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1.
V. O. Mikhailov T. Parsons R. W. Simpson E. P. Timoshkina C. Williams 《Izvestiya Physics of the Solid Earth》2007,43(1):75-90
Data on present-day heat flow, subsidence history, and paleotemperature for the Sacramento Delta region, California, have
been employed to constrain a numerical model of tectonic subsidence and thermal evolution of forearc basins. The model assumes
an oceanic basement with an initial thermal profile dependent on its age subjected to refrigeration caused by a subducting
slab. Subsidence in the Sacramento Delta region appears to be close to that expected for a forearc basin underlain by normal
oceanic lithosphere of age 150 Ma, demonstrating that effects from both the initial thermal profile and the subduction process
are necessary and sufficient. Subsidence at the eastern and northern borders of the Sacramento Valley is considerably less,
approximating subsidence expected from the dynamics of the subduction zone alone. These results, together with other geophysical
data, show that Sacramento Delta lithosphere, being thinner and having undergone deeper subsidence, must differ from lithosphere
of the transitional type under other parts of the Sacramento Valley. Thermal modeling allows evaluation of the rheological
properties of the lithosphere. Strength diagrams based on our thermal model show that, even under relatively slow deformation
(10−17 s−1), the upper part of the delta crystalline crust (down to 20–22 km) can fail in brittle fashion, which is in agreement with
deeper earthquake occurrence. Hypocentral depths of earthquakes under the Sacramento Delta region extend to nearly 20 km,
whereas, in the Coast Ranges to the west, depths are typically less than 12–15 km. The greater width of the seismogenic zone
in this area raises the possibility that, for fault segments of comparable length, earthquakes of somewhat greater magnitude
might occur than in the Coast Ranges to the west.
The text was submitted by the authors in English. 相似文献
2.
V. O. Mikhailov V. M. Gordin E. P. Timoshkina E. A. Kiseleva E. I. Smolyaninova 《Izvestiya Physics of the Solid Earth》2007,43(1):2-12
The paper presents a review of investigations in the field of the theory and practice of the interpretation of geological and geophysical data with geodynamic models that were carried out mainly by researchers of the Institute of Physics of the Earth, Russian Academy of Sciences. Evolutionary models of platform structures, passive continental margins, rift zones, and orogens are examined. The review presents formulations of inverse problems and results of interpretation for various regions, including sedimentary basins of the East European Platform, Atlantic Ocean margins, the Caucasus, the South Urals, and others. 相似文献
3.
The disturbance of mechanical and thermal equilibria in the upper shell of the Earth as a result of mantle or local within-plate
processes related to periodic tectonic activity gives rise to the formation of convective flows in the low-viscosity asthenosphere.
These flows affect the lithosphere and create domains of subsidence and uplift, which can continue to develop long after the
cessation of active periods. If the density of the lithosphere does not decrease with depth, then small-scale flows increase
uplift in zones of compression of the continental lithosphere and create domains of extension at their margins. In our opinion,
small-scale convection is the main geodynamic factor that forms foredeeps. The results of detailed numerical modeling of foredeep
formation at the margins of adjoining orogens are presented in the current paper. In order to set the initial conditions for
the stage of continental collision, the precollision stages of the foldbelt evolution are considered, including the stage
of trough formation on the thinned continental crust or on the oceanic lithosphere and the stage of sedimentary basin formation;
depending on the degree of extension, this can be an inner sea or a passive continental margin. Such initial conditions were
used in modeling of the compression stage (continental collision), when the orogen-foredeep system is formed. The parameters
of the model and the tectonic processes are chosen so as to bring the results of numerical computation in line with the data
on the Greater Caucasus and northern Forecaucasus, including the thickness of the crustal layers and sedimentary cover, structure
of the foredeeps, rate of tectonic subsidence, heat flow, etc. Comparison of the numerical modeling results with the formation
history of the Caucasus foredeeps confirms that the first stage of regional compression of the Greater Caucasus took place
before the deposition of the Maikop sediments. At least three compression stages followed: 16.6–15.8 Ma (Tarchanian), 14.3–12.3
Ma (Konkian-early Sarmatian), and 7.0–5.2 Ma (Pontian). The next stage of regional compression is apparently occurring at
present. 相似文献
4.
