Earthquake focal mechanisms, deformation state, and seismotectonics of the Pamir-Tien Shan region, Central Asia

1995 ◽  
Vol 100 (B10) ◽  
pp. 20321-20343 ◽  
Author(s):  
Albert A. Lukk ◽  
Sergei L. Yunga ◽  
Vladimir I. Shevchenko ◽  
Michael W. Hamburger
Keyword(s):  
Central Asia ◽  
Focal Mechanisms ◽  
Tien Shan ◽  
Earthquake Focal Mechanisms ◽  
Deformation State

scholarly journals Submeridional boundary zone in Asia: seismicity, lithosphere structure, and the distribution of convective flows in the upper mantle

2018 ◽  
Vol 9 (3) ◽  
pp. 1007-1023 ◽  
Author(s):  
N. A. Bushenkova ◽  
O. A. Kuchay ◽  
V. V. Chervov
Keyword(s):  
Central Asia ◽  
Upper Mantle ◽  
Convective Flow ◽  
Focal Mechanisms ◽  
Boundary Zone ◽  
Earthquake Focal Mechanisms ◽  
Principal Axes ◽  
Geodynamic Processes ◽  
Lithosphere Thickness ◽  
Velocity Anomalies

The study is focused on the submeridional transregional boundary that stretches as a wide band along 105°E in Central Asia. In modern seismic models, it is traceable to a depth of ~600 km. In the continental area to the west of this boundary, seismic activity is increased. Following the study of the origin of the transregional boundary zone, it becomes possible to assess its contribution to the current geodynamic processes in Asia. This article presents a comprehensive analysis based on comparison of the available data with the results obtained in our study using independent methods. The distribution of earthquakes was analyzed by depth. We revealed a correlation between the characteristics of seismotectonic deformation (STD) reconstructed from earthquake focal mechanisms, the structure of P-velocity anomalies, and the distribution of convection flows in the upper mantle. The pattern of seismic velocity anomalies in the upper mantle was investigated on the basis of the data from the ISC catalogue for the period of 1964–2011. The modeling was carried out for two regional tomographic schemes, using the first arrivals of P-waves from [Koulakov et al., 2002 and PP-phases from [Bushenkova et al., 2002, with the subsequent summation with weight coefficients depending on the distribution of the input data in each scheme. A similar approach was applied in [Koulakov, Bushenkova, 2010 for the territory of Siberia; however, that model only partially covered the submeridional transregional boundary zone and was based on fewer ISC data (until 2001). The parameters of the combined model were used to estimate variations in the lithosphere thickness, which can significantly influence the structure of convection flows in the upper mantle [Chervov et al., 2014; Bushenkova et al., 2014, 2016. The thickness variations were taken into account when setting boundary conditions in the numerical modeling of thermal convection, which followed the algorithm described in [Chervov, Chernykh, 2014. The STD field was reconstructed from the earthquake focal mechanisms (M≥4.6) which occurred in Central Asia in 1976–2017. The analysis shows that the zone, wherein the seismic regime changes, correlates with the band wherein the STD principal axes are turning, the submeridional high/low velocity elongated boundary in the seismotomographic model, as well as with the submeridionally elongated descending convective flow in the upper mantle. Shortening of the STD principal axes is observed in the submeridional direction in the western part and in the sublatitudinal direction in the eastern part of the study area. The directions of the principal axes turn in the 93–105°E zone. It is thus probable that the submeridionally elongated descending convective flow in the upper mantle of this region, which results from the superposition of the lithosphere thickness heterogeneities, is a barrier to propagation of seismically manifested active geodynamic processes caused by lithospheric plates collision.

