The stress state of the northern Tien Shan crust based on the KNET seismic network data
| Autor: | N. A. Sycheva, A. V. Marinin, S. I. Kuzikov, Yu. L. Rebetsky, V. N. Sychev |
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| Rok vydání: | 2016 |
| Předmět: |
Focal mechanism
010504 meteorology & atmospheric sciences Cauchy stress tensor Geology Crust Cataclastic rock Slip (materials science) 010502 geochemistry & geophysics Overburden pressure 01 natural sciences Geophysics Sinistral and dextral Brittleness Seismology 0105 earth and related environmental sciences |
| Zdroj: | Russian Geology and Geophysics. 57:387-408 |
| ISSN: | 1068-7971 |
| DOI: | 10.1016/j.rgg.2016.03.003 |
| Popis: | In this study we present a detailed analysis of natural stresses in the Northern Tien Shan crust averaged in a window of 10–15 km obtained from seismological data of the local KNET network. The transformation of focal mechanism data into the parameters of the stress tensor was based on the method of cataclastic analysis of rupture displacement elaborated by Yu.L. Rebetsky (Institute of Physic of the Earth, Moscow). The results, including the orientation of the principal stress axes and the reduced stresses, are presented for four depth layers. It was shown that the central part of the study area is dominated by horizontal compression, while multiple domains characterized by horizontal shear and superimposed compression or pure horizontal shear are also present (uppermost layers in the eastern part of the Chuya depression, Suusamyr depression and adjoining regions, in the central part of the Kyrgyz Range). There are also several large domains of high and low effective confining pressure, which defines the corresponding deviator stress, according to the Coulomb–Mohr law. It was shown that relatively strong earthquakes are correlated with zones with low levels of effective pressure where the ruptures are characterized by lower resistance to brittle fracturing, i.e., Coulomb friction stresses. It was also shown that a distinct segment of the ~ 60 km E–W striking fault on the northern slope of the Kyrgyz Range generates a uniform distribution of stresses, corresponding to a dextral slip along of its edges. |
| Databáze: | OpenAIRE |
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