Earthquake hypocenters within the subducting Juan de Fuca plate beneath Washington and northern Oregon are interpreted as showing that the direction of plate dip changes from northeast beneath the Puget Sound region to east-southeast beneath southwestern Washington. The shallowest hypocenters within the Juan de Fuca plate are between 30- to 40-km depth, and the distribution of these events strikes north-northeast from near the mouth of the Columbia River to the northern Olympic Mountains. The distribution of hypocenters between 40 to 50 km generally strikes parallel with the shallowest events, but shows a significant broadening beneath the eastern Olympic Mountains and Puget Sound. Events with depths greater than 50 km south of the 1965 Seattle earthquake (mb = 6.5) strike north-northeast, approximately parallel with the shallower distributions; however, north of this event, the distribution of these deeper hypocenters strikes northwest. This change in the distribution of earthquake hypocenters reflects an upward arching of the Juan de Fuca plate plate beneath Puget Sound compared with the depth of the plate beneath southwestern Washington. The T axis calculated for the 1949 South Puget Sound earthquake (MS = 7.1) is oriented to the southeast, and the 20° plunge of the T axis is in good agreement with the plate dip angle determined from the earthquake hypocenters. We conclude that the 1949 earthquake resulted at least in part from down-dip tensional forces within the subducting Juan de Fuca plate. One consequence of the change in the direction of plate dip is that volcanic front in Washington is everywhere perpendicular to the dip of the Juan de Fuca plate.
","language":"English","publisher":"Seismological Society of America","doi":"10.1785/BSSA0780010264","usgsCitation":"Weaver, C., and Baker, G., 1988, Geometry of the Juan de Fuca plate beneath Washington and northern Oregon from seismicity: Bulletin of the Seismological Society of America, v. 78, no. 1, p. 264-275, https://doi.org/10.1785/BSSA0780010264.","productDescription":"12 p.","startPage":"264","endPage":"275","numberOfPages":"12","costCenters":[],"links":[{"id":226105,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Oregon, Washington","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -126.57431348966908,\n 50.332968063146296\n ],\n [\n -126.57431348966908,\n 42.70034938825228\n ],\n [\n -116.15927442716894,\n 42.70034938825228\n ],\n [\n -116.15927442716894,\n 50.332968063146296\n ],\n [\n -126.57431348966908,\n 50.332968063146296\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"78","issue":"1","noUsgsAuthors":false,"publicationDate":"1988-02-01","publicationStatus":"PW","scienceBaseUri":"505a2770e4b0c8380cd598b7","contributors":{"authors":[{"text":"Weaver, C.S.","contributorId":57874,"corporation":false,"usgs":true,"family":"Weaver","given":"C.S.","email":"","affiliations":[],"preferred":false,"id":369158,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Baker, G.E.","contributorId":90744,"corporation":false,"usgs":true,"family":"Baker","given":"G.E.","email":"","affiliations":[],"preferred":false,"id":369159,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014733,"text":"70014733 - 1988 - The mechanics of ground deformation precursory to dome-building extrusions at Mount St. Helens 1981-1982","interactions":[],"lastModifiedDate":"2024-05-30T16:48:17.685689","indexId":"70014733","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"The mechanics of ground deformation precursory to dome-building extrusions at Mount St. Helens 1981-1982","docAbstract":"Detailed monitoring at Mount St. Helens since 1980 has enabled prediction of the intermittent eruptive activity (mostly dome growth) with unprecedented success. During 1981 and 1982, accelerating deformation of the crater floor around the vent (including radial cracks, thrust faults, and ground tilt) was the earliest indicator of impending activity. Numerical experiments using the finite element method to model the mechanics of the crater floor show that all deformation features can be explained by a uniform shear-stress boundary condition along the conduit wall. The magnitude of the shear stress required to match observed displacements (1–7 MPa) is inversely proportional to the conduit diameter (estimated to be 25–100 m). The most probable source of this shear stress is the flow of viscous magma up the conduit and into the lava dome. We propose a model in which the accelerating deformation, beginning as much as 4 weeks before extrusions, is caused by the increasing velocity of ascending magma in the conduit. This model is examined by using deformation data of the dome before four extrusions in 1981 and 1982 to estimate the volumetric flow rate through the conduit. This flow rate and an estimate of the effective viscosity of the magma enable calculation of an ascent velocity and an applied shear stress that, again, depend on the conduit diameter. The results of these calculations are consistent with the finite element experiments and show that the proposed model is feasible. In light of this model, events observed just before or near the time extrusions began, such as reversals of ground tilt direction from outward to inward and the sudden decrease in the number of shallow earthquakes, may indicate an abrupt decrease of shear stress in the conduit. This could be explained by a decrease in either the ascent velocity, or the effective viscosity of the magma ascending through the shallow conduit, or both, near the time of extrusion. Precursory deformation like that measured at Mount St. Helens should be observable at similar volcanoes elsewhere because it is caused by the fundamental process of magma ascent.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB093iB05p04351","issn":"01480227","usgsCitation":"Chadwick, W., Archuleta, R., and Swanson, D.A., 1988, The mechanics of ground deformation precursory to dome-building extrusions at Mount St. Helens 1981-1982: Journal of Geophysical Research Solid Earth, v. 93, no. B5, p. 4351-4366, https://doi.org/10.1029/JB093iB05p04351.","productDescription":"16 p.","startPage":"4351","endPage":"4366","numberOfPages":"16","costCenters":[],"links":[{"id":226104,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"B5","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505badc4e4b08c986b323dd6","contributors":{"authors":[{"text":"Chadwick, W.W. Jr.","contributorId":35876,"corporation":false,"usgs":true,"family":"Chadwick","given":"W.W.","suffix":"Jr.","email":"","affiliations":[],"preferred":false,"id":369156,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Archuleta, R.J.","contributorId":79245,"corporation":false,"usgs":true,"family":"Archuleta","given":"R.J.","affiliations":[],"preferred":false,"id":369157,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Swanson, D. A.","contributorId":34102,"corporation":false,"usgs":true,"family":"Swanson","given":"D.","email":"","middleInitial":"A.","affiliations":[],"preferred":false,"id":369155,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014732,"text":"70014732 - 1988 - A statistical method for estimating rates of soil development and ages of geologic deposits: A design for soil-chronosequence studies","interactions":[],"lastModifiedDate":"2012-03-12T17:19:32","indexId":"70014732","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","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":"A statistical method for estimating rates of soil development and ages of geologic deposits: A design for soil-chronosequence studies","docAbstract":"A statistical method for estimating rates of soil development in a given region based on calibration from a series of dated soils is used to estimate ages of soils in the same region that are not dated directly. The method is designed specifically to account for sampling procedures and uncertainties that are inherent in soil studies. Soil variation and measurement error, uncertainties in calibration dates and their relation to the age of the soil, and the limited number of dated soils are all considered. Maximum