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91.
Yu. F. Kopnichev D. D. Gordienko I. N. Sokolova 《Journal of Volcanology and Seismology》2009,3(1):44-58
This paper deals with characteristics of the short period S-wave attenuation field in the rupture zones of 37 large and great earthquakes with M s = 7.0–8.6, as well as in low seismicity areas. We estimate the effective quality factor from Sn and Lg coda envelopes in two time intervals (Q 1 and Q 2). The quantity Q 1 is a measure of shear wave attenuation in the uppermost mantle, at depths of down to approximately 200–250 km, while Q 2 is relevant to deeper horizons of the upper mantle. We studied variations in the attenuation field in the rupture zone of the 1950 Assam earthquake. We examined the parameters Q 1, Q 2, and Q 1/Q 2 as functions of the time ΔT elapsed after a large earthquake. It is shown that the parameter Q 2 in rupture zones is practically independent of ΔT, while the quantities Q 1 and Q 1/Q 2 increase until ΔT ～ 20–25 years, especially rapidly for normal, normal-oblique, and strike-slip earthquake mechanisms. This analysis provides evidence that, as ΔT increases, so does the quality factor in the upper mantle for shear waves. It is supposed that this is related to the rise of mantle fluids to the crust. Geodynamic mechanisms are discussed that can support a comparatively rapid “drying” of the upper mantle beneath earthquake rupture zones. 相似文献
92.
Izvestiya, Atmospheric and Oceanic Physics - The characteristics of the short-period S-wave attenuation field in the source zone of the strongest Tohoku earthquake of March 11, 2011 in the... 相似文献
93.
Obzhirov A. I. Mishukova G. I. Shakirov R. B. Mishukov V. F. Maltseva E. V. Sokolova N. L. Okulov A. K. Yatsuk A. V. Lifanskiy E. V. 《Oceanology》2019,59(6):853-859
Oceanology - Intra-annual variability in methane fluxes at the water–atmosphere boundary was shown for the first time in the water area of the Sea of Okhotsk east of Sakhalin Island. The... 相似文献
94.
Mikhailova N. N. Sokolova I. N. Poleshko N. N. 《Izvestiya Atmospheric and Oceanic Physics》2020,56(8):869-886
Izvestiya, Atmospheric and Oceanic Physics - According to the current maps of general seismic zoning of the Republic of Kazakhstan (2006), the territory of the Semipalatinsk Test Site (STS) is... 相似文献
95.
The Mesozoic-Cenozoic rhythmic continental sedimentary rocks are analyzed for every particular period and epoch from the Triassic
to the Pliocene. The maximal distribution areas of rhythmic deposits are within the latitudinal zone of 20°-40°. Investigation
of rhythmic Mesozoic-Cenozoic carbonate-containing deposits of Europe and North America enables us to attribute rhythmicity
to climate change owing to insolation and eustatic variations of oceanosphere’s level, on the one hand, and to compare duration
values of the rhythmic unit and rhythmic sequence with cycles of orbital precession, ecliptic plane inclination, and the eccentricity
of the Earth’s orbit, on the other hand. 相似文献
96.
97.
This paper presents results from a study of variations in short-period shear-wave attenuation in the lithosphere of the Baikal Rift Zone (BRZ). We used earthquake records made at the Ulan-Bator station (ULN) at epicentral distances of ～400–1300 km. The ratios of maximum amplitudes in the Sn and Pn waves were considered. We show that these ratios are on the whole considerably higher than those in other areas of Central Asia. It was found that zones of low shear wave attenuation coincide with the rupture zones of large earthquakes that occurred during the 19th and 20th centuries. We identified zones of high attenuation where no large (M～ > 7.0) seismic events have occurred during at least 180 years. The hypothesis we propose is that precursory processes before future large earthquakes may be occurring in these zones. We discuss the question of whether wave attenuation characteristics may be related to seismicity. 相似文献
98.
Yu. O. Gavrilov Yu. V. Kushcheva I. V. Latysheva A. I. Gushchin A. L. Sokolova 《Moscow University Geology Bulletin》2016,71(2):137-150
The variations in the structural, textural, mineralogical, and geochemical (isotope) features of Lower to Middle Jurassic siliciclastic sediments along the Chanty-Argun River in Mountainous Chechnya and Georgia are discussed. This profile transects areas with various types of deformed sediments, from the northern comparatively weakly deformed and altered zone, to the southern zone of intense deformation and cleavage. Southward along the profile, these alterations are accompanied by the evolution of clay mineral assemblages, as well as polytypic modifications of micas and their crystallinity index. Increasing intensity of rock alteration and cleavage leads to a change of the K–Ar system, which results in a substantially rejuvenated isotope age of the sediments with a simultaneous increase of their stratigraphic age. 相似文献
99.
Izvestiya, Atmospheric and Oceanic Physics - The article considers the characteristics of the short-period S-wave attenuation field in the lithosphere of Southwestern Japan. Records of local... 相似文献
100.
Alekseeva T. A. Sokolova J. V. Tikhonov V. V. Smolyanitsky V. M. Afanasyeva E. V. Raev M. D. Sharkov E. A. 《Izvestiya Atmospheric and Oceanic Physics》2021,57(12):1690-1704
Izvestiya, Atmospheric and Oceanic Physics - In the period of intense ice melting, algorithms retrieving sea-ice concentration from satellite microwave radiometry (SMR) data may fail to detect vast... 相似文献