Rationale and operational plan to upgrade the U.S. gravity database

Hildenbrand, Thomas G.; Briesacher, Allen; Flanagan, Guy; Hinze, William J.; Hittelman, Allen M.; Keller, G. Randy; Kucks, R.P.; Plouff, Donald; Roest, W. R.; Seeley, John; Webring, Mike

doi:10.3133/ofr02463

Cited by 23 publications

(26 citation statements)

References 11 publications

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“…Gravity data for numerical test originate from the U.S. gravity database, which is available at the website of University of Texas at El Paso (Hildenbrand et al, 2002). Large, regional area of Bouguer gravity data (around 6˚×9˚) is useful for work with various resolutions of the gravity signal.…”

Section: Gravity Samples and Test Assumptionsmentioning

confidence: 99%

A priori noise and regularization in least squares collocation of gravity anomalies

Jarmołowski¹

2013

Geodesy and Cartography

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Abstract:The paper describes the estimation of covariance parameters in least squares collocation (LSC) by the cross-validation (CV) technique called leave-one-out (LOO). Two parameters of Gauss-Markov third order model (GM3) are estimated together with a priori noise standard deviation, which contributes signifi cantly to the covariance matrix composed of the signal and noise. Numerical tests are performed using large set of Bouguer gravity anomalies located in the central part of the U.S. Around 103 000 gravity stations are available in the selected area. This dataset, together with regular grids generated from EGM2008 geopotential model, give an opportunity to work with various spatial resolutions of the data and heterogeneous variances of the signal and noise. This plays a crucial role in the numerical investigations, because the spatial resolution of the gravity data determines the number of gravity details that we may observe and model. This establishes a relation between the spatial resolution of the data and the resolution of the gravity fi eld model. This relation is inspected in the article and compared to the regularization problem occurring frequently in data modeling.

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Section: Gravity Samples and Test Assumptionsmentioning

confidence: 99%

A priori noise and regularization in least squares collocation of gravity anomalies

Jarmołowski¹

2013

Geodesy and Cartography

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“…Finally, Bouguer gravity anomalies are free from the height correlation to the suitable level. Terrestrial, Bouguer gravity anomalies have been extracted from the US gravity database, which is available at the Web site of University of Texas at El Paso (Hildenbrand et al 2002). The original data spacing is variable over the region, but reaches around 0.03°in better covered areas.…”

Section: Example Gravity Data For Numerical Studymentioning

confidence: 99%

Fast Estimation of Covariance Parameters in Least-Squares Collocation by Fisher Scoring with Levenberg–Marquardt Optimization

Jarmołowski

2017

Surv Geophys

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Maximum likelihood (ML) and restricted maximum likelihood (REML) are nowadays very popular in geophysics, geodesy and many other fields. There is also a growing number of investigations into how to calculate covariance parameters by ML/ REML accurately and fast, and assure the convergence of the iteration steps in derivativebased approaches. The latter condition is not satisfied in many solutions, as it requires composed procedures or takes an unacceptable amount of time. The article implements efficient Fisher scoring (FS) to covariance parameter estimation in least-squares collocation (LSC). FS is optimized through Levenberg-Marquardt (LM) optimization, which provides stability in convergence when estimating two covariance parameters necessary for LSC. The motivation for this work was a very large number of non-optimized FS in the literature, as well as a deficiency of its scientific and engineering applications. The example work adds some usefulness to maximum likelihood estimation (ML) and FS and shows a new application-an alternative approach to LSC-a parametrization with no empirical covariance estimation. The results of LM damping applied to FS (FSLM) require some additional research related with optimal LM parameter. However, the method appears to be a milestone in relation to non-optimized FS, in terms of convergence. The FS with LM provides a reliable convergence, whose speed can be adjusted by manipulating the LM parameter.

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“…In conformity with the new standards set by the U.S. Geological Survey (USGS) (Hildebrand et al, 2002) and the Standards/Format Working Group of the North American Gravity Database Committee (Hinze, 2003), the Bouguer anomaly computations are based on ellipsoidal heights (Holom and Oldow, 2007). All gravity data for our survey are referenced to ellipsoidal heights directly acquired from GNSS positioning.…”

Section: Observed Gravitymentioning

confidence: 99%

Late Cenozoic displacement transfer in the eastern Sylvania Mountain fault system and Lida Valley pull-apart basin, southwestern Nevada, based on three-dimensional gravity depth inversion and forward models

Dunn¹,

Oldow²,

Mueller³

2015

Geosphere

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The Sylvania Mountain fault system is a major left-oblique structure that extends east from the Furnace Creek-Fish Lake Valley fault in southwestern Nevada (USA). The system interacts with a series of north-northeast-striking structures that bound a rectilinear pull-apart basin, Lida Valley, and serve as part of a displacement transfer system relaying slip from the eastern California shear zone to the Walker Lane. On the basis of gravity analysis, the Lida Valley basin is internally dissected by a complex system of faults. The subsurface basin morphology differs from north to south. Major extensional faults localized displacement in the north and formed deep basins, but in the south, displacement was distributed on widely spaced structures with modest displacement. Localized extension in the north is separated from the southern domain of distributed deformation by a west-northwest oblique-slip fault. The subsurface geometry of the basin was determined from a gravity survey with measurements depth inverted in three dimensions. Geologic cross sections were constructed and their gravity signatures forward modeled for compatibility with observations. Projections of mapped faults together with structures determined from gravity modeling were combined to construct the subsurface geometry of the Lida Valley fault system and to evaluate a fault displacement budget. By conserving fault slip on the array of structures, restoration of the pre-Neogene basement to a reference datum indicates a cumulative vertical displacement of 2.3-2.5 km since the onset of basin formation. Vertical displacement estimates were used to compute the horizontal component of extension, which ranges from 1.3 to 1.4 km.

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Rationale and operational plan to upgrade the U.S. gravity database

Cited by 23 publications

References 11 publications

A priori noise and regularization in least squares collocation of gravity anomalies

A priori noise and regularization in least squares collocation of gravity anomalies

Fast Estimation of Covariance Parameters in Least-Squares Collocation by Fisher Scoring with Levenberg–Marquardt Optimization

Late Cenozoic displacement transfer in the eastern Sylvania Mountain fault system and Lida Valley pull-apart basin, southwestern Nevada, based on three-dimensional gravity depth inversion and forward models

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