Characteristics of short-period S-wave attenuation field in the lithosphere of Turkmenistan and North-Eastern Iran and their relation to seismicity
Yu.F. Kopnichev1, I.N. Sokolova2
1 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
2 Institute of Geophysical Research ME RK, Alma-Ata, Kazakhstan
Corresponding author: Yu.F. Kopnichev, e-mail: yufk@kndc.kz
Abstract. We have considered characteristics of short-period S-wave attenuation field in the lithosphere of Turkmenistan and north-eastern Iran. We used data obtained by Karatau station at distances up to 1750 km. Ratios of maximum amplitudes of Pn and Sn waves (parameter Sn/Pn) were analyzed. We have obtained correlation dependence of this parameter on distance. A comparison of the data obtained with data for the regions of Caucasus, Pamir and Baikal rift zone was carried out. Essentially lower attenuation corresponds to the region of West-Turkmen depression, intermediate one – to the region of Turan plate and higher one – to the region of Elburz range. It was shown that attenuation in the source zones diminishes essentially with time after large earthquakes. An area of higher attenuation was picked out at the eastern part of Elburz range, probably connected with large earthquake preparation. We discuss a connection of attenuation field heterogeneities with deep-seated fluids migration.
Keywords: lithosphere, attenuation, Sn wave, large earthquakes, deep-seated fluids
About the authors
KOPNICHEV Yuri Fedorovich – Doctor of Physical and Mathematical Sciences, Professor, Chief Researcher, Schmidt Institute of Physics of the Earth, Russian Academy of Sciences. Russia, 123242, Moscow, ul. Bolshaya Gruzinskaya 10, building 1. E-mail: yufk@kndc.kz
SOKOLOVA Inna Nikolayevna – Doctor of Physical and Mathematical Sciences, Senior Researcher, Institute of Geophysical Research, Ministry of Energy of Republic of Kazakhstan. Kazakhstan, 050020, Almaty, Chaikinoy ul., 4. E-mail: sokolova.inessa@mail.ru
Cite this article as: Kopnichev Yu.F., Sokolova I.N. Characteristics of short-period S-wave attenuation field in the lithosphere of Turkmenistan and North-Eastern Iran and their relation to seismicity, Seismicheskie Pribory, 2020, vol. 56, no. 1, pp. 56–66. (in Russian). https://doi.org/10.21455/si2020.1-5
English translation of the article will be published in Seismic Instruments, ISSN: 0747-9239 (Print) 1934-7871 (Online), https://link.springer.com/journal/11990).