with weak faults the width of the shear zone has a considerable effect on the surficial extent and amplitude of the vertical and horizontal deformation and on the amount of rotation around horizontal and vertical axes. Strong fault models have more localized deformation at the tip of the faults, and the deformation is partly distributed outside the fault zone. The dimensions of large basins along strike-slip faults, such as the Rukwa and Dead Sea basins, and the absence of uplift around pull-apart basins fit models with weak faults better than models with strong faults. Our models also suggest that the length-to-width ratio of pull-apart basins depends on the width of the shear zone and the shear strength of the faults and is not constant as previously suggested. We show that pure strike-slip motion can produce tectonic features, such as elongate half grabens along a single fault, rotated blocks at the ends of parallel faults, or extension perpendicular to overlapping en echelon faults, which can be misinterpreted to indicate a regional component of extension. Zones of subsidence or uplift can become wider than expected for transform plate boundaries when a minor component of oblique motion is added to a system of parallel strike-slip faults.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JB00877","issn":"01480227","usgsCitation":"ten Brink, U., Katzman, R., and Lin, J., 1996, Three-dimensional models of deformation near strike-slip faults: Journal of Geophysical Research B: Solid Earth, v. 101, no. 7, p. 16205-16220, https://doi.org/10.1029/96JB00877.","productDescription":"16 p.","startPage":"16205","endPage":"16220","numberOfPages":"16","costCenters":[{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"links":[{"id":226856,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"7","noUsgsAuthors":false,"publicationDate":"1996-07-10","publicationStatus":"PW","scienceBaseUri":"505bb340e4b08c986b325c89","contributors":{"authors":[{"text":"ten Brink, Uri S. 0000-0001-6858-3001 utenbrink@usgs.gov","orcid":"https://orcid.org/0000-0001-6858-3001","contributorId":127560,"corporation":false,"usgs":true,"family":"ten Brink","given":"Uri S.","email":"utenbrink@usgs.gov","affiliations":[{"id":186,"text":"Coastal and Marine Geology Program","active":true,"usgs":true},{"id":678,"text":"Woods Hole Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":false,"id":381463,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Katzman, Rafael","contributorId":79249,"corporation":false,"usgs":true,"family":"Katzman","given":"Rafael","email":"","affiliations":[],"preferred":false,"id":381462,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lin, J.","contributorId":33065,"corporation":false,"usgs":true,"family":"Lin","given":"J.","email":"","affiliations":[],"preferred":false,"id":381461,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70019037,"text":"70019037 - 1996 - Recent volcanism in the Siqueiros transform fault: Picritic basalts and implications for MORB magma genesis","interactions":[],"lastModifiedDate":"2023-12-09T00:38:00.386052","indexId":"70019037","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Recent volcanism in the Siqueiros transform fault: Picritic basalts and implications for MORB magma genesis","docAbstract":"Small constructional volcanic landforms and very fresh-looking lava flows are present along one of the inferred active strike-slip faults that connect two small spreading centers (A and B) in the western portion of the Siqueiros transform domain. The most primitive lavas (picritic and olivine-phyric basalts), exclusively recovered from the young-looking flows within the A-B strike-slip fault, contain millimeter-sized olivine phenocrysts (up to 20 modal%) that have a limited compositional range (Fo91.5-Fo89.5) and complexly zoned Cr-Al spinels. High-MgO (9.5-10.6 wt%) glasses sampled from the young lava flows contain 1-7% olivine phenocrysts (Fo90.5-Fo89) that could have formed by equilibrium crystallization from basaltic melts with Mg# values between 71 and 74. These high MgO (and high Al2O3) glasses may be near-primary melts from incompatible-element depleted oceanic mantle and little modified by crustal mixing and/or fractionation processes. Phase chemistry and major element systematics indicate that the picritic basalts are not primary liquids and formed by the accumulation of olivine and minor spinel from high-MgO melts (10% < MgO < 14%). Compared to typical N-MORB from the East Pacific Rise, the Siqueiros lavas are more primitive and depleted in incompatible elements. Phase equilibria calculations and comparisons with experimental data and trace element modeling support this hypothesis. They indicate such primary mid-ocean ridge basalt magmas formed by 10-18% accumulative decompression melting in the spinel peridotite field (but small amounts of melting in the garnet peridotite field are not precluded). The compositional variations of the primitive magmas may result from the accumulation of different small batch melt fractions from a polybaric melting column.","language":"English","publisher":"Elsevier","doi":"10.1016/0012-821X(96)00052-0","issn":"0012821X","usgsCitation":"Perfit, M., Fornari, D., Ridley, W., Kirk, P., Casey, J.F., Kastens, K., Reynolds, J., Edwards, M., Desonie, D., Shuster, R., and Paradis, S., 1996, Recent volcanism in the Siqueiros transform fault: Picritic basalts and implications for MORB magma genesis: Earth and Planetary Science Letters, v. 141, no. 1-4, p. 91-108, https://doi.org/10.1016/0012-821X(96)00052-0.","productDescription":"18 p.","startPage":"91","endPage":"108","numberOfPages":"18","costCenters":[],"links":[{"id":226943,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"141","issue":"1-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a9659e4b0c8380cd81f41","contributors":{"authors":[{"text":"Perfit, M.R.","contributorId":45467,"corporation":false,"usgs":true,"family":"Perfit","given":"M.R.","email":"","affiliations":[],"preferred":false,"id":381479,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Fornari, D.J.","contributorId":49520,"corporation":false,"usgs":true,"family":"Fornari","given":"D.J.","email":"","affiliations":[],"preferred":false,"id":381481,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Ridley, W.I.","contributorId":72122,"corporation":false,"usgs":true,"family":"Ridley","given":"W.I.","email":"","affiliations":[],"preferred":false,"id":381484,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kirk, P.D.","contributorId":30769,"corporation":false,"usgs":true,"family":"Kirk","given":"P.D.","email":"","affiliations":[],"preferred":false,"id":381478,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Casey, John F.","contributorId":29550,"corporation":false,"usgs":true,"family":"Casey","given":"John","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":381477,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Kastens, K.A.","contributorId":70917,"corporation":false,"usgs":true,"family":"Kastens","given":"K.A.","email":"","affiliations":[],"preferred":false,"id":381483,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Reynolds, J.R.","contributorId":72942,"corporation":false,"usgs":true,"family":"Reynolds","given":"J.R.","email":"","affiliations":[],"preferred":false,"id":381485,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Edwards, M.","contributorId":8627,"corporation":false,"usgs":true,"family":"Edwards","given":"M.","affiliations":[],"preferred":false,"id":381476,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Desonie, D.","contributorId":78099,"corporation":false,"usgs":true,"family":"Desonie","given":"D.","email":"","affiliations":[],"preferred":false,"id":381486,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Shuster, R.","contributorId":69725,"corporation":false,"usgs":true,"family":"Shuster","given":"R.","email":"","affiliations":[],"preferred":false,"id":381482,"contributorType":{"id":1,"text":"Authors"},"rank":10},{"text":"Paradis, S.","contributorId":46704,"corporation":false,"usgs":true,"family":"Paradis","given":"S.","email":"","affiliations":[],"preferred":false,"id":381480,"contributorType":{"id":1,"text":"Authors"},"rank":11}]}} ,{"id":70019043,"text":"70019043 - 1996 - The 1992 M=7 Cape Mendocino, California, earthquake: Coseismic deformation at the south end of the Cascadia megathrust","interactions":[],"lastModifiedDate":"2024-11-12T17:46:55.966205","indexId":"70019043","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"The 1992 M=7 Cape Mendocino, California, earthquake: Coseismic deformation at the south end of the Cascadia megathrust","docAbstract":"We invert geodetic measurements of coseismic surface displacements to determine a dislocation model for the April 25, 1992, M = 7 Cape Mendocino, California, earthquake. The orientation of the model slip vector, which nearly