SEISMIC BELTS AND ZONES OF THE EARTH: FORMALIZATION OF NOTIONS, POSITIONS IN THE LITHOSPHERE, AND STRUCTURAL CONTROL

• Published in: Geodynamics & Tectonophysics
• Main Authors: Semen I. Sherman, Olga G. Zlogodukhova, Семен Иойнович Шерман, Ольга Геннадьевна Злогодухова
• Other Authors: Госконтракты 2.740.11.0446 и 14.740.11.0411, СО РАН, Президиум РАН, ОНЗ РАН, А.Д. Завьялов, В.И. Мельникова
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Institute of the Earth's crust of the Russian Academy of Sciences, Siberian Branch 2015
• Subjects: литосфера; seismic belt; seismicity; earthquake; fault; lithosphere; сейсмический пояс; сейсмичность; землетрясение; разлом; Arctic
• Online Access: https://www.gt-crust.ru/jour/article/view/121; https://doi.org/10.5800/GT-2011-2-1-0031

This publication is aimed at formalization of the notions of «seismic zone» and «seismic belt». A seismic zone (SZ) is a territory defined and contoured in a technically active area. Within the limits of this territory, more than 10 seismic event with М>3 (К>9) occurred in the specified period of time (typically, 50 years), or the number of seismic event is not below a certain statistically relevant value. The external contour of SZ should be drawn according to the isolines of the corresponding density of registered earthquakes with М≥3, pending no less than three events within the given square area. In each case, selection of contours of SZ should be determined so that it can provide for classification of SZs. SZ should correspond to one or several tectonic structures. The interior structure of SZ can be zoned according to densities of earthquake epicentres.A seismic belt (SB) is a structure with a uniform geodynamic regime, wherein seismic zones are closely spaced. Typically, such structures are margins of plates or large intra­plate blocks. In real time, SB is generally characterized by a permanent state of lithospheric stresses. Stress vectors in local segments of SB may differ from the dominant type of stresses. They can be variable due to changes in strike of local and regional faults which control seismicity and also due to various directions of zones of the recent lithospheric destruction.The Earth’s SBs and SZs are mapped. SBs and a number of most important SZs are briefly described. Main parameters of SBs and SZs are tabulated. Based on the available data on SBs and SZs and taking into account the common geodynamical settings and elongated localities of earthquake foci, we suggest that it is required to evaluate structural factors controlling the seismic process and its components (locations of earthquake foci) at all the hierarchic levels, i.e. seismic belts, seismic zones, fault zones wherein stresses are concentrated, and structures wherein earthquake foci are located. Due to differences in ...