likelihood (ML) is employed to estimate a parametric linear calibration curve, relating soil development to time or age on suitably transformed scales. Soil variation on a geomorphic surface of a certain age is characterized by replicate sampling of soils on each surface; such variation is assumed to have a Gaussian distribution. The age of a geomorphic surface is described by older and younger bounds. This technique allows age uncertainty to be characterized by either a Gaussian distribution or by a triangular distribution using minimum, best-estimate, and maximum ages. The calibration curve is taken to be linear after suitable (in certain cases logarithmic) transformations, if required, of the soil parameter and age variables. Soil variability, measurement error, and departures from linearity are described in a combined fashion using Gaussian distributions with variances particular to each sampled geomorphic surface and the number of sample replicates. Uncertainty in age of a geomorphic surface used for calibration is described using three parameters by one of two methods. In the first method, upper and lower ages are specified together with a coverage probability; this specification is converted to a Gaussian distribution with the appropriate mean and variance. In the second method, \"absolute\" older and younger ages are specified together with a most probable age; this specification is converted to an asymmetric triangular distribution with mode at the most probable age. The statistical variability of the ML-estimated calibration curve is assessed by a Monte Carlo method in which simulated data sets repeatedly are drawn from the distributional specification; calibration parameters are reestimated for each such simulation in order to assess their statistical variability. Several examples are used for illustration. The age of undated soils in a related setting may be estimated from the soil data using the fitted calibration curve. A second simulation to assess age estimate variability is described and applied to the examples. ?? 1988 International Association for Mathematical Geology.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Mathematical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Kluwer Academic Publishers-Plenum Publishers","doi":"10.1007/BF00903188","issn":"08828121","usgsCitation":"Switzer, P., Harden, J., and Mark, R.K., 1988, A statistical method for estimating rates of soil development and ages of geologic deposits: A design for soil-chronosequence studies: Mathematical Geology, v. 20, no. 1, p. 49-61, https://doi.org/10.1007/BF00903188.","startPage":"49","endPage":"61","numberOfPages":"13","costCenters":[],"links":[{"id":226041,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205676,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF00903188"}],"volume":"20","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059e5afe4b0c8380cd46f01","contributors":{"authors":[{"text":"Switzer, P.","contributorId":66432,"corporation":false,"usgs":true,"family":"Switzer","given":"P.","email":"","affiliations":[],"preferred":false,"id":369154,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Harden, J.W. 0000-0002-6570-8259","orcid":"https://orcid.org/0000-0002-6570-8259","contributorId":38585,"corporation":false,"usgs":true,"family":"Harden","given":"J.W.","affiliations":[],"preferred":false,"id":369153,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Mark, R. K.","contributorId":32159,"corporation":false,"usgs":true,"family":"Mark","given":"R.","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":369152,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014718,"text":"70014718 - 1988 - Pb, Sr, and Nd isotopic compositions of a suite of Late Archean, igneous rocks, eastern Beartooth Mountains: Implications for crust-mantle evolution","interactions":[],"lastModifiedDate":"2023-12-09T15:46:54.517196","indexId":"70014718","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","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":"Pb, Sr, and Nd isotopic compositions of a suite of Late Archean, igneous rocks, eastern Beartooth Mountains: Implications for crust-mantle evolution","docAbstract":"A series of compositionally diverse, Late Archean rocks (2.74–2.79 Ga old) from the eastern Beartooth Mountains, Montana and Wyoming, U.S.A., have the same initial Pb, Sr, and Nd isotopic ratios. Lead and Sr initial ratios are higher and Nd initial ratios lower than would be expected for rocks derived from model mantle sources and strongly indicate the involvement of an older crustal reservoir in the genesis of these rocks. Crustal contamination during emplacement can be ruled out for a variety of reasons. Instead a model involving subduction of continental detritus and contamination of the overlying mantle as is often proposed for modern subduction environments is preferred. This contaminated mantle would have all the isotopic characteristics of mantle enriched by internal mantle metasomatism but would require no long-term growth or changes in parent to daughter element ratios. This contaminated mantle would make a good source for some of the Cenozoic mafic volcanics of the Columbia River, Snake River Plain, and Yellowstone volcanic fields that are proposed to come from ancient, enriched lithospheric mantle. The isotopic characteristics of the 2.70 Ga old Stillwater Complex are a perfect match for the proposed contaminated mantle which provides an alternative to crustal contamination during emplacement. The Pb isotopic characteristics of the Late Archean rocks of the eastern Beartooth Mountains are similar to those of other Late Archean rocks of the Wyoming Province and suggest that Early Archean, upper crustal rocks were common in this terrane. The isotopic signatures of Late Archean rocks in the Wyoming Province are distinctive from those of other Archean cratons in North America which are dominated by a MORB-like, Archean mantle source (Superior Province) and/or a long-term depleted crustal source (Greenland).
No abstract available.
","language":"English","publisher":"Elsevier","doi":"10.1016/0025-326X(88)90396-7","issn":"0025326X","usgsCitation":"Luoma, S.N., and Phillips, D., 1988, Distribution, variability, and impacts of trace elements in San Francisco Bay: Marine Pollution Bulletin, v. 19, no. 9, p. 413-425, https://doi.org/10.1016/0025-326X(88)90396-7.","productDescription":"13 p.","startPage":"413","endPage":"425","numberOfPages":"13","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":552,"text":"San Francisco Bay-Delta","active":false,"usgs":true},{"id":589,"text":"Toxic Substances Hydrology Program","active":true,"usgs":true},{"id":5079,"text":"Pacific Regional Director's Office","active":true,"usgs":true}],"links":[{"id":225722,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California","otherGeospatial":"San Francisco Bay","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"type\": \"Polygon\",\n \"coordinates\": [\n [\n [\n -123.26660156249999,\n 37.28279464911045\n ],\n [\n -121.640625,\n 37.28279464911045\n ],\n [\n -121.640625,\n 38.22091976683121\n ],\n [\n -123.26660156249999,\n 38.22091976683121\n ],\n [\n -123.26660156249999,\n 37.28279464911045\n ]\n ]\n ]\n }\n }\n ]\n}","volume":"19","issue":"9","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0326e4b0c8380cd50373","contributors":{"authors":[{"text":"Luoma, Samuel N. 0000-0001-5443-5091 snluoma@usgs.gov","orcid":"https://orcid.org/0000-0001-5443-5091","contributorId":2287,"corporation":false,"usgs":true,"family":"Luoma","given":"Samuel","email":"snluoma@usgs.gov","middleInitial":"N.","affiliations":[{"id":438,"text":"National Research Program - Western Branch","active":true,"usgs":true}],"preferred":true,"id":779729,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Phillips, D.J.H.","contributorId":80829,"corporation":false,"usgs":true,"family":"Phillips","given":"D.J.H.","email":"","affiliations":[],"preferred":false,"id":369072,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014712,"text":"70014712 - 1988 - An economic and geographic appraisal of a