parallels North America-Juan de Fuca relative plate convergence, and the location and orientation of the model fault relative to the offshore Cascadia megathrust, suggest that the 1992 Cape Mendocino earthquake is the first well-recorded event to relieve strain associated with the Cascadia subduction zone. We use data from three geodetic techniques: (1) the horizontal and vertical displacements of 13 monuments surveyed with the Global Positioning System, corrected for observed horizontal interseismic strain accumulation, (2) 88 section-elevation differences between leveling monuments, and (3) the uplift of 12 coastal sites observed from the die-off of intertidal marine organisms. Maximum observed displacements are 0.4 m of horizontal movement and 1.5 m of uplift along the coast. We use Monte Carlo techniques to estimate an optimal uniform slip rectangular fault geometry and its uncertainties. The optimal model using all the data resolves 4.9 m of slip on a 14 by 15 km fault that dips 28° SE. The fault extends from 1.5 to 8.7 km in depth and the main-shock hypocenter is close to the downdip projection of the fault. The shallowly dipping fault plane is consistent with the observed aftershock locations, and the estimated geodetic moment is 3.1 × 1019 N m, 70% of the seismic moment. Other models that exclude leveling data collected in 1935 and 1942 are more consistent with seismological estimates of the fault geometry. If the earthquake is characteristic for this segment, the estimated horizontal slip vector compared with plate convergence rates suggests a recurrence interval of 140 years, with a 95% confidence range of 100–670 years. The coseismic uplift occurred in a region that also has high Quaternary uplift rates determined from marine terrace studies. If repeated ruptures of this southernmost segment of the Cascadia megathrust are responsible for the Quaternary uplift, a comparison of the coseismic uplift with coastal uplift rates suggests a recurrence interval of 200–400 years. Thus comparing horizontal and vertical coseismic to long-term deformation suggests a recurrence interval of about 100–300 years for M = 7 events at the south end of the Cascadia megathrust.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95JB02623","issn":"01480227","usgsCitation":"Murray, M., Marshall, G., Lisowski, M., and Stein, R., 1996, The 1992 M=7 Cape Mendocino, California, earthquake: Coseismic deformation at the south end of the Cascadia megathrust: Journal of Geophysical Research B: Solid Earth, v. 101, no. 8, p. 17707-17725, https://doi.org/10.1029/95JB02623.","productDescription":"19 p.","startPage":"17707","endPage":"17725","numberOfPages":"19","costCenters":[],"links":[{"id":226313,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"8","noUsgsAuthors":false,"publicationDate":"1996-08-10","publicationStatus":"PW","scienceBaseUri":"505ba632e4b08c986b320f61","contributors":{"authors":[{"text":"Murray, M.H.","contributorId":50171,"corporation":false,"usgs":true,"family":"Murray","given":"M.H.","email":"","affiliations":[],"preferred":false,"id":381501,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Marshall, G.A.","contributorId":42615,"corporation":false,"usgs":true,"family":"Marshall","given":"G.A.","email":"","affiliations":[],"preferred":false,"id":381500,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lisowski, M.","contributorId":70381,"corporation":false,"usgs":true,"family":"Lisowski","given":"M.","email":"","affiliations":[],"preferred":false,"id":381502,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Stein, R.S.","contributorId":8875,"corporation":false,"usgs":true,"family":"Stein","given":"R.S.","email":"","affiliations":[],"preferred":false,"id":381499,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70019058,"text":"70019058 - 1996 - Constraints on the thermal history of Taylorsville Basin, Virginia, U.S.A., from fluid-inclusion and fission-track analyses: Implications for subsurface geomicrobiology experiments","interactions":[],"lastModifiedDate":"2013-01-20T17:13:56","indexId":"70019058","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1213,"text":"Chemical Geology","active":true,"publicationSubtype":{"id":10}},"title":"Constraints on the thermal history of Taylorsville Basin, Virginia, U.S.A., from fluid-inclusion and fission-track analyses: Implications for subsurface geomicrobiology experiments","docAbstract":"Microbial populations have been found at the depth of 2621-2804 m in a borehole near the center of Triassic Taylorsville Basin, Virginia. To constrain possible scenarios for long-term survival in or introduction of these microbial populations to the deep subsurface, we attempted to refine models of thermal and burial history of the basin by analyzing aqueous and gaseous fluid inclusions in calcite/quartz veins or cements in cuttings from the same borehole. These results are complemented by fission-track data from the adjacent boreholes. Homogenization temperatures of secondary aqueous fluid inclusions range from 120?? to 210??C between 2027- and 3069-m depth, with highest temperatures in the deepest samples. The salinities of these aqueous inclusions range from 0 to ??? 4.3 eq wt% NaCl. Four samples from the depth between 2413 and 2931 m contain both two-phase aqueous and one-phase methane-rich inclusions in healed microcracks. The relative CH4 and CO2 contents of these gaseous inclusions was estimated by microthermometry and laser Raman spectroscopy. If both types of inclusions in sample 2931 m were trapped simultaneously, the density of the methane-rich inclusions calculated from the Peng - Robinson equation of state implies an entrapment pressure of 360 ?? 20 bar at the homogenization temperature (162.5 ?? 12.5??C) of the aqueous inclusions. This pressure falls between the hydrostatic and lithostatic pressures at the present depth 2931 m of burial. If we assume that the pressure regime was hydrostatic at the time of trapping, then the inclusions were trapped at 3.6 km in a thermal gradient of ??? 40??C/km. The high temperatures recorded by the secondary aqueous inclusions are consistent with the pervasive resetting of zircon and apatite fission-track dates. In order to fit the fission-track length distributions of the apatite data, however, a cooling rate of 1-2??C/Ma following the thermal maximum is required. To match the integrated dates, the thermal maximum would have occurred at ??? 200 Ma. The timing of the maximum temperature is consistent with rapid burial of the Taylorsville Basin to twice its present-day depth and thermal re-equilibration with a 40??C/km geothermal gradient, followed by slow exhumation. The results may imply that the microorganisms did not survive in situ, but were transported from the cooler portions of the basin sometime after maximum burial and heating.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Chemical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier","doi":"10.1016/0009-2541(95)00130-1","issn":"00092541","usgsCitation":"Tseng, H., Onstott, T., Burruss, R., and Miller, D.S., 1996, Constraints on the thermal history of Taylorsville Basin, Virginia, U.S.A., from fluid-inclusion and fission-track analyses: Implications for subsurface geomicrobiology experiments: Chemical Geology, v. 127, no. 4, p. 297-311, https://doi.org/10.1016/0009-2541(95)00130-1.","startPage":"297","endPage":"311","numberOfPages":"15","costCenters":[],"links":[{"id":205745,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0009-2541(95)00130-1"},{"id":226535,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"127","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059fa10e4b0c8380cd4d900","contributors":{"authors":[{"text":"Tseng, H.-Y.","contributorId":77672,"corporation":false,"usgs":true,"family":"Tseng","given":"H.