The current state of crustal stresses in the Caucasus according to the unified catalogue of earthquake focal mechanisms

The current state of crustal stresses in the Caucasus and adjacent territories has been reconstructed. Stress inversion was performed by the cataclastic analysis of earthquake focal mechanisms considered as seismological strain indicators. The data were taken from the unified catalogue of focal mechanisms of the Northern Eurasia, which was consolidated by the Laboratory of Tectonophysics of IPE RAS in the early 1990s. It contains the information from many seismological data sources of various authors who worked both in the USSR and abroad. Seismological data for the last years after the collapse of the USSR were taken from Global CMT catalogue. The study area has been quite densely covered by reconstructions of the principal stress axes. At the same time, the area of stress averaging has been considerably reduced by the iterative use of a window for stress averaging, which was gradually expanded for zones with reduced densities of earthquake epicenters. The revealed regularities of the current stress field based on the unified catalogue of focal mechanisms collected by different authors correlate with the reconstructions performed according to the Global CMT catalogue. The cataclastic analysis of displacements along fractures allowed estimating the stress magnitudes, and the crust of the study area was zoned with respect to the intensity of normalized values of the lowest and highest stresses of horizontal compression, as well as to the normalized values of shear stresses acting on the crustal basement. In all cases, the values were normalized to the rock strength. The stress parameters are presented in “Tectonic Stresses of Eurasia”. This new Internet resource created by the Laboratory of Tectonophysics on the IPE RAS website shows the stress data in different scales and levels of details.

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Modern state of crustal stresses of the Apennine Peninsula and adjacent territories (Central Mediterranean region)

Geodynamics & Tectonophysics ◽

10.5800/gt-2019-10-4-0449 ◽

2019 ◽

Vol 10 (4) ◽

pp. 921-935

Author(s):

P. A. Savvichev ◽

Yu. L. Rebetsky

Keyword(s):

Mediterranean Region ◽

Focal Mechanisms ◽

Geodynamic Setting ◽

Published Data ◽

Shear Stresses ◽

Principal Stresses ◽

Central Mediterranean ◽

Crustal Stresses ◽

Earthquake Focal Mechanisms ◽

Relative Stress

This paper discusses models showing the formation of the Central Mediterranean region and the geodynamic setting of the Apennine Peninsula. Cataclastic analysis is used for a repeated reconstruction of the Central Mediterranean region. The catalogue of earthquake focal mechanisms includes 662 events (3.6≤Mb≤6.5) recorded in the study area from 1977 to 2015 (Global CMT, http://www.globalcmt.org; RCMT, http://rcmt2.bo.ingv.it/index.html; Italian CMT dataset, http://rcmt2.bo.ingv.it/Italydataset.html). The reconstruction yielded the directions of principal stresses (including algebraically maximum and minimum ones), locations of domains differing in geodynamic regime, Lode – Nadai coefficients, and orientation of tangential shear stresses acting from the mantle to the crust. By comparing our results to the published data obtained by M.‐L. Zoback’s method, we have identified differences in the orientations of maximum horizontal compression axes at points where the stress ellipsoid takes on its critical values. It is revealed that the strongest earthquakes (M>6) were generated in the areas characterized by the minimum and average relative stress magnitudes.

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Geobotanical studies at the Caucasus: a review of materials of the International Conference “Flora and conservation in the Caucasus: history and current state of knowledge” (Pyatigorsk, May 22–25, 2019)

Vegetation of Russia ◽

10.31111/vegrus/2019.36.91 ◽

2019 ◽

pp. 91-94

Author(s):

T. M. Lysenko ◽

V. Yu. Neshatayeva ◽

Z. V. Dutova

Keyword(s):

Plant Communities ◽

Aquatic Vegetation ◽

Plant Cover ◽

Floristic Composition ◽

Current Status ◽

Wide Field ◽

The Caucasus ◽

International Conference ◽

Rare And Endangered Species ◽

Current State

The International conference “Flora and conservation in the Caucasus: history and current state of knowledge” dedicated to the 130-year anniversary of the Perkalsky Arboretum took place at 22–25 of May 2019 in Pyatigorsk (Stavropol Territory) on the base of the Pyatigorsk Museum of local lore and natural history. The participants were from 11 cities of Russia and 7 Republics of the Caucasus and represented 14 institutions. Proceedings of the conference were published by the beginning of the meeting the book of abstracts includes 49 papers on the study of vascular plants, bryophytes, lichens and fungi, plant communities, as well as the protection of rare and endangered species, unique plant communities, and ecological problems in the Caucasus. The following geobotanical topics were highlighted in 13 papers: forest communities (3 reports), meadow and steppe vegetation (2), xeric open forests (2), communities of ecotone areas (1), structure of populations of rare plant species (3), as well as the history and current status of nature protected areas (2). The great emphasis has been focused on the study of floristic composition and plant populations. Thus, the conference showed that very few studies от vegetation are currently carried out in the Caucasus, and a lot of districts are not affected by the research. The greatest attention is paid to forest vegetation while meadow, steppe, alpine heath and xerophytic communities are studied rather poorly. Besides, there are “white spots” — mire, floodplain and aquatic vegetation. In nowadays, when the anthropogenic impact on the plant cover of the Caucasus is intensively increasing, it is especially important to study natural undisturbed communities preserved in protected natural areas. Another important issue is the conservation of the unique vegetation cover of the whole Caucasus. Thus, the study of vegetation of this region opens a wide field for researchers using various methods of modern plant science.

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