spatial natural hazard risk: a study of landslide mitigation rules","interactions":[],"lastModifiedDate":"2013-03-13T21:03:32","indexId":"70014712","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1525,"text":"Environment and Planning A","active":true,"publicationSubtype":{"id":10}},"title":"An economic and geographic appraisal of a spatial natural hazard risk: a study of landslide mitigation rules","docAbstract":"Efficient mitigation of natural hazards requires a spatial representation of the risk, based upon the geographic distribution of physical parameters and man-related development activities. Through such a representation, the spatial probability of landslides based upon physical science concepts is estimated for Cincinnati, Ohio. Mitigation programs designed to reduce loss from landslide natural hazards are then evaluated. An optimum mitigation rule is suggested that is spatially selective and is determined by objective measurements of hillside slope and properties of the underlying soil. -Authors","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Environment and Planning A","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1068/a200621","usgsCitation":"Bernknopf, R., Brookshire, D., Campbell, R.H., and Shapiro, C., 1988, An economic and geographic appraisal of a spatial natural hazard risk: a study of landslide mitigation rules: Environment and Planning A, v. 20, no. 5, p. 621-631, https://doi.org/10.1068/a200621.","startPage":"621","endPage":"631","numberOfPages":"11","costCenters":[],"links":[{"id":225657,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":269305,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1068/a200621"}],"volume":"20","issue":"5","noUsgsAuthors":false,"publicationDate":"1988-05-01","publicationStatus":"PW","scienceBaseUri":"5059ea2ce4b0c8380cd486a2","contributors":{"authors":[{"text":"Bernknopf, R. L.","contributorId":46082,"corporation":false,"usgs":true,"family":"Bernknopf","given":"R. L.","affiliations":[],"preferred":false,"id":369070,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Brookshire, D.S.","contributorId":43335,"corporation":false,"usgs":true,"family":"Brookshire","given":"D.S.","email":"","affiliations":[],"preferred":false,"id":369069,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Campbell, R. H.","contributorId":52160,"corporation":false,"usgs":true,"family":"Campbell","given":"R.","email":"","middleInitial":"H.","affiliations":[],"preferred":false,"id":369071,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Shapiro, C.D.","contributorId":24796,"corporation":false,"usgs":true,"family":"Shapiro","given":"C.D.","email":"","affiliations":[],"preferred":false,"id":369068,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70014710,"text":"70014710 - 1988 - Using laser micro mass spectrometry with the LAMMA-1000 instrument for monitoring relative elemental concentrations in vitrinite","interactions":[],"lastModifiedDate":"2012-03-12T17:19:33","indexId":"70014710","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2742,"text":"Mikrochimica Acta","active":true,"publicationSubtype":{"id":10}},"title":"Using laser micro mass spectrometry with the LAMMA-1000 instrument for monitoring relative elemental concentrations in vitrinite","docAbstract":"The variation in relative elemental concentrations among a series of coal macerals belonging to the vitrinite maceral group was determined using laser micro mass spectrometry (LAMMS). Variations in Ba, Cr, Ga, Sr, Ti, and V concentrations among the coals were determined using the LAMM A-1000 instrument. LAMMS analysis is not limited to these elements; their selection illustrates the application of the technique. Ba, Cr, Ga, Sr, Ti, and V have minimal site-to-site variance in the vitrinite macerals of the studied coals as measured by LAMMS. The LAMMS data were compared with bulk elemental data obtained by instrumental neutron activation analysis (INAA) and D. C. arc optical emission spectroscopy (DCAS) in order to determine the reliability of the LAMMS data. The complex nature of the ionization phenomena in LAMMS and the lack of standards characterized on a microscale makes obtaining quantitative elemental data within the ionization microvolume difficult; however, we demonstrate that the relative variation of an element among vitrinites from different coal beds in the eastern United States can be observed using LAMMS in a \"bulk\" mode by accumulating signal intensities over several microareas of each vitrinite. Our studies indicate gross changes (greater than a factor of 2 to 5 depending on the element) can be monitored when the elemental concentration is significantly above the detection limit. \"Bulk\" mode analysis was conducted to evaluate the accuracy of future elemental LAMMS microanalyses. The primary advantage of LAMMS is the inherent spatial resolution, ~ 20 ??m for coal. Two different vitrite bands in the Lower Bakerstown coal bed (CLB-1) were analyzed. The analysis did not establish any certain concentration differences in Ba, Cr, Ga, Sr, Ti, and V between the two bands. ?? 1988 Springer-Verlag.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Mikrochimica Acta","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisherLocation":"Springer-Verlag","doi":"10.1007/BF01236096","issn":"00263672","usgsCitation":"Morelli, J., Hercules, D., Lyons, P., Palmer, C., and Fletcher, J., 1988, Using laser micro mass spectrometry with the LAMMA-1000 instrument for monitoring relative elemental concentrations in vitrinite: Mikrochimica Acta, v. 96, no. 1-6, p. 105-118, https://doi.org/10.1007/BF01236096.","startPage":"105","endPage":"118","numberOfPages":"14","costCenters":[],"links":[{"id":205644,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1007/BF01236096"},{"id":225655,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"96","issue":"1-6","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bc066e4b08c986b32a0de","contributors":{"authors":[{"text":"Morelli, J.J.","contributorId":90891,"corporation":false,"usgs":true,"family":"Morelli","given":"J.J.","email":"","affiliations":[],"preferred":false,"id":369065,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hercules, D.M.","contributorId":86905,"corporation":false,"usgs":true,"family":"Hercules","given":"D.M.","email":"","affiliations":[],"preferred":false,"id":369063,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lyons, P.C.","contributorId":87285,"corporation":false,"usgs":true,"family":"Lyons","given":"P.C.","email":"","affiliations":[],"preferred":false,"id":369064,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Palmer, C.A.","contributorId":81894,"corporation":false,"usgs":true,"family":"Palmer","given":"C.A.","email":"","affiliations":[],"preferred":false,"id":369062,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Fletcher, J.D.","contributorId":24928,"corporation":false,"usgs":true,"family":"Fletcher","given":"J.D.","email":"","affiliations":[],"preferred":false,"id":369061,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70014709,"text":"70014709 - 1988 - Anomalous shear wave attenuation in the shallow crust beneath the Coso volcanic region, California","interactions":[],"lastModifiedDate":"2024-06-05T14:38:46.831799","indexId":"70014709","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Anomalous shear wave attenuation in the shallow crust beneath the Coso volcanic region, California","docAbstract":"We use seismograms of local earthquakes to image relative shear wave attenuation structure in the shallow crust beneath the region containing the Coso volcanic-geothermal area of eastern California. SV and P wave amplitudes were measured from vertical component seismograms of earthquakes that occurred in the Cososouthem Sierra Nevada region from July 1983 to August 1985. Seismograms of 16 small earthquakes show SV amplitudes which are greatly diminished at some azimuths and takeoff angles, indicating strong lateral variations in S wave attenuation in the area. Three-dimensional images of the relative S wave attenuation structure are obtained from forward modeling and a back projection inversion of the amplitude data. The results indicate regions within a 20 by 30 by 10 km volume of the shallow crust (one shallower than 5 km) that severely attenuate SV waves passing through them. These anomalies lie beneath the Indian Wells Valley, 30 km south of the Coso volcanic field, and are coincident with the epicentral locations of recent earthquake swarms. No anomalous attenuation is seen beneath the Coso volcanic field above about 5 km depth. Geologic relations and the coincidence of anomalously slow P wave velocities suggest that the attenuation anomalies may be related to magmatism along the eastern Sierra front.