Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology
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| Date: | 2010 |
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Інститут геофізики ім. С.I. Субботіна НАН України
2010
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| Cite this: | Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology / A. Kuzin, L. Shumlyanska // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 82-83. — Бібліогр.: 7 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859629456822370304 |
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| author | Kuzin, A. Shumlyanska, L. |
| author_facet | Kuzin, A. Shumlyanska, L. |
| citation_txt | Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology / A. Kuzin, L. Shumlyanska // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 82-83. — Бібліогр.: 7 назв. — англ. |
| collection | DSpace DC |
| container_title | Геофизический журнал |
| first_indexed | 2025-12-07T13:08:53Z |
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Some common features in the picture of distributions of
elastic heterogeneities of the crust and upper mantle of the
Northern Caucasus accordingly to the earthquake
converted-wave method, the deep seismic sounding and
seismology
A. Kuzin1, L. Shumlyanska2, 2010
1Institute of Oil and Gas, RAS, Moscow, Russia
amkouzin@ya.ru
2Institute of Geophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
lashum@ukr.net
Analysis is based on generalizations of regional
ECWM and DSS works [Belyaevsky et al., 2006;
2007]. We used a model of the velocity of longitudi-
nal waves for the mantle, calculated by the method
of Teylor’s approximation by Geyko V. S. [Geyko
et al., 2005; Bugaienko et al., 2008]. Due to the
fact that seismic methods differ by the type and
frequency spectrum of the used waves in this work
we consider the relative values of the velocity only.
Epicenters of the earthquakes weakly correlates
with distributions of velocities of longitudinal (VP) and
transverse (VS) waves and VP/VS in the crust and
below the M boundary that are constructed accor-
dingly to the ECWM and DSS data. These distribu-
tions are evidently dominated by the direction or-
thogonal to the strike of the folded structure of the
North Caucasus and its main regional faults. Some
correlation with discontinuous tectonics can be seen
along the 45—46 longitude (fragment of the Tran-
scaucasian regional fault), where at the latitude 44
a stepwise shift to the south for a cut of VP/VS is
observed. In general, contours of the parameter VP/VS
reflect more clearly the distribution of velocity het-
erogeneities in the crust compared with VP and VS
slices. Clearly visible is the flexural bend of the con-
tours along the longitude 46 coinciding with a high
absorption zone [Shempelev et al., 2010]; more
contrast arrear the maximum of decreased VP/VS
values beneath the Stavropol uplift (45—44 latitude,
41—43 longitude) and prevailed in central parts of
plots south-western strike of VP/VS isolines. The
highest values of VP, VS and VP/VS are in better
agreement with the regions of recent volcanic activity
compared to the discontinuous tectonics of the
Northern Caucasus folded structures. Comparison
with the contemporaneous geokinematic tectonic
map of the region [Kopp, 2005] allows us to inter-
pret the distribution pattern of VP, VS and VP/VS in
the crust of the North Caucasus as a reflection of
its horizontal compression by the Arabian plate.
If we turn now to the results of processing and
interpreting of seismological data, on the section
corresponding to the 50 km depth a correlation bet-
ween the earthquakes focies with the gradient zone
of low values of the longitudinal wave velocities be-
comes evident. In the next section (H=100 km) a
picture of VP/VS distribution similar to the lower part
of the crust attracts one’s attention. Lower values
of VP/VS for the Stavropol uplift correlate with a pro-
jection of low VP values. This area coincides with
area of the recent volcanic activity (Elbrus, Kazbek,
etc.). Taking into account presence of gas fields
within the Stavropol uplift and its frame the region of
low VP/VS values in the lower crust may be explained
by high gas content. In the middle crust the area of
the relatively low VP/VS values expands that agrees
with such interpretation. On sections at 150 and
200 km the VP distribution pattern changes dramati-
cally. From the depths of 150 to 200 km the low-
velocity area beneath the Stavropol uplift is replaced
by the high-velocity one, while the prevailed direc-
tion of the velocity contours changes to the south-
west and south-east.
At depths of 250 and 300 km of the mantle be-
neath the North Caucasus is represented by the
high-velocity area. In the depth interval of 350—
400 km a pattern of the velocity distribution chan-
ges again — the sublatitudinal strikes of the low
velocity isolines become apparent in the northern
and southern parts of the region. In the 450—500 km
depth interval the VP in the northern part becomes
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more slow, we assume that underthrusting of the
Scythian plate beneath the East European platform
may occur at this depth interval.
From the above analysis we assume that from
depths interval of approximately 70—120 km inversion
of the velocity distribution and correspondingly of the
distribution of mantle heterogeneities starts. [Kras-
nopevtseva, Kuzin, 2009] on the seismic profile Vol-
gograd — Nakhichevan have shown that the relatively
high-velocity folded structure of the Greater Cauca-
sus has a tendency to dive under the Scythian plate,
this interval corresponds to the immersion of M
(H=50 km). At about the same interval a consistent
series of mantle earthquakes with depths of focies
74, 97, 100, 115, 123, 150 km was recorded along the
profile. Obviously, such a coincidence of focal depths
of earthquakes and the beginning of the interval of in-
version of elastic inhomogeneities distribution in the
upper mantle is not accidental.
