In 1954, four earthquakes of M > 6.0 occurred within a 30 km radius in a period of six months. The Rainbow Mountain-Fairview Peak-Dixie Valley earthquakes are among the largest to have been recorded geodetically in the Basin and Range province. The Fairview Peak earthquake (M = 7.2, December 12, 1954) followed two events in the Rainbow Mountains (M = 6.2, July 6, and M = 6.5, August 24, 1954) by 6 months. Four minutes later the Dixie Valley fault ruptured (M = 6.7, December 12, 1954). The changes in static stresses caused by the events are calculated using the Coulomb-Navier failure criterion and assuming uniform slip on rectangular dislocations embedded in an elastic half-space. Coulomb stress changes are resolved on optimally oriented faults and on each of the faults that ruptured in the chain of events. These calculations show that each earthquake in the Rainbow Mountain-Fairview Peak-Dixie Valley sequence was preceded by a static stress change that encouraged failure. The magnitude of the stress increases transferred from one earthquake to another ranged from 0.01 MPa (0.1 bar) to over 0.1 MPa (1 bar). Stresses were reduced by up to 0.1 MPa over most of the Rainbow Mountain-Fairview Peak area as a result of the earthquake sequence.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JB01302","issn":"01480227","usgsCitation":"Hodgkinson, K., Stein, R., and King, G., 1996, The 1954 Rainbow Mountain-Fairview Peak-Dixie Valley earthquakes: A triggered normal faulting sequence: Journal of Geophysical Research B: Solid Earth, v. 101, no. B11, p. 25459-25471, https://doi.org/10.1029/96JB01302.","productDescription":"13 p.","startPage":"25459","endPage":"25471","numberOfPages":"13","costCenters":[],"links":[{"id":226999,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"B11","noUsgsAuthors":false,"publicationDate":"1996-11-10","publicationStatus":"PW","scienceBaseUri":"505ba61be4b08c986b320eca","contributors":{"authors":[{"text":"Hodgkinson, K.M.","contributorId":99314,"corporation":false,"usgs":true,"family":"Hodgkinson","given":"K.M.","affiliations":[],"preferred":false,"id":380353,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Stein, R.S.","contributorId":8875,"corporation":false,"usgs":true,"family":"Stein","given":"R.S.","email":"","affiliations":[],"preferred":false,"id":380351,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"King, G.C.P.","contributorId":18510,"corporation":false,"usgs":true,"family":"King","given":"G.C.P.","email":"","affiliations":[],"preferred":false,"id":380352,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018657,"text":"70018657 - 1996 - Low-velocity fault-zone guided waves: Numerical investigations of trapping efficiency","interactions":[],"lastModifiedDate":"2023-10-23T12:02:51.102592","indexId":"70018657","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":"Low-velocity fault-zone guided waves: Numerical investigations of trapping efficiency","docAbstract":"Recent observations have shown that shear waves trapped within low-velocity fault zones may be the most sensitive measure of fault-zone structure (Li et al., 1994a, 1994b). Finite-difference simulations demonstrate the effects of several types of complexity on observations of fault-zone trapped waves. Overlying sediments with a thickness more than one or two fault-zone widths and fault-zone step-overs more than one or two fault widths disrupt the wave guide. Fault kinks and changes in fault-zone width with depth leave readily observable trapped waves. We also demonstrate the effects of decreased trapped wave excitation with increasing hypocentral offset from the fault and the effects of varying the contrast between the velocity in the fault zone and surrounding hard rock. Careful field studies may provide dramatic improvements in our knowledge of fault-zone structure.
Continental North America's greatest earthquake sequence struck on the western frontier of the United States. The frontier was not then California but the valley of the continent's greatest river, the Mississippi, and the sequence was the New Madrid earthquakes of the winter of 1811–1812. Their described impacts on the land and the river were so dramatic as to produce widespread modern disbelief. However, geological, geophysical, and historical research, carried out mostly in the past two decades, has verified much in the historical accounts. The sequence included at least six (possibly nine) events of estimated moment magnitude M ≥ 7 and two of M ≃ 8. The faulting was in the intruded crust of a failed intracontinental rift, beneath the saturated alluvium of the river valley, and its violent shaking resulted in massive and extensive liquefaction. The largest earthquakes ruptured at least six (and possibly more than seven) intersecting fault segments, one of which broke the surface as a thrust fault that disrupted the bed of the Mississippi River in at least 2 (and possibly four) places.
","language":"English","publisher":"Annual Reviews","doi":"10.1146/annurev.earth.24.1.339","usgsCitation":"Johnston, A.C., and Schweig, E., 1996, The enigma of the New Madrid earthquakes of 1811-1812: Annual Review of Earth and Planetary Sciences, v. 24, p. 339-384, https://doi.org/10.1146/annurev.earth.24.1.339.","productDescription":"46 p.","startPage":"339","endPage":"384","numberOfPages":"46","costCenters":[],"links":[{"id":227619,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Arkansas, Kentucky, Missouri, Tennessee","otherGeospatial":"New Madrid seismic zone","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -91,\n 37\n ],\n [\n -91,\n 35\n ],\n [\n -89,\n 35\n ],\n [\n -89,\n 37\n ],\n [\n -91,\n 37\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"24","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505babcde4b08c986b3230a3","contributors":{"authors":[{"text":"Johnston, A. C.","contributorId":85574,"corporation":false,"usgs":true,"family":"Johnston","given":"A.","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":380335,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Schweig, E.S.","contributorId":34538,"corporation":false,"usgs":true,"family":"Schweig","given":"E.S.","email":"","affiliations":[],"preferred":false,"id":380334,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018650,"text":"70018650 - 1996 - Rare, large earthquakes at the laramide deformation front - Colorado (1882) and Wyoming (1984)","interactions":[],"lastModifiedDate":"2023-10-23T12:07:36.108923","indexId":"70018650","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":"Rare, large earthquakes at the laramide deformation front - Colorado (1882) and Wyoming (1984)","docAbstract":"The largest historical earthquake known in Colorado occurred on 7 November 1882. Knowledge of its size, location, and specific tectonic environment is important for the design of critical structures in the rapidly growing region of the Southern Rocky Mountains. More than one century later, on 18 October 1984, an mb 5.3 earthquake occurred in the Laramie Mountains, Wyoming. By studying the 1984 earthquake, we are able to provide constraints on the location and size of the 1882 earthquake. Analysis of broadband seismic data shows the 1984 mainshock to have nucleated at a depth of 27.5 ± 1.0 km and to have ruptured ‖ 2.7 km updip, with a corresponding average displacement of about 48 cm and average stress drop of about 180 bars. This high stress drop may explain why the earthquake was felt over an area about 3.5 times that expected for a shallow earthquake of the same magnitude in this region. A microearthquake survey shows aftershocks to be just above the mainshock's rupture, mostly in a volume measuring 3 to 4 km across. Focal mechanisms for the mainshock and aftershocks have NE-SW-trending T axes, a feature shared by most earthquakes in western Colorado and by the induced Denver earthquakes of 1967.