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB093iB04p03321","issn":"01480227","usgsCitation":"Sanders, C., Ho-Liu, P., Rinn, D., and Hiroo, K., 1988, Anomalous shear wave attenuation in the shallow crust beneath the Coso volcanic region, California: Journal of Geophysical Research Solid Earth, v. 93, no. B4, p. 3321-3338, https://doi.org/10.1029/JB093iB04p03321.","productDescription":"18 p.","startPage":"3321","endPage":"3338","numberOfPages":"18","costCenters":[],"links":[{"id":480029,"rank":2,"type":{"id":41,"text":"Open Access External Repository Page"},"url":"https://doi.org/10.1029/jb093ib04p03321","text":"External Repository"},{"id":225654,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"B4","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"5059ec4be4b0c8380cd4919b","contributors":{"authors":[{"text":"Sanders, C.","contributorId":91640,"corporation":false,"usgs":true,"family":"Sanders","given":"C.","email":"","affiliations":[],"preferred":false,"id":369059,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ho-Liu, P.","contributorId":36689,"corporation":false,"usgs":true,"family":"Ho-Liu","given":"P.","email":"","affiliations":[],"preferred":false,"id":369057,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rinn, D.","contributorId":92436,"corporation":false,"usgs":true,"family":"Rinn","given":"D.","email":"","affiliations":[],"preferred":false,"id":369060,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Hiroo, Kanamori","contributorId":60784,"corporation":false,"usgs":true,"family":"Hiroo","given":"Kanamori","affiliations":[],"preferred":false,"id":369058,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70014701,"text":"70014701 - 1988 - Radioactive and nonradioactive solutes in drinking water from Rn-charging devices","interactions":[],"lastModifiedDate":"2012-03-12T17:19:34","indexId":"70014701","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1884,"text":"Health Physics","active":true,"publicationSubtype":{"id":10}},"title":"Radioactive and nonradioactive solutes in drinking water from Rn-charging devices","docAbstract":"[No abstract available]","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Health Physics","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00179078","usgsCitation":"Landa, E.R., Miller, C., and Brich, R., 1988, Radioactive and nonradioactive solutes in drinking water from Rn-charging devices: Health Physics, v. 54, no. 1, p. 99-106.","startPage":"99","endPage":"106","numberOfPages":"8","costCenters":[],"links":[{"id":225462,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"54","issue":"1","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a93a7e4b0c8380cd80f61","contributors":{"authors":[{"text":"Landa, E. R.","contributorId":100002,"corporation":false,"usgs":true,"family":"Landa","given":"E.","email":"","middleInitial":"R.","affiliations":[],"preferred":false,"id":369038,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Miller, C.L.","contributorId":86788,"corporation":false,"usgs":true,"family":"Miller","given":"C.L.","email":"","affiliations":[],"preferred":false,"id":369036,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Brich, R.F.","contributorId":89673,"corporation":false,"usgs":true,"family":"Brich","given":"R.F.","email":"","affiliations":[],"preferred":false,"id":369037,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014700,"text":"70014700 - 1988 - Analytical approach to calculation of response spectra from seismological models of ground motion","interactions":[],"lastModifiedDate":"2013-03-13T15:26:08","indexId":"70014700","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1434,"text":"Earthquake Engineering and Structural Dynamics","active":true,"publicationSubtype":{"id":10}},"title":"Analytical approach to calculation of response spectra from seismological models of ground motion","docAbstract":"An analytical approach to calculate response spectra from seismological models of ground motion is presented. Seismological models have three major advantages over empirical models: (1) they help in an understanding of the physics of earthquake mechanisms, (2) they can be used to predict ground motions for future earthquakes and (3) they can be extrapolated to cases where there are no data available. As shown with this study, these models also present a convenient form for the calculation of response spectra, by using the methods of random vibration theory, for a given magnitude and site conditions. The first part of the paper reviews the past models for ground motion description, and introduces the available seismological models. Then, the random vibration equations for the spectral response are presented. The nonstationarity, spectral bandwidth and the correlation of the peaks are considered in the calculation of the peak response.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Earthquake Engineering and Structural Dynamics","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Wiley","doi":"10.1002/eqe.4290160109","issn":"03756297","usgsCitation":"Safak, E., 1988, Analytical approach to calculation of response spectra from seismological models of ground motion: Earthquake Engineering and Structural Dynamics, v. 16, no. 1, p. 121-134, https://doi.org/10.1002/eqe.4290160109.","startPage":"121","endPage":"134","numberOfPages":"14","costCenters":[],"links":[{"id":225461,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":269246,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1002/eqe.4290160109"}],"volume":"16","issue":"1","noUsgsAuthors":false,"publicationDate":"2006-12-18","publicationStatus":"PW","scienceBaseUri":"5059e62ee4b0c8380cd47204","contributors":{"authors":[{"text":"Safak, Erdal","contributorId":73984,"corporation":false,"usgs":true,"family":"Safak","given":"Erdal","email":"","affiliations":[],"preferred":false,"id":369035,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70013749,"text":"70013749 - 1988 - Leaching characteristics of a high-calcium fly ash as a function of pH: A potential source of selenium toxicity","interactions":[],"lastModifiedDate":"2023-03-15T12:19:45.169849","indexId":"70013749","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","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":"Leaching characteristics of a high-calcium fly ash as a function of pH: A potential source of selenium toxicity","docAbstract":"Using a modified extraction procedure, the effect of pH on the leaching of selected elements from Ca-rich (Type C) power plant fly ash was studied. Continuous additions of acetic acid were used to maintain pH values of fly ash slurries at 4.0, 6.0 and 8.0 for 24 h and an additional set was leached at its natural pH (average 11.8) value. Analyses for Se, As, Ca, Cd, Cr, Fe, Na and Pb showed that the highest concentrations occur in the leachate at pH 4.0 and decline with increasing pH. Concentrations of Cr and Fe increased slightly between neutral and high pH. Arsenic, Cd, Cr, Pb and Se concentrations exceeded the Environmental Protection Agency's toxicity criteria at pH 4.0. Selenium was above its toxicity level at pH values near 7 but the other elements were below their respective toxicity levels near neutral pH. Because recent studies show adverse effects of Se on aquatic life at far lower concentrations than the current Environmental Protection Agency's standard, high-Ca, power plant fly ashes represent a potentially hazardous pollutant to surface and subsurface waters.