Izvestiya, Physics of the Solid Earth - The main results obtained at the Institute of Physics of the Earth of the Russian Academy of Sciences (IPE RAS) in the numerical geodynamic modeling of the... 相似文献
5.
V. O. Mikhailov M. Diament A. A. Lyubushin E. P. Timoshkina S. A. Khairetdinov 《Izvestiya Physics of the Solid Earth》2016,52(5):692-703
The refinement of the accuracy and resolution of the monthly global gravity field models from the GRACE satellite mission, together with the accumulation of more than a decade-long series of these models, enabled us to reveal the processes that occur in the regions of large (Mw≥8) earthquakes that have not been studied previously. The previous research into the time variations of the gravity field in the regions of the giant earthquakes, such as the seismic catastrophes in Sumatra (2004) and Chile (2010), and the Tohoku mega earthquake in Japan (2011), covered the coseismic gravity jump followed by the long postseismic changes reaching almost the same amplitude. The coseismic gravity jumps resulting from the lower-magnitude events are almost unnoticeable. However, we have established a long steady growth of gravity anomalies after a number of such earthquakes. For instance, in the regions of the subduction earthquakes, the growth of the positive gravity anomaly above the oceanic trench was revealed after two events with magnitudes Mw=8.5 in the Sumatra region (the Nias earthquake of March 2005 and the Bengkulu event of September 2007 near the southern termination of Sumatra Island), after the earthquake with Mw=8.5 on Hokkaido in September 2007, a doublet Simushir earthquake with the magnitudes Mw = 8.3 and 8.1 in the Kuriles in November 2006 and January 2007, and after the earthquake off the Samoa Island in September 2009 (Mw=8.1). The steady changes in the gravity field have also been recorded after the earthquake in the Sichuan region (May 2008, Mw = 8.0) and after the doublet event with magnitudes 8.6 and 8.2, which occurred in the Wharton Basin of the Indian Ocean on April 11, 2012. The detailed analysis of the growth of the positive anomaly in gravity after the Simushir earthquake of November 2006 is presented. The growth started a few months after the event synchronously with the seismic activation on the downdip extension of the coseismically ruptured fault plane zone. The data demonstrating the increasing depth of the aftershocks since March 2007 and the approximately simultaneous change in the direction and average velocity of the horizontal surface displacements at the sites of the regional GPS network indicate that this earthquake induced postseismic displacements in a huge area extending to depths below 100 km. The total displacement since the beginning of the growth of the gravity anomaly up to July 2012 is estimated at 3.0 m in the upper part of the plate’s contact and 1.5 m in the lower part up to a depth of 100 km. With allowance for the size of the region captured by the deformations, the released total energy is equivalent to the earthquake with the magnitude Mw = 8.5. In our opinion, the growth of the gravity anomaly in these regions indicates a large-scale aseismic creep over the areas much more extensive than the source zone of the earthquake. These processes have not been previously revealed by the ground-based techniques. Hence, the time series of the GRACE gravity models are an important source of the new data about the locations and evolution of the locked segments of the subduction zones and their seismic potential. 相似文献
6.
