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A correlation method for eliminating topographic effect in the VLF-method

July 1984

Authors:

Lev V. Eppelbaum

Tel Aviv University

A correlation method is proposed to unmask VLF anomalies observed in the Lesser and Greater Caucasus ore deposits under mountainous conditions (uneven topography and complex geological media). The developed methodology demonstrates its effectiveness in several field examples.

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Methodological Specificities of Geophysical Studies in the Complex Environments of the Caucasus

Chapter

Apr 2012

Geophysical studies of the Caucasus need to cope with the mountainous environments of many of its regions and their inclined (oblique) magnetization in temperate latitudes. The uneven topography impedes geophysical surveys in mountainous areas due to poor accessibility and distorts the measurement results.

Regional Physical-Geological Models and Regioning

Chapter

Apr 2012

The initial development of a medium model is the most crucial stage since the results of interpretation and the investigation, in general, depend considerably upon its quality. A preliminary model is devised to represent the geological objective when preparing a geophysical project for the given area. Otherwise, it is impossible to select the set of methods and interpretation procedures. The latter is revised before interpreting, if necessary.

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Article

Full-text available

РАЗМЕР ПРОБНОЙ ПЛОЩАДИ ДЛЯ ВЫЯВЛЕНИЯ ТРАВЯНО-КУСТАРНИЧКОВОГО ЯРУСА В ТЕМНОХВОЙНЫХ ЛЕСАХ СЕВЕРО-ЗАПАД...

April 2016

Принято считать, что размер пробной площади при описании лесных сообществ должен составлять не менее 0,2 га. Однако, пробная площадь должна быть однородной, что при ее больших размерах в условиях горного рельефа почти невозможно. Мы поставили цель определить размер пробной площади, при котором а) выявляется большинство видов травяно-кустарничкового яруса и б) учетная площадка вписана в однородный ... [Show full abstract] контур. В пихтовых лесах Кавказа провели подсчет количества видов на сериях площадок размером от 25 см2 до 900 м2 в 14 повторностях. В 9 сериях площадка становилась неоднородной начиная с площади 400 м2, и приближаясь к этому же значению прирост числа видов уменьшается, и кривая выявления начинает выходить на плато. Поэтому оптимальным для выявления флористического состава сообщества в темнохвойных лесах Кавказа можно считать размер пробной площади в 400 м2.

Article

Variation in crustal structure in Iran and the surrounding region

December 2007

We present a model for the topography of the Moho discontinuity for Iran and its surrounding regions. This is produced using data from field deployments within Iran by the University of Cambridge (UK) and the Universite Joseph-Fourier (FRA) in conjunction with International Institute of Earthquake Engineering and Seismology (Iran), in addition to data from IRIS and Geofone. We determine ... [Show full abstract] tomographic group velocity maps for periods between 10 and 60 s from multiple filter analysis of ~5500 seismograms. Because of the dense path coverage, these images have substantially higher lateral resolution for this region than is currently available from global and regional group velocity studies. Joint inversion of receiver functions and Rayleigh wave dispersion give accurate crustal velocity structures at 96 sites within Iran These provide a constraint for the less sharp crustal velocity profile produced by inverting the Rayleigh wave dispersion curve across all of Iran. We observe variations in the crustal thickness across the region, consistent with the surface topography. The thickest crust (55-60 km) is found beneath the central Zagros mountains, with the crust in the remainder of Iran having a thicknesses of 40-50 km. No significant increase in Moho depth is seen beneath the Alborz or Kopet Dagh mountains. The structure of the South Caspian Basin is presented with a different structure to that found in previous studies, with a crustal thickness of 50 km in the west, and beneath the Caucasus and Talesh mountains, in the middle part of the basin, over the course of the ~100km, this decreases to 40km, and continues to 35 km beneath the Turkmen Platform. Comparisons are also made between the joint inversion results, and accurate hypocentre depths for regional earthquakes. This shows most events occur in the upper crystalline crust (~10-20km depth), with few in the lowest velocity layer. Almost no events are located in the lower crust, and only in the Makran and Aspheron- Balkhan Sill do earthquakes appear in the Upper Mantle.