-Y.","email":"","affiliations":[],"preferred":false,"id":381547,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Onstott, T.C.","contributorId":47006,"corporation":false,"usgs":true,"family":"Onstott","given":"T.C.","affiliations":[],"preferred":false,"id":381545,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Burruss, R.C. 0000-0001-6827-804X","orcid":"https://orcid.org/0000-0001-6827-804X","contributorId":99574,"corporation":false,"usgs":true,"family":"Burruss","given":"R.C.","affiliations":[],"preferred":false,"id":381548,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Miller, D. S.","contributorId":64260,"corporation":false,"usgs":true,"family":"Miller","given":"D.","email":"","middleInitial":"S.","affiliations":[],"preferred":false,"id":381546,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70019066,"text":"70019066 - 1996 - The upper mantle structure of the central Rio Grande rift region from teleseismic P and S wave travel time delays and attenuation","interactions":[],"lastModifiedDate":"2024-11-12T17:50:20.69341","indexId":"70019066","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"The upper mantle structure of the central Rio Grande rift region from teleseismic P and S wave travel time delays and attenuation","docAbstract":"The lithosphere beneath a continental rift should be significantly modified due to extension. To image the lithosphere beneath the Rio Grande rift (RGR), we analyzed teleseismic travel time delays of both P and S wave arrivals and solved for the attenuation of P and S waves for four seismic experiments spanning the Rio Grande rift. Two tomographic inversions of the P wave travel time data are given: an Aki-Christofferson-Husebye (ACH) block model inversion and a downward projection inversion. The tomographic inversions reveal a NE-SW to NNE-SSW trending feature at depths of 35 to 145 km with a velocity reduction of 7 to 8% relative to mantle velocities beneath the Great Plains. This region correlates with the transition zone between the Colorado Plateau and the Rio Grande rift and is bounded on the NW by the Jemez lineament, a N52°E trending zone of late Miocene to Holocene volcanism. S wave delays plotted against P wave delays are fit with a straight line giving a slope of 3.0 ± 0.4. This correlation and the absolute velocity reduction imply that temperatures in the lithosphere are close to the solidus, consistent with, but not requiring, the presence of partial melt in the mantle beneath the Rio Grande rift. The attenuation data could imply the presence of partial melt. We compare our results with other geophysical and geologic data. We propose that any north-south trending thermal (velocity) anomaly that may have existed in the upper mantle during earlier (Oligocene to late Miocene) phases of rifting and that may have correlated with the axis of the rift has diminished with time and has been overprinted with more recent structure. The anomalously low-velocity body presently underlying the transition zone between the core of the Colorado Plateau and the rift may reflect processes resulting from the modern (Pliocene to present) regional stress field (oriented WNW-ESE), possibly heralding future extension across the Jemez lineament and transition zone.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JB00109","issn":"01480227","usgsCitation":"Slack, P., Davis, P., Baldridge, W., Olsen, K., Glahn, A., Achauer, U., and Spence, W., 1996, The upper mantle structure of the central Rio Grande rift region from teleseismic P and S wave travel time delays and attenuation: Journal of Geophysical Research B: Solid Earth, v. 101, no. 7, p. 16003-16023, https://doi.org/10.1029/96JB00109.","productDescription":"21 p.","startPage":"16003","endPage":"16023","numberOfPages":"21","costCenters":[],"links":[{"id":226676,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"7","noUsgsAuthors":false,"publicationDate":"1996-07-10","publicationStatus":"PW","scienceBaseUri":"505bb151e4b08c986b3252cb","contributors":{"authors":[{"text":"Slack, P.D.","contributorId":42370,"corporation":false,"usgs":true,"family":"Slack","given":"P.D.","email":"","affiliations":[],"preferred":false,"id":381575,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Davis, P.M.","contributorId":15229,"corporation":false,"usgs":true,"family":"Davis","given":"P.M.","email":"","affiliations":[],"preferred":false,"id":381573,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Baldridge, W.S.","contributorId":63956,"corporation":false,"usgs":true,"family":"Baldridge","given":"W.S.","affiliations":[],"preferred":false,"id":381576,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Olsen, K.H.","contributorId":95201,"corporation":false,"usgs":true,"family":"Olsen","given":"K.H.","email":"","affiliations":[],"preferred":false,"id":381578,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Glahn, A.","contributorId":21293,"corporation":false,"usgs":true,"family":"Glahn","given":"A.","email":"","affiliations":[],"preferred":false,"id":381574,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Achauer, U.","contributorId":91998,"corporation":false,"usgs":true,"family":"Achauer","given":"U.","affiliations":[],"preferred":false,"id":381577,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Spence, W.","contributorId":7721,"corporation":false,"usgs":true,"family":"Spence","given":"W.","email":"","affiliations":[],"preferred":false,"id":381572,"contributorType":{"id":1,"text":"Authors"},"rank":7}]}} ,{"id":70019071,"text":"70019071 - 1996 - Paleomagnetism of Jurassic radiolarian chert above the Coast Range ophiolite at Stanley Mountain, California, and implications for its paleogeographic origins","interactions":[],"lastModifiedDate":"2023-12-22T00:29:40.341843","indexId":"70019071","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Paleomagnetism of Jurassic radiolarian chert above the Coast Range ophiolite at Stanley Mountain, California, and implications for its paleogeographic origins","docAbstract":"Upper Jurassic red tuffaceous chert above the Coast Range ophiolite at Stanley Mountain, California (lat 35°N, long 240°E), contains three components of remanent magnetization. The first component (A; removed by ≈100–≈200°C) has a direction near the present-day field for southern California and is probably a recently acquired thermoviscous magnetization. A second component (B; removed between ≈100 and ≈600°C) is identical to that observed by previous workers in samples of underlying pillow basalt and overlying terrigenous sedimentary rocks. This component has constant normal polarity and direction throughout the entire section, although these rocks were deposited during a mixed polarity interval of the geomagnetic field. The B magnetization, therefore, is inferred to be a secondary magnetization acquired during accretion, uplift, or Miocene volcanism prior to regional clockwise rotation. The highest temperature component (C; removed between ≈480 and 680°C) is of dual polarity and is tentatively interpreted as a primary magnetization, although it fails a reversal test possibly due to contamination by B. Separation of the B and C components is best shown by samples with negative-inclination C directions, and a corrected mean direction using only these samples indicates an initial paleolatitude of 32°N ± 8°. Paleobiogeographic models relating radiolarian faunal distribution patterns to paleolatitude have apparently been incorrectly calibrated using the overprint B component. Few other paleomagnetic data have been incorporated in these models, and faunal distribution patterns are poorly known and mostly unquantified. The available data, therefore, do not support formation of the Coast Range ophiolite at Stanley Mountain near the paleoequator or accretion at ≈10°N paleolatitude, as has been previously suggested based on paleomagnetic data, but indicate deposition near expected paleolatitudes for North America (35°N ± 4°) during Late Jurassic time.
Loess of late Quaternary age mantles most of Nebraska south of the Platte River Valley. At least five late Quaternary loesses are recognized: from oldest to youngest, one or more undifferentiated pre-Illinoian loesses, the Loveland Loess, the Gilman Canyon Loess, which exhibits a well developed soil and rests unconformably on the Sangamon soil, the Peoria Loess capped by the Brady soil, and the Bignell Loess, which is distributed discontinuously. Previous research shows that the Loveland Loess is Illinoian, the Gilman Canyon Loess and Peoria Loess are Wisconsin, and the Bignell Loess is Holocene. We present here the first thermoluminescence (TL) age estimates and new 14C ages for these late Quaternary loesses at two key sections in southwestern Nebraska, the Eustis ash pit and the Bignell Hill road cut. TL age estimates from all samples collected from Eustis ash pit and Bignell Hill were internally consistent. TL and 14C age estimates from these two sections generally agree and support previous age determinations.
The TL age estimate on Loveland Loess indicates deposition at 163 ka. TL and radiocarbon age estimates indicate that Gilman Canyon Loess, believed to be deposited during the Farmdale interstade, first began to accumulate at about 40 ka: the lower part of the Gilman Canyon Loess is 36 ka at Eustis and the middle of the unit is 30 ka at Bignell Hill. The lower and upper parts of the Peoria Loess give age estimates of 24 ka and 17 ka, respectively. TL age estimates for deposition of the Bignell Loess are 9 ka near the base, in agreement with radiocarbon age estimates, and 6 ka immediately below the modern soil, substantiating its Holocene age. Comparisons of TL age estimates with δ18O and insolation curves which show loess deposition during interglacial and interstadial as well as glacial periods, indicate that loess deposition on the Great Plains can occur under a variety of climatic conditions.