","language":"English","publisher":"Seismological Society of America","doi":"10.1785/BSSA0860061804","issn":"00371106","usgsCitation":"Spence, W., Langer, C., and Choy, G.L., 1996, Rare, large earthquakes at the laramide deformation front - Colorado (1882) and Wyoming (1984): Bulletin of the Seismological Society of America, v. 86, no. 6, p. 1804-1819, https://doi.org/10.1785/BSSA0860061804.","productDescription":"16 p.","startPage":"1804","endPage":"1819","numberOfPages":"16","costCenters":[],"links":[{"id":227574,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Colorado, Wyoming","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -101.94648145393926,\n 37.026768153146406\n ],\n [\n -101.94648145393926,\n 42.930368896228686\n ],\n [\n -109.50507520393931,\n 42.930368896228686\n ],\n [\n -109.50507520393931,\n 37.026768153146406\n ],\n [\n -101.94648145393926,\n 37.026768153146406\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"86","issue":"6","noUsgsAuthors":false,"publicationDate":"1996-12-01","publicationStatus":"PW","scienceBaseUri":"505a9527e4b0c8380cd81833","contributors":{"authors":[{"text":"Spence, W.","contributorId":7721,"corporation":false,"usgs":true,"family":"Spence","given":"W.","email":"","affiliations":[],"preferred":false,"id":380325,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Langer, C.J.","contributorId":31395,"corporation":false,"usgs":true,"family":"Langer","given":"C.J.","email":"","affiliations":[],"preferred":false,"id":380326,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Choy, G. L. 0000-0002-0217-5555","orcid":"https://orcid.org/0000-0002-0217-5555","contributorId":78322,"corporation":false,"usgs":true,"family":"Choy","given":"G.","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":380327,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018641,"text":"70018641 - 1996 - The composition of fluid inclusions in ore and gangue minerals from the Silesian-Cracow Mississippi Valley-type Zn-Pb deposits Poland: Genetic and environmental implications","interactions":[],"lastModifiedDate":"2012-03-12T17:19:25","indexId":"70018641","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3108,"text":"Prace - Panstwowego Instytutu Geologicznego","active":true,"publicationSubtype":{"id":10}},"title":"The composition of fluid inclusions in ore and gangue minerals from the Silesian-Cracow Mississippi Valley-type Zn-Pb deposits Poland: Genetic and environmental implications","docAbstract":"The composition of fluids extracted from ore and gangue sulfide minerals that span most of the paragenesis of the Silesian-Cracow district was determined using a newly developed ion chromatographic (IC) technique. Ionic species determined were Na+, NH+4, Ca2+, Mg2+, K+, Rb+, Sr2+, Ba2+, Cl-, Br-, F-, I-, PO3-4, CO2-3, HS-, S2O2-3, SO2-4, NO-3, and acetate. Mineral samples included six from the Pomorzany mine and one from the Trzebionka mine which are hosted in the Triassic Muschelkalk Formation, and two samples of drill core from mineralized Upper Devonian strata. Nine paragenetically identifiable sulfide minerals occur throughout the Silesian-Cracow district. These include from earliest to latest: early iron sulfides, granular sphalerite, early galena, light-banded sphalerite, galena, dark-banded sphalerite, iron sulfides, late dark-banded sphalerite with late galena, and late iron sulfides. Seven of the minerals were sampled for fluid inclusion analysis in this study. Only the early iron sulfides and the last galena stage were not sampled. Although the number of analyses are limited to nine samples and two replicates and there is uncertainty about the characteristics of the fluid inclusions analyzed, the data show clear temporal trends in the composition of the fluids that deposited these minerals. Fluid inclusions in minerals deposited later in the paragenesis have significantly more K+, Br-, NH+4, and acetate but less Sr2+ than those deposited earlier in the paragenesis. The later minerals are also characterized by isotopically lighter sulfur and significantly more Tl and As in the solid minerals. The change in ore-fluid chemistry is interpreted to reflect a major change in the hydrologic regime of the district. Apparently, the migrational paths of ore fluids from the Upper Silesian basin changed during ore deposition and the fluids which deposited early minerals reacted with aquifers with very different geochemical characteristics than those that deposited late minerals. The early fluids may have reacted primarily with Devonian and Lower Carboniferous carbonate aquifers deeper in the basin, whereas the later fluids appear to have had extensive contact with organic-rich rocks, probably the shallower Middle and Upper Carboniferous flysch associated with coal measures. High concentrations of toxic Tl and As occur in the readily oxidized marcasite and pyrite minerals deposited by the later fluids. In general, the geochemistry of both the early and late fluids may be explained by an evaporite related origin or by water-rock modification of a saline basinal brine. When compared to the composition of fluid inclusions in Mississippi Valley-type (MVT) ore minerals from the Ozark region of the United States, fluid inclusions in minerals from Silesian-Cracow are fundamentally different, containing more Ca2+, Mg2+, NH+4, Br-, Sr2+ and acetate in all mineral stages with significantly more K+ in later stage minerals. The differences in ore fluid chemistry between the two regions are consistent with the lithologic differences of the respective basins thought to be the source of the mineralizing brines.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Prace - Panstwowego Instytutu Geologicznego","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"08669465","usgsCitation":"Viets, J., Hofstra, A., Emsbo, P., and Kozlowski, A., 1996, The composition of fluid inclusions in ore and gangue minerals from the Silesian-Cracow Mississippi Valley-type Zn-Pb deposits Poland: Genetic and environmental implications: Prace - Panstwowego Instytutu Geologicznego, v. 154, p. 85-103.","startPage":"85","endPage":"103","numberOfPages":"19","costCenters":[],"links":[{"id":227435,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"154","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505baa4be4b08c986b3227ba","contributors":{"authors":[{"text":"Viets, J.G.","contributorId":82300,"corporation":false,"usgs":true,"family":"Viets","given":"J.G.","affiliations":[],"preferred":false,"id":380299,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hofstra, A. H. 0000-0002-2450-1593","orcid":"https://orcid.org/0000-0002-2450-1593","contributorId":41426,"corporation":false,"usgs":true,"family":"Hofstra","given":"A. H.","affiliations":[],"preferred":false,"id":380296,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Emsbo, P.","contributorId":59901,"corporation":false,"usgs":true,"family":"Emsbo","given":"P.","affiliations":[],"preferred":false,"id":380298,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Kozlowski, A.","contributorId":49124,"corporation":false,"usgs":true,"family":"Kozlowski","given":"A.","email":"","affiliations":[],"preferred":false,"id":380297,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70018618,"text":"70018618 - 1996 - Soil and soil solution chemistry under red spruce stands across the northeastern united states","interactions":[],"lastModifiedDate":"2012-03-12T17:19:26","indexId":"70018618","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3419,"text":"Soil Science","active":true,"publicationSubtype":{"id":10}},"title":"Soil and soil solution chemistry under red spruce stands across the northeastern united states","docAbstract":"Red spruce ecosystems in the northeastern United States are of interest because this species is undergoing regional decline. Their underlying soils have been examined closely at only a few sites, and information available on red spruce soils throughout this region is limited.This study was conducted to examine soil and soil solution chemistry at red spruce sites in the northeastern US that encompass the range of soil conditions in which red spruce grow. Soils and soil solutions from Oa and B horizons were obtained over a 2-year period from 12 undisturbed red spruce forests (elevations of 80-975 m) in New York, Vermont, New Hampshire, and Maine. All sites had extremely acid Spodosols (Oa soil pH range 2.56 to 3.11 in 0.01 M CaCl2), with generally low concentrations of base cations and high concentrations of Al on soil exchange sites. There was considerable range in exchange chemistry across the sites, however, with exchangeable Ca in Oa horizons ranging from 2.1 to 21.6 cmolckg-1 and exchangeable Al from 3.6 to 18.3 cmolckg-1. Solution chemistry had high concentrations of DOC in the Oa horizons (1160-15200 ??mol L-1), with higher concentrations in the fall than in the spring, which was probably a reflection of fresh litter inputs. Despite high concentrations of DOC in all solutions, inorganic Al was found in some Oa solutions at concentrations as high as 26 ??mol L-1. Ratios of Ca2+ to inorganic Al concentraturns were less than 1.0 in the Oa horizon of one site, and were well below 1.0 in B horizons of all sites. That soil chemistry was related to soil solution chemistry was demonstrated by solution Al concentrations in the forest floor having significant relationships with pyrophosphate extractable Al, although it was not related in the B horizon. Soil exchangeable Ca/Al ratios in the Oa horizon explained 75% of the variation in solution Ca2+/inorganic Al ratios when mean values were used for each site. Our studies have expanded the range of soil chemical conditions measured for red spruce soils. By characterizing the regional variability, these results will enable site intensive process studies to be better applied to regional problems such as spruce decline.