A strong test of our understanding of the earthquake cycle is the ability to reproduce extant fault-bounded geological structures, such as basins and ranges, which are built by repeated cycles of deformation. Along strike-slip faults, the coseismic and interseismic deformation can be nearly equal in magnitude and opposite in sign, resulting in little permanent deformation except for the fault offset. For dip-slip faults, portions of the crust are lifted and dropped, and so buoyancy forces are exerted. The seismic and interseismic deformations do not balance, and structures grow and become subject to erosion and deposition. We consider three examples for which the structure and fault geometry are well known: the White Wolf reverse fault in California, site of the 1952 Kern County M=7.3 earthquake, the Lost River normal fault in Idaho, site of the 1983 Borah Peak M=7.0 earthquake, and the Cricket Mountain normal fault in Utah, site of Quaternary slip events. Basin stratigraphy and seismic reflection records are used to profile the structure, and coseismic deformation measured by leveling surveys is used to estimate the fault geometry. To reproduce these structures, we add the deformation associated with the earthquake cycle (the coseismic slip and postseismic relaxation) to the flexure caused by the observed sediment load, treating the crust as a thin elastic plate overlying a fluid substrate. The cumulative deformation is principally dependent on the elastic plate thickness, modestly sensitive to the sediment-substrate density difference, and insensitive to the fluid viscosity for the 4- to 8-Ma structures. We deduce a longterm flexural rigidity of 2–15 × 1019 Nm; this is equivalent to an elastic plate thickness of 2–4 km for a Young's modulus of 2.5 × 1010 Nm−2. This value is found where independent estimates of the elastic thickness from the coherence between surface topography and gravity yield values of about 4 km, but where coseismic fault slip extends to a depth of 10–15 km. Thus much of the seismogenic crust must weaken substantially during the life of active faults, causing the fault-bounded basins to narrow over time.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB093iB11p13319","issn":"01480227","usgsCitation":"Stein, R., King, G., and Rundle, J.B., 1988, The growth of geological structures by repeated earthquakes: 2, Field examples of continental dip-slip faults: Journal of Geophysical Research Solid Earth, v. 93, no. B11, p. 13319-13331, https://doi.org/10.1029/JB093iB11p13319.","productDescription":"13 p.","startPage":"13319","endPage":"13331","costCenters":[],"links":[{"id":225835,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"B11","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505baca9e4b08c986b32364a","contributors":{"authors":[{"text":"Stein, R.S.","contributorId":8875,"corporation":false,"usgs":true,"family":"Stein","given":"R.S.","email":"","affiliations":[],"preferred":false,"id":368441,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"King, G.C.P.","contributorId":18510,"corporation":false,"usgs":true,"family":"King","given":"G.C.P.","email":"","affiliations":[],"preferred":false,"id":368443,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rundle, J. B.","contributorId":17766,"corporation":false,"usgs":false,"family":"Rundle","given":"J.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":368442,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014455,"text":"70014455 - 1988 - Vapor-dominated zones within hydrothermal systems: Evolution and natural state","interactions":[],"lastModifiedDate":"2024-06-05T14:53:15.43716","indexId":"70014455","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Vapor-dominated zones within hydrothermal systems: Evolution and natural state","docAbstract":"Three conceptual models illustrate the range of hydrothermal systems in which vapor-dominated conditions are found. The first model (model I) represents a system with an extensive near-vaporstatic vapor-dominated zone and limited liquid throughflow and is analogous to systems such as The Geysers, California. Such systems can evolve within low-permeability barriers without changes in boundary conditions or rock properties, given an adequate supply of heat. Their scarcity in nature may be due to the need for a long-lived, potent heat source and for a low-permeability aureole that remains intact for significant lengths of time. Models II and III represent systems with significant liquid throughflow and include steam-heated discharge features at higher elevations and high-chloride springs at lower elevations, connected to and fed by a single circulation system at depth. In model II, as in model I, the vapor-dominated zone has a near-vaporstatic vertical pressure gradient and is generally underpressured with respect to local hydrostatic pressure. The vapor-dominated zone in model III is quite different, in that phase separation takes place at pressures close to local hydrostatic and the overall pressure gradient is near hydrostatic. A relatively large number of high-temperature systems in regions of moderate to great topographic relief are similar to either model II or model III; however, in most cases there are insufficient data to establish a single preferred model.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB093iB11p13635","issn":"01480227","usgsCitation":"Ingebritsen, S.E., and Sorey, M., 1988, Vapor-dominated zones within hydrothermal systems: Evolution and natural state: Journal of Geophysical Research Solid Earth, v. 93, no. B11, p. 13635-13655, https://doi.org/10.1029/JB093iB11p13635.","productDescription":"21 p.","startPage":"13635","endPage":"13655","costCenters":[],"links":[{"id":225776,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"B11","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505bc120e4b08c986b32a461","contributors":{"authors":[{"text":"Ingebritsen, S. E.","contributorId":8078,"corporation":false,"usgs":true,"family":"Ingebritsen","given":"S.","email":"","middleInitial":"E.","affiliations":[],"preferred":false,"id":368433,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Sorey, M.L.","contributorId":73185,"corporation":false,"usgs":true,"family":"Sorey","given":"M.L.","affiliations":[],"preferred":false,"id":368434,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014442,"text":"70014442 - 1988 - Using exogenous variables in testing for monotonic trends in hydrologic time series","interactions":[],"lastModifiedDate":"2018-02-21T11:06:06","indexId":"70014442","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","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":"Using exogenous variables in testing for monotonic trends in hydrologic time series","docAbstract":"One approach that has been used in performing a nonparametric test for monotonic trend in a hydrologic time series consists of a two-stage analysis. First, a regression equation is estimated for the variable being tested as a function of an exogenous variable. A nonparametric trend test such as the Kendall test is then performed on the residuals from the equation. By analogy to stagewise regression and through Monte Carlo experiments, it is demonstrated that this approach will tend to underestimate the magnitude of the trend and to result in some loss in power as a result of ignoring the interaction between the exogenous variable and time. An alternative approach, referred to as the adjusted variable Kendall test, is demonstrated to generally have increased statistical power and to provide more reliable estimates of the trend slope. In addition, the utility of including an exogenous variable in a trend test is examined under selected conditions.
Variations in streamwater temperature at the outlet of a 41-ha forested watershed at Panola Mountain in the Georgia Piedmont indicate that the initial rapid hydrologic response is caused by a combination of groundwater discharge and channel interception of rainwater. A storm in May 1986 caused a rapid increase in discharge that was accompanied by a decrease in streamwater temperature and a rise in the water table level adjacent to the stream. The higher water table provided the hydraulic gradient necessary to increase the discharge of colder groundwater to the stream. Storms that occurred under very dry antecedent conditions in July 1986 and June 1987 caused a rapid hydrologic response but no change in water table level, indicating the response was caused by channel interception of rainwater. This conclusion was supported by increases in streamwater temperature in the June storm and by chemical changes in the July storm. When rainfall is sufficient, flow in the ephemeral part of the stream in the catchment headwaters generates a second and larger discharge peak that reflects the chemistry and temperature of runoff from a 3-ha granite outcrop in the headwaters; sulfate concentration and temperature increase and alkalinity decreases relative to prestorm conditions. The initial response, however, results from channel interception and groundwater discharge. Rapid rises in the water table level during some storms suggest that macropore flow may play a major role in the hydrologic response of the watershed to rainstorms.