The peak accelerations recorded on alluvial sites during the Northridge earthquake were about 50% larger than the median value predicted by current empirical attenuation relations at distances less than about 30 km. This raises the question of whether the ground motions from the Northridge earthquake are anomalous for thrust events or are representative of ground motions expected in future thrust earthquakes. Since the empirical data base contains few strong-motion records close to large-thrust earthquakes, it is difficult to assess whether the Northridge ground motions are anomalous based on recorded data alone. For this reason, we have used a broadband strong-motion simulation procedure to help assess whether the ground motions were anomalous. The simulation procedure has been validated against a large body of strong-motion data from California earthquakes, and so we expect it to produce accurate estimates of ground motions for any given rupture scenario, including blind-thrust events for which no good precedent existed in the strong-motion data base until the occurrence of the Northridge earthquake. The ground motions from the Northridge earthquake and our simulations of these ground motions have a similar pattern of departure from empirical attenuation relations for thrust earthquakes: the peak accelerations are at about the 84th percentile level for distances within 20 to 30 km and follow the median level for larger distances. This same pattern of departure from empirical attenuation relations was obtained in our simulations of the peak accelerations of an Elysian Park blind-thrust event prior to the occurrence of the Northridge earthquake. Since we are able to model this pattern with broadband simulations, and had done so before the Northridge earthquake occurred, this suggests that the Northridge strong-motion records are not anomalous and are representative of ground motions close to thrust faults. Accordingly, it seems appropriate to include these recordings in strong-motion data sets that are used to develop empirical ground-motion attenuation relations for thrust faults and to use this augmented data set as the basis for evaluating the need for modifications in design coefficients in the seismic provisions of building codes.
The friction-slope term in the unsteady open-channel flow equations is examined using two numerical models based on different formulations of the governing equations and employing different solution methods. The purposes of the study are to analyze, evaluate, and demonstrate the behavior of the term in a set of controlled numerical experiments using varied types and combinations of boundary conditions. Results of numerical experiments illustrate that a given model can respond inconsistently for the identical resistance-coefficient value under different types and combinations of boundary conditions. Findings also demonstrate that two models employing different dependent variables and solution methods can respond similarly for the identical resistance-coefficient value under similar types and combinations of boundary conditions. Discussion of qualitative considerations and quantitative experimental results provides insight into the proper treatment, evaluation, and significance of the friction-slope term, thereby offering practical guidelines for model implementation and calibration.
","language":"English","publisher":"ASCE","doi":"https://doi.org/10.1061/(ASCE)0733-9429(1996)122:2(73)","issn":"07339429","usgsCitation":"Schaffranek, R., and Lai, C., 1996, Friction-term response to boundary-condition type in flow models: Journal of Hydraulic Engineering, v. 122, no. 2, p. 73-81, https://doi.org/https://doi.org/10.1061/(ASCE)0733-9429(1996)122:2(73).","productDescription":"9 p.","startPage":"73","endPage":"81","numberOfPages":"9","costCenters":[],"links":[{"id":226783,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"122","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a13ede4b0c8380cd54826","contributors":{"authors":[{"text":"Schaffranek, R.W.","contributorId":61468,"corporation":false,"usgs":true,"family":"Schaffranek","given":"R.W.","affiliations":[],"preferred":false,"id":382304,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lai, C.","contributorId":27622,"corporation":false,"usgs":true,"family":"Lai","given":"C.","email":"","affiliations":[],"preferred":false,"id":382303,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019310,"text":"70019310 - 1996 - Observed and simulated movement of bank-storage water","interactions":[],"lastModifiedDate":"2020-01-07T13:44:39","indexId":"70019310","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Observed and simulated movement of bank-storage water","docAbstract":"Detailed hydrologic and water-chemistry data were collected that document the movement of bank-storage water during March 7-April 17, 1990, in an alluvial aquifer adjacent to the Cedar River, Iowa. Hydrologic data included 745 daily ground-water-level measurements from 27 observation wells. Water-chemistry data indicate that bank-storage water had smaller specific conductance and larger concentration of atrazine than ambient ground water. To quantify the movement of the bank-storage water, a two-dimensional ground-water flow model was constructed, and the resulting calibrated model accurately simulated observed conditions. Analysis of water chemistry and model results indicate that a 2-meter rise in the river stage caused bank-storage water to move horizontally at least 30 meters into the aquifer and vertically about 4 meters below the river bottom, whereas the remaining 30 percent moved laterally through the riverbank. The model also showed that bank storage caused the ground-water flux to the river to increase by a factor of five during the first three weeks of base flow after runoff and that it required about five weeks for bank-storage water to discharge from the alluvial aquifer after the peak river stage. These results quantitatively demonstrate the importance of bank storage as a source of recharge to the alluvial aquifer and as a source of water to the river during early base-flow conditions.
","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.1996.tb01872.x","issn":"0017467X","usgsCitation":"Squillace, P.J., 1996, Observed and simulated movement of bank-storage water: Ground Water, v. 34, no. 1, p. 121-134, https://doi.org/10.1111/j.1745-6584.1996.tb01872.x.","productDescription":"14 p.","startPage":"121","endPage":"134","numberOfPages":"14","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":351,"text":"Iowa Water Science Center","active":true,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":226874,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Iowa","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -91.53173446655273,\n 41.91415807933598\n ],\n [\n -91.53173446655273,\n 41.930219515373096\n ],\n [\n -91.50856018066406,\n 41.930219515373096\n ],\n [\n -91.50856018066406,\n 41.91415807933598\n ],\n [\n -91.53173446655273,\n 41.91415807933598\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"34","issue":"1","noUsgsAuthors":false,"publicationDate":"2005-08-04","publicationStatus":"PW","scienceBaseUri":"505a6aebe4b0c8380cd74406","contributors":{"authors":[{"text":"Squillace, P. J.","contributorId":8878,"corporation":false,"usgs":true,"family":"Squillace","given":"P.","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":382310,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70019311,"text":"70019311 - 1996 - The generation of HCl in the system CaCl2-H2O: Vapor-liquid relations from 380-500°C","interactions":[],"lastModifiedDate":"2015-05-21T13:37:58","indexId":"70019311","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1759,"text":"Geochimica et Cosmochimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"The generation of HCl in the system CaCl2-H2O: Vapor-liquid relations from 380-500°C","docAbstract":"We determined vapor-liquid relations (P-T-x) and derived critical parameters for the system CaCl2-H2O from 380-500??C. Results show that the two-phase region of this system is extremely large and occupies a significant portion of the P-T space to which circulation of fluids in the Earth's crust is constrained. Results also show the system generates significant amounts of HCl (as much as 0.1 mol/kg) in the vapor phase buffered by the liquid at surprisingly high pressures (???230 bars at 380??C, <580 bars at 500??C), presumably by hydrolysis of CaCl2: CaCl2 + 2H2O = Ca(OH)2 + 2HCl. We interpret the abundance of HCl in the vapor as due to its preference for the vapor phase, and by the preference of Ca(OH)2 for either the liquid phase or solid. The recent recognition of the abundance of CaCl2 in deep brines of the Earth's crust and their hydrothermal mobilization