scholarly journals Review of Environmental and Geological Microgravity Applications and Feasibility of Its Employment at Archaeological Sites in Israel

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Lev V. Eppelbaum
Keyword(s):  
Gravity Anomalies ◽  
Gravity Potential ◽  
Archaeological Sites ◽  
Useful Signal ◽  
Geometric Size ◽  
Archaeological Models ◽  
Vertical Gravity ◽  
Transformation Methods ◽  
Derivatives Of ◽  
Archaeological Objects

Microgravity investigations are widely applied at present for solving various environmental and geological problems. Unfortunately, microgravity survey is comparatively rarely used for searching for hidden ancient targets. It is caused mainly by small geometric size of the desired archaeological objects and various types of noise complicating the observed useful signal. At the same time, development of modern generation of field gravimetric equipment allows to register promptly and digitally microGal (10-8 m/s2) anomalies that offer a new challenge in this direction. An advanced methodology of gravity anomalies analysis and modern 3D modeling, intended for ancient targets delineation, is briefly presented. It is supposed to apply in archaeological microgravity the developed original methods for the surrounding terrain relief computing. Calculating second and third derivatives of gravity potential are useful for revealing some closed peculiarities of the different Physical-Archaeological Models (PAMs). It is underlined that physical measurement of vertical gravity derivatives in archaeological studying has a significant importance and cannot be replaced by any transformation methods. Archaeological targets in Israel have been ranged by their density/geometrical characteristics in several groups. The performed model computations indicate that microgravity investigations might be successfully applied at least in 20–25% of archaeological sites in Israel.

Conjugate complex variables method for the computation of gravity anomalies

Geophysics ◽  
1989 ◽  
Vol 54 (12) ◽  
pp. 1629-1637 ◽  
Author(s):  
Yue‐Kuen Kwok
Keyword(s):  
Gravity Anomalies ◽  
Higher Order ◽  
Complex Variables ◽  
Gravity Potential ◽  
Gravity Gradient ◽  
Horizontal Distance ◽  
Contour Integrals ◽  
Vertical Gravity ◽  
Analytical Expressions ◽  
Derivatives Of

Using conjugate complex variables, a generalized method is presented to derive formulas to calculate first‐ and higher‐order derivatives of the gravity potential due to selected mass models. Double integrals in the computation of gravity‐gradient anomalies are transformed into complex contour integrals. Analytical expressions for higher‐order derivatives of the gravitational potential in arbitrary directions due to two‐dimensional (2‐D) polygonal mass models are derived. The method is extended to 2‐D polygonal bodies whose density contrasts vary with depth and horizontal distance and can be generalized to deal with 2‐D bodies of any shape. The vertical gravity field and its first derivatives due to a homogeneous radially symmetric body are also computed using conjugate complex variables. Derivation of gravity and gravity gradient formulas generally is greatly simplified by the use of complex variables.

Analytical expressions for gravity anomalies due to homogeneous polyhedral bodies and translations into magnetic anomalies

Geophysics ◽  
1979 ◽  
Vol 44 (4) ◽  
pp. 730-741 ◽  
Author(s):  
M. Okabe
Keyword(s):  
Gravitational Potential ◽  
Computing Time ◽  
Gravity Anomalies ◽  
Magnetic Anomalies ◽  
Two Dimensions ◽  
First Derivative ◽  
Second Derivatives ◽  
Analytical Expressions ◽  
Derivatives Of ◽  
The Magnetic Field

Complete analytical expressions for the first and second derivatives of the gravitational potential in arbitrary directions due to a homogeneous polyhedral body composed of polygonal facets are developed, by applying the divergence theorem definitively. Not only finite but also infinite rectangular prisms then are treated. The gravity anomalies due to a uniform polygon are similarly described in two dimensions. The magnetic potential due to a uniformly magnetized body is directly derived from the first derivative of the gravitational potential in a given direction. The rule for translating the second derivative of the gravitational potential into the magnetic field component is also described. The necessary procedures for practical computer programming are discussed in detail, in order to avoid singularities and to save computing time.

scholarly journals Long Periodic Variation of Orbital Elements of A Satellite Perturbed by Discrete Gravity Anomalies