","language":"English","publisher":"Elsevier","doi":"10.1016/0169-7722(88)90040-X","issn":"01697722","usgsCitation":"Shanley, J.B., and Peters, N., 1988, Preliminary observations of streamflow generation during storms in a forested Piedmont watershed using temperature as a tracer: Journal of Contaminant Hydrology, v. 3, no. 2-4, p. 349-365, https://doi.org/10.1016/0169-7722(88)90040-X.","productDescription":"17 p.","startPage":"349","endPage":"365","numberOfPages":"17","costCenters":[],"links":[{"id":225708,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"3","issue":"2-4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a8936e4b0c8380cd7dd41","contributors":{"authors":[{"text":"Shanley, J. B.","contributorId":52226,"corporation":false,"usgs":true,"family":"Shanley","given":"J.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":368424,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Peters, N.E.","contributorId":33332,"corporation":false,"usgs":true,"family":"Peters","given":"N.E.","email":"","affiliations":[],"preferred":false,"id":368423,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014449,"text":"70014449 - 1988 - Geochemistry of some gases in hydrothermal fluids from the southern Juan de Fuca Ridge","interactions":[],"lastModifiedDate":"2024-06-05T15:00:24.666864","indexId":"70014449","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Geochemistry of some gases in hydrothermal fluids from the southern Juan de Fuca Ridge","docAbstract":"Five samples of hydrothermal fluids from two vent areas on the southern Juan de Fuca Ridge were analyzed for dissolved gases. Concentrations in the end-member hydrothermal fluid of H2 (270–527 μmol/kg), CH4 (82–118 μmol/kg), and CO2 (3920–4460 μmol/kg) are well above values in ambient seawater and are similar to concentrations reported for other ridge crest hydrothermal systems. The carbon isotopic ratios of the CH4 (δ13C = −17.8 to −20.8) and CO2 (δ13C = −3.6 to −4.7) suggest that at least some of the CH4 and CO2 in the fluids is basalt-derived. The range of δ13C values for the basalt-derived CO2 is −6.8 to −9.7, calculated by assuming conservation of recharge ΣCO2 during hydrothermal circulation. Apparent temperatures of equilibration between the CH4 and the basalt-derived CO2 range from 640°C to 750°C. Small amounts of ethane (C2H6/CH4 ≅ 0.9 × 10−3−2.2 × 10−3), propane, and butane detected in the samples may also have formed in the basalt. One sample of almost pure (95.5%) hydrothermal fluid contained a significant fraction, up to 63% and 74%, respectively, of the recharge Ar and N2. This suggests that the fluid has not undergone extensive vapor-liquid phase separation.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB093iB12p15305","issn":"01480227","usgsCitation":"Evans, W.C., White, L.D., and Rapp, J.B., 1988, Geochemistry of some gases in hydrothermal fluids from the southern Juan de Fuca Ridge: Journal of Geophysical Research Solid Earth, v. 93, no. B12, p. 15305-15313, https://doi.org/10.1029/JB093iB12p15305.","productDescription":"9 p.","startPage":"15305","endPage":"15313","costCenters":[],"links":[{"id":225706,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"B12","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a1713e4b0c8380cd55387","contributors":{"authors":[{"text":"Evans, William C.","contributorId":104903,"corporation":false,"usgs":true,"family":"Evans","given":"William","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":368420,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"White, L. D.","contributorId":14330,"corporation":false,"usgs":true,"family":"White","given":"L.","email":"","middleInitial":"D.","affiliations":[],"preferred":false,"id":368418,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Rapp, J. B.","contributorId":28987,"corporation":false,"usgs":true,"family":"Rapp","given":"J.","email":"","middleInitial":"B.","affiliations":[],"preferred":false,"id":368419,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014445,"text":"70014445 - 1988 - Deuterium in interstitial water from deep-sea cores","interactions":[],"lastModifiedDate":"2024-06-05T15:02:47.571472","indexId":"70014445","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Deuterium in interstitial water from deep-sea cores","docAbstract":"As part of the Joint Oceanographic Institutions Deep Earth Sampling project, the interstitial waters of cores from 69 holes were sampled for deuterium analysis. Sixteen of the cores penetrated sediments as old as Eocene, and several sampled Cretaceous sediments, which allowed us to examine changes in the deuterium content of the oceans with time. Deuterium is shown to be a conservative constituent of the pore water. Its abundance in the pore fluids can be changed by diffusion, but the rate is slow, and corrections for this effect have been made. Changes in the abundance of deuterium can be related to changes in the amount of ice stored in continental glaciers, inasmuch as precipitation in the form of snow is highly depleted in deuterium compared with the oceans. Many of the cores show a change in isotopic composition of samples from early to late Miocene that can be ascribed to the buildup of the Antarctic ice sheets. After correcting for the role of diffusion in reducing the isotopic contrast between samples from a single core, we estimate an increase of 10 per mil (‰) δD (corresponding to a° δ18O change of about 1.2‰) between the early and late Miocene. A similiar analysis of Pleistocene to Holocene changes indicates a δD rise of 8‰ during the time of maximum continental ice, which corresponds to a δ18O increase of about 1.0‰. On the basis of limited data, we find no δD change in the oceans from Cretaceous to Miocene.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JC093iC07p08249","issn":"01480227","usgsCitation":"Friedman, I., and Hardcastle, K., 1988, Deuterium in interstitial water from deep-sea cores: Journal of Geophysical Research Solid Earth, v. 93, no. C7, p. 8249-8263, https://doi.org/10.1029/JC093iC07p08249.","productDescription":"15 p.","startPage":"8249","endPage":"8263","numberOfPages":"15","costCenters":[],"links":[{"id":225638,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"C7","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a0004e4b0c8380cd4f539","contributors":{"authors":[{"text":"Friedman, I.","contributorId":95596,"corporation":false,"usgs":true,"family":"Friedman","given":"I.","email":"","affiliations":[],"preferred":false,"id":368411,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hardcastle, K.","contributorId":45825,"corporation":false,"usgs":true,"family":"Hardcastle","given":"K.","affiliations":[],"preferred":false,"id":368410,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014444,"text":"70014444 - 1988 - Multitemporal Landsat multispectral scanner and thematic mapper data of the Hubbard Glacier region, southeast Alaska","interactions":[],"lastModifiedDate":"2017-01-18T14:30:26","indexId":"70014444","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3052,"text":"Photogrammetric Engineering and Remote Sensing","active":true,"publicationSubtype":{"id":10}},"title":"Multitemporal Landsat multispectral scanner and thematic mapper data of the Hubbard Glacier region, southeast Alaska","docAbstract":"In late May 1986, the advancing Hubbard Glacier blocked the entrance to Russell Fiord near Yakutat, Alaska, creating a large ice-dammed lake. Runoff from the surrounding glaciated mountains raised the level of the lake to about 25 m above sea level by 8 October, when the ice dam failed. Remote sensing offers one method to monitor this large tidal glacier system, particularly the glacier activity that would portend the re-closure of Russell Fiord. -Authors","language":"English","usgsCitation":"Walker, K., and Zenone, C., 1988, Multitemporal Landsat multispectral scanner and thematic mapper data of the Hubbard Glacier region, southeast Alaska: Photogrammetric Engineering and Remote Sensing, v. 54, no. 3, p. 373-376.","productDescription":"4 p.","startPage":"373","endPage":"376","numberOfPages":"4","costCenters":[{"id":222,"text":"Earth Resources Observation and Science (EROS) Center","active":true,"usgs":true}],"links":[{"id":225637,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"54","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a60afe4b0c8380cd71614","contributors":{"authors":[{"text":"Walker, K.-M.","contributorId":87957,"corporation":false,"usgs":true,"family":"Walker","given":"K.-M.","email":"","affiliations":[],"preferred":false,"id":368409,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Zenone, C.","contributorId":30374,"corporation":false,"usgs":true,"family":"Zenone","given":"C.","affiliations":[],"preferred":false,"id":368408,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014418,"text":"70014418 - 1988 - Effects of three-dimensional velocity structure on the seismicity of the 1984 Morgan Hill, California, aftershock sequence","interactions":[],"lastModifiedDate":"2023-10-28T00:03:13.198919","indexId":"70014418","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","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":"Effects of three-dimensional velocity structure on the seismicity of the 1984 Morgan Hill, California, aftershock sequence","docAbstract":"A three-dimensional velocity model for the area surrounding the 24 April 1984 Morgan Hill earthquake has been developed by simultaneously inverting local earthquake and refraction arrival-time data. This velocity model corresponds well to the surface geology of the region, predominantly showing a low-velocity region associated with the sedimentary sequence to the southwest of the Madrone Springs fault. This low-velocity sequence extends to a depth of approximately 5 km. Previously constructed geologic cross-sections for this region had suggested that these sediments extended to a depth of less than 2 km. Relocation of 2,179 hypocenters with the three-dimensional velocity model did not show great differences when compared to locations done with a one-dimensional velocity model with station corrections. In both cases, the Calaveras fault is steep but has a noticeable dip to the northeast and the seismicity does not intersect the surface along the trace of the Calaveras fault in the southern half of the rupture zone. The greatest differences between the two sets of locations was that the locations using the three-dimensional velocity model were deeper, and fewer earthquakes were located within the low-velocity region. The focal mechanisms were also determined for 946 earthquakes using both the one-dimensional and three-dimensional earth models. Both earth models yield similar focal mechanisms for these earthquakes.