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Soil Science","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"0038075X","usgsCitation":"David, M., and Lawrence, G., 1996, Soil and soil solution chemistry under red spruce stands across the northeastern united states: Soil Science, v. 161, no. 5, p. 314-328.","startPage":"314","endPage":"328","numberOfPages":"15","costCenters":[],"links":[{"id":227039,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"161","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b91eae4b08c986b319ba2","contributors":{"authors":[{"text":"David, M.B.","contributorId":20089,"corporation":false,"usgs":true,"family":"David","given":"M.B.","email":"","affiliations":[],"preferred":false,"id":380231,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Lawrence, G.B. 0000-0002-8035-2350","orcid":"https://orcid.org/0000-0002-8035-2350","contributorId":76347,"corporation":false,"usgs":true,"family":"Lawrence","given":"G.B.","affiliations":[],"preferred":false,"id":380232,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018617,"text":"70018617 - 1996 - Factors affecting suspended-solids concentrations in South San Francisco Bay, California","interactions":[],"lastModifiedDate":"2024-04-30T16:30:32.812079","indexId":"70018617","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2315,"text":"Journal of Geophysical Research C: Oceans","active":true,"publicationSubtype":{"id":10}},"title":"Factors affecting suspended-solids concentrations in South San Francisco Bay, California","docAbstract":"Measurements of suspended-solids concentration (SSC) were made at two depths at three sites in South San Francisco Bay (South Bay) to determine the factors that affect SSC. Twenty-eight segments of reliable and continuous SSC time series data longer than 14 days were collected from late 1991 or 1992 through September 1993. Spectral analysis and singular spectrum analysis were used to relate these data segments to time series of several potential forcing factors, including diurnal and semidiurnal tides, the spring-neap tidal cycle, wind shear, freshwater runoff, and longitudinal density differences. SSC is greatest during summer, when a landward wind shear is applied to South Bay by the afternoon sea breeze. About one half the variance of SSC is caused by the spring-neap cycle, and SSC lags the spring-neap cycle by about 2 days. Relatively short duration of slack water limits the duration of deposition of suspended solids and consolidation of newly deposited bed sediment during the tidal cycle, so suspended solids accumulate in the water column as a spring tide is approached and slowly deposit as a neap tide is approached. Perturbations in SSC caused by wind and local runoff from winter storms during the study period were usually much smaller than SSC variations caused by the spring-neap cycle. Variations of SSC at the study sites at tidal timescales are tidally forced, and nonlinear physical processes are significant. Advective transport dominates during spring tides, when water with higher SSC due to wind wave resuspension is advected to the main channel from shallow water, but, during neap tides, advective transport is less significant. The findings of this and other studies indicate that the tidally averaged transport of suspended solids responds to seasonal variations of wind shear in South Bay.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/96JC00747","issn":"01480227","usgsCitation":"Schoellhamer, D., 1996, Factors affecting suspended-solids concentrations in South San Francisco Bay, California: Journal of Geophysical Research C: Oceans, v. 101, no. C5, p. 12087-12095, https://doi.org/10.1029/96JC00747.","productDescription":"9 p.","startPage":"12087","endPage":"12095","numberOfPages":"9","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":552,"text":"San Francisco Bay-Delta","active":false,"usgs":true},{"id":5079,"text":"Pacific Regional Director's Office","active":true,"usgs":true}],"links":[{"id":227038,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"C5","noUsgsAuthors":false,"publicationDate":"1996-05-15","publicationStatus":"PW","scienceBaseUri":"505a0ea8e4b0c8380cd5356c","contributors":{"authors":[{"text":"Schoellhamer, D. H. 0000-0001-9488-7340","orcid":"https://orcid.org/0000-0001-9488-7340","contributorId":85624,"corporation":false,"usgs":true,"family":"Schoellhamer","given":"D. H.","affiliations":[],"preferred":false,"id":380230,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018607,"text":"70018607 - 1996 - The long-term salinity field in San Francisco Bay","interactions":[],"lastModifiedDate":"2019-02-20T09:36:12","indexId":"70018607","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1333,"text":"Continental Shelf Research","active":true,"publicationSubtype":{"id":10}},"title":"The long-term salinity field in San Francisco Bay","docAbstract":"Data are presented on long-term salinity behaviour in San Francisco Bay, California. A two-level, width averaged model of the tidally averaged salinity and circulation has been written in order to interpret the long-term (days to decades) salinity variability. The model has been used to simulate daily averaged salinity in the upper and lower levels of a 51 segment discretization of the Bay over the 22-yr period 1967-1988. Monthly averaged surface salinity from observations and monthly-averaged simulated salinity are in reasonable agreement. Good agreement is obtained from comparison with daily averaged salinity measured in the upper reaches of North Bay. The salinity variability is driven primarily by freshwater inflow with relatively minor oceanic influence. All stations exhibit a marked seasonal cycle in accordance with the Mediterranean climate, as well as a rich spectrum of variability due to extreme inflow events and extended periods of drought. Monthly averaged salinity intrusion positions have a pronounced seasonal variability and show an approximately linear response to the logarithm of monthly averaged Delta inflow. Although few observed data are available for studies of long-term salinity stratification, modelled stratification is found to be strongly dependent on freshwater inflow; the nature of that dependence varies throughout the Bay. Near the Golden Gate, stratification tends to increase up to very high inflows. In the central reaches of North Bay, modelled stratification maximizes as a function of inflow and further inflow reduces stratification. Near the head of North Bay, lowest summer inflows are associated with the greatest modelled stratification. Observations from the central reaches of North Bay show marked spring-neap variations in stratification and gravitational circulation, both being stronger at neap tides. This spring-neap variation is simulated by the model. A feature of the modelled stratification is a hysteresis in which, for a given spring-neap tidal range and fairly steady inflows, the stratification is higher progressing from neaps to springs than from springs to neaps. The simulated responses of the Bay to perturbations in coastal sea salinity and Delta inflow have been used to further delineate the time-scales of salinity variability. Simulations have been performed about low inflow, steady-state conditions for both salinity and Delta inflow perturbations. For salinity perturbations a small, sinusoidal salinity signal with a period of 1 yr has been applied at the coastal boundary as well as a pulse of salinity with a duration of one day. For Delta inflow perturbations a small, sinusoidally varying inflow signal with a period of 1 yr has been superimposed on an otherwise constant Delta inflow, as well as a pulse of inflow with a duration of one day. Perturbations is coastal salinity dissipate as they move through the Bay. Seasonal perturbations require about 40-45 days to propagate from the coastal ocean to the Delta and to the head of South Bay. The response times of the model to perturbations in freshwater inflow are faster than this in North Bay and comparable in South Bay. In North Bay, time-scales are consistent with advection due to lower level, up-estuary transport of coastal salinity perturbations; for inflow perturbations, faster response times arise from both upper level, down-estuary advection and much faster, down-estuary migration of isohalines in response to inflow volume continuity. In South Bay, the dominant time-scales are governed by tidal dispersion.
","language":"English","publisher":"Elsevier","doi":"10.1016/0278-4343(96)00032-5","issn":"02784343","usgsCitation":"Uncles, R., and Peterson, D.H., 1996, The long-term salinity field in San Francisco Bay: Continental Shelf Research, v. 16, no. 15, p. 2005-2039, https://doi.org/10.1016/0278-4343(96)00032-5.","productDescription":"35 p.","startPage":"2005","endPage":"2039","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":227571,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"},{"id":205950,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0278-4343(96)00032-5"}],"volume":"16","issue":"15","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505bada5e4b08c986b323d44","contributors":{"authors":[{"text":"Uncles, R.J.","contributorId":33468,"corporation":false,"usgs":true,"family":"Uncles","given":"R.J.","affiliations":[],"preferred":false,"id":380208,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Peterson, D. H.","contributorId":92229,"corporation":false,"usgs":true,"family":"Peterson","given":"D.","middleInitial":"H.","affiliations":[],"preferred":false,"id":380209,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018595,"text":"70018595 - 1996 - Trace fossils and sedimentary facies from a Late Cambrian‐Early Ordovician tide‐dominated shelf (Santa Rosita Formation, northwest Argentina): Implications for ichnofacies models of shallow marine successions","interactions":[],"lastModifiedDate":"2018-03-06T15:46:15","indexId":"70018595","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1965,"text":"Ichnos: An International Journal for Plant and Animal Traces","onlineIssn":"1563-5236","printIssn":"1042-0940","active":true,"publicationSubtype":{"id":10}},"title":"Trace fossils and sedimentary facies from a Late Cambrian‐Early Ordovician tide‐dominated shelf (Santa Rosita Formation, northwest Argentina): Implications for ichnofacies models of shallow marine successions","docAbstract":"The Santa Rosita Formation is one the most widely distributed lower Paleozoic units of northwest Argentina. At the Quebrada del Salto Alto section, east of Purmamarca, Jujuy Province, it is represented by four sedimentary facies: thick‐bedded planar cross‐stratified quartzose sandstones (A), thin‐bedded planar cross‐stratified quartzose sandstones and mudstones (B), wave‐rippled sandstones and bioturbated mudstones (C), and black and greenish gray shales (D). Paleocurrent data, sandstone architecture, and sedimentary structures from faciès A and B indicate bipolar/bimodal paleoflows, suggesting the action of tidal currents. The succession is interpreted as that of a tide‐dominated shelf, with only secondary influence of wave processes. Trace fossils are restricted to facies B and C.
The Cruziana ichnocoenosis is preserved on the soles of thin‐bedded planar cross‐stratified quartzose sandstones (faciès B). This ichnocoenosis consists of Conostichus isp., Cruziana omanica, C. semiplicata, C. cf. tortworthi, Cruziana isp. Helminthopsis abeli, Monomorphichnus bilinearis, M. multilineatus, Palaeophycus tubularis, Rusophycus carbonarias, R. latus, and R. isp. The occurrence of Cruziana semiplicata, C. omanica, C. cf. tortworthi, and Rusophycus latus supports a Late Cambrian‐Tremadoc age. Slabbing of Cruziana shows complex interactions between biologic and sedimentologic processes, and suggests a predominance of exhumed traces, washed out and recast by tractive sand deposition. Sandstone soles are densely packed with biogenic structures and exhibit distinctive clusters of Rusophycus isp. that most likely represent trilobite nesting burrows. The Cruziana ichnocoenosis records the resident fauna of a protected, lower intertidal to subtidal interbar setting.
The Skolithos ichnocoenosis is represented by high to low density vertical burrows of Skolithos linearis, which extend downwards to the quartzose sandstone soles of faciès B and cross the Cruziana ichnocoenosis. The Skolithos ichnocoenosis represents colonization by suspension‐feeding organisms following a major change in environmental conditions, related to the migration of lower intertidal to subtidal sandwaves.
The Planolites ichnocoenosis consists exclusively of Planolites montanus within mudstones overlying wave‐rippled sandstones (facies C). The Planolites ichnocoenosis records opportunistic colonization by inf aunal deposit feeders that mined the organic‐rich fine‐grained sediment during the waning phase of storms that scoured organic detritus from the sea bottom.
