Refinement of the deep structure and tectonic movements kinematics in the area of the Salsk earthquake 2001 based on new geophysical data

A.V. Gorbatikov1, I.P. Gabsatarova2, E.A. Rogozhin1,2, M.Yu. Stepanova1, Yu.V. Kharazova1, A.I. Sysolin1, V.A. Pogrebchenko1

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

2 Federal Research Center – Geophysical Survey of Russian Academy of Sciences, Obninsk, Russia

Corresponding author: M.Yu. Stepanova, e-mail: maris.terras@gmail.com

Abstract. The results of a comprehensive study of seismotectonic, geological, geophysical, geodynamic, and seismological data in the region of the Salsk earthquake on May 22, 2001, M = 4.7 in the low-seismic region of the junction of the Scythian plate and the East European platform are presented. The earthquake source, described with parameters obtained from seismological and macroseismic data, is associated with a deep tectonic structure estimated using the method of microseismic sounding (MMS). The section of the MMS through the region of the Salsk earthquake was obtained along a near-meridional profile about 65 km long across the strike of the Manych deflection zone. It was established that the hypocenter of the 2001 Salsk earthquake is confined to the fault zone included in the Manych faults system, which is expressed in a section in the form of a narrow subvertical strip with reduced seismic velocities traced from the Earth’s surface to a depth of more than 40 km. Directly in the area of an earthquake below a depth of 10 km, the designated fault zone has a local expansion at the point of transition through the plane of sedimentary cover contact with the Proterozoic basement. The assessment of the hypocenter position and the focal mechanism solution (the gentle thrust of the northern side at an angle of 25–33 degrees) correlates well here with the depth and inclination of the surface of the Proterozoic basement, whose elements are also traced in the section of the MMS.

Keywords: hypocentre deep structure, microseismic sounding method, earthquake mechanism solution, Manych deflection

About the authors

GORBATIKOV Andrey Veniaminovich − Candidate of Physical and Mathematical Sciences, Leading Researcher, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1. e-mail: avgor70@mail.ru

GABSATAROVA Irina Petrovna − Candidate of Physical and Mathematical Sciences, Leading Researcher, Federal Research Center – Geophysical Survey of Russian Academy of Sciences. Lenina av. 189, Obninsk, Kaluga region, Russia, 249035. e-mail: ira@gsras.ru

ROGOZHIN Evgeny Aleksandrovich − Professor, Doctor of Geological and Mineralogical Sciences, Chief Researcher, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1; Federal Research Center – Geophysical Survey of Russian Academy of Sciences. Lenina av. 189, Obninsk, Kaluga region, Russia, 249035. e-mail: eurog@ifz.ru

STEPANOVA Marina Yuryevna − Candidate of Physical and Mathematical Sciences, Senior Researcher, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1. e-mail: maris.terras@gmail.com

KHARAZOVA Yulia Vyacheslavovna − Research Fellow, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1. e-mail: uh69@mail.ru

SYSOLIN Alexander Ivanovich − Research Fellow, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1. e-mail: alexandr.sysolin@gmail.com

POGREBCHENKO Vladimir Aleksandrovich − Senior Researcher, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1. e-mail: pogr@ifz.ru

Cite this article as: Gorbatikov A.V., Gabsatarova I.P., Rogozhin E.A., Stepanova M.Yu., Kharazova Yu.V., Sysolin A.I., Pogrebchenko V.A. Refinement of the deep structure and tectonic movements kinematics in the area of the Salsk earthquake 2001 based on new geophysical data, Voprosy Inzhenernoi Seismologii (Problems of Engineering Seismology). 2019. V. 46, No. 2. P. 5–15. [in Russian]. https://doi.org/10.21455/VIS2019.2-1

English translation of the article will be published in Seismic Instruments, ISSN: 0747-9239 (Print) 1934-7871 (Online), https://link.springer.com/journal/11990