The results of the analysis of motions of the Earth's crust from the ground gravity repeated data and satellite magnetic data in geodynamic test site regions

The results of the study of the influence of the deep factor on the process of melting of the ice cover of the Arctic Ocean and the formation of dangerous natural phenomena are presented. The peculiarities of the structure of the earth’s crust contributing to the ice destruction are visualized based on the interpretation of anomalies of the magnetic field and gravity. Density and magnetic sections of the bottom structures are constructed taking into account seismic and seismological data. Two-dimensional density calculations of the Arctic crust density have been performed to detect fluid-saturated layers. Analysis of satellite observations of ice condition together with interpretation of gravity and magnetic data made it possible to identify natural phenomena of endogenous origin, caused by influence of thermo fluid flows of the earth’s crust. The study of annual and seasonal changes in the thickness of multiyear ice over the period 2007–2020 has shown that a decisive role in the thawing process is played by fluid-supplying channels of deep-seated fault zones. The role of an endogenous factor in the destruction of ice of different ages and in the emergence of dangerous phenomena in the areas of hydrate development has been revealed. This makes it possible to predict the localization of zones of variability in the thickness of multiyear ice, the nature of the destruction of its edges and reduce the risks of navigation.

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Study on structure of the Earth’s crust in Thua Thien-Hue province and adjacent areas by using gravity and magnetic data in combination

Tạp chí Khoa học và Công nghệ Biển ◽

10.15625/1859-3097/19/4/14903 ◽

2020 ◽

Vol 19 (4) ◽

pp. 517-526

Author(s):

Pham Nam Hung ◽

Cao Dinh Trong ◽

Le Van Dung ◽

Thai Anh Tuan ◽

Mai Xuan Bach ◽

...

Keyword(s):

Lower Layer ◽

Structural Characteristics ◽

Average Density ◽

Earth’S Crust ◽

Magnetic Data ◽

Adjacent Area ◽

Gravity And Magnetic ◽

Basaltic Layer ◽

Earth's Crust ◽

Gravity And Magnetic Data

This paper presents the structural characteristics of the Earth’s crust in Thua Thien-Hue province and adjacent area based on interpretation of gravity and magnetic data in combination. Research results have shown that: The depth of crystalline basement varies complicatedly, in the range of 0–11 km. The depth of Conrad surface increases from Northeast (12 km) to Southwest (18 km) and the depth of Moho surface is 23–34 km; The density of sedimentary layer changes from 2.61 g/cm3 to 2.65 g/cm3. Meanwhile, the density of granitic layer is in the range of 2.68–2.73 g/cm3. The basaltic layer has the density value of 2.88–2.93 g/cm3 and the average density of lower layer of the Earth’s crust is about 3.30 g/cm3; The depth of second-order faults, Red River and A Luoi - Rao Quan, is through the Earth’s crust. Meanwhile, the depth of influence of third-order faults, Chay river, Dong Ha - Phu Vang, Vinh Linh, Hue - Son Tra and Tam Ky - Phuoc Son, is within the thickness of the Earth’s crust.

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Analysis and monitoring modern Earth’s surface deformation velocity for local geodynamic polygons with scale effect

MINING INFORMATIONAL AND ANALYTICAL BULLETIN ◽

10.25018/0236-1493-2020-61-0-194-203 ◽

2020 ◽

pp. 194-203

Author(s):

A. I. Manevich

Keyword(s):

Scale Effect ◽

Surface Deformation ◽

Test Site ◽

Local Area ◽

Earth’S Crust ◽

Global Navigation Satellite Systems ◽

Tectonic Activity ◽

Deformation Analysis ◽

Deformation Velocity ◽

Earth's Crust

For assessing the geodynamic state of areas with different tectonic activity it is necessary to correctly ass the deformations of the Earth’s crust. One of the methods to study the destruction of the Earth’s crust is to make observations using global navigation satellite systems (GNSS). The use of GNSS to observe the current movements of the Earth’s crust makes it possible to collect the most reliable data at different scales (local or regional). The analysis of data on the Earth’s surface deformations allows obtaining fundamental knowledge about the geodynamic regime of the region or local area under study and assessing the engineering state of natural and technical systems. The purpose of this study is to develop and test a method for analyzing the deformation rates of the Earth’s surface, taking into account the scale effect on local geodynamic polygons. The tasks of the work included: creation of a catalogue of deformation velocity data; deformation analysis taking into account their spatial scalability; assessment of the prospects of application of the obtained results. The effect of deformation rates reduction and their derivatives with increasing distance between observation points was investigated. The paper presents the calculation procedure, obtained distributions and regression dependencies of strain rates. Based on the revealed generalized dependencies, it is possible to a priori evaluate the deformation regime on the geodynamic test site (either to specify the degree of tectonic activity or to predict abnormally possible deformations).

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Deep structure and metallogeny of the earth's crust

Exploration Geophysics ◽

10.1071/eg989037 ◽

1989 ◽

Vol 20 (2) ◽

pp. 37

Author(s):

V.A. Erkhow

Keyword(s):

Crustal Structure ◽

Upper Mantle ◽

Deep Structure ◽

Earth’S Crust ◽

Magnetic Data ◽

Crust And Upper Mantle ◽

Geophysical Field ◽

Deep Crust ◽

Deep Crustal Structure ◽

Earth's Crust

Considerable experience with integrated geological and geophysical studies has enabled definition of deep crustal structures and, within limits, composition and processes within the deep crust, and to determine their association with metallogeny in the USSR.By means of seismic experiments, stratification of the Earth's crust and the upper mantle to a depth of about 100 km has been revealed. Numerous heat flow data have been compiled. Magneto-telluric soundings made it possible to determine the position of conductive strata in the crust and upper mantle for a number of areas. Gravity surveys coupled with the results of seismic profiling enabled the finding of a number of empirical laws that are useful for investigation into the deep crust. Magnetic data analysis has enabled evaluation of the magnetic layering of the deep crust. Kimberlite and ore provinces can be considered examples of these concepts.For more detailed studies of deep crustal structure the territory of the USSR is the subject of a system of regional investigation of the deep crust and upper mantle. This system is based principally upon a network of interconnected regional profiles (geotraverses) tied to deep and superdeep boreholes. The system includes predicted geophysical observations to control investigation of the geophysical field data. The geotraverse network is the basis for detailed studies within the bounds of petroleum and ore provinces.The most accurate data obtained allows the formation of a crustal model and reveals empirical relationships with metallogeny.Based on the deep crustal structure data a regional oregenesis prediction map has been made. The endogenous mineralization prediction was based on special features of the upper layering of the crust and on data relating to deep crustal permeability zones.

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