نتایج جستجو برای: gravity anomaly

تعداد نتایج: 100927  

Journal: :فیزیک زمین و فضا 0
مرتضی عرفانیان نوروززاده دانشگاه تهران وحید ابراهیم زاده اردستانی هیأت علمی بخش گرانی سنجی-مؤسسه ژئوفیزیک دانشگاه تهران

in this paper, a new formula is applied for the calculation of gravity anomalies from a cylinder model representing a geological body. compared to conventional methods, this new development allows the cylinder to be freely oriented in space. 38 gravity forward models are produced each of which anomaly attributes are calculated. then a linear relationship is established between attributes and so...

Journal: :فیزیک زمین و فضا 0
مهدی گلی دانشکده مهندسی عمران، دانشگاه صنعتی شاهرود

generally, gravity anomaly is the difference between the observed acceleration of earth's gravity and a normal value. topography (all masses above geoid) plays a main role in definition of the gravity anomaly. based on modeling of the effect of topography, there are different models of gravity anomaly such as free-air and bouguer anomaly. the main goal of the bouguer anomaly is removing of...

Estimating the gravity anomaly causative bodies boundary can facilitate the gravity field interpretation. In this paper, 2D discrete wavelet transform (DWT) is employed as a method to delineate the boundary of the gravity anomaly sources. Hence, the GRACE’ satellite gravity data is decomposed using DWT. DWT decomposites a single approximation coefficients into four distinct components: the appr...

Journal: Journal of Tethys 2017

This paper presents a new interpretation of the geometry of Triassic alignment of J. Sidi Mahdi –J. Zitoun in Medjerda Valley Plain (Northern Tunisia) based on detailed analysis of gravity and seismic reflection data. The main results of gravity analysis do not show a distinguish gravity anomaly over Triassic evaporites bodies. The positive gravity anomaly seems to be related to the entire stru...

Journal: :فیزیک زمین و فضا 0
عبدالرحیم عسکری وحید ابراهیم زاده اردستانی علیرضا آزموده اردلان

changing altimetry information from satellites on the surface of seas and oceans, into anomaly gravity for example free air anomaly, is a fundamentally new method presented by researches. the determination of the free air gravity anomaly over the earth’s marine regions has led to a major improvement in our understanding of plate tectonic processes relating to oceanic ridges, the formation of ma...

Journal: :فیزیک زمین و فضا 0
فائزه بهرامی دانشجوی کارشناسی ارشد، دانشگاه آزاد اسلامی واحد همدان، ایران وحید ابراهیم زاده اردستانی استاد، گروه فیزیک زمین، موسسه ژئوفیزیک دانشگاه تهران، ایران

the gravity method is one of the first geophysical techniques used in oil and gas exploration. an algorithm is developed for a fast quantitative interpretation of gravity data generated by geometrically simple but also the estimated depths and other model parameters of a buried structure. following abdelrahman et al (1989). the general gravity anomaly expression produced by a sphere, an infinit...

Journal: :iranian journal of science and technology (sciences) 2011
a. h. ansari

in order to obtain maximum information from magnetic and gravity anomaly maps, application of an edgedetection method is necessary. in this regard two commonly used methods are derivative filters and local phase filters. in this paper, a matlab code is expanded to combine an analytic signal filter and a tilt angle filter as a new edge detection filter called asta filter. this method was demonst...

Journal: :فیزیک زمین و فضا 0
عبدالرضا صفری دانشیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران محمدعلی شریفی استادیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران اسماعیل فروغی دانشجوی کارشناسی ارشد ژئودزی، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران هادی امین دانشجوی کارشناسی ارشد ژئودزی، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی دانشگاه تهران، ایران

one of the most important problems in geodesy is the unification of height datum. generally in geodesy; there are two types of height systems, the geometrical height based on ellipsoid and the physical height based on gravity-defined surface (zhang et al, 2009).local height datum is determined according to mean sea level (msl). in regarding to mismatch of mean sea level and geoid, on the one ha...

2015
Jianbo Wang Youge Xie

In this paper , we proposed a new method to build covariance matrix of gravity anomaly based on the spherical harmonic expansion of gravity anomaly , and then combined with the measured gravity data we can realize the fast and high precision interpolation and extrapolation of gravity anomaly according to the principle of least squares and the remove-compute-restore technique. The feasibility of...

Journal: :فیزیک زمین و فضا 0
عبدالرحیم عسکری استادیار، گروه فیزیک، دانشگاه حکیم سبزواری، سبزوار، ایران براتعلی فیض آبادی استادیار، گروه فیزیک، دانشگاه حکیم سبزواری، سبزوار، ایران وحید ابراهیم زاده اردستانی دانشیار، گروه فیزیک زمین، موسسه ﮊئوفیزیک دانشگاه تهران، ایران

the mapping of the crust-mantle boundary surface is an important geophysical task, which the method of seismic profiling has dealt with profitably. there are, however, areas where the crustal structure is not known up to the present, and where the moho has as yet not been determined by geophysical sounding. in such areas the isostatic theory may be applied to give a first estimate of the depths...

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