The section records, from base to top, a Cruziana‐Skolithos ichnofacies zone, a Skolithos ichnofacies zone and an unbioturbated zone typified by the thick‐bedded cross‐stratified quartzose sandstone (fades A). This trend reflects progressively higher energy conditions linked to the establishment of a large sand wave complex. The presence of a mixed Cruziana‐Skolithos ichnofacies in the lower interval reflects changes in substrate and energy levels, rather than water depth. Accordingly, contrasting ichnocoenoses from interbars (Cruziana) and sandwaves (Skolithos) must be considered an example of ichnofacies controlled by local parameters instead of general bathymétrie trends. Conversely, the vertical replacement of the Cruziana ichnofacies by the Skolithos ichnofacies towards the middle interval of the section reflects the environmental changes associated with the transition between the intertidal and subtidal zones. As overall tidal energy increases from supratidal to subtidal settings, the Skolithos ichnofacies tends to occur seaward of the Cruzianaichnofacies in tide‐dominated shallow marine environments. Therefore, onshore‐offshore ichnofacies replacement in tide‐dominated shallow seas is opposite to that in wave‐dominated marine settings.
","language":"English","publisher":"Taylor & Francis","doi":"10.1080/10420949609386406","usgsCitation":"Mángano, M., Buatois, L.A., and Acenolaza, G.F., 1996, Trace fossils and sedimentary facies from a Late Cambrian‐Early Ordovician tide‐dominated shelf (Santa Rosita Formation, northwest Argentina): Implications for ichnofacies models of shallow marine successions: Ichnos: An International Journal for Plant and Animal Traces, v. 5, no. 1, p. 53-88, https://doi.org/10.1080/10420949609386406.","productDescription":"36 p.","startPage":"53","endPage":"88","costCenters":[],"links":[{"id":227306,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"Argentina","geographicExtents":"{\"type\":\"FeatureCollection\",\"features\":[{\"type\":\"Feature\",\"geometry\":{\"type\":\"MultiPolygon\",\"coordinates\":[[[[-65.5,-55.2],[-66.45,-55.25],[-66.95992,-54.89681],[-67.56244,-54.87001],[-68.63335,-54.8695],[-68.63401,-52.63637],[-68.25,-53.1],[-67.75,-53.85],[-66.45,-54.45],[-65.05,-54.7],[-65.5,-55.2]]],[[[-64.96489,-22.07586],[-64.37702,-22.79809],[-63.98684,-21.99364],[-62.84647,-22.03499],[-62.68506,-22.24903],[-60.84656,-23.88071],[-60.02897,-24.0328],[-58.80713,-24.77146],[-57.77722,-25.16234],[-57.63366,-25.60366],[-58.61817,-27.12372],[-57.60976,-27.3959],[-56.4867,-27.5485],[-55.69585,-27.38784],[-54.78879,-26.62179],[-54.62529,-25.73926],[-54.13005,-25.54764],[-53.62835,-26.12487],[-53.64874,-26.92347],[-54.49073,-27.47476],[-55.16229,-27.88192],[-56.2909,-28.85276],[-57.62513,-30.21629],[-57.87494,-31.01656],[-58.14244,-32.0445],[-58.13265,-33.04057],[-58.34961,-33.26319],[-58.42707,-33.90945],[-58.49544,-34.43149],[-57.22583,-35.28803],[-57.36236,-35.97739],[-56.73749,-36.41313],[-56.78829,-36.90157],[-57.74916,-38.18387],[-59.23186,-38.72022],[-61.23745,-38.92842],[-62.33596,-38.82771],[-62.12576,-39.4241],[-62.33053,-40.17259],[-62.14599,-40.6769],[-62.7458,-41.02876],[-63.77049,-41.16679],[-64.73209,-40.80268],[-65.11804,-41.06431],[-64.97856,-42.058],[-64.30341,-42.35902],[-63.75595,-42.04369],[-63.45806,-42.56314],[-64.3788,-42.87356],[-65.1818,-43.49538],[-65.32882,-44.50137],[-65.56527,-45.03679],[-66.50997,-45.03963],[-67.29379,-45.5519],[-67.58055,-46.30177],[-66.59707,-47.03392],[-65.64103,-47.23613],[-65.98509,-48.13329],[-67.16618,-48.69734],[-67.81609,-49.86967],[-68.72875,-50.26422],[-69.13854,-50.73251],[-68.81556,-51.7711],[-68.14999,-52.34998],[-68.57155,-52.29944],[-69.49836,-52.14276],[-71.9148,-52.00902],[-72.3294,-51.42596],[-72.30997,-50.67701],[-72.97575,-50.74145],[-73.32805,-50.37879],[-73.41544,-49.31844],[-72.64825,-48.87862],[-72.33116,-48.24424],[-72.44736,-47.73853],[-71.91726,-46.88484],[-71.55201,-45.56073],[-71.65932,-44.97369],[-71.22278,-44.78424],[-71.3298,-44.40752],[-71.79362,-44.20717],[-71.46406,-43.78761],[-71.91542,-43.40856],[-72.1489,-42.25489],[-71.7468,-42.05139],[-71.91573,-40.83234],[-71.68076,-39.80816],[-71.41352,-38.91602],[-70.81466,-38.553],[-71.11863,-37.57683],[-71.12188,-36.65812],[-70.36477,-36.00509],[-70.38805,-35.16969],[-69.81731,-34.19357],[-69.81478,-33.27389],[-70.0744,-33.09121],[-70.53507,-31.36501],[-69.91901,-30.33634],[-70.01355,-29.36792],[-69.65613,-28.45914],[-69.00123,-27.52121],[-68.29554,-26.89934],[-68.5948,-26.50691],[-68.386,-26.18502],[-68.41765,-24.51855],[-67.32844,-24.0253],[-66.98523,-22.98635],[-67.10667,-22.73592],[-66.27334,-21.83231],[-64.96489,-22.07586]]]]},\"properties\":{\"name\":\"Argentina\"}}]}","volume":"5","issue":"1","noUsgsAuthors":false,"publicationDate":"2008-12-17","publicationStatus":"PW","scienceBaseUri":"505bb665e4b08c986b326c3c","contributors":{"authors":[{"text":"Mángano, M. Gabriela","contributorId":57619,"corporation":false,"usgs":false,"family":"Mángano","given":"M. Gabriela","affiliations":[{"id":35641,"text":"Kansas Geological Survey","active":true,"usgs":false}],"preferred":false,"id":380163,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Buatois, Luis A. 0000-0001-9523-750X","orcid":"https://orcid.org/0000-0001-9523-750X","contributorId":195823,"corporation":false,"usgs":false,"family":"Buatois","given":"Luis","email":"","middleInitial":"A.","affiliations":[{"id":35641,"text":"Kansas Geological Survey","active":true,"usgs":false}],"preferred":false,"id":380165,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Acenolaza, Guillermo F.","contributorId":24936,"corporation":false,"usgs":false,"family":"Acenolaza","given":"Guillermo","email":"","middleInitial":"F.","affiliations":[],"preferred":false,"id":380164,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018576,"text":"70018576 - 1996 - Film cameras or digital sensors? The challenge ahead for aerial imaging","interactions":[],"lastModifiedDate":"2012-03-12T17:19:26","indexId":"70018576","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Film cameras or digital sensors? The challenge ahead for aerial imaging","docAbstract":"Cartographic aerial cameras continue to play the key role in producing quality products for the aerial photography business, and specifically for the National Aerial Photography Program (NAPP). One NAPP photograph taken with cameras capable of 39 lp/mm system resolution can contain the equivalent of 432 million pixels at 11 ??m spot size, and the cost is less than $75 per photograph to scan and output the pixels on a magnetic storage medium. On the digital side, solid state charge coupled device linear and area arrays can yield quality resolution (7 to 12 ??m detector size) and a broader dynamic range. If linear arrays are to compete with film cameras, they will require precise attitude and positioning of the aircraft so that the lines of pixels can be unscrambled and put into a suitable homogeneous scene that is acceptable to an interpreter. Area arrays need to be much larger than currently available to image scenes competitive in size with film cameras. Analysis of the relative advantages and disadvantages of the two systems show that the analog approach is more economical at present. However, as arrays become larger, attitude sensors become more refined, global positioning system coordinate readouts become commonplace, and storage capacity becomes more affordable, the digital camera may emerge as the imaging system for the future. Several technical challenges must be overcome if digital sensors are to advance to where they can support mapping, charting, and geographic information system applications.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Photogrammetric Engineering and Remote Sensing","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"00991112","usgsCitation":"Light, D., 1996, Film cameras or digital sensors? The challenge ahead for aerial imaging: Photogrammetric Engineering and Remote Sensing, v. 62, no. 3, p. 285-291.","startPage":"285","endPage":"291","numberOfPages":"7","costCenters":[],"links":[{"id":227036,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"62","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a1007e4b0c8380cd53adb","contributors":{"authors":[{"text":"Light, D.L.","contributorId":57606,"corporation":false,"usgs":true,"family":"Light","given":"D.L.","email":"","affiliations":[],"preferred":false,"id":380093,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018575,"text":"70018575 - 1996 - Comparison of damping in buildings under low-amplitude and strong motions","interactions":[],"lastModifiedDate":"2024-05-23T14:55:48.207317","indexId":"70018575","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":2511,"text":"Journal of Wind Engineering and Industrial Aerodynamics","active":true,"publicationSubtype":{"id":10}},"title":"Comparison of damping in buildings under low-amplitude and strong motions","docAbstract":"This paper presents a comprehensive assessment of damping values and other dynamic characteristics of five buildings using strong-motion and low-amplitude (ambient vibration) data. The strong-motion dynamic characteristics of five buildings within the San Francisco Bay area are extracted from recordings of the 17 October 1989 Loma Prieta earthquake (LPE). Ambient vibration response characteristics for the same five buildings were inferred using data collected in 1990 following LPE. Additional earthquake data other than LPE for one building and ambient vibration data collected before LPE for two other buildings provide additional confirmation of the results obtained. For each building, the percentages of critical damping and the corresponding fundamental periods determined from low-amplitude test data are appreciably lower than those determined from strong-motion recordings. These differences are attributed mainly to soil-structure interaction and other non-linear behavior affecting the structures during strong shaking. Significant contribution of radiation damping to the effective damping of a specific building is discussed in detail.
