1 - 25 of 100
Number of results to display per page
CreatorTitleDescriptionSubjectDate
1 Thorne, Michael S.Viterbi sparse spike detectionAccurate interpretation of seismic traveltimes and amplitudes in the exploration and global scales is complicated by the band-limited nature of seismic data. We discovered a stochastic method to reduce a seismic waveform into a most probable constituent spike train. Model waveforms were constructed ...2013-01-01
2 Solomon, Douglas KipTracer applications of noble gas radionuclides in the geosciencesNoble gas radionuclides, including 81Kr (t1/2 = 229,000 yr), 85Kr (t1/2 = 10.8 yr), and 39Ar (t1/2 = 269 yr), possess nearly ideal chemical and physical properties for studies of earth and environmental processes. Recent advances in Atom Trap Trace Analysis (ATTA), a laser-based atom counting method...2014-01-01
3 Zhdanov, MichaelQuasi-analytical boundary condition for three-dimensional finite difference electromagnetic modelingNumerical modeling of the quasi-static electromagnetic (EM) field in the frequency domain in a three-dimensional (3-D) inhomogeneous medium is a very challenging problem in computational physics. We present a new approach to the finite difference (FD) solution of this problem. The FD discretization ...2004-01-01
4 Zhdanov, MichaelTwo-dimensional magnetotelluric inversion of blocky geoelectrical structuresThis paper demonstrates that there are alternative approaches to the magnetotelluric (MT) inverse problem solution based on different types of geoelectrical models. The traditional approach uses smooth models to describe the conductivity distribution in underground formations. In this paper, we pres...2002-01-01
5 Zhdanov, MichaelContraction integral equation method in three-dimensional electromagnetic modelingThe integral equation method has been proven to be an efficient tool to model threedimensional electromagnetic problems . Owing to the full linear system to be solved, the method has been considered effective only in the case of models consisting of a strongly limited number of cells. However, recen...2002-01-01
6 Zhdanov, MichaelQuasi-linear series in three-dimensional electromagnetic modelingWe have recently introduced a quasi-linear (QL) approximation for the solution of the three-dimension(a3l -D) electromagnetic modeling problem. In this paper we discuss an approach to improving its accuracy by considering the QL approximation so f the higher order. This approach can be considered th...1997-01-01
7 Zhdanov, MichaelThree-dimensional quasi linear electromagnetic inversionOne of the most challenging problems of electromagnetic (EM) geophysical methods is developing three-dimension(a3l- D) EM inversion techniques. This problem is of utmost importance in practical applications because of the 3-D nature of the geological structures.T he main difficulties in 3-D inversio...1996-01-01
8 Hu, LihaiTrace elements in the hairStudy of uneven distribution of trace elements in elephant hair and compare the result with animal horns.2013
9 Chapman, David S.Air, ground, and groundwater recharge temperatures in an alpine setting, Brighton Basin, UtahNoble gases are useful tracers for constraining groundwater recharge temperature and elevation, critical in determining source areas of groundwater recharge in mountainous terrain. A monitoring network in the alpine Brighton Basin in the Wasatch Mountains of northern Utah, USA, was established to ex...2012-01-01
10 Zhdanov, MichaelDiscussion and reply: comments on "electromagnetic geophysics: notes from the past and the road ahead"The direct current and electromagnetic methods have been around for almost 180 years and have been applied successfully in mining, petroleum, geotechnical, engineering, environmental, groundwater, and tectonic studies. Over such a long period of time, it is possible to lose track of who the pioneers...2012-01-01
11 Zhdanov, Michael3D inversion of airborne electromagnetic dataTime-domain airborne surveys gather hundreds of thousands of multichannel, multicomponent samples. The volume of data and other complications have made 1D inversions and transforms the only viable method to interpret these data, in spite of their limitations. We have developed a practical methodolog...2012-01-01
12 Chapman, David S.Borehole temperatures and climate change: ground temperature change in south India over the past two centuriesVariations in surface g round temperature (SGT) at the Earth's surface diffuse downward in a predictable way causing systematic perturbations to the subsurface temperature field. The pioneering study of Lachenbruch and Marsh all [1986] in Alaska demonstrated that present-day borehole temperature-dep...2012-01-01
13 Jewell, PaulGeochemical variations in an alpine lake and watershed underlain by siliciclastic bedrock, Uinta Mountains, UtahA small watershed which includes several small lakes in the Uinta Mountains of northern Utah is underlain by monolithologic Precambrian siliciclastic rock with extremely limited buffering capacity. In spite of this, s\ stematic spatial and temporal variations in alkalinity, pH, and major elements oc...1998-01-01
