The head of the scientific research group — Professor V.I. Starostenko
The Division of Deep Earth's processed and Gravimetry of the Institute of Geophysics NAS of the Ukraine includes a scientific research group whose members are:
The domains of the group's interests:
- The purpose of the group is to set up modern powerful and flexible software of solving direct and inverse gravity problems and their use.
- Interpreting the gravity field in a 3-D version to study the Earth's crust and mantle structure of different regions by using the software complexes that are worked out.
The computer basis of the researches is an automated complex of solving direct and inverse gravity problems for inhomogeneous 3-D layered media that has been worked out by V.I.Starostenko and O.V.Legostaeva
1,2,3.
The system consists of the blocks of:
an automated input of images of
geophysical maps to a computer by a scanner and setting up their digital models whose values serve as
initial data for solving a direct or inverse gravity problems;
solving a direct and inverse gravity problems for three-dimensional inhomogeneous layers approximated by a totality of vertical prisms with the arbitrarily placed upper and lower base and an inhomogeneous density which assumes its given values at the prism apices, changes according to the linear law along the horizontal coordinates at the upper and the lower
bases and linearly or exponentially along any vertical line;
presentation of the results of the calculation in graphical form.
The system is oriented at the use in the exploration and regional geophysics as the
solutions of direct or inverse gravity problems are given in a rectangular and a spherical system of coordinates.
The system is written in an algorithmic language C and operates in the operational system MS Windows.
It has a modern user's interface, is easy and suitable for use. The system is widely used in solving
practical problems associated with studies of different geological structures by using gravity data.
This computer complex enables us to solve a direct or inverse gravity
problems within an arbitrarily dense network from media with a complicated relief of the discontinuities
and an arbitrary density distribution in each layer. It is especially effective in studying sedimentary basins.
The methodical basis is the method of comparing the obtained gravity effects of Earth's crust of the study structures and the crustal effect of the "normal" (non-activized) Precambrian platforms. The latter has been obtained by summarizing data of density modeling of the Earth's crustusing the results of print and profile DSSs made on platforms of different continents and is – 870 mGal with the observed zero field in the Bouger reduction. For the "normal" mantle the density distribution from 3.32 g/cm3 under the M-discontinuity to 3.55 g/cm3 at the upper mantle base at » 500 km depth is assumed. The calculated density is taken as the difference between the real density and the upper mantle density under the M-discontinuity (3.32 g/cm3), i.e. it is negative values.
This method enables us:
- to compare the obtained density models of the Earth's crust;
- to separate the mantle component of the gravity field which is one of the characteristics of the type of tectonic process and its intensity (stage). In the tectonically active regions the upper mantle is generally less dense than in the non-activized Precambrian platforms especially because of high temperature of the occurring tectonic process. Therefore the separated gravity effect of the mantle is always negative 4.
The spheres of the group's interests:
- Continental crust— The Western East — European Platform (including the TTZ) and similar regions of other continents.
- Subcontinental and suboceanic crust — inner seas (Black Sea, Mediterranean Sea a. o.).
- Oceanic crust — Red Sea.
At present, we perform a 3-D modeling of the Earth's crust of:
- The East Mediterranean region
- Volyn' monocline
The results of the studies were presented at the XXIII General Assembly (20-24 April 1998, Nice, France), 9th Tectonic geomorphology and sedimentary basin dynamics (September, 1998, Oliana, Spain), Seventh EUROBRIDGE Workshop (May 26-30 1999, Szelment near Suwalki, Poland), Second Balkan Geophysical Congress and Exhibition (July 5-9, 1999, Istanbul, Turkey), Joint Meeting of EUROPROBE TESZ, PANCARDI AND GEORIFT PROJECTS (25 September - 6 October 1999, Tulcea, Romania).
Abstracts in proceedings of a conference
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