","language":"English","publisher":"Elsevier","doi":"10.1016/0167-6105(96)00014-1","issn":"01676105","usgsCitation":"Çelebi, M., 1996, Comparison of damping in buildings under low-amplitude and strong motions: Journal of Wind Engineering and Industrial Aerodynamics, v. 59, no. 2-3, p. 309-323, https://doi.org/10.1016/0167-6105(96)00014-1.","productDescription":"15 p.","startPage":"309","endPage":"323","numberOfPages":"15","costCenters":[],"links":[{"id":227035,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"59","issue":"2-3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"5059f859e4b0c8380cd4d03c","contributors":{"authors":[{"text":"Çelebi, M.","contributorId":36946,"corporation":false,"usgs":true,"family":"Çelebi","given":"M.","affiliations":[],"preferred":false,"id":380092,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018561,"text":"70018561 - 1996 - Integrating a geographic information system, a scientific visualization system and an orographic precipitation model","interactions":[],"lastModifiedDate":"2012-03-12T17:19:25","indexId":"70018561","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1934,"text":"IAHS-AISH Publication","active":true,"publicationSubtype":{"id":10}},"title":"Integrating a geographic information system, a scientific visualization system and an orographic precipitation model","docAbstract":"Investigating natural, potential, and man-induced impacts on hydrological systems commonly requires complex modelling with overlapping data requirements, and massive amounts of one- to four-dimensional data at multiple scales and formats. Given the complexity of most hydrological studies, the requisite software infrastructure must incorporate many components including simulation modelling, spatial analysis and flexible, intuitive displays. There is a general requirement for a set of capabilities to support scientific analysis which, at this time, can only come from an integration of several software components. Integration of geographic information systems (GISs) and scientific visualization systems (SVSs) is a powerful technique for developing and analysing complex models. This paper describes the integration of an orographic precipitation model, a GIS and a SVS. The combination of these individual components provides a robust infrastructure which allows the scientist to work with the full dimensionality of the data and to examine the data in a more intuitive manner.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"IAHS-AISH Publication","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","issn":"01447815","usgsCitation":"Hay, L., and Knapp, L., 1996, Integrating a geographic information system, a scientific visualization system and an orographic precipitation model: IAHS-AISH Publication, no. 235, p. 123-131.","startPage":"123","endPage":"131","numberOfPages":"9","costCenters":[],"links":[{"id":227480,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"issue":"235","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a3c74e4b0c8380cd62d50","contributors":{"authors":[{"text":"Hay, L.","contributorId":72103,"corporation":false,"usgs":true,"family":"Hay","given":"L.","email":"","affiliations":[],"preferred":false,"id":380046,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Knapp, L.","contributorId":83290,"corporation":false,"usgs":true,"family":"Knapp","given":"L.","email":"","affiliations":[],"preferred":false,"id":380047,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018552,"text":"70018552 - 1996 - Grazing trails formed by soldier fly larvae (Diptera: Stratiomyidae) and their paleoenvironmental and paleoecological implications for the fossil record","interactions":[],"lastModifiedDate":"2018-03-06T15:43:32","indexId":"70018552","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1965,"text":"Ichnos: An International Journal for Plant and Animal Traces","onlineIssn":"1563-5236","printIssn":"1042-0940","active":true,"publicationSubtype":{"id":10}},"title":"Grazing trails formed by soldier fly larvae (Diptera: Stratiomyidae) and their paleoenvironmental and paleoecological implications for the fossil record","docAbstract":"Recent trails formed by soldier fly larvae (Díptera: Stratiomyidae) were examined in a shallow pond in the floodplain of a braided river in Jujuy Province, northwestern Argentina. Collected specimens were identified as Stratiomys convexa van der Wulp. Simple, irregularly meandering trails were produced across the surface of a muddy‐silty substrate. Since soldier fly larvae extend their caudal respiratory tube to the water‐air interface, they are restricted to extremely shallow water. The presence of benthic algal remains within the mouthparts of the larvae suggests a feeding habit of algal grazing. If preserved, these trails would be included in the ichno‐genus Helminthopsis, a common element in ancient freshwater ichno‐faunas. Helminthopsis preserved in pond and lacustrine margin deposits younger than Late Jurassic is regarded as one possible trace fossil analogue of the trails documented herein. Additionally, it is suggested that larvae of many aquatic Diptera with similar ecologic restrictions are potential tracemakers of Helminthopsis and other simple trails in these environments, particularly in post‐Paleozoic deposits. Studies of modern shallow aquatic habitats and reex‐amination of the ichnologic record stress the importance of fly larvae as tracemakers in lake margin and pond ecosystems. Ecologic requirements of soldier fly larvae make them inappropriate analogues of Helminthopsis tracemakers in deeper water, lacustrine settings.
","language":"English","publisher":"Taylor & Francis","doi":"10.1080/10420949609380124","usgsCitation":"Mángano, M., Buatois, L.A., and Claps, G.L., 1996, Grazing trails formed by soldier fly larvae (Diptera: Stratiomyidae) and their paleoenvironmental and paleoecological implications for the fossil record: Ichnos: An International Journal for Plant and Animal Traces, v. 4, no. 3, p. 163-167, https://doi.org/10.1080/10420949609380124.","productDescription":"5 p.","startPage":"163","endPage":"167","costCenters":[],"links":[{"id":227345,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"4","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a2a50e4b0c8380cd5b087","contributors":{"authors":[{"text":"Mángano, M. Gabriela","contributorId":57619,"corporation":false,"usgs":false,"family":"Mángano","given":"M. Gabriela","affiliations":[{"id":35641,"text":"Kansas Geological Survey","active":true,"usgs":false}],"preferred":false,"id":380020,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Buatois, Luis A. 0000-0001-9523-750X","orcid":"https://orcid.org/0000-0001-9523-750X","contributorId":195823,"corporation":false,"usgs":false,"family":"Buatois","given":"Luis","email":"","middleInitial":"A.","affiliations":[{"id":35641,"text":"Kansas Geological Survey","active":true,"usgs":false}],"preferred":false,"id":380021,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Claps, Guillermo L.","contributorId":92444,"corporation":false,"usgs":false,"family":"Claps","given":"Guillermo","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":380022,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018548,"text":"70018548 - 1996 - Diagenesis, compaction, and fluid chemistry modeling of a sandstone near a pressure seal: Lower Tuscaloosa Formation, Gulf Coast","interactions":[],"lastModifiedDate":"2023-01-20T17:05:59.703758","indexId":"70018548","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":701,"text":"American Association of Petroleum Geologists Bulletin","active":true,"publicationSubtype":{"id":10}},"title":"Diagenesis, compaction, and fluid chemistry modeling of a sandstone near a pressure seal: Lower Tuscaloosa Formation, Gulf Coast","docAbstract":"Petrographic, isotopic, and fluid-inclusion evidence from normally and overpressured sand-stones of the lower Tuscaloosa Formation (Upper Cretaceous) in the Gulf Coast documents quartz-overgrowth precipitation at 90°C or less, calcite cement precipitation at approximately 100° and 135°C, and prismatic quartz cement precipitation at about 125°C. Textural evidence suggests that carbonate cement dissolution occurred before the second phases of calcite and quartz precipitation, and was followed by precipitation of grain-rimming chlorite and pore-filling kaolinite. Geochemical calculations demonstrate that present-day lower Tuscaloosa Formation water from 5500 m depth could either dissolve or precipitate calcite cements in model simulations of upward water low. Calcite dissolution or precipitation depends on PCO2 variability with depth (i.e., whether there is one or two-phase flow) or on the rate of generation of CO2 with depth. Calculations suggest that 105-106 rock volumes of water are required to flow through the section to precipitate 1-10% calcite cement.
Compaction analysis suggests that late-stage compaction occurred in normally pressured sandstones after dissolution of carbonate cements, but was hindered in overpressured sandstones despite the presence of high porosity. These results document the inhibition of compaction by overpressured fluids and constrain the timing of pressure seal formation. Modeling results demonstrate that the proposed paragenesis used to constrain timing of pressure seal formation is feasible, and that most of the cement diagenesis occurred before the pressure seal became effective as a permeability barrier.
