COMPARISON OF SEISMICITY AND AVERAGE FOCAL MECHANISMS OF JAVAKHETI HIGHLAND EARTHQUAKES WITH REGIONAL GRAVITATIONAL FIELD ANOMALIES

* e-mail: burmin@ifz.ru

¹Institute of Geophysics and Engineering Seismology named after academician A. Nazarov, National Academy of Sciences of the Republic of Armenia, Gyumri, Armenia

²Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia

Abstract. The article provides a comparative analysis of the anomalies in the values of the regional gravity field with the spatial distribution of the earthquake epicenters in the Javakheti Highland. It is shown that the epicenters of earthquakes with magnitudes M ≥ 4 are confined to the gradient zones, where significant relative minima and maxima of the anomalies of the gravitational field in the Bouguer reduction are observed. The average mechanisms of earthquakes in individual seismogenic blocks of the region were obtained for the observation period from 1971 to 2015, which indicate that normal faulting is the dominant type of movements in the earthquake foci. The result is explained by the processes occurring in the subcrustal layer and leading to decompaction of matter in the uplift zones, which is one of the main factors in the occurrence of negative gravity anomalies in the area under consideration.

Keywords: seismicity, earthquakes, block structure, gravitational field, Bouguer reduction.

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

AVETISYAN Andrei Mergevosovich – 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: avet.andrey@mail.ru

Cite this article as: Kazaryan K.S., Burmin V.Yu., Avetisyan A.M. Comparison of seismicity and average focal mechanisms of Javakheti Highland earthquakes with regional gravitational field anomalies, Geofizicheskie Protsessy i Biosfera (Geophysical Processes and Biosphere), 2020, vol. 19, no. 4, pp. 117–126 (in Russian). https://doi.org/10.21455/gpb2020.4-8

English version: Izvestiya, Atmospheric and Oceanic Physics, 2020, vol. 56, iss. 11. ISSN: 0001-4338 (Print), 1555-628X (Online). https://link.springer.com/journal/volumesAndIssues/11485