14 Chapman, David S.Techniques, analysis, and noise in a Salt Lake Valley 4D gravity experimentRepeated high-precision gravity measurements using an automated gravimeter and analysis of time series of 1-Hz samples allowed gravity measurements to be made with an accuracy of 5 μGal or better. Nonlinear instrument drift was removed using a new empirical staircase function built from multiple ...Gravity measurements2008
15 Jarrard, Richard D.Geometry of Pleistocene facies on the Great Barrier Reef outer shelf and upper slope - seismic stratigraphy of sites 819, 820, and 821Seismic stratigraphic analysis of the sedimentary succession intersected in Ocean Drilling Program (ODP) Sites 819, 820, and 821, on the outer shelf and upper slope seaward of the Great Barrier Reef, provides a clear indication of the importance of sediment supply and depositional base-level as two ...1993
16 Jarrard, Richard D.Sedimentary response to paleoclimate from downhole logs at Site 693, Antarctic Continental MarginThe first well logs collected below the Antarctic circle were obtained during Leg 113 at Site 693 on the Dronning Maud Land Margin (Antarctica) in the Weddell Sea. Gamma-ray, resistivity, and sonic logs were collected between 108.0 and 439.0 mbsf. The downhole logs show good agreement with the data...1990
17 Fernandez, Diego P.Near-criticality in dilute binary mixtures: distribution of azulene between coexisting liquid and vapor carbon dioxideThe equilibrium distribution of dilute solutes between vapor and liquid coexisting phases of near-critical solvents exhibits a simple dependence on the solvent's liquid density which extends over a wide temperature range; however, theory predicts this dependence only as an asymptotic limit. In order...Near-critical solvents; Azulene; Binary mixtures; Dilute solutions2002
18 Brown, Francis HaroldA summary of the geology, geochemistry, and geophysics of the Roosevelt Hot Springs thermal area, Utah1978
19 Jarrard, Richard D.Seismic stratigraphy and history of deep circulation and sediment drift development in Baffin Bay and the Labrador SeaDrilling results and seismic-reflection records at and across Ocean Drilling Program (ODP) Sites 645 (western Baffin Bay), 646, and 647 (Labrador Sea) provide important constraints on the history of deep-water circulation and sedimentation in response to Cenozoic climatic change, as well as the tect...1989
20 Jarrard, Richard D.Results of borehole televiewer observations in the Celebes and Sulu SeasBorehole televiewer data were collected during Ocean Drilling Program Leg 124 to investigate stress orientations in the Sulu and Celebes sea basins. At Site 768C, in the Sulu Sea, televiewer logs were collected from 809-870 and 950-1250 meters below sea floor (mbsf). At Site 770C, in the Celebes Se...1991
21 Zhdanov, Michael S.Rigorous 3D inversion of marine CSEM data based on the integral equation methodMarine controlled-source electromagnetic (MCSEM) surveys have become an important part of offshore petroleum exploration. However, due to enormous computational difficulties with full 3D inversion, practical interpretation of MCSEM data is still a very challenging problem. We present a new approach ...2007
22 Zhdanov, Michael S.Three-dimensional quasi-linear electromagnetic modeling and inversionThe quasi-linear (QL) approximation replaces the (unknown) total field in the integral equation of electromagnetic (EM) scattering with a linear transformation of the primary field. This transformation involves the product of the primary field with a reflectivity tensor, which is assumed to vary slo...1999-01-01
23 Chapman, David S.Global warming - just hot air?We know from weather station records that Earth's surface temperature has increased on average by 0.6 degrees C in the last 100 years. The 1990s have been the warmest decade on record. Over the same period, global sea level has increased by 10-20 cm. We know also that planet Earth has an atmosphere ...Greenhouse Effect; Climate change1998
24 Jarrard, Richard D.Velocity and density of carbonate-rich sediments from northeastern Australian margin: integration of core and log dataDuring Ocean Drilling Program (ODP) Leg 133, shipboard scientists obtained a remarkable quantity of both core and log measurements of the physical properties of carbonate-rich sediments. This suite of measurements provides a unique opportunity to evaluate the robustness of each measurement technique...1993
25 Jarrard, Richard D.Resistivity/porosity/velocity relationships from downhole logs: an aid for evaluating pore morphologyRelationships between downhole resistivity/velocity logs and porosity styles, controlled by cementation/dissolution/recrystallization, are investigated using core and downhole logging data from the carbonate-rich sediments encountered during Leg 133 of the Ocean Drilling Program (ODP), northeastern ...1993
1 - 25 of 100