","language":"English","publisher":"American Association of Petroleum Geologists","doi":"10.1306/64ED8C8C-1724-11D7-8645000102C1865D","usgsCitation":"Weedman, S., Brantley, S.L., Shiraki, R., and Poulson, S.R., 1996, Diagenesis, compaction, and fluid chemistry modeling of a sandstone near a pressure seal: Lower Tuscaloosa Formation, Gulf Coast: American Association of Petroleum Geologists Bulletin, v. 80, no. 7, p. 1045-1063, https://doi.org/10.1306/64ED8C8C-1724-11D7-8645000102C1865D.","productDescription":"19 p.","startPage":"1045","endPage":"1063","costCenters":[],"links":[{"id":227256,"rank":1,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"country":"United States","state":"Louisiana","geographicExtents":"{\n \"type\": \"FeatureCollection\",\n \"features\": [\n {\n \"type\": \"Feature\",\n \"properties\": {},\n \"geometry\": {\n \"coordinates\": [\n [\n [\n -92.16262732679756,\n 30.939723848711253\n ],\n [\n -92.16262732679756,\n 30.464362041821246\n ],\n [\n -90.94537494973406,\n 30.464362041821246\n ],\n [\n -90.94537494973406,\n 30.939723848711253\n ],\n [\n -92.16262732679756,\n 30.939723848711253\n ]\n ]\n ],\n \"type\": \"Polygon\"\n }\n }\n ]\n}","volume":"80","issue":"7","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a0099e4b0c8380cd4f7f2","contributors":{"authors":[{"text":"Weedman, Suzanne","contributorId":87411,"corporation":false,"usgs":true,"family":"Weedman","given":"Suzanne","email":"","affiliations":[],"preferred":false,"id":380008,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Brantley, Susan L. 0000-0003-4320-2342","orcid":"https://orcid.org/0000-0003-4320-2342","contributorId":184201,"corporation":false,"usgs":false,"family":"Brantley","given":"Susan","email":"","middleInitial":"L.","affiliations":[],"preferred":false,"id":380009,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Shiraki, R.","contributorId":107443,"corporation":false,"usgs":true,"family":"Shiraki","given":"R.","email":"","affiliations":[],"preferred":false,"id":380011,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Poulson, Simon R.","contributorId":187411,"corporation":false,"usgs":false,"family":"Poulson","given":"Simon","email":"","middleInitial":"R.","affiliations":[{"id":33648,"text":"Department of Geological Sciences and Engineering, University of Nevada","active":true,"usgs":false}],"preferred":false,"id":380010,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70018541,"text":"70018541 - 1996 - Thermal conductivity of water-saturated rocks from the KTB pilot hole at temperatures of 25 to 300°C","interactions":[],"lastModifiedDate":"2019-05-14T08:58:07","indexId":"70018541","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":1807,"text":"Geophysical Research Letters","active":true,"publicationSubtype":{"id":10}},"title":"Thermal conductivity of water-saturated rocks from the KTB pilot hole at temperatures of 25 to 300°C","docAbstract":"The conductivitites of selected gneiss (two) and amphibolite (one) core samples have been measured under conditions of elevated temperature and pressure with a needle‐probe. Water‐saturated thermal conductivity measurements spanning temperatures from 25 to 300°C and hydrostatic pressures of 0.1 and 34 MPa confirm the general decrease in conductivity with increasing temperature but deviate significantly from results reported from measurements on dry samples over the same temperature range. The thermal conductivity of water‐saturated amphibolite decreases with temperature at a rate approximately 40% less than the rate for dry amphibolite, and the conductivity of water‐saturated gneiss decreases at a rate approximately 20% less than the rate for dry gneiss. The available evidence points to thermal cracking as the primary cause of the more rapid decrease in dry thermal conductivity with temperature. The effects of thermal cracking were also observed in the water‐saturated samples but resulted in a net decrease in room‐temperature conductivity of less than 3%. These results highlight the importance of duplicating in‐situ conditions when determining thermal conductivity for the deep crust.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95GL00253","issn":"00948276","usgsCitation":"Pribnow, D., Williams, C., Sass, J., and Keating, R., 1996, Thermal conductivity of water-saturated rocks from the KTB pilot hole at temperatures of 25 to 300°C: Geophysical Research Letters, v. 23, no. 4, p. 391-394, https://doi.org/10.1029/95GL00253.","productDescription":"4 p.","startPage":"391","endPage":"394","onlineOnly":"N","additionalOnlineFiles":"N","costCenters":[{"id":615,"text":"Volcano Hazards Program","active":true,"usgs":true}],"links":[{"id":227121,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"23","issue":"4","noUsgsAuthors":false,"publicationDate":"1996-02-15","publicationStatus":"PW","scienceBaseUri":"505bb219e4b08c986b3255cb","contributors":{"authors":[{"text":"Pribnow, D.","contributorId":13386,"corporation":false,"usgs":true,"family":"Pribnow","given":"D.","affiliations":[],"preferred":false,"id":379981,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Williams, C.F. 0000-0003-2196-5496","orcid":"https://orcid.org/0000-0003-2196-5496","contributorId":20401,"corporation":false,"usgs":true,"family":"Williams","given":"C.F.","affiliations":[{"id":312,"text":"Geology, Minerals, Energy, and Geophysics Science Center","active":true,"usgs":true}],"preferred":false,"id":379982,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Sass, J.H.","contributorId":70749,"corporation":false,"usgs":true,"family":"Sass","given":"J.H.","email":"","affiliations":[{"id":595,"text":"U.S. Geological Survey","active":false,"usgs":true}],"preferred":false,"id":379984,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Keating, R.","contributorId":29968,"corporation":false,"usgs":true,"family":"Keating","given":"R.","email":"","affiliations":[],"preferred":false,"id":379983,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70018533,"text":"70018533 - 1996 - Effect of horizontal heat and fluid flow on the vertical temperature distribution in a semiconfining layer","interactions":[],"lastModifiedDate":"2018-03-08T15:55:52","indexId":"70018533","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":"Effect of horizontal heat and fluid flow on the vertical temperature distribution in a semiconfining layer","docAbstract":"By including the constant flow of heat and fluid in the horizontal direction, we develop an analytical solution for the vertical temperature distribution within the semiconfining layer of a typical aquifer system. The solution is an extension of the previous one-dimensional theory by Bredehoeft and Papadopulos [1965]. It provides a quantitative tool for analyzing the uncertainty of the horizontal heat and fluid flow. The analytical results demonstrate that horizontal flow of heat and fluid, if at values much smaller than those of the vertical, has a negligible effect on the vertical temperature distribution but becomes significant when it is comparable to the vertical.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95WR03095","usgsCitation":"Lu, N., and Ge, S., 1996, Effect of horizontal heat and fluid flow on the vertical temperature distribution in a semiconfining layer: Water Resources Research, v. 32, no. 5, p. 1449-1453, https://doi.org/10.1029/95WR03095.","productDescription":"5 p.","startPage":"1449","endPage":"1453","costCenters":[],"links":[{"id":226994,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"32","issue":"5","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a05e9e4b0c8380cd51008","contributors":{"authors":[{"text":"Lu, Ning","contributorId":191360,"corporation":false,"usgs":false,"family":"Lu","given":"Ning","email":"","affiliations":[{"id":12620,"text":"U.S. Army Corp. of Engineers","active":true,"usgs":false}],"preferred":false,"id":379960,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Ge, Shemin","contributorId":37366,"corporation":false,"usgs":true,"family":"Ge","given":"Shemin","affiliations":[],"preferred":false,"id":379959,"contributorType":{"id":1,"text":"Authors"},"rank":2}]}} ,{"id":70018510,"text":"70018510 - 1996 - Effects of thermal vapor diffusion on seasonal dynamics of water in the unsaturated zone","interactions":[],"lastModifiedDate":"2018-03-30T12:32:33","indexId":"70018510","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":"Effects of thermal vapor diffusion on seasonal dynamics of water in the unsaturated zone","docAbstract":"The response of water in the unsaturated zone to seasonal changes of temperature (T) is determined analytically using the theory of nonisothermal water transport in porous media, and the solutions are tested against field observations of moisture potential and bomb fallout isotopic (36Cl and 3H) concentrations. Seasonally varying land surface temperatures and the resulting subsurface temperature gradients induce thermal vapor diffusion. The annual mean vertical temperature gradient is close to zero; however, the annual mean thermal vapor flux is downward, because the temperature‐dependent vapor diffusion coefficient is larger, on average, during downward diffusion (occurring at high T) than during upward diffusion (low T). The annual mean thermal vapor flux is shown to decay exponentially with depth; the depth (about 1 m) at which it decays to e−1of its surface value is one half of the corresponding decay depth for the amplitude of seasonal temperature changes. This depth‐dependent annual mean flux is effectively a source of water, which must be balanced by a flux divergence associated with other transport processes. In a relatively humid environment the liquid fluxes greatly exceed the thermal vapor fluxes, so such a balance is readily achieved without measurable effect on the dynamics of water in the unsaturated zone. However, if the mean vertical water flux through the unsaturated zone is very small (<1 mm y−1), as it may be at many locations in a desert landscape, the thermal vapor flux must be balanced mostly by a matric‐potential‐induced upward flux of water. This return flux may include both vapor and liquid components. Below any near‐surface zone of weather‐related fluctuations of matric potential, maintenance of this upward flux requires an increase with depth in the annual mean matric potential; this theoretical prediction is supported by long‐term field measurements in the Chihuahuan Desert. The analysis also makes predictions, confirmed by the field observations, regarding the seasonal variations of matric potential at a given depth. The conceptual model of unsaturated zone water transport developed here implies the possibility of near‐surface trapping of any aqueous constituent introduced at the surface.