1978 ◽  
Vol 41 ◽  
pp. 240-240
Author(s):  
M.P. Ananda
Keyword(s):  
Gravity Field ◽  
Gravity Anomalies ◽  
Large Data ◽  
Periodic Variation ◽  
Static Case ◽  
Orbital Elements ◽  
Disturbing Potential ◽  
Data Set ◽  
Simple Matrix ◽  
Derivatives Of

AbstractA method for generating long periodic variations in satellite orbital elements when perturbed by discrete gravity anomalies is presented. The method consists of developing a disturbing potential as a function of orbital and gravity anomaly parameters, and generating partial derivatives of the potential with respect to the orbital elements. The partials are averaged over the period of the satellite to eliminate the short periodic variations. The averaged partials are substituted into the variation of parameter equations to give the mean orbital rates. Classically orbital elements are used in generating gravity field and thus the method is dynamic in nature. The problem is extremely cumbersome and complex when multi-state parameters have to be estimated from a considerably large data set. However, when mean orbital rates are used, the problem reduces to a simple linear static case, where only the gravity parameters have to be estimated, and it is a simple matrix inversion problem. Thus the method developed here was utilized in reducing Appolo 15 and 16 subsatellite radio tracking data to produce a lunar gravity field represented by point masses.

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.

A LEAST‐SQUARES PROCEDURE FOR GRAVITY INTERPRETATION

Geophysics ◽  
1965 ◽  
Vol 30 (2) ◽  
pp. 228-233 ◽  
Author(s):  
Charles E. Corbató
Keyword(s):  
Least Squares ◽  
High Speed ◽  
Gravity Anomalies ◽  
The Body ◽  
Two Dimensional ◽  
Partial Derivatives ◽  
Dimensional Gravity ◽  
Gravity Interpretation ◽  
Relationship Of ◽  
Derivatives Of

A procedure suitable for use on high‐speed digital computers is presented for interpreting two‐dimensional gravity anomalies. In order to determine the shape of a disturbing mass with known density contrast, an initial model is assumed and gravity anomalies are calculated and compared with observed values at n points, where n is greater than the number of unknown variables (e.g. depths) of the model. Adjustments are then made to the model by a least‐squares approximation which uses the partial derivatives of the anomalies so that the residuals are reduced to a minimum. In comparison with other iterative techniques, convergence is very rapid. A convenient method to use for both the calculation of the anomalies and the adjustments is the two‐dimensional method of Talwani, Worzel, and Landisman, (1959) in which the outline of the body is polygonized and the anomalies and the partial derivatives of the anomaly with respect to the depth of a vertex on the body can be expressed as functions of the coordinates of the vertex. Not only depths but under certain circumstances regional gravity values may be evaluated; however, the relationship of the disturbing body to the gravity information may impose certain limitations on the application of the procedure.

A COMPREHENSIVE SYSTEM OF AUTOMATIC COMPUTATION IN MAGNETIC AND GRAVITY INTERPRETATION

Geophysics ◽  
1960 ◽  
Vol 25 (3) ◽  
pp. 569-585 ◽  
Author(s):  
Roland G. Henderson
Keyword(s):  
Effective Means ◽  
Gravity Anomalies ◽  
Comprehensive System ◽  
Diagnostic Features ◽  
Special Cases ◽  
Desk Calculator ◽  
Concentric Circles ◽  
Gravity Interpretation ◽  
Magnetic And Gravity Anomalies ◽  
Derivatives Of

In the interpretation of magnetic and gravity anomalies, downward continuation of fields and calculation of first and second vertical derivatives of fields have been recognized as effective means for bringing into focus the latent diagnostic features of the data. A comprehensive system has been devised for the calculation of any or all of these derived fields on modern electronic digital computing equipment. The integral for analytic continuation above the plane is used with a Lagrange extrapolation polynomial to derive a general determinantal expression from which the field at depth and the various derivatives on the surface and at depth can be obtained. It is shown that the general formula includes as special cases some of the formulas appearing in the literature. The process involves a “once for all depths” summing of grid values on a system of concentric circles about each point followed by application of the appropriate one or more of the 19 sets of coefficients derived for the purpose. Theoretical and observed multilevel data are used to illustrate the processes and to discuss the errors. The coefficients can be used for less extensive computations on a desk calculator.

scholarly journals Archaeology of Semirechye at the End of the 19th Century (Based on the Materials of the Expedition Led by Ch.-E. Ujfalvy)

