Geodesy and geophysics


Mean Gravity Field

Anomalies by definition would require that we understand something about our selves that we did not know before, in that the whole history of you, is a large synopsis of everything that thinks and breath? Imagine indeed that such a vast resource could defined you as in some book to know that what would come next would be the unfolding of what you have been to what you shall become.

So I veered away from this act of who you are, toward a question of our relationship with understanding the world around us. What can exist in nature as some anomaly is really our inability to describe something in nature that awes us and had never gone deeper then then on the surface observance of who we are and where we live.

Map of free-air gravity anomalies around Britain and Ireland

Variations in the strength of gravity occur from place to place according to the density distribution of the rocks beneath the surface. Such gravity anomalies have been mapped across the British Isles and the surrounding seas and they reveal aspects of these islands’ geological structure.

(Bouguer) gravity anomaly map of the state of New Jersey (USGS)

 The Bouguer anomalies usually are negative in the mountains because of isostasy: the rock density of their roots is lower, compared with the surrounding earth’s mantle. Typical anomalies in the Central Alps are −150 milligals (−1.5 mm/s²). Rather local anomalies are used in applied geophysics: if they are positive, this may indicate metallic ores. At scales between entire mountain ranges and ore bodies, Bouguer anomalies may indicate rock types. For example, the northeast-southwest trending high across central New Jersey (see figure) represents a graben of Triassic age largely filled with dense basalts. Salt domes are typically expressed in gravity maps as lows, because salt has a low density compared to the rocks the dome intrudes. Anomalies can help to distinguish sedimentary basins whose fill differs in density from that of the surrounding region – see Gravity Anomalies of Britain and Ireland for example.

Bouguer Anomaly Map of Belgium and Surrounding areas

The anomalies are calculated using a uniform Bouguer reduction density of 2.67 gr/cm3 the grid was obtained by Krigging, cell size : 5 km, search radius : 30 km. The French data are copyrighted by BRGM (France).

While the examples above help to shed light on how we can perceive earth in a way that we are not accustomed too, this idea of gravity is important to understand the way in which gravitationally we my look at the world/earth. In our early years abstractly the idea of curvature was something that did not make sense until one moved beyond the Euclidean lines of understanding to a Non Euclidean view?

To that point we did not understand what the earth look like in its pearl form in space without having left the confines of earth?

I want you too look at space as well to understand what may be conceivable even though we may talk about an anomaly in nature that to this point we did not necessarily understand until we were presented with the examples as to confront and require an explanation. So you have the earth and space to contend with here.

LTool

So we graduate with the understanding with how we have seen the earth in observatory implicitness to have it detailed in a more “ugly definition of its composed parts?” To me it’s not really that ugly at all,  although as you venture to take in the color representation of the component parts of our earth’s geological structure,  you learn to understand the concreteness of our definitions.

This entry was posted in Grace, Grace Satellite, lagrangian and tagged , , . Bookmark the permalink.

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