V. O. Mikhailov E. A. Kiseleva E. I. Smol’yaninova P. N. Dmitriev V. I. Golubev Yu. S. Isaev K. A. Dorokhin E. P. Timoshkina S. A. Khairetdinov 《Izvestiya Physics of the Solid Earth》2014,50(4):576-587
The problems of processing and interpreting the data provided by radar satellite interferometry for the conditions of landslides covered by vegetation are analyzed in two case studies of landslides in the Northern Caucasus in the region of Kepsha and Mamaika villages in the vicinity of the railway tunnels. The estimates of the displacement fields are obtained by the method of persistent scatterers using the StaMPS program package. The five-year experience of landslide monitoring shows that in the unfavorable conditions of satellite radar interferometry, proper selection of the strategy of satellite image processing is vital. In the present paper, we discuss, in particular, the crop selection, the selection of the master image, reference area, and digital elevation model. For the landslide located in the sparsely populated region near Kepsha village, we used the data from the ascending and descending tracks of the long-wavelength ALOS and shorter-wavelength ENVISAT satellites. For the landslide in the region of Mamaika village with a large number of different buildings serving as good scatterers for radar signals, we used the images from the ENVISAT and from TerraSAR satellite, which transmits even shorter waves. The average line-of-sight (LOS) displacement velocities V LOS for the landslide near Kepsha village measure at most 10 mm per annum, which means that this landslide has remained stable at least since 2004. The landslide in Mamaika village is significantly more active. The average LOS displacement velocities in the active part of this landslide attain 60 mm per annum. The artificial corner reflector installed on the segment of the landslide where natural scatterers of radar signal are absent made it possible to estimate the LOS displacement velocity on this segment of the slope at 49 mm per annum. 相似文献
7.
Mikhailov V. O. Timofeeva V. A. Smirnov V. B. Timoshkina E. P. Shapiro N. M. 《Izvestiya Physics of the Solid Earth》2022,58(2):230-242
Izvestiya, Physics of the Solid Earth - Abstract—A new model of the rupture surface of the Mw = 7.8 Near Islands Aleutian earthquake that occurred on July 17, 2017 in the region of the... 相似文献
8.
The GRACE data make it possible to detect the areas where the earthquakes initiate postseismic creep in regions much larger than the focal area. This information is important for estimation of the seismic potential and position of the locked segments in the subduction zones. 相似文献
9.
V.?O.?MikhailovEmail author E.?A.?Kiseleva K.?Arora E.?P.?Timoshkina V.?B.?Smirnov R.?Chadda A.?V.?Ponomarev D.?Shrinagesh 《Journal of Volcanology and Seismology》2018,12(3):213-220
A coseismic displacement field based on SAR interferometry data was determined for the area of the April 20, 2006 Olyutorskii earthquake. The resulting image shows displacements toward the satellite (“uplifts”) to the northwest of the surface rupture area where the epicenters of most aftershocks lie. The displacement- affected area extends as far as the Vyvenka–Vatyna tectonic suture. We have developed a model for the rupture surface that is in agreement with the hypothesis of A.V. Lander and T.K. Pinegina stating that the largest displacements occurred along a fault northwest of the surface rupture zone; the fault dips southeast and is not exposed. The slip on the fault is close to a pure thrust type. These results furnish another confirmation of the fact that advanced satellite technologies can provide important additional information on the dynamics of seismic regions, especially where the existing observing networks are sparse. 相似文献
10.
V. O. Mikhailov A. N. Nazaryan V. B. Smirnov M. Diament N. Shapiro E. A. Kiseleva S. A. Tikhotskii S. A. Polyakov E. I. Smol’yaninova E. P. Timoshkina 《Izvestiya Physics of the Solid Earth》2010,46(2):91-103
Based on the data of differential satellite interferometry, the field of displacements of the Earth’s surface in the line-of-sight direction is determined for the region of the Altai Earthquake that struck on September 27, 2003. The displacements are estimated for unforested areas of Chuia and the Kurai depressions, and for a part of their mountainous surroundings. In that part of the region where unwrapping of the data was possible, the amplitude of displacements amounts up to 150 cm for Chuia and 100 cm for the Kurai depressions. In order to locate the surface of the seismic rupture and to find the field of displacements on this surface, the method for the combined inversion of the displacements data, provided by satellite interferometry (the present work) and geodesy [Gol’din et al., 2005], is suggested and applied. The admissible range of the parameters of the rupture was specified from the seismology and seismotectonics data. The combined use of geodetic and satellite interferometry data makes the solution of the inverse problem more stable and yields a seismic momentum estimate, which is consistent with the seismological determinations. We discuss the possible contributions of various postseismic processes; in particular, based on analyzing the energy of the aftershocks, we assess the contribution of the postseismic creep to the displacements, determined from the interferometry and geodesy data, for different coseismic and postseismic time intervals. 相似文献