STRESS-STRAIN STATE OF THE EARTHʼS CRUST IN THE CENTRAL CAUCASUS
K.S. Kazaryan1, V.Yu. Burmin2, R.S. Sargsyan1,3
1 Institute of Geophysics and Engineering Seismology named after academician A. Nazarov, National Academy of Sciences of the Republic of Armenia, Gyumri, Armenia
2 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
3 M. Nalbandian Shirak State University, Gyumri, Armenia
Corresponding author: V.Yu. Burmin, e-mail: burmin@ifz.ru
Abstract. The continental collision region of Eurasia and Arabia is one of the most seismically active and rapidly deforming continental regions of the Earth. The wide range of deformation processes occurring in this relatively limited region makes the Caucasus as a whole, and in particular its central parts, a unique place where we can improve our understanding of the complexities of the stress-strain state, as well as the seismicity associated with them. During the instrumental observation period, strong earthquakes were recorded here, such as Bezhtinskoe of 04.08.1974 (Mb = 5.4), 1978 earthquake with magnitude 5.7, Gavaz of 23.02.1981 (Mb = 5), Barisakho of 12.10.1992 (Mb = 6.1), Zagatala of 05.07.2012 (Mb = 5.7). We have constructed the mechanisms of strong earthquakes and compared the results with the tectonic situation of the studied region. Based on the morphostructural analysis of the modern relief of the central and eastern parts of the Greater Caucasus, the scheme of morphostructural blocks of the studied territory is compiled. The average earthquake mechanisms were constructed for highlighted blocks and the prevailing types of movements in the earthquake hypocenters in each selected block were identified. Fault kinematics was reconstructed. The solution of this problem was based on generally accepted tectonophysical theoretical views, with a wide application of modern structural-geomorphological methods, modern GIS technologies, and morphological analysis of the modern relief of the studied territory. Reconstruction of the modern tectonic stress field was carried out by the use of seismological data on recorded earthquakes, for the entire instrumental period of observations (1971–2019).
Keywords: earthquakes, focal mechanisms, neotectonics, modern tectonics, stress-strain state, block structure
About the authors
KAZARYAN Karlen Surenovich – Institute of Geophysics and Engineering Seismology named after academician A. Nazarov, National Academy of Sciences of the Republic of Armenia. Armenia, 3115, Gyumri, V. Sargsyan st., 5. E-mail: g.karlen90@bk.ru
BURMIN Valery Yurievich – Schmidt Institute of Physics of the Earth, Russian Academy of Sciences. Russia, 123242, Moscow, Bolshaya Gruzinskaya st., 10-1. E-mail: burmin@ifz.ru
SARGSYAN Rudolf Surenovich – Institute of Geophysics and Engineering Seismology named after academician A. Nazarov, National Academy of Sciences of the Republic of Armenia. Armenia, 3115, Gyumri, V. Sargsyan st., 5; M. Nalbandian Shirak State University. Armenia, 3126, Gyumri, P. Sevak st., 4. E-mail: rudolf-sargsyan@mail.ru
Cite this article as: Kazaryan K.S., Burmin V.Yu., Sargsyan R.S. Stress-strain state of the Earthʼs crust in the Central Caucasus, Voprosy Inzhenernoi Seismologii (Problems of Engineering Seismology). 2020. V. 47, No. 3. P. 126–138. [in Russian]. https://doi.org/10.21455/VIS2020.3-7
English translation of the article will be published in Seismic Instruments, ISSN: 0747-9239 (Print) 1934-7871 (Online), https://link.springer.com/journal/11990