makes the hydrolysis of CaCl2 geologically important. The boiling of Ca-rich brines produces abundant HCl buffered by the presence of the liquid at moderate pressures. The resultant Ca(OH)2 generated by this process reacts with silicates to form a variety of alteration products, such as epidote, whereas the vapor produces acid-alteration of rocks through which it ascends.","language":"English","publisher":"Elsevier","doi":"10.1016/0016-7037(95)00365-7","issn":"00167037","usgsCitation":"Bischoff, J.L., Rosenbauer, R.J., and Fournier, R.O., 1996, The generation of HCl in the system CaCl2-H2O: Vapor-liquid relations from 380-500°C: Geochimica et Cosmochimica Acta, v. 60, no. 1, p. 7-16, https://doi.org/10.1016/0016-7037(95)00365-7.","productDescription":"10 p.","startPage":"7","endPage":"16","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[],"links":[{"id":205800,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0016-7037(95)00365-7"},{"id":226875,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"60","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bac3de4b08c986b323370","contributors":{"authors":[{"text":"Bischoff, James L. jbischoff@usgs.gov","contributorId":1389,"corporation":false,"usgs":true,"family":"Bischoff","given":"James","email":"jbischoff@usgs.gov","middleInitial":"L.","affiliations":[],"preferred":true,"id":382311,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Rosenbauer, Robert J. brosenbauer@usgs.gov","contributorId":204,"corporation":false,"usgs":true,"family":"Rosenbauer","given":"Robert","email":"brosenbauer@usgs.gov","middleInitial":"J.","affiliations":[{"id":520,"text":"Pacific Coastal and Marine Science Center","active":true,"usgs":true}],"preferred":true,"id":382312,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Fournier, Robert O.","contributorId":73202,"corporation":false,"usgs":true,"family":"Fournier","given":"Robert","email":"","middleInitial":"O.","affiliations":[],"preferred":false,"id":382313,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70019329,"text":"70019329 - 1996 - Reactive solute transport in streams: 2. Simulation of a pH modification experiment","interactions":[],"lastModifiedDate":"2019-02-20T09:43:37","indexId":"70019329","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Reactive solute transport in streams: 2. Simulation of a pH modification experiment","docAbstract":"We present an application of an equilibrium-based solute transport model to a pH-modification experiment conducted on the Snake River, an acidic, metal-rich stream located in the Rocky Mountains of Colorado. During the experiment, instream pH decreased from 4.2 to 3.2, causing a marked increase in dissolved iron concentrations. Model application requires specification of several parameters that are estimated using tracer techniques, mass balance calculations, and geochemical data. Two basic questions are addressed through model application: (1) What are the processes responsible for the observed increase in dissolved iron concentrations? (2) Can the identified processes be represented within the equilibrium-based transport model? Simulation results indicate that the increase in iron was due to the dissolution of hydrous iron oxides and the photoreduction of ferric iron. Dissolution from the streambed is represented by considering a trace compartment consisting of freshly precipitated hydrous iron oxide and an abundant compartment consisting of aged precipitates that are less soluble. Spatial variability in the solubility of hydrous iron oxide is attributed to heterogeneity in the streambed sediments, temperature effects, and/or variability in the effects of photoreduction. Solubility products estimated via simulation fall within a narrow range (pKsp from 40.2 to 40.8) relative to the 6 order of magnitude variation reported for laboratory experiments (pKsp from 37.3 to 43.3). Results also support the use of an equilibrium-based transport model as the predominate features of the iron and pH profiles are reproduced. The model provides a valuable tool for quantifying the nature and extent of pH-dependent processes within the context of hydrologic transport.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95WR03107","usgsCitation":"Runkel, R.L., McKnight, D.M., Bencala, K.E., and Chapra, S.C., 1996, Reactive solute transport in streams: 2. Simulation of a pH modification experiment: Water Resources Research, v. 32, no. 2, p. 419-430, https://doi.org/10.1029/95WR03107.","productDescription":"12 p.","startPage":"419","endPage":"430","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":226510,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"32","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a9588e4b0c8380cd81a93","contributors":{"authors":[{"text":"Runkel, Robert L. 0000-0003-3220-481X runkel@usgs.gov","orcid":"https://orcid.org/0000-0003-3220-481X","contributorId":685,"corporation":false,"usgs":true,"family":"Runkel","given":"Robert","email":"runkel@usgs.gov","middleInitial":"L.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":382369,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"McKnight, Diane M.","contributorId":59773,"corporation":false,"usgs":false,"family":"McKnight","given":"Diane","email":"","middleInitial":"M.","affiliations":[{"id":16833,"text":"INSTAAR, University of Colorado","active":true,"usgs":false}],"preferred":false,"id":382368,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bencala, Kenneth E. kbencala@usgs.gov","contributorId":1541,"corporation":false,"usgs":true,"family":"Bencala","given":"Kenneth","email":"kbencala@usgs.gov","middleInitial":"E.","affiliations":[],"preferred":true,"id":382370,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Chapra, Steven C.","contributorId":189667,"corporation":false,"usgs":false,"family":"Chapra","given":"Steven","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":382367,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70019334,"text":"70019334 - 1996 - Combined use of flowmeter and time-drawdown data to estimate hydraulic conductivities in layered aquifer systems","interactions":[],"lastModifiedDate":"2018-06-01T14:42:35","indexId":"70019334","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Combined use of flowmeter and time-drawdown data to estimate hydraulic conductivities in layered aquifer systems","docAbstract":"The vertical distribution of hydraulic conductivity in layered aquifer systems commonly is needed for model simulations of ground-water flow and transport. In previous studies, time-drawdown data or flowmeter data were used individually, but not in combination, to estimate hydraulic conductivity. In this study, flowmeter data and time-drawdown data collected from a long-screened production well and nearby monitoring wells are combined to estimate the vertical distribution of hydraulic conductivity in a complex multilayer coastal aquifer system. Flowmeter measurements recorded as a function of depth delineate nonuniform inflow to the wellbore, and this information is used to better discretize the vertical distribution of hydraulic conductivity using analytical and numerical methods. The time-drawdown data complement the flowmeter data by giving insight into the hydraulic response of aquitards when flow rates within the wellbore are below the detection limit of the flowmeter. The combination of these field data allows for the testing of alternative conceptual models of radial flow to the wellbore.","language":"English","publisher":"Wiley","doi":"10.1111/j.1745-6584.1996.tb01868.x","issn":"0017467X","usgsCitation":"Hanson, R.T., and Nishikawa, T., 1996, Combined use of flowmeter and time-drawdown data to estimate hydraulic conductivities in layered aquifer systems: Ground Water, v. 34, no. 1, p. 84-94, https://doi.org/10.1111/j.1745-6584.1996.tb01868.x.","productDescription":"11 p.","startPage":"84","endPage":"94","numberOfPages":"11","costCenters":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"links":[{"id":226597,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"34","issue":"1","noUsgsAuthors":false,"publicationDate":"2005-08-04","publicationStatus":"PW","scienceBaseUri":"5059f7dbe4b0c8380cd4cd31","contributors":{"authors":[{"text":"Hanson, R. T.","contributorId":91148,"corporation":false,"usgs":true,"family":"Hanson","given":"R.","email":"","middleInitial":"T.","affiliations":[],"preferred":false,"id":382380,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Nishikawa, Tracy 0000-0002-7348-3838 tnish@usgs.gov","orcid":"https://orcid.org/0000-0002-7348-3838","contributorId":1515,"corporation":false,"usgs":true,"family":"Nishikawa","given":"Tracy","email":"tnish@usgs.gov","affiliations":[{"id":154,"text":"California Water Science