Conference Paper

Effects of Wedge Disruption and South Caspian Subsidence on the Dynamic Stability of the Greater Cau...

December 2011

The west-northwest trending Greater Caucasus Mountains form the northern margin of the Arabia-Eurasia collision between 40° and 50°E and appear to represent the main locus of shortening since the early Pliocene in this central part of the collision. Compared to similar mountain ranges, few detailed cross sections exist that extend across the whole range, but previous work suggests the first order ... [Show full abstract] structure of the Greater Caucasus comprises a bivergent wedge, with the southern and northern margins of the Greater Caucasus as pro- and retro-wedges respectively. However, it is apparent that the plan-view morphology, topography, and drainage networks of the Greater Caucasus do not neatly conform to many of the characteristics of an idealized bivergent wedge. We hypothesize that the along-strike deviations from such idealized geometries are the result of disruption of the Greater Caucasus wedge by collision with the Lesser Caucasus to the south, combined with efficient removal of material from the southeastern margin of Greater Caucasus and transport to the Kura and South Caspian basins, the latter of which contains ~10 km of post-Pliocene deposits. We further suggest that the simplest explanation for the current morphologic and topographic state of the Greater Caucasus is a transient response to these factors, indicating the range is not currently in steady state. In detail, the Greater Caucasus are underthrust from the south by a microplate in the Lesser Caucasus, producing dominantly south directed thrusts throughout the range and also, most recently, within the Kura fold-thrust belt along the SE margin of the orogen in Georgia and Azerbaijan, similar to the structural geometries expected in an ideal pro-wedge. The NE margin of the range also has well-developed north-directed thrust systems consistent with a retro-wedge. Yet, one of the hallmarks of bivergent wedges, a pronounced asymmetry between a wide pro- and narrow retro-wedge, is not observed in the Greater Caucasus. There is no dominant asymmetry consistent along-strike, but rather two distinct domains: a western one, in which the range is nearly symmetric, and an eastern one, where the pro- (southern) side is narrower than the north retro- side. The boundary between these domains is marked by the intersection of the Greater and Lesser Caucasus on the pro-side and a reentrant on the retro-side. The two domains also exhibit significant differences in various characteristics, including depth of exposure, position of the drainage divide relative to maximum topography, and presence or absence of flanking fold-thrust belts. We suggest that entrance of Lesser Caucasus material into the central and SW Greater Caucasus pro-wedge shifted the locus of deformation eastward, consistent with published GPS data indicating eastward-increasing rates of shortening within the eastern domain. Within the eastern pro-wedge we observe topographic, structural, and stratigraphic evidence of efficient removal of material from the wedge coeval with eastern propagation. We suggest that the rapid subsidence of the South Caspian basin provided accommodation space that enabled efficient removal of material from the SE pro-wedge and that the Greater Caucasus have not yet reached a steady state balance between these two competing factors.

Article

The cossacks' military and economic daily life on the caucasus frontier as described by g. kalmberg,...

January 2014

T.A. Kolosovskaya

The article apparently for the first time in the Russian historiographical tradition attempts to analyse the rare primary source: a military statistical description of the Left flank of the Caucasus Defence Line. It was made by the officer of the Russian General Staff G.K. Kalmberg in 1834. Being virtually unknown for historians, his manuscript is kept in the State Archive of Stavropol Krai. The ... [Show full abstract] article specifies the conditions under which the primary source appeared and focuses on analysing its core points. In 1834 Kalmberg inspected the Cossacks' fortified forts and villages (stanitsas), located on the Tereck's banks. The information he collected was requested by the Separate Caucasus Military Corps' commanding staff, in order to strengthen the defence system of the Left flank of the Caucasus Line during the Caucasian War (1817-1864). Finally, the author concludes that the Kalmberg's manuscript reconstructs the authentic scene of both military and economic daily life of the Cossackinhabitants of the frontier area. It enables to realize the precise picture of extremely hard conditions, under which the Cossacks had to assert their right to live in the new borderland of the Russian Empire.