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95WR03489","usgsCitation":"Milly, P., 1996, Effects of thermal vapor diffusion on seasonal dynamics of water in the unsaturated zone: Water Resources Research, v. 32, no. 3, p. 509-518, https://doi.org/10.1029/95WR03489.","productDescription":"10 p.","startPage":"509","endPage":"518","costCenters":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"links":[{"id":227386,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"32","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a080ae4b0c8380cd51947","contributors":{"authors":[{"text":"Milly, Paul C.D. 0000-0003-4389-3139 cmilly@usgs.gov","orcid":"https://orcid.org/0000-0003-4389-3139","contributorId":2119,"corporation":false,"usgs":true,"family":"Milly","given":"Paul C.D.","email":"cmilly@usgs.gov","affiliations":[{"id":436,"text":"National Research Program - Eastern Branch","active":true,"usgs":true}],"preferred":false,"id":379872,"contributorType":{"id":1,"text":"Authors"},"rank":1}]}} ,{"id":70018505,"text":"70018505 - 1996 - Testing and validating environmental models","interactions":[],"lastModifiedDate":"2012-03-12T17:19:25","indexId":"70018505","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","noYear":false,"publicationType":{"id":2,"text":"Article"},"publicationSubtype":{"id":10,"text":"Journal Article"},"seriesTitle":{"id":3352,"text":"Science of the Total Environment","active":true,"publicationSubtype":{"id":10}},"title":"Testing and validating environmental models","docAbstract":"Generally accepted standards for testing and validating ecosystem models would benefit both modellers and model users. Universally applicable test procedures are difficult to prescribe, given the diversity of modelling approaches and the many uses for models. However, the generally accepted scientific principles of documentation and disclosure provide a useful framework for devising general standards for model evaluation. Adequately documenting model tests requires explicit performance criteria, and explicit benchmarks against which model performance is compared. A model's validity, reliability, and accuracy can be most meaningfully judged by explicit comparison against the available alternatives. In contrast, current practice is often characterized by vague, subjective claims that model predictions show 'acceptable' agreement with data; such claims provide little basis for choosing among alternative models. Strict model tests (those that invalid models are unlikely to pass) are the only ones capable of convincing rational skeptics that a model is probably valid. However, 'false positive' rates as low as 10% can substantially erode the power of validation tests, making them insufficiently strict to convince rational skeptics. Validation tests are often undermined by excessive parameter calibration and overuse of ad hoc model features. Tests are often also divorced from the conditions under which a model will be used, particularly when it is designed to forecast beyond the range of historical experience. In such situations, data from laboratory and field manipulation experiments can provide particularly effective tests, because one can create experimental conditions quite different from historical data, and because experimental data can provide a more precisely defined 'target' for the model to hit. We present a simple demonstration showing that the two most common methods for comparing model predictions to environmental time series (plotting model time series against data time series, and plotting predicted versus observed values) have little diagnostic power. We propose that it may be more useful to statistically extract the relationships of primary interest from the time series, and test the model directly against them.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Science of the Total Environment","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/0048-9697(95)04971-1","issn":"00489697","usgsCitation":"Kirchner, J., Hooper, R.P., Kendall, C., Neal, C., and Leavesley, G., 1996, Testing and validating environmental models: Science of the Total Environment, v. 183, no. 1-2, p. 33-47, https://doi.org/10.1016/0048-9697(95)04971-1.","startPage":"33","endPage":"47","numberOfPages":"15","costCenters":[],"links":[{"id":205884,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0048-9697(95)04971-1"},{"id":227301,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"183","issue":"1-2","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505ba5bfe4b08c986b320c4c","contributors":{"authors":[{"text":"Kirchner, J.W.","contributorId":45846,"corporation":false,"usgs":true,"family":"Kirchner","given":"J.W.","email":"","affiliations":[],"preferred":false,"id":379853,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Hooper, R. P.","contributorId":26321,"corporation":false,"usgs":true,"family":"Hooper","given":"R.","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":379851,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Kendall, C. 0000-0002-0247-3405","orcid":"https://orcid.org/0000-0002-0247-3405","contributorId":35050,"corporation":false,"usgs":true,"family":"Kendall","given":"C.","affiliations":[],"preferred":false,"id":379852,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Neal, C.","contributorId":89269,"corporation":false,"usgs":true,"family":"Neal","given":"C.","email":"","affiliations":[],"preferred":false,"id":379854,"contributorType":{"id":1,"text":"Authors"},"rank":4},{"text":"Leavesley, G.","contributorId":90483,"corporation":false,"usgs":true,"family":"Leavesley","given":"G.","email":"","affiliations":[],"preferred":false,"id":379855,"contributorType":{"id":1,"text":"Authors"},"rank":5}]}} ,{"id":70018470,"text":"70018470 - 1996 - Spatial radon anomalies on active faults in California","interactions":[],"lastModifiedDate":"2012-03-12T17:19:24","indexId":"70018470","displayToPublicDate":"1996-01-01T00:00:00","publicationYear":"1996","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":"Spatial radon anomalies on active faults in California","docAbstract":"Radon emanation has been observed to be anomalously high along active faults in many parts of the world. We tested this relationship by conducting and repeating soil air radon surveys with a portable radon meter across several faults in California. The results confirm the existence of fault-associated radon anomalies, which show characteristic features that may be related to fault structures but vary in time due to other environmental changes, such as rainfall. Across two creeping faults in San Juan Bautista and Hollister, the radon anomalies showed prominent double peaks straddling the fault gouge zone during dry summers, but the peak-to-background ratios diminished after significant rain fall during winter. Across a locked segment of the San Andreas fault near Olema, the anomaly has a single peak located several meters southwest of the slip zone associated with the 1906 San Francisco earthquake. Across two fault segments that ruptured during the magnitude 7.5 Landers earthquake in 1992, anomalously high radon concentration was found in the fractures three weeks after the earthquake. We attribute the fault-related anomalies to a slow vertical gas flow in or near the fault zones. Radon generated locally in subsurface soil has a concentration profile that increases three orders of magnitude from the surface to a depth or several meters; thus an upward flow that brings up deeper and radon-richer soil air to the detection level can cause a significantly higher concentration reading. This explanation is consistent with concentrations of carbon dioxide and oxygen, measured in soil-air samples collected during one of the surveys.","largerWorkType":{"id":2,"text":"Article"},"largerWorkTitle":"Applied Geochemistry","largerWorkSubtype":{"id":10,"text":"Journal Article"},"language":"English","doi":"10.1016/0883-2927(96)00003-0","issn":"08832927","usgsCitation":"King, C., King, B., Evans, W.C., and Zhang, W., 1996, Spatial radon anomalies on active faults in California: Applied Geochemistry, v. 11, no. 4, p. 497-510, https://doi.org/10.1016/0883-2927(96)00003-0.","startPage":"497","endPage":"510","numberOfPages":"14","costCenters":[],"links":[{"id":205883,"rank":9999,"type":{"id":10,"text":"Digital Object Identifier"},"url":"https://dx.doi.org/10.1016/0883-2927(96)00003-0"},{"id":227300,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"11","issue":"4","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505b94a2e4b08c986b31abba","contributors":{"authors":[{"text":"King, C.-Y.","contributorId":81225,"corporation":false,"usgs":true,"family":"King","given":"C.-Y.","affiliations":[],"preferred":false,"id":379707,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"King, B.-S.","contributorId":54592,"corporation":false,"usgs":true,"family":"King","given":"B.-S.","email":"","affiliations":[],"preferred":false,"id":379706,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Evans, William C.","contributorId":104903,"corporation":false,"usgs":true,"family":"Evans","given":"William","email":"","middleInitial":"C.","affiliations":[],"preferred":false,"id":379709,"contributorType":{"id":1,"text":"Authors"},"rank":3},{"text":"Zhang, W.","contributorId":92399,"corporation":false,"usgs":true,"family":"Zhang","given":"W.","email":"","affiliations":[],"preferred":false,"id":379708,"contributorType":{"id":1,"text":"Authors"},"rank":4}]}} ,{"id":70018451,"text":"70018451 - 1996 - Origin and depositional environment of clastic deposits in the Hilo drill hole, Hawaii","interactions":[],"lastModifiedDate":"2019-03-15T10:42:16","indexId":"70018451","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":"Origin and depositional environment of clastic deposits in the Hilo drill hole, Hawaii","docAbstract":"Volcaniclastic units cored at depths of about 87, 164, 178, 226, and 246 m below sea level and carbonate units located between depths of 27 and 53 m below sea level in the Hilo drill core were found to be deposited at or near sea level. Four of these units are hydroclastic deposits, formed when subaerially erupted Mauna Loa lava flows entered the ocean and fragmented to produce quenched, glassy fragments during hydrovolcanic explosions. Ash units 24 and 26, at 178 m depth, accumulated at sea level in a freshwater bog. They contain pyroxenes crystallized from tholeiitic magma that we infer erupted explosively at the summit of Kilauea volcano. Two carbon‐rich layers from these ashes have a weighted average radiocarbon age of 38.6 ± 0.9 ka; the ashes probably correlate with the oldest and thickest part of the Pahala ash. Ash unit 44, at the transition from Mauna Kea to Mauna Loa lava flows, was probably nearly 3.2 m thick and is inferred to be equivalent to the lower thick part of the composite Homelani ash mapped in Hilo and on the flanks of Mauna Kea. The age of this part of Homelani ash is between 128 ± 33 and 200 ± 10 ka; it may have erupted subglacially during the Pohakuloa glacial maxima on Mauna Kea. Beach sand units 12 and 22 were derived from nearby Mauna Loa and Mauna Kea lava flows. The middle of beach sand unit 38 was derived mainly from lava erupted near the distal end of the subaerial east rift zone of Kilauea volcano; these sands were transported about 33 km northwest to Hilo Bay by prevailing longshore currents. Combined age, depth, and sea level markers in the core allow us to determine that lava flow recurrence intervals averaged one flow every 4 kyr during the past 86 kyr and one flow every 16 kyr between 86 and 200 ka at the drill site and that major explosive eruptions that deposit thick ash in Hilo have occurred only twice in the last 400 kyr. These recurrence intervals support the moderate lava flow hazard zonation (zone 3) for coastal Hilo previously determined from surficial mapping.