Center","active":true,"usgs":true}],"preferred":true,"id":382379,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019338,"text":"70019338 - 1996 - Direct simulation of groundwater age","interactions":[],"lastModifiedDate":"2018-03-08T15:45:15","indexId":"70019338","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3722,"text":"Water Resources Research","onlineIssn":"1944-7973","printIssn":"0043-1397","active":true,"publicationSubtype":{"id":10}},"title":"Direct simulation of groundwater age","docAbstract":"A new method is proposed to simulate groundwater age directly, by use of an advection-dispersion transport equation with a distributed zero-order source of unit (1) strength, corresponding to the rate of aging. The dependent variable in the governing equation is the mean age, a mass-weighted average age. The governing equation is derived from residence-time-distribution concepts for the case of steady flow. For the more general case of transient flow, a transient governing equation for age is derived from mass-conservation principles applied to conceptual “age mass.” The age mass is the product of the water mass and its age, and age mass is assumed to be conserved during mixing. Boundary conditions include zero age mass flux across all noflow and inflow boundaries and no age mass dispersive flux across outflow boundaries. For transient-flow conditions, the initial distribution of age must be known. The solution of the governing transport equation yields the spatial distribution of the mean groundwater age and includes diffusion, dispersion, mixing, and exchange processes that typically are considered only through tracer-specific solute transport simulation. Traditional methods have relied on advective transport to predict point values of groundwater travel time and age. The proposed method retains the simplicity and tracer-independence of advection-only models, but incorporates the effects of dispersion and mixing on volume-averaged age. Example simulations of age in two idealized regional aquifer systems, one homogeneous and the other layered, demonstrate the agreement between the proposed method and traditional particle-tracking approaches and illustrate use of the proposed method to determine the effects of diffusion, dispersion, and mixing on groundwater age.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95WR03401","usgsCitation":"Goode, D., 1996, Direct simulation of groundwater age: Water Resources Research, v. 32, no. 2, p. 289-296, https://doi.org/10.1029/95WR03401.","productDescription":"8 p.","startPage":"289","endPage":"296","costCenters":[{"id":532,"text":"Pennsylvania Water Science Center","active":true,"usgs":true}],"links":[{"id":480178,"rank":1,"type":{"id":40,"text":"Open Access Publisher Index Page"},"url":"https://doi.org/10.1029/95wr03401","text":"Publisher Index Page"},{"id":226693,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"32","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a01b2e4b0c8380cd4fd08","contributors":{"authors":[{"text":"Goode, Daniel J. 0000-0002-8527-2456 djgoode@usgs.gov","orcid":"https://orcid.org/0000-0002-8527-2456","contributorId":2433,"corporation":false,"usgs":true,"family":"Goode","given":"Daniel J.","email":"djgoode@usgs.gov","affiliations":[{"id":532,"text":"Pennsylvania Water Science Center","active":true,"usgs":true}],"preferred":false,"id":382393,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70019353,"text":"70019353 - 1996 - Equatorial origin for Lower Jurassic radiolarian chert in the Franciscan Complex, San Rafael Mountains, southern California","interactions":[],"lastModifiedDate":"2024-11-13T17:42:31.002502","indexId":"70019353","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Equatorial origin for Lower Jurassic radiolarian chert in the Franciscan Complex, San Rafael Mountains, southern California","docAbstract":"Lower Jurassic radiolarian chert sampled at two localities in the San Rafael Mountains of southern California (∼20 km north of Santa Barbara) contains four components of remanent magnetization. Components A, B′, and B are inferred to represent uplift, Miocene volcanism, and subduction/accretion overprint magnetizations, respectively. The fourth component (C), isolated between 580° and 680°C, shows a magnetic polarity stratigraphy and is interpreted as a primary magnetization acquired by the chert during, or soon after, deposition. Both sequences are late Pliensbachian to middle Toarcian in age, and an average paleolatitude calculated from all tilt-corrected C components is 1° ± 3° north or south. This result is consistent with deposition of the cherts beneath the equatorial zone of high biologic productivity and is similar to initial paleolatitudes determined for chert blocks in northern California and Mexico. This result supports our model, in which deep-water Franciscan-type cherts were deposited on the Farallon plate as it moved eastward beneath the equatorial productivity high, were accreted to the continental margin at low paleolatitudes, and were subsequently distributed northward by strike-slip faulting associated with movements of the Kula, Farallon, and Pacific plates. Upper Cretaceous turbidites of the Cachuma Formation were sampled at Agua Caliente Canyon to determine a constraining paleolatitude for accretion of the Jurassic chert sequences. These apparently unaltered rocks, however, were found to be completely overprinted by the A component of magnetization. Similar in situ directions and demagnetization behaviors observed in samples of other Upper Cretaceous turbidite sequences in southern and Baja California imply that these rocks might also give unreliable results.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95JB02854","issn":"01480227","usgsCitation":"Hagstrum, J., Murchey, B., and Bogar, R., 1996, Equatorial origin for Lower Jurassic radiolarian chert in the Franciscan Complex, San Rafael Mountains, southern California: Journal of Geophysical Research B: Solid Earth, v. 101, no. 1, p. 613-626, https://doi.org/10.1029/95JB02854.","productDescription":"14 p.","startPage":"613","endPage":"626","numberOfPages":"14","costCenters":[],"links":[{"id":226921,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"1","noUsgsAuthors":false,"publicationDate":"1996-01-10","publicationStatus":"PW","scienceBaseUri":"505a0a27e4b0c8380cd52206","contributors":{"authors":[{"text":"Hagstrum, J.T.","contributorId":75922,"corporation":false,"usgs":true,"family":"Hagstrum","given":"J.T.","email":"","affiliations":[],"preferred":false,"id":382437,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Murchey, B.L.","contributorId":93074,"corporation":false,"usgs":true,"family":"Murchey","given":"B.L.","email":"","affiliations":[],"preferred":false,"id":382438,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Bogar, R.S.","contributorId":21295,"corporation":false,"usgs":true,"family":"Bogar","given":"R.S.","email":"","affiliations":[],"preferred":false,"id":382436,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70019356,"text":"70019356 - 1996 - Tectonics and seismicity of the southern Washington Cascade range","interactions":[],"lastModifiedDate":"2023-10-22T14:04:17.446545","indexId":"70019356","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Tectonics and seismicity of the southern Washington Cascade range","docAbstract":"Geophysical, geological, and seismicity data are combined to develop a transpressional strain model for the southern Washington Cascades region. We use this model to explain oblique fold and fault systems, transverse faults, and a linear seismic zone just west of Mt. Rainier known as the western Rainier zone. We also attempt to explain a concentration of earthquakes that connects the northwest-trending Mount St. Helens seismic zone to the north-trending western Rainier zone. Our tectonic model illustrates the pervasive effects of accretionary processes, combined with subsequent transpressive forces generated by oblique subduction, on Eocene to present crustal processes, such as seismicity and volcanism.
A finite-fault statistical model of the earthquake source is used to confirm observed magnitude and distance saturation scaling in a large peak-acceleration data set. This model allows us to determine the form of peak-acceleration attenuation curves without a priori assumptions about their shape or scaling properties. The source is composed of patches having uniform size and statistical properties. The primary source parameters are the patch peak-acceleration distribution mean, the distribution standard deviation, the patch size, and patch-rupture duration. Although our model assumes no scaling of peak acceleration with magnitude at the patch, the peak-acceleration attenuation curves, nevertheless, strongly scale with magnitude (dap/dM) ≠ 0, and the scaling is distance dependent (dap/dM) ∝ f(r).