Present-day tectonic stress regime in Egypt and surrounding area based on inversion of earthquake focal mechanisms

2013 ◽  
Vol 81 ◽  
pp. 1-15 ◽  
Author(s):  
H.M. Hussein ◽  
K.M. Abou Elenean ◽  
I.A. Marzouk ◽  
I.M. Korrat ◽  
I.F. Abu El-Nader ◽  
...  
Keyword(s):  
Tectonic Stress ◽  
Focal Mechanisms ◽  
Surrounding Area ◽  
Stress Regime ◽  
Earthquake Focal Mechanisms

Paleozoic accretion and Cenozoic redeformation of the Chinese Tien Shan Range, central Asia

Geology ◽  
1990 ◽  
Vol 18 (2) ◽  
pp. 128 ◽  
Author(s):  
B. F. Windley ◽  
M. B. Allen ◽  
C. Zhang ◽  
Z-Y Zhao ◽  
G-R Wang
Keyword(s):  
Central Asia ◽  
Tien Shan

Earthquake Focal Mechanisms in the New Madrid Seismic Zone

2014 ◽  
Vol 85 (2) ◽  
pp. 257-267 ◽  
Author(s):  
G. A. Johnson ◽  
S. P. Horton ◽  
M. Withers ◽  
R. Cox
Keyword(s):  
Focal Mechanisms ◽  
New Madrid Seismic Zone ◽  
Seismic Zone ◽  
Earthquake Focal Mechanisms ◽  
New Madrid

Permafrost warming in the Tien Shan Mountains, Central Asia

2007 ◽  
Vol 56 (3-4) ◽  
pp. 311-327 ◽  
Author(s):  
S.S. Marchenko ◽  
A.P. Gorbunov ◽  
V.E. Romanovsky
Keyword(s):  
Central Asia ◽  
Tien Shan ◽  
Permafrost Warming ◽  
Tien Shan Mountains

scholarly journals Pupilla loessica LOŽEK 1954 (Gastropoda: Pulmonata: Pupillidae) - „A living Fossil“ in Central Asia?

2009 ◽  
Vol 58 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Stefan Meng ◽  
Matthias H. Hoffmann
Keyword(s):  
Central Asia ◽  
Baikal Region ◽  
Shell Morphology ◽  
Tien Shan ◽  
European Region ◽  
Living Fossil ◽  
Central European ◽  
South Eastern ◽  
Central European Region ◽  
Northern Mongolia

Abstract. LOŽEK (1986) is of the opinion that Pupilla loessica has been found recently in Central Asia. The aim of this study is to provide some initial, concrete contributions to the discussion of this subject. It should be understood as a basis for further investigations. During recent visits on site between 1995 and 2006 in Central Asia in the Russian Altay, in Northern Mongolia, in the Baikal region and in the Tien Shan, numerous recent malacocenoses were examined. In many places evidence was found of a form of Pupilla which had not previously been described from this region; its shell morphology cannot be distinguished from Pupilla loessica. Its distribution is concentrated in the strongly continental Khrebet Saylyugem in the South Eastern Altay. The probability of the occurrence of Pupilla loessica in Central Asia is supported, apart from the shell morphology criteria, by the preference of this species for more continental types of habitat with average annual temperatures markedly below 0° C and the corresponding accompanying fauna adapted to the cold, including e.g. Columella columella, Vertigo genesii, Vallonia tenuilabris, etc., which make these fauna easily comparable to the Pleistocene glacial associations of the Central European region.

Empirical relationship between particulate matter and aerosol optical depth over Northern Tien-Shan, Central Asia

2012 ◽  
Vol 6 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Boris B. Chen ◽  
Leonid G. Sverdlik ◽  
Sanjar A. Imashev ◽  
Paul A. Solomon ◽  
Jeffrey Lantz ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Central Asia ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Empirical Relationship ◽  
Tien Shan ◽  
Northern Tien Shan

Tsunamis In and Near Greece and Their Relation to the Earthquake Focal Mechanisms

1991 ◽  
pp. 161-170 ◽  
Author(s):  
B. C. Papazachos ◽  
P. P. Dimitriu
Keyword(s):  
Focal Mechanisms ◽  
Earthquake Focal Mechanisms
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