scholarly journals Noise-reduced vertical gravity gradient, airborne gravity gradiometer survey of the Blatchford Lake area, NTS 85-I/2 and parts of 85-I/1 and 85-I/3, Northwest Territories

2013 ◽  
Author(s):  
M Pilkington ◽  
R Dumont ◽  
W Miles ◽  
A Jones
Keyword(s):  
Northwest Territories ◽  
Airborne Gravity ◽  
Gravity Gradient ◽  
Lake Area ◽  
Gravity Gradiometer ◽  
Vertical Gravity Gradient ◽  
Vertical Gravity

Mathematical properties and physical meaning of the gravity gradient tensor eigenvalues

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. G115-G124
Author(s):  
Carlos Cevallos
Keyword(s):  
Physical Meaning ◽  
Airborne Gravity ◽  
Gravity Gradient ◽  
Model Data ◽  
Gradient Tensor ◽  
Gravity Gradient Tensor ◽  
Mathematical Properties ◽  
Vertical Gravity Gradient ◽  
Vertical Gravity ◽  
Two Parameters

The eigenvalues of the gravity gradient tensor can be expressed as functions of two parameters: a magnitude and a phase. The decomposition gives physical meaning to the eigenvalues: The magnitude measures the amount of curvature, and the phase is related to the type of source. Their understanding allows one to propose new quantities to interpret. As an example, a modified phase eigenvalue offers the interpreter a subtle enhanced version of the vertical gravity gradient, which is evaluated with model data and applied to FALCON airborne gravity gradiometer data from the Perth Basin, Australia.

Seafloor topography variations mapped by regional gravity tensor analysis 

2021 ◽  
Author(s):  
Lucia Seoane ◽  
Guillaume Ramillien ◽  
José Darrozes ◽  
Frédéric Frappart ◽  
Didier Rouxel ◽  
...  
Keyword(s):  
New England ◽  
Static Field ◽  
Gravity Gradient ◽  
Seafloor Topography ◽  
Central Pacific ◽  
Goce Mission ◽  
Vertical Gravity Gradient ◽  
Seamount Chain ◽  
Vertical Gravity ◽  
Regional Gravity

<p>The AGOSTA project initially proposed by our team and lately funded by CNES TOSCA consists of developing efficient approaches to restore seafloor shape (or bathymetry), as well as lithospheric parameters such as the crust and elastic thicknesses, by combining different types of observations including gravity gradient data. As it is based on the second derivatives of the potential versus the space coordinates, gravity gradiometry provides more information inside the Earth system at short wavelengths. The GOCE mission has measured the gravity gradient components of the static field globally and give the possibility to detect more details on the structure of the lithosphere at spatial resolutions less than 200 km. We propose to analyze these satellite-measured gravity tensor components to map the undersea relief more precisely than using geoid or vertical gravity previously considered for this purpose. Inversion of vertical gravity gradient data derived from the radar altimetry technique also offers the possibility to reach greater resolutions (at least 50 km) than the GOCE mission one. The seafloor topography estimates are tested in areas well-covered by independent data for validation, such as around the Great Meteor guyot [29°57′10.6″N, 28°35′31.3″W] and New England seamount chain [37°24′N 60°00′W, 120° 10' 30.4" W] in the Atlantic Ocean as well as the Acapulco seamount [13° 36' 15.4" N, 120° 10' 30.4" W] in the Central Pacific.</p>

VERTICAL GRADIENT OF GRAVITY ON AXIS FOR HOLLOW AND SOLID CYLINDERS

Geophysics ◽  
1966 ◽  
Vol 31 (4) ◽  
pp. 816-820 ◽  
Author(s):  
Thomas A. Elkins
Keyword(s):  
Hollow Cylinder ◽  
Sudden Change ◽  
Vertical Gradient ◽  
Outer Radius ◽  
Gravity Gradient ◽  
Gradient Effect ◽  
Vertical Gravity Gradient ◽  
Vertical Gravity ◽  
Special Case ◽  
Vertical Gradient Of Gravity

