TECTONOPHYSICAL INTERPRETATION OF EARTHQUAKE FOCAL MECHANISMS OF THE ZAGROS SYSTEM
Structural-paragenetic and kinematic methods of tectonophysics are applied to study earthquake focal mechanisms of the Zagros system. Nodal planes of focal mechanisms are identified as L-, L′- and R-, R′-shears by the first method, whereby coordinates of principal stress axes P, T and N (i.e. in tec...
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Institute of the Earth's crust, Siberian Branch of RAS
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doaj-c7a15088d0bb4c22ac06ab340b717d782021-07-29T08:39:49ZengInstitute of the Earth's crust, Siberian Branch of RASGeodinamika i Tektonofizika2078-502X2015-09-015130531910.5800/GT-2014-5-1-012990TECTONOPHYSICAL INTERPRETATION OF EARTHQUAKE FOCAL MECHANISMS OF THE ZAGROS SYSTEMO. B. Gintov0E. Ya. Kolesnikova1A. V. Murovskaya2Y. M. Volfman3S.I. Subbotin Institute of Geophysics, National Academy of Sciences of UkraineИнститут геофизики им. С.И. Субботина НАН УкраиныS.I. Subbotin Institute of Geophysics, National Academy of Sciences of UkraineS.I. Subbotin Institute of Geophysics, National Academy of Sciences of UkraineStructural-paragenetic and kinematic methods of tectonophysics are applied to study earthquake focal mechanisms of the Zagros system. Nodal planes of focal mechanisms are identified as L-, L′- and R-, R′-shears by the first method, whereby coordinates of principal stress axes P, T and N (i.e. in tectonophysics, σ1, σ3 and σ2, if σ1 ≥ σ2 ≥ σ3) are defined. ‘Working’ nodal planes corresponding to activated ruptures are revealed. Axes of the main normal stresses are combined into local groups on the basis of the kinematic identity of planes of seismogenic ruptures (Figure 2). The second method is applied to construct stereograms of the main axes P, T and N, to construct and interpret stereograms of vectors of seismogenic shifts (Figure 3), and to more clearly define coordinates of principal axes σ1, σ3 и σ2. As evidenced by their comparison, coordinates of the principal axes obtained by the two tectonophysical methods are well coincident (see Figure 2). Five groups of seismogenesis are distinguished; they differ in combination of deformation regimes and kinematic conditions. Locations are determined of the areas wherein earthquake foci of similar parameters are located. This means that seismogenic zones are distinguished; structural and kinematic characteristics of such zones are determined by parameters of stereographic models of corresponding types of seismogenesis (Figures 4 and 5). It is established that the region is dominated by shear and upthrust deformation regimes due to regional submeridional compression and SW-NE compression (see Figures 4 and 5). Submeridional subhorizontal compression is explained by the northward movement of the Arabian plate, and SW-NE compression is explained by divergent processes within the limits of the Red Sea rift. The time pattern of the seismogenic processes from 1979 to 2001 shows that submeridional compression and SW-NE compression are associated with different deep mechanisms. Processes of SE-NW compression, which are observed in the northern part of the Arabian plate, are caused by its interaction with the Eastern Black Sea microplate.https://www.gt-crust.ru/jour/article/view/91earthquake focal mechanismsdeformation regimeseismogenic zonetectonophysical method of structural paragenesiseskinematic methodstress axis |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
O. B. Gintov E. Ya. Kolesnikova A. V. Murovskaya Y. M. Volfman |
spellingShingle |
O. B. Gintov E. Ya. Kolesnikova A. V. Murovskaya Y. M. Volfman TECTONOPHYSICAL INTERPRETATION OF EARTHQUAKE FOCAL MECHANISMS OF THE ZAGROS SYSTEM Geodinamika i Tektonofizika earthquake focal mechanisms deformation regime seismogenic zone tectonophysical method of structural paragenesises kinematic method stress axis |
author_facet |
O. B. Gintov E. Ya. Kolesnikova A. V. Murovskaya Y. M. Volfman |
author_sort |
O. B. Gintov |
title |
TECTONOPHYSICAL INTERPRETATION OF EARTHQUAKE FOCAL MECHANISMS OF THE ZAGROS SYSTEM |
title_short |
TECTONOPHYSICAL INTERPRETATION OF EARTHQUAKE FOCAL MECHANISMS OF THE ZAGROS SYSTEM |
title_full |
TECTONOPHYSICAL INTERPRETATION OF EARTHQUAKE FOCAL MECHANISMS OF THE ZAGROS SYSTEM |
title_fullStr |
TECTONOPHYSICAL INTERPRETATION OF EARTHQUAKE FOCAL MECHANISMS OF THE ZAGROS SYSTEM |
title_full_unstemmed |
TECTONOPHYSICAL INTERPRETATION OF EARTHQUAKE FOCAL MECHANISMS OF THE ZAGROS SYSTEM |
title_sort |
tectonophysical interpretation of earthquake focal mechanisms of the zagros system |
publisher |
Institute of the Earth's crust, Siberian Branch of RAS |
series |
Geodinamika i Tektonofizika |
issn |
2078-502X |
publishDate |
2015-09-01 |
description |
Structural-paragenetic and kinematic methods of tectonophysics are applied to study earthquake focal mechanisms of the Zagros system. Nodal planes of focal mechanisms are identified as L-, L′- and R-, R′-shears by the first method, whereby coordinates of principal stress axes P, T and N (i.e. in tectonophysics, σ1, σ3 and σ2, if σ1 ≥ σ2 ≥ σ3) are defined. ‘Working’ nodal planes corresponding to activated ruptures are revealed. Axes of the main normal stresses are combined into local groups on the basis of the kinematic identity of planes of seismogenic ruptures (Figure 2). The second method is applied to construct stereograms of the main axes P, T and N, to construct and interpret stereograms of vectors of seismogenic shifts (Figure 3), and to more clearly define coordinates of principal axes σ1, σ3 и σ2. As evidenced by their comparison, coordinates of the principal axes obtained by the two tectonophysical methods are well coincident (see Figure 2). Five groups of seismogenesis are distinguished; they differ in combination of deformation regimes and kinematic conditions. Locations are determined of the areas wherein earthquake foci of similar parameters are located. This means that seismogenic zones are distinguished; structural and kinematic characteristics of such zones are determined by parameters of stereographic models of corresponding types of seismogenesis (Figures 4 and 5). It is established that the region is dominated by shear and upthrust deformation regimes due to regional submeridional compression and SW-NE compression (see Figures 4 and 5). Submeridional subhorizontal compression is explained by the northward movement of the Arabian plate, and SW-NE compression is explained by divergent processes within the limits of the Red Sea rift. The time pattern of the seismogenic processes from 1979 to 2001 shows that submeridional compression and SW-NE compression are associated with different deep mechanisms. Processes of SE-NW compression, which are observed in the northern part of the Arabian plate, are caused by its interaction with the Eastern Black Sea microplate. |
topic |
earthquake focal mechanisms deformation regime seismogenic zone tectonophysical method of structural paragenesises kinematic method stress axis |
url |
https://www.gt-crust.ru/jour/article/view/91 |
work_keys_str_mv |
AT obgintov tectonophysicalinterpretationofearthquakefocalmechanismsofthezagrossystem AT eyakolesnikova tectonophysicalinterpretationofearthquakefocalmechanismsofthezagrossystem AT avmurovskaya tectonophysicalinterpretationofearthquakefocalmechanismsofthezagrossystem AT ymvolfman tectonophysicalinterpretationofearthquakefocalmechanismsofthezagrossystem |
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