","language":"English","publisher":"Seismological Society of America","doi":"10.1785/BSSA0780031199","usgsCitation":"Michael, A., 1988, Effects of three-dimensional velocity structure on the seismicity of the 1984 Morgan Hill, California, aftershock sequence: Bulletin of the Seismological Society of America, v. 78, no. 3, p. 1199-1221, https://doi.org/10.1785/BSSA0780031199.","productDescription":"23 p.","startPage":"1199","endPage":"1221","numberOfPages":"23","costCenters":[],"links":[{"id":422213,"rank":2,"type":{"id":15,"text":"Index Page"},"url":"https://pubs.geoscienceworld.org/ssa/bssa/article/78/3/1199/102327/Effects-of-three-dimensional-velocity-structure-on"},{"id":226221,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"California","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -121.76463433600294,\n 37.421031586189955\n ],\n [\n -121.76463433600294,\n 36.94800385988415\n ],\n [\n -121.0560161719405,\n 36.94800385988415\n ],\n [\n -121.0560161719405,\n 37.421031586189955\n ],\n [\n -121.76463433600294,\n 37.421031586189955\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"78","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a080ce4b0c8380cd5194f","contributors":{"authors":[{"text":"Michael, A.J. 0000-0002-2403-5019","orcid":"https://orcid.org/0000-0002-2403-5019","contributorId":52192,"corporation":false,"usgs":true,"family":"Michael","given":"A.J.","affiliations":[],"preferred":false,"id":368358,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014417,"text":"70014417 - 1988 - Three-dimensional P velocity structure of the crust below Newberry Volcano, Oregon","interactions":[],"lastModifiedDate":"2024-06-05T15:46:28.611033","indexId":"70014417","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Three-dimensional P velocity structure of the crust below Newberry Volcano, Oregon","docAbstract":"Utilizing teleseismic P residuals, we have detected a column of high P velocity material extending from within 10 km of the surface below the summit of Newberry Volcano, Oregon, to midcrustal depths near 25 km. We interpret this column to be the expression of a swarm of predominantly subsolidus gabbroic sills and dikes which were intruded as the volcano was built. The high P velocities observed below the volcano severely limit the size of magma chambers which could presently exist in the crust below Newberry Volcano. Those possible include a few percent of partial melt distributed through large volumes of a mafic intrusion zone in the midcrust; a few, smaller, higher melt fraction zones in the midcrust with dimensions less than 6 km and whose aggregate volume is only a few percent of enclosing volumes of 200 km3; small magma bodies with dimensions of a few kilometers located within the upper 10 km of the crust; or a mafic, crystal-rich magma of arbitrary dimensions located in the upper few km. The low P velocities detected in the upper 4 km beneath the center of the summit caldera may be partially caused by a magma chamber in the second of these catagories.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB093iB09p10095","issn":"01480227","usgsCitation":"Stauber, D., Green, S., and Iyer, H.M., 1988, Three-dimensional P velocity structure of the crust below Newberry Volcano, Oregon: Journal of Geophysical Research Solid Earth, v. 93, no. B9, p. 10095-10107, https://doi.org/10.1029/JB093iB09p10095.","productDescription":"13 p.","startPage":"10095","endPage":"10107","costCenters":[],"links":[{"id":226220,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"B9","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505bb31ee4b08c986b325bb4","contributors":{"authors":[{"text":"Stauber, D.A.","contributorId":52183,"corporation":false,"usgs":true,"family":"Stauber","given":"D.A.","email":"","affiliations":[],"preferred":false,"id":368357,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Green, S.M.","contributorId":30378,"corporation":false,"usgs":true,"family":"Green","given":"S.M.","email":"","affiliations":[],"preferred":false,"id":368356,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Iyer, H. M.","contributorId":17997,"corporation":false,"usgs":true,"family":"Iyer","given":"H.","middleInitial":"M.","affiliations":[],"preferred":false,"id":368355,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014416,"text":"70014416 - 1988 - On the state of lithospheric stress in the absence of applied tectonic forces","interactions":[],"lastModifiedDate":"2024-06-05T15:13:21.965867","indexId":"70014416","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"On the state of lithospheric stress in the absence of applied tectonic forces","docAbstract":"Numerous published analyses of the nontectonic state of stress are based on Hooke's law and the boundary condition of zero horizontal deformation. This approach has been used to determine the gravitational stress state as well as the effects of processes such as erosion and temperature changes on the state of lithospheric stress. The major disadvantage of these analyses involves the assumption of lateral constraint which seems unrealistic in view of the observational fact that the crust can deform horizontally in response to applied loads. If the same problems are addressed by assuming that the remote stress state is constant, instead of the condition of zero horizontal deformation, then the resulting stress states are entirely different and in good accord with observations. In the absence of applied tectonic forces the only likely gravitational stress states are those for which all three principal stresses are nearly equal. To the contrary, the gravitational stress states developed on the basis of the lateral constraint assumption can be ruled out. The processes of erosion and sedimentation have slight tendencies to increase and decrease, respectively, the state of deviatoric stress. In particular, for initial stress states in the range of slightly extensional to compressional, erosion has the effect of enhancing the ratio of average horizontal to vertical stress, which may explain, at least in part, the common observation of high near-surface horizontal stresses. Temperature changes have only minor effects on the stress state, as averaged over the thickness of the lithosphere.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB093iB11p13609","issn":"01480227","usgsCitation":"McGarr, A., 1988, On the state of lithospheric stress in the absence of applied tectonic forces: Journal of Geophysical Research Solid Earth, v. 93, no. B11, p. 13609-13617, https://doi.org/10.1029/JB093iB11p13609.","productDescription":"9 p.","startPage":"13609","endPage":"13617","costCenters":[],"links":[{"id":226219,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"B11","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a6dfde4b0c8380cd75431","contributors":{"authors":[{"text":"McGarr, Art 0000-0001-9769-4093","orcid":"https://orcid.org/0000-0001-9769-4093","contributorId":43491,"corporation":false,"usgs":true,"family":"McGarr","given":"Art","affiliations":[],"preferred":false,"id":368354,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70014415,"text":"70014415 - 1988 - Paleomagnetic investigation of some volcanic rocks from the McMurdo volcanic province, Antarctica","interactions":[],"lastModifiedDate":"2024-06-05T15:16:00.789139","indexId":"70014415","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":6453,"text":"Journal of Geophysical Research Solid Earth","active":true,"publicationSubtype":{"id":10}},"title":"Paleomagnetic investigation of some volcanic rocks from the McMurdo volcanic province, Antarctica","docAbstract":"Paleomagnetic data for lava flows from sporadic but long-lived eruptions in the McMurdo Sound region are combined with previously published geologic and geochronologic data to determine the general eruptive sequence of the area. Lava flows in the Walcott Bay area were erupted during the Gauss Normal, Matuyama Reversed, and Brunhes Normal Polarity Chrons. The youngest flows on Black Island probably erupted near the boundary between the Gilbert and Gauss chrons. The most recent activity was concentrated on the volcanic edifices of Mounts Morning and Discovery and on Ross Island where Mount Erebus is currently active. Combining virtual geomagnetic poles calculated for 39 units sampled during this study with those of eight flows that were published previously yields a mean paleomagnetic pole at 87.3°N, 317.3°E (α95 = 6.3°). The ancient geomagnetic field dispersion about this mean pole is 23.5°, with upper and lower limits of 95% confidence equal to 27.4° and 20.5°, respectively. This value probably is a reasonable estimate of secular variation for the Antarctic continent during Pliocene and Pleistocene time.