2020 ◽  
Vol 19 (7) ◽  
pp. 44-51
Author(s):  
Alisa Yu. Borisenko
Keyword(s):  
Central Asia ◽  
Aral Sea ◽  
Archaeological Sites ◽  
The North ◽  
Archaeological Materials ◽  
French Author ◽  
The Subject ◽  
The 19Th Century ◽  
Illustrative Material ◽  
Archaeological Objects

Purpose. This article analyzes the archaeological materials gathered by French explorer of Hungarian descent Charles-Eugène Ujfalvy in the course of his expedition into Semirechye (Jetysu). In 1879 his work “French scientific expedition to Russia, Siberia and Turkestan” (“Expédition scientifique française en Russe, en Sibérie et dans le Turkestan”) was published in Paris, where the author expounded extensive and diverse materials on the history, demography, natural economic and cultural specificities of Central Asia. Results. Activities of the European explorers, French in particular, in the territory of Central Asia not once have been the subject of attention and research by specialists. However, only a few mentions in scientific literature can be found about the work of Ch.-E. Ujfalvy in the territory of Jetysu. They are particularly small in number and contain either mentions about the fact of that journey or general descriptions of the expedition. Analysis of archaeological materials gathered by scientists has not been carried out before. The expeditionary route passed through territories that the French author called the Russian Turkestan, by limiting it to Semey in the north, Zarafshan in the south, Fergana Valley in the east and Aral Sea in the west. Ch.-E. Ujfalvy was one of those whose work was distinguished by a great variety and volume of collected material on the history, geography, and traditional culture of the peoples living in the studied territories. Conclusion. Ch.-E. Ujfalvy’s monograph includes not only texts, but also illustrative material. He also outlined the archaeological sites and findings among the landscaping and natural attractions described by the explorer. He has covered some of them in text and some are simply sketched and attached as illustrations to the monograph. The scientist highlights several types of archaeological objects. The article provides a data review about archaeological antiquities of the Jetysu region, gathered by Ch.-E. Ujfalvy in the course of his expedition.

scholarly journals Archaeology in the Making of Nations: The Juxtaposition of Postcolonial Archaeological Study

AMERTA ◽  
2019 ◽  
Vol 37 (1) ◽  
pp. 55
Author(s):  
Hendri Asyhari Fajrian Kaharudin ◽  
Muhammad Asyrafi
Keyword(s):  
White Supremacy ◽  
Colonial Period ◽  
The Other ◽  
Archaeological Sites ◽  
Archaeological Theory ◽  
Historical Legacy ◽  
Political Propaganda ◽  
Political Interests ◽  
Neutral Field ◽  
Archaeological Objects

The development of archaeological theory is inseparable from the evolution of cultural thinking in global society. This two-way relationship can develop both synchronically and diachronically. Archaeological sites and artefacts are often used to legitimize various opinions and beliefs. In the colonial period, the interpretation of archaeological objects was often biased by racial, religious, and ethnic perspectives. The postcolonial paradigm emerged in criticism of white supremacy hegemony. However, even in the era of post-colonialism, prejudice practices continue to occur. The perspective of neo-colonialism can still be found today. Archaeology, and the sciences generally, are considered a neutral field however, it regularly plays a central role in symbolic personifications of identity, pride, and political propaganda. Similar controversies can also be seen in the museum field. The discourse of repatriation between ex-colonies and 'universal museums' often devolves into extensive controversy. Resolution for many of these disputes remains out of reach due to the lack of equal cooperation and communication between respective parties. On the other hand, there are a number of countries that impose very strict regulations on foreign research (or ban it altogether) to protect their historical legacy. This policy unfortunately, often hampers the development of research and collaborations in the country. In effect, archaeology will never be completely separated from its various interested parties, and so efforts to harmonise academic, ethical, and political interests must be pursued.Perkembangan teori arkeologi tidak terlepas dari evolusi budaya berpikir masyarakat global. Hubungan yang saling mempengaruhi secara dua arah ini dapat dilihat secara sinkronik maupun diakronik. Situs dan artefak arkeologi kerap digunakan untuk meligitimasi berbagai macam kepentingan. Pada masa kolonial, interpretasi terhadap benda arkeologi kerap diselimuti oleh bias ras, agama, dan kesukuan. Paradigma postkolonialisme hadir sebagai kritik terhadap hegemoni berpikir supremasi kulit putih tersebut. Namun kenyataannya, bahkan di era pasca kolonialisme, praktik serupa masih kerap terjadi. Cara pandang neo-kolonialisme masih dapat ditemui hingga saat ini. Arkeologi tidak hanya ditempatkan sebagai bidang ilmu yang netral, namun masih menjadi salah satu isu sentral sebagai simbol personifikasi jati diri, harga diri, maupun propaganda politik. Kontroversi serupa juga dapat dilihat di ranah permuseuman. Wacana repatriasi antara negara ex- koloni dengan ‘universal museums’ selalu menuai perdebatan yang panjang. Perselisihan ini kerap kali tidak berujung pada suatu solusi karena salah satu pihak cenderung menutup pintu dialog. Di sisi lain, tidak sedikit pula negara-negara yang menutup atau memberlakukan regulasi yang sangat ketat (atau bahkan melarang sepenuhnya) terhadap penelitian asing demi melindungi kekayaan sejarah mereka. Kebijakan ini tidak jarang menghambat berkembangnya penelitian di negara tersebut. Kenyataannya, arkeologi tidak akan pernah sepenuhnya lepas dari berbagai kepentingan, namun usaha untuk menyelaraskan kepentingan akademik, etik, dan politik harus terus dilakukan.