","language":"English","publisher":"Seismological Society of America","doi":"10.1785/BSSA08601A0079","issn":"00371106","usgsCitation":"Rogers, A.M., and Perkins, D.M., 1996, Monte Carlo simulation of peak-acceleration attenuation using a finite-fault uniform-patch model including isochrone and extremal characteristics: Bulletin of the Seismological Society of America, v. 86, no. 1 SUPPL. A, p. 79-92, https://doi.org/10.1785/BSSA08601A0079.","productDescription":"14 p.","startPage":"79","endPage":"92","numberOfPages":"14","costCenters":[],"links":[{"id":226600,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"86","issue":"1 SUPPL. A","noUsgsAuthors":false,"publicationDate":"1996-02-01","publicationStatus":"PW","scienceBaseUri":"505a5e13e4b0c8380cd707a8","contributors":{"authors":[{"text":"Rogers, A. M.","contributorId":92251,"corporation":false,"usgs":true,"family":"Rogers","given":"A.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":382510,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Perkins, D. M.","contributorId":83922,"corporation":false,"usgs":true,"family":"Perkins","given":"D.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":382509,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70019378,"text":"70019378 - 1996 - Comparison of denitrification activity measurements in groundwater using cores and natural-gradient tracer tests","interactions":[],"lastModifiedDate":"2020-01-07T13:52:14","indexId":"70019378","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1565,"text":"Environmental Science & Technology","onlineIssn":"1520-5851","printIssn":"0013-936X","active":true,"publicationSubtype":{"id":10}},"title":"Comparison of denitrification activity measurements in groundwater using cores and natural-gradient tracer tests","docAbstract":"The transport of many solutes in groundwater is dependent upon the relative rates of physical flow and microbial metabolism. Quantifying rates of microbial processes under subsurface conditions is difficult and is most commonly approximated using laboratory studies with aquifer materials. In this study, we measured in situ rates of denitrification in a nitrate-contaminated aquifer using small-scale, natural-gradient tracer tests and compared the results with rates obtained from laboratory incubations with aquifer core material. Activity was measured using the acetylene block technique. For the tracer tests, co-injection of acetylene and bromide into the aquifer produced a 30 μM increase in nitrous oxide after 10 m of transport (23−30 days). An advection−dispersion transport model was modified to include an acetylene-dependent nitrous oxide production term and used to simulate the tracer breakthrough curves. The model required a 4-day lag period and a relatively low sensitivity to acetylene to match the narrow nitrous oxide breakthrough curves. Estimates of in situ denitrification rates were 0.60 and 1.51 nmol of N2O produced cm-3 aquifer day-1 for two successive tests. Aquifer core material collected from the tracer test site and incubated as mixed slurries in flasks and as intact cores yielded rates that were 1.2−26 times higher than the tracer test rate estimates. Results with the coring-dependent techniques were variable and subject to the small-scale heterogeneity within the aquifer, while the tracer tests integrated the heterogeneity along a flow path, giving a rate estimate that is more applicable to transport at the scale of the aquifer.
An equilibrium-based solute transport model is developed for the simulation of trace metal fate and transport in streams. The model is formed by coupling a solute transport model with a chemical equilibrium submodel based on MINTEQ. The solute transport model considers the physical processes of advection, dispersion, lateral inflow, and transient storage, while the equilibrium submodel considers the speciation and complexation of aqueous species, precipitation/dissolution and sorption. Within the model, reactions in the water column may result in the formation of solid phases (precipitates and sorbed species) that are subject to downstream transport and settling processes. Solid phases on the streambed may also interact with the water column through dissolution and sorption/desorption reactions. Consideration of both mobile (water-borne) and immobile (streambed) solid phases requires a unique set of governing differential equations and solution techniques that are developed herein. The partial differential equations describing physical transport and the algebraic equations describing chemical equilibria are coupled using the sequential iteration approach.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95WR03106","usgsCitation":"Runkel, R.L., Bencala, K.E., Broshears, R.E., and Chapra, S.C., 1996, Reactive solute transport in streams: 1. Development of an equilibrium- based model: Water Resources Research, v. 32, no. 2, p. 409-418, https://doi.org/10.1029/95WR03106.","productDescription":"10 p.","startPage":"409","endPage":"418","costCenters":[{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true}],"links":[{"id":226742,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"32","issue":"2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a9587e4b0c8380cd81a8d","contributors":{"authors":[{"text":"Runkel, Robert L. 0000-0003-3220-481X runkel@usgs.gov","orcid":"https://orcid.org/0000-0003-3220-481X","contributorId":685,"corporation":false,"usgs":true,"family":"Runkel","given":"Robert","email":"runkel@usgs.gov","middleInitial":"L.","affiliations":[{"id":191,"text":"Colorado Water Science Center","active":true,"usgs":true}],"preferred":true,"id":382526,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Bencala, Kenneth E. kbencala@usgs.gov","contributorId":1541,"corporation":false,"usgs":true,"family":"Bencala","given":"Kenneth","email":"kbencala@usgs.gov","middleInitial":"E.","affiliations":[],"preferred":true,"id":382527,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Broshears, Robert E.","contributorId":40675,"corporation":false,"usgs":true,"family":"Broshears","given":"Robert","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":382525,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Chapra, Steven C.","contributorId":189667,"corporation":false,"usgs":false,"family":"Chapra","given":"Steven","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":382524,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":27118,"text":"wri944181 - 1996 - Geohydrology and water quality of stratified-drift aquifers in the middle Connecticut River basin, west-central New Hampshire","interactions":[],"lastModifiedDate":"2023-04-10T21:06:38.391798","indexId":"wri944181","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":18,"text":"Report"},"publicationSubtype":{"id":5,"text":"USGS Numbered Series"},"seriesTitle":{"id":342,"text":"Water-Resources Investigations Report","code":"WRI","active":false,"publicationSubtype":{"id":5}},"seriesNumber":"94-4181","title":"Geohydrology and water quality of stratified-drift aquifers in the middle Connecticut River basin, west-central New Hampshire","docAbstract":"A study was done by the U.S. Geological Survey, in cooperation with the New Hampshire Department of Environmental Services, Water Resources Division, to describe the geohydrology and water quality of stratified-drift aquifers in the Middle Connecticut River Basin, west-central New Hampshire Stratified-drift aquifers discontinuously underlie 123 mi2 (square miles) of the Middle Connecticut River Basin, which has a total drainage area of 987 mi 2. Saturated thicknesses of stratified drift in the study area are locally greater than 500 feet but generally are less than 100 feet. Aquifer transmissivity locally exceeds 4,000 ft2/d (feet squared per day) but is generally less than 1,000 ft2/d. In only 17.2 mi2 of the study area are the aquifers identified as having a transmissivity greater than 1,000 ft2/d. As of 1990, total groundwater withdrawals from stratified drift for municipal supply were about 1.5 Mgal/d (million gallons per day) in the study area. Many of the stratified-drift aquifers underlying the study area are not developed to their fullest potential. The geohydrologic investigation of the stratified-drift aquifers focused on aquifer properties, including aquifer boundaries; recharge, discharge, and direction of ground-water flow; saturated thickness and storage; and transmissivity. Surficial-geologic mapping assisted in the determination of aquifer boundaries. Data from more than 1,000 wells, test borings, and springs were used to prepare maps of water-table altitude, saturated thickness, and transmissivity of stratified drift. More than 11 miles of seismic-refraction profiling at 95 sites was used in the preparation of the water-table-altitude and saturated-thickness maps. Seismic-reflection data collected along 1.6 miles of Mascoma Lake also were used in preparation of the saturated-thickness maps. Four stratified-drift aquifers in the towns of Franconia, Haverhill, and Lisbon were analyzed to estimate the water availability on the basis of analytical ground-water model simulation based on the Theis confined-flow equation adjusted to account for boundary effects commonly associated with stratified-drift aquifers. Conservative estimates of water availability during a 180-day period of no recharge were estimated to be 1.9 Mgal/d for the Meadow Brook aquifer; 1.8 Mgal/d for the Ham Branch Brook aquifer; 1.5 Mgal/d for the Salmon Hole aquifer; and 1.4 Mgal/d for the Haverhill-French Pond aquifer. Water-availability estimates would be higher if periods of recharge were accounted for and if less conservative boundary conditions were used in the model. Results of analysis of water samples from 26 observation wells, 3 municipal water-supply wells, and 1 public-supply spring show that, with the exception of dissolved iron and manganese in some samples, water in the stratified-drift aquifers generally meets the U.S. Environmental Protection Agency's primary and secondary drinking-water standards.","language":"English","publisher":"U.S. Geological Survey","doi":"10.3133/wri944181","usgsCitation":"Flanagan, S.M., 1996, Geohydrology and water quality of stratified-drift aquifers in the middle Connecticut River basin, west-central New Hampshire: U.S. Geological Survey Water-Resources Investigations Report 94-4181, Report: vi, 224 p.; 8 Plates: 35.00 x 39.83 inches or smaller, https://doi.org/10.3133/wri944181.","productDescription":"Report: vi, 224 p.; 8 Plates: 35.00 x 39.83 inches or smaller","costCenters":[],"links":[{"id":415543,"rank":11,"type":{"id":36,"text":"NGMDB Index Page"},"url":"https://ngmdb.usgs.gov/Prodesc/proddesc_48056.htm","linkFileType":{"id":5,"text":"html"}},{"id":55979,"rank":7,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/wri/1994/4181/plate-5.