The recent interest in borehole gravimeters and vertical gravity gradient meters makes it worthwhile to analyze the simple case of the vertical gravity gradient on the axis of a hollow cylinder, simulating a borehole. From the viewpoint of potential theory the results are interesting because of the discontinuities which may occur when a vertical gradient profile crosses a sudden change in density. Formulas for the vertical gradient effect are given for observations above, inside, and below a hollow cylinder and a solid cylinder. The special case of an infinitely large outer radius for the cylinders is also considered, leading to formulas for the vertical gradient effect inside a borehole on its axis and inside a horizontal slab. Some remarks are made on the influence of the shape of a buried vertical gradient meter on the correction factor for changing the meter reading to density.

Reduction to the pole of the North American magnetic anomalies

Geophysics ◽  
1990 ◽  
Vol 55 (2) ◽  
pp. 218-225 ◽  
Author(s):  
J. Arkani‐Hamed ◽  
W. E. S. Urquhart
Keyword(s):  
North America ◽  
Gravity Anomalies ◽  
Magnetic Anomalies ◽  
Gravity Gradient ◽  
Plate Boundaries ◽  
Gravity Gradients ◽  
The North ◽  
Vertical Gravity Gradient ◽  
Regional Tectonic ◽  
Vertical Gravity

Magnetic anomalies of North America are reduced to the pole using a generalized technique which takes into account the variations in the directions of the core field and the magnetization of the crust over North America. The reduced‐to‐the‐pole magnetic anomalies show good correlations with a number of regional tectonic features, such as the Mid‐Continental rift and the collision zones along plate boundaries, which are also apparent in the vertical gravity gradient map of North America. The magnetic anomalies do not, however, show consistent correlation with the vertical gravity gradients, suggesting that magnetic and gravity anomalies do not necessarily arise from common sources.

On: “Gravity vertical gradient measurements for the detection of small geologic and anthropogenic forms” by Z. J. Fajklewicz (GEOPHYSICS, October 1976, p. 1016–1030)

Geophysics ◽  
1977 ◽  
Vol 42 (4) ◽  
pp. 872-873
Author(s):  
Stephen Thyssen‐Bornemisza
Keyword(s):  
Research Work ◽  
Vertical Gradient ◽  
Gravity Gradient ◽  
Wind Gust ◽  
Near Surface ◽  
New Methods ◽  
Vertical Gravity Gradient ◽  
Surface Variation ◽  
Gradient Measurements ◽  
Vertical Gravity

In his paper, Fajklewicz discusses the improvement of vertical gravity gradient measurements arising from a very stable tower apparently not affected by wind gust vibration and climatic changes. Further, the lower plate where the gravity meter is resting can be changed in position to avoid possible disturbances from surface and near‐surface variation, and new methods for correcting and interpreting observed gradients over the vertical interval of about 3 m are presented. Some 1000 field stations were observed, including research work and industrial application.

POSSIBLE APPLICATION OF THE ANOMALOUS FREE‐AIR VERTICAL GRADIENT TO MARINE EXPLORATION

Geophysics ◽  
1966 ◽  
Vol 31 (1) ◽  
pp. 260-263
Author(s):  
Stephen Thyssen‐Bornemisza
Keyword(s):  
Vertical Cylinder ◽  
Vertical Gradient ◽  
Gravity Gradient ◽  
Average Gradient ◽  
Vertical Gravity Gradient ◽  
Free Air ◽  
Vertical Gravity ◽  
Lithologic Unit ◽  
Marine Exploration ◽  
Anomalous Average

Recently it could be shown (Thyssen‐Bornemisza, 1965) that a vertical lithologic unit cylinder generates a relatively strong anomalous free‐air vertical gravity gradient F′ along the cylinder axis. The following simple example may serve as a demonstration. A small vertical cylinder made of gold or tungsten, where radius r and length L are identical, would generate the anomalous average gradient F′∼3,223 Eötvös units over the interval h=r=L going from the cylinders top surface upward. Suppose r=l=1 cm, then an average gradient exceeding the earth’s normal free‐air vertical gradient F is present over the interval h=1 cm.

Sign in / Sign up

Export Citation Format

Share Document