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/JB093iB10p11599","issn":"01480227","usgsCitation":"Mankinen, E., and Cox, A., 1988, Paleomagnetic investigation of some volcanic rocks from the McMurdo volcanic province, Antarctica: Journal of Geophysical Research Solid Earth, v. 93, no. B10, p. 11599-11612, https://doi.org/10.1029/JB093iB10p11599.","productDescription":"14 p.","startPage":"11599","endPage":"11612","costCenters":[],"links":[{"id":226155,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"93","issue":"B10","noUsgsAuthors":false,"publicationDate":"2012-09-20","publicationStatus":"PW","scienceBaseUri":"505a7410e4b0c8380cd773fd","contributors":{"authors":[{"text":"Mankinen, E. A. 0000-0001-7496-2681","orcid":"https://orcid.org/0000-0001-7496-2681","contributorId":31786,"corporation":false,"usgs":true,"family":"Mankinen","given":"E. A.","affiliations":[],"preferred":false,"id":368352,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Cox, A.","contributorId":89266,"corporation":false,"usgs":true,"family":"Cox","given":"A.","email":"","affiliations":[],"preferred":false,"id":368353,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70014400,"text":"70014400 - 1988 - Major- and minor-metal composition of three distinct solid material fractions associated with Juan de Fuca hydrothermal fluids (northeast Pacific), and calculation of dilution fluid samples","interactions":[],"lastModifiedDate":"2013-01-21T08:27:29","indexId":"70014400","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","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":"Major- and minor-metal composition of three distinct solid material fractions associated with Juan de Fuca hydrothermal fluids (northeast Pacific), and calculation of dilution fluid samples","docAbstract":"Three distinct types of solid material are associated with each sample of the hydrothermal fluid that was collected from the vents of the Southern Juan de Fuca Ridge. The solid materials appear to be representative of deposits on ocean floors near mid-ocean ridges, and interpretation of the chemistry of the hydrothermal solutions requires understanding of them. Sr isotopic evidence indicates that at least two and probably all three of these solid materials were removed from the solution with which they are associated, by precipitation or adsorption. This occurred after the \"pure\" hydrothermal fluid was diluted and thoroughly mixed with ambient seawater. The three types of solid materials, are, respectively, a coarse Zn- and Fe-rich material with small amounts of Na and Ca; a finer material also rich in Zn and Fe, but with alkali and alkaline-earth metals; and a scum composed of Ba or Zn, with either considerable Fe or Si, and Sr. Mineral identification is uncertain because of uncertain anion composition. Only in the cases of Ba and Zn were metal masses greater in solid materials than in the associated fluids. For all other metals measured, masses in fluids dwarf those in solids. The fluids themselves contain greater concentrations of all metals measured, except Mg, than seawater. We discuss in detail the relative merits of two methods of determining the mixing proportions of \"pure\" hydrothermal solution and seawater in the fluids, one based on Sr isotopes, and another previously used method based on Mg concentrations. Comparison of solute concentrations in the several samples shows that degree of dilution of \"pure\" hydrothermal solutions by seawater, and amounts of original solutes that were removed from it as solid materials, are not related. There is no clear evidence that appreciable amounts of solid materials were not conserved (lost) either during or prior to sample collection. ?? 1988.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Chemical Geology","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","publisher":"Elsevier","doi":"10.1016/0009-2541(88)90095-2","issn":"00092541","usgsCitation":"Hinkley, T.K., Seeley, J.L., and Tatsumoto, M., 1988, Major- and minor-metal composition of three distinct solid material fractions associated with Juan de Fuca hydrothermal fluids (northeast Pacific), and calculation of dilution fluid samples: Chemical Geology, v. 70, no. 3, p. 235-248, https://doi.org/10.1016/0009-2541(88)90095-2.","startPage":"235","endPage":"248","numberOfPages":"14","costCenters":[],"links":[{"id":266097,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0009-2541(88)90095-2"},{"id":225894,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"70","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a4c25e4b0c8380cd69a3c","contributors":{"authors":[{"text":"Hinkley, T. K. 0000-0001-8507-6271","orcid":"https://orcid.org/0000-0001-8507-6271","contributorId":78731,"corporation":false,"usgs":true,"family":"Hinkley","given":"T.","email":"","middleInitial":"K.","affiliations":[],"preferred":false,"id":368321,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Seeley, J. L.","contributorId":57864,"corporation":false,"usgs":true,"family":"Seeley","given":"J.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":368319,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Tatsumoto, M.","contributorId":76798,"corporation":false,"usgs":true,"family":"Tatsumoto","given":"M.","email":"","affiliations":[],"preferred":false,"id":368320,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70014398,"text":"70014398 - 1988 - Acid neutralizing processes in an alpine watershed front range, Colorado, U.S.A.-1: Buffering capacity of dissolved organic carbon in soil solutions","interactions":[],"lastModifiedDate":"2023-03-20T11:27:04.369244","indexId":"70014398","displayToPublicDate":"1988-01-01T00:00:00","publicationYear":"1988","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":"Acid neutralizing processes in an alpine watershed front range, Colorado, U.S.A.-1: Buffering capacity of dissolved organic carbon in soil solutions","docAbstract":"Soil interstitial waters in the Green Lakes Valley, Front Range, Colorado were studied to evaluate the capacity of the soil system to buffer acid deposition. In order to determine the contribution of humic substances to the buffering capacity of a given soil, dissolved organic carbon (DOC) and pH of the soil solutions were measured. The concentration of the organic anion, Ai−, derived from DOC at sample pH and the concentration of organic anion, Ax− at the equivalence point were calculated using car☐yl contents from isolated and purified humic material from soil solutions. Subtracting Ax− from Ai− yields the contribution of humic substances to the buffering capacity (Aequiv.−). Using this method, one can evaluate the relative contribution of inorganic and organic constituents to the acid neutralizing capacity (ANC) of the soil solutions. The relative contribution of organic acids to the overall ANC was found to be extremely important in the alpine wetland (52%) and the forest-tundra ecotone (40%), and somewhat less important in the alpine tundra sites (20%). A failure to recognize the importance of organic acids in soil solutions to the ANC will result in erroneous estimates of the buffering capacity in the alpine environment of the Front Range, Colorado.