","language":"English","publisher":"AGU","doi":"10.1029/95JB03703","issn":"01480227","usgsCitation":"Beeson, M., Clague, D., and Lockwood, J.P., 1996, Origin and depositional environment of clastic deposits in the Hilo drill hole, Hawaii: Journal of Geophysical Research B: Solid Earth, v. 101, no. 5, p. 11617-11629, https://doi.org/10.1029/95JB03703.","productDescription":"13 p.","startPage":"11617","endPage":"11629","costCenters":[{"id":615,"text":"Volcano Hazards Program","active":true,"usgs":true}],"links":[{"id":227647,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"101","issue":"5","noUsgsAuthors":false,"publicationDate":"1996-05-10","publicationStatus":"PW","scienceBaseUri":"505a709de4b0c8380cd76125","contributors":{"authors":[{"text":"Beeson, M.H.","contributorId":83118,"corporation":false,"usgs":true,"family":"Beeson","given":"M.H.","email":"","affiliations":[],"preferred":false,"id":379621,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Clague, D.A.","contributorId":36129,"corporation":false,"usgs":true,"family":"Clague","given":"D.A.","email":"","affiliations":[],"preferred":false,"id":379620,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Lockwood, J. P.","contributorId":104473,"corporation":false,"usgs":true,"family":"Lockwood","given":"J.","email":"","middleInitial":"P.","affiliations":[],"preferred":false,"id":379622,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018447,"text":"70018447 - 1996 - Groundwater inflow measurements in wetland systems","interactions":[],"lastModifiedDate":"2018-03-08T15:30:04","indexId":"70018447","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":"Groundwater inflow measurements in wetland systems","docAbstract":"Our current understanding of wetlands is insufficient to assess the effects of past and future wetland loss. While knowledge of wetland hydrology is crucial, groundwater flows are often neglected or uncertain. In this paper, groundwater inflows were estimated in wetlands in southwestern Wisconsin using traditional Darcy's law calculations and three independent methods that included (1) stable isotope mass balances, (2) temperature profile modeling, and (3) numerical water balance modeling techniques. Inflows calculated using Darcy's law were lower than inflows estimated using the other approaches and ranged from 0.02 to 0.3 cm/d. Estimates obtained using the other methods generally were higher (0.1 to 1.1 cm/d) and showed similar spatial trends. An areal map of groundwater flux generated by the water balance model demonstrated that areas of both recharge and discharge exist in what is considered a regional discharge area. While each method has strengths and weaknesses, the use of more than one method can reduce uncertainty in the estimates.
","language":"English","publisher":"American Geophysical Union","doi":"10.1029/95WR03724","usgsCitation":"Hunt, R.J., Krabbenhoft, D.P., and Anderson, M.P., 1996, Groundwater inflow measurements in wetland systems: Water Resources Research, v. 32, no. 3, p. 495-507, https://doi.org/10.1029/95WR03724.","productDescription":"13 p.","startPage":"495","endPage":"507","costCenters":[],"links":[{"id":227604,"rank":0,"type":{"id":24,"text":"Thumbnail"},"url":"https://pubs.usgs.gov/thumbnails/outside_thumb.jpg"}],"volume":"32","issue":"3","noUsgsAuthors":false,"publicationStatus":"PW","scienceBaseUri":"505a2da7e4b0c8380cd5bf89","contributors":{"authors":[{"text":"Hunt, Randy J.","contributorId":25903,"corporation":false,"usgs":false,"family":"Hunt","given":"Randy","email":"","middleInitial":"J.","affiliations":[],"preferred":false,"id":379610,"contributorType":{"id":1,"text":"Authors"},"rank":1},{"text":"Krabbenhoft, David P. 0000-0003-1964-5020 dpkrabbe@usgs.gov","orcid":"https://orcid.org/0000-0003-1964-5020","contributorId":1658,"corporation":false,"usgs":true,"family":"Krabbenhoft","given":"David","email":"dpkrabbe@usgs.gov","middleInitial":"P.","affiliations":[{"id":5044,"text":"National Research Program - Central Branch","active":true,"usgs":true},{"id":677,"text":"Wisconsin Water Science Center","active":true,"usgs":true},{"id":37464,"text":"WMA - Laboratory & Analytical Services Division","active":true,"usgs":true},{"id":37947,"text":"Upper Midwest Water Science Center","active":true,"usgs":true}],"preferred":true,"id":379611,"contributorType":{"id":1,"text":"Authors"},"rank":2},{"text":"Anderson, Mary P.","contributorId":147842,"corporation":false,"usgs":false,"family":"Anderson","given":"Mary","email":"","middleInitial":"P.","affiliations":[{"id":16925,"text":"University of Wisconsin-Madison","active":true,"usgs":false}],"preferred":false,"id":379612,"contributorType":{"id":1,"text":"Authors"},"rank":3}]}} ,{"id":70018445,"text":"70018445 - 1996 - Uranium-series disequilibrium, sedimentation, diatom frustules, and paleoclimate change in Lake Baikal","interactions":[],"lastModifiedDate":"2023-12-09T00:46:15.253825","indexId":"70018445","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":"Uranium-series disequilibrium, sedimentation, diatom frustules, and paleoclimate change in Lake Baikal","docAbstract":"The large volume of water, approximately one-fifth of the total surface fresh water on the planet, contained in Lake Baikal in southeastern Siberia is distinguished by having a relatively high concentration of uranium (ca. 2 nM), and, together with the surface sediments, an unusually high234U238U alpha activity ratio of 1.95. About 80% of the input of uranium to the lake, with a234U238U ratio of 2.0, comes from the Selenga River. Profiles of uranium, as well as the extent of isotopic disequilibrium in a 9 m sediment core collected on Academic Ridge, generally show high values during interglacial periods corresponding to high diatom frustule numbers (DiFr) and biogenic silica (BSi) data that have been reported elsewhere. During glacial periods (low DiFr and BSi), uranium progeny (234U and230Th) were in secular equilibrium with low concentrations of their parent238U. Radionuclide distributions were interpreted in terms of a quantitative model allowing for adsorption of riverine inputs of uranium onto two classes of sedimenting particles with differing238U232Th ratios and uranium progeny in secular equilibrium. If the234U238U activity ratio of adsorbed uranium has remained constant, mean sedimentation rates can be independently estimated as 3.6 ± 0.6 and 3.7 ± 0.9 cm · kyr−1 for the decay of234U and in-growth of230Th, respectively. These rates are consistent with a mean rate of 3.76 cm · kyr−1, calculated by optimization of the correspondence between adsorbed238U and δ18O in dated oceanic sediments. The adsorbed uranium apparently tracks variable river flow during interglacials and is drastically reduced during periods of glaciation. Evidently, uranium has not been significantly redistributed within Baikal sediments over at least the past 250 kyr and is a unique, biologically non-essential, tracer for climate-sensitive processes, which provide their own internal geochronometers, potentially useful for ages up to 1 Myr BP.