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":55977,"rank":5,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/wri/1994/4181/plate-3.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":55975,"rank":3,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/wri/1994/4181/plate-1.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":55983,"rank":2,"type":{"id":11,"text":"Document"},"url":"https://pubs.usgs.gov/wri/1994/4181/report.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":55982,"rank":10,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/wri/1994/4181/plate-8.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":55981,"rank":9,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/wri/1994/4181/plate-7.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":55980,"rank":8,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/wri/1994/4181/plate-6.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":55978,"rank":6,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/wri/1994/4181/plate-4.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":55976,"rank":4,"type":{"id":17,"text":"Plate"},"url":"https://pubs.usgs.gov/wri/1994/4181/plate-2.pdf","linkFileType":{"id":1,"text":"pdf"}},{"id":123612,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/wri/1994/4181/report-thumb.jpg"}],"country":"United States","state":"New Hampshire","otherGeospatial":"middle Connecticut River","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -71.3,\n 44.4578\n ],\n [\n -72.35,\n 44.4578\n ],\n [\n -72.35,\n 43.5222\n ],\n [\n -71.3,\n 43.5222\n ],\n [\n -71.3,\n 44.4578\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4b1be4b07f02db6a8b84","contributors":{"authors":[{"text":"Flanagan, S. M.","contributorId":12523,"corporation":false,"usgs":true,"family":"Flanagan","given":"S.","email":"","middleInitial":"M.","affiliations":[],"preferred":false,"id":197583,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":85643,"text":"85643 - 1996 - Hydrologic modification to improve habitat in riverine lakes: Management objectives, experimental approach, and initial conditions","interactions":[],"lastModifiedDate":"2012-02-02T00:04:06","indexId":"85643","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":5,"text":"Book chapter"},"publicationSubtype":{"id":24,"text":"Book Chapter"},"title":"Hydrologic modification to improve habitat in riverine lakes: Management objectives, experimental approach, and initial conditions","docAbstract":"The Finger Lakes habitat-rehabilitation project is intended to improve physical and chemical conditions for fish in six connected back water lakes in Navigation Pool 5 of the upper Missouri River. The primary management objective is to improve water temperature, dissolved oxygen concentration and current velocity during winter for bluegills, Lepomis macrochirus, and black crappies, Pomoxis nigromaculatus, two of the primary sport fishes in the lakes. The lakes will be hydrologically altered by Installing culverts to Introduce controlled flows of oxygenated water into four lakes, and an existing unregulated culvert on a fifth lake will be equipped with a control gate to regulate inflow. These habitat modifications constitute a manipulative field experiment that will compare pre-project (1991 to summer 1993) and post-project (fall 1993 to 1996) conditions in the lakes, including hydrology, chemistry, rooted vegetation, and fish and macroinvertebrate communities. Initial data indicate that the Finger Lakes differ in water chemistry, hydrology, and macrophyte abundance. Macroinvertebrate communities also differed among lakes: species diversity was highest in lakes with dense aquatic macrophytes. The system seems to support a single fish community, although some species concentrated in individual lakes at different times. The introduction of similar flows into five of the lakes will probably reduce the existing physical and chemical differences among lakes. However, our ability to predict the effects of hydrologic modification on fish populations is limited by uncertainties concerning both the interactions of temperature, oxygen and current in winter and the biological responses of primary and secondary producers. Results from this study should provide guidance for similar habitat-rehabilitation projects in large rivers.","largerWorkType":{"id":4,"text":"Book"},"largerWorkTitle":"Problems of Aquatic Toxicology, Biotesting, and Water Quality Management","largerWorkSubtype":{"id":4,"text":"Other Government Series"},"language":"English","publisher":"Environmental Protection Agency","publisherLocation":"Athens, GA","usgsCitation":"Johnson, B.L., Barko, J.W., Gerasimov, Y., James, W., Litvinov, A., Naimo, T.J., Wiener, J.G., Gaugush, R.F., Rogala, J.T., and Rogers, S.J., 1996, Hydrologic modification to improve habitat in riverine lakes: Management objectives, experimental approach, and initial conditions, chap. of Problems of Aquatic Toxicology, Biotesting, and Water Quality Management, 239-258.","productDescription":"239-258","costCenters":[{"id":606,"text":"Upper Midwest Environmental Sciences Center","active":true,"usgs":true}],"links":[{"id":128638,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"4f4e4a1ae4b07f02db606ae3","contributors":{"editors":[{"text":"Schoettger, R.A.","contributorId":19519,"corporation":false,"usgs":true,"family":"Schoettger","given":"R.A.","affiliations":[],"preferred":false,"id":504629,"contributorType":{"id":2,"text":"Editors"},"rank":1}],"authors":[{"text":"Johnson, Barry L. bljohnson@usgs.gov","contributorId":608,"corporation":false,"usgs":true,"family":"Johnson","given":"Barry","email":"bljohnson@usgs.gov","middleInitial":"L.","affiliations":[],"preferred":true,"id":296182,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Barko, John W.","contributorId":65413,"corporation":false,"usgs":true,"family":"Barko","given":"John","email":"","middleInitial":"W.","affiliations":[],"preferred":false,"id":296187,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Gerasimov, Yuri","contributorId":73538,"corporation":false,"usgs":true,"family":"Gerasimov","given":"Yuri","email":"","affiliations":[],"preferred":false,"id":296188,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"James, William F.","contributorId":75472,"corporation":false,"usgs":true,"family":"James","given":"William F.","affiliations":[],"preferred":false,"id":296189,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Litvinov, Alexander","contributorId":25891,"corporation":false,"usgs":true,"family":"Litvinov","given":"Alexander","affiliations":[],"preferred":false,"id":296186,"contributorType":{"id":1,"text":"Authors"},"rank":5},{"text":"Naimo, Teresa J.","contributorId":8039,"corporation":false,"usgs":true,"family":"Naimo","given":"Teresa","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":296185,"contributorType":{"id":1,"text":"Authors"},"rank":6},{"text":"Wiener, James G.","contributorId":93853,"corporation":false,"usgs":false,"family":"Wiener","given":"James","email":"","middleInitial":"G.","affiliations":[{"id":17913,"text":"River Studies Center, University of Wisconsin-La Crosse","active":true,"usgs":false}],"preferred":false,"id":296191,"contributorType":{"id":1,"text":"Authors"},"rank":7},{"text":"Gaugush, Robert F. rgaugush@usgs.gov","contributorId":5873,"corporation":false,"usgs":true,"family":"Gaugush","given":"Robert","email":"rgaugush@usgs.gov","middleInitial":"F.","affiliations":[{"id":606,"text":"Upper Midwest Environmental Sciences Center","active":true,"usgs":true}],"preferred":true,"id":296184,"contributorType":{"id":1,"text":"Authors"},"rank":8},{"text":"Rogala, James T. 0000-0002-1954-4097 jrogala@usgs.gov","orcid":"https://orcid.org/0000-0002-1954-4097","contributorId":2651,"corporation":false,"usgs":true,"family":"Rogala","given":"James","email":"jrogala@usgs.gov","middleInitial":"T.","affiliations":[{"id":606,"text":"Upper Midwest Environmental Sciences Center","active":true,"usgs":true}],"preferred":true,"id":296183,"contributorType":{"id":1,"text":"Authors"},"rank":9},{"text":"Rogers, Sara J.","contributorId":85534,"corporation":false,"usgs":true,"family":"Rogers","given":"Sara","email":"","middleInitial":"J.","affiliations":[{"id":606,"text":"Upper Midwest Environmental Sciences Center","active":true,"usgs":true}],"preferred":false,"id":296190,"contributorType":{"id":1,"text":"Authors"},"rank":10}]}} ]}