scholarly journals Archaeological geophysics in Israel: past, present and future

2010 ◽  
Vol 24 ◽  
pp. 45-68 ◽  
Author(s):  
L. V. Eppelbaum
Keyword(s):  
Geophysical Methods ◽  
Archaeological Sites ◽  
Magnetic Survey ◽  
Main Attention ◽  
Near Surface ◽  
The Past ◽  
Geophysical Investigations ◽  
Limited Application ◽  
Three Stages ◽  
Archaeological Objects

Abstract. In Israel occur a giant number of archaeological objects of various age, origin and size. Different kinds of noise complicate geophysical methods employment at archaeological sites. Geodynamical active, multi-layered, and geologically variable surrounding media in many cases damages ancient objects and disturbs their physical properties. This calls to application of different geophysical methods armed by the modern interpretation technology. The main attention is focused on the geophysical methods most frequently applying in Israeli archaeological sites: GPR and high-precise magnetic survey. Other methods (paleomagnetic, resistivity, near-surface seismics, piezoelectric, etc.) are briefly described and reviewed. The number of employed geophysical methodologies is constantly increasing, and now Israeli territory may be considered as a peculiar polygon for various geophysical methods testing. Several examples illustrate effective application of geophysical methods over some typical archaeological remains. The geophysical investigations at archaeological sites in Israel could be tentatively divided on three stages: (1) past (1990), (2) present (1990–2009), and (3) future (2010). The past stage with several archaeoseismic reviews and very limited application of geophysical methods was replaced by the present stage with the violent employment of numerous geophysical techniques. It is supposed that the future stage will be characterized by extensive development of multidiscipline physical-archaeological databases, employment of all possible indicators for 4-D monitoring and ancient sites reconstruction, as well as application of combined geophysical multilevel surveys using remote operated vehicles at low altitudes.

scholarly journals ВЫЧИСЛЕНИЕ ВЫСШИХ ПРОИЗВОДНЫХ ГРАВИТАЦИОННОГО ПОТЕНЦИАЛА НА ОСНОВЕ F-АППРОКСИМАЦИИ

2016 ◽  
Author(s):  
И.А. Керимов
Keyword(s):  
Gravitational Field ◽  
Approximate Method ◽  
Gravitational Potential ◽  
Basic Data ◽  
Gravity Potential ◽  
Irregular Grid ◽  
Field Transformation ◽  
Gravimetric Data ◽  
Derivatives Of

В статье рассмотрен метод трансформации гравитационного поля (определение различных компонент потенциала силы тяжести) на аппроксимационной основе. Разработанный автором метод и компьютерные технологии F-аппроксимации позволяют вычислять горизонтальные и вертикальные  производные гравитационного потенциала для исходных данных, заданных как на регулярной, так и на нерегулярной сети. Метод апробирован на модельных и фактических гравиметрических данных This article considers an approximate method of the gravitational field transformation (the determination of different components of the gravity potential). The method developed by the author and computer technologies of the F-approximation permit the calculation of horizontal and vertical derivatives of the gravitational potential for basic data defined both on a regular and on an irregular grid. The method is tested on model and actual gravimetric data.

Sign in / Sign up

Export Citation Format

Share Document