Vertical sections provide an opportunity to ana-
lyze the distribution of longitudinal velocities along
45, 43 and 41 N to a depth of 2500 km. Beneath
the Stavropol uplift a picture of the velocity distribu-
tion differs significantly. To the east of 41—42 E
the upper mantle represented by alternating layers:
a low-velocity layer at a depth interval 50—150 km
replaced by high-velocity layer at 150—250 km in-
terval and again turn into low-velocity layer that cross
the 670 km border of the upper mantle and extend
down to 1300 km. In the lower mantle velocity chan-
ges do not exceed 0.025 km/s from the reference
zero velocity. In the western part of the area both
the depth of the layers and velocity values change
with the tendency to increase. The depth of the up-
per low-velocity layer increases to 300 km, of the
underlying high-velocity layer — down to 500 km,
while the low velocity layer appear at depths of 500—
700 km. Anomalies of the velocity in the lower man-
tle are noteworthy. In contrast to the eastern part,
here the alternation of high and low-velocity anoma-
lies with deviations of 0.10 km/s from a depth of
1300 km to 2500 km are observed. Stavropol uplift
and Volcano Elbrus with their specific set of anom-
alies of geophysical fields such as positive anoma-
lies of the thermal field and electrical conductivity
are confined to the area of gradient change in the
distribution of longitudinal velocities which can be
traced throughout the section to a depth of 2500 km.
In general, there is a good correlation between
different surface structures of the crust of the North
Caucasus and the distributions of velocity of longi-
tudinal waves at all sections.
Belyaevsky V. V., Egorkin A. V., Solodilov L. N.,
Rakitov V. A., Yakovlev A. G. Some results of
applying methods of natural electromagnetic and
seismic fields in the North Caucasus // Phys. Earth.
— 2007. — ���4. — P. 4—14 (in Russian).
Belyaevsky V. V., Egorkin A. V., Zolotov E. E., Raki-
tov V. A., Avenisyan V. I., Konovalov Y. F., Nedyad-
ko V. V. In-depth geological and geophysical stu-
dies by seismic prospecting (ECWM) and resistiv-
ity (MTS, GMTS, AMTS) methods in the regional pro-
files Eisk — Stavropol — Neftekumsk — Caspian
Sea (850 km) and Corfe-Top Penzhina (500 km).
Analysis and compilation of deep geophysical stu-
dies conducted in the North Caucasus, Kamchat-
ka, and southern Siberia (report). — Moscow, 2006
(in Russian).
Bugaienko I. V., Shumlyanskaya L. A., Zaiets L. N.,
Tsvetkova T. A. Three-dimensional P-velocity mo-
del of the mantle of the Black Sea and the adjacent
territory // Geophys. J. — 2008. — 30, � 5. —
P. 145—160 (in Russian).
References
Geyko V� S�,�Tsvetkova T� A���Shumlyanskaya L� A�
Bugaienko I� V���Zaiets L� N. Regional 3-D P-ve-
locity model of the mantle of Sarmatia (south-west
of the East European Platform) // Geophys. J. —
2005. — 27, � 6. — P. 927—939 (in Russian).
Kopp M. L. Mobilistic neotectonics of platforms in
South-Eastern Europe. — Moscow: Nauka, 2005.
— 340 p. (in Russian).
Krasnopevtseva G. V, Kuzin A. M. The mapping of
tectonic activity of the junction zone of the Cauca-
sus and the Scythian plate according to the inter-
pretation of seismic profile of the DSS “Volgograd
— Nakhichevan”. Geologic hazards // Mater. XV All-
Russian Conf. with int. participation. — Arkhan-
gelsk: Institute of Ecological Problems of the North
ASC UB RAS, 2009. — P. 250—253 (in Russian).
Shempelev A. G., Feldman I. S., Belyavsky V. V.,
Kuhmazov S. U. Results of deep geophysical in-
vestigations of the eastern part of the Terek-Kuma
Depression // Mater. XLIII tectonic meeting. 2. —
Moscow: GEOS, 2010. — P. 450—455 (in Russian).
|
| id | nasplib_isofts_kiev_ua-123456789-101761 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0203-3100 |
| language | English |
| last_indexed | 2025-12-07T13:08:53Z |
| publishDate | 2010 |
| publisher | Інститут геофізики ім. С.I. Субботіна НАН України |
| record_format | dspace |
| spelling | Kuzin, A. Shumlyanska, L. 2016-06-06T19:45:53Z 2016-06-06T19:45:53Z 2010 Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology / A. Kuzin, L. Shumlyanska // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 82-83. — Бібліогр.: 7 назв. — англ. 0203-3100 https://nasplib.isofts.kiev.ua/handle/123456789/101761 en Інститут геофізики ім. С.I. Субботіна НАН України Геофизический журнал Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology Article published earlier |
| spellingShingle | Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology Kuzin, A. Shumlyanska, L. |
| title | Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology |
| title_full | Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology |
| title_fullStr | Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology |
| title_full_unstemmed | Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology |
| title_short | Some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the Northern Caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology |
| title_sort | some common features in the picture of distributions of elastic heterogeneities of the crust and upper mantle of the northern caucasus accordingly to the earthquake converted-wave method, the deep seismic sounding and seismology |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/101761 |
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