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71.
Izvestiya, Atmospheric and Oceanic Physics - We have mapped a short-period S-wave attenuation field of in the lithosphere of the Caucasus. We have used a method based on the analysis of the ratio... 相似文献
72.
We have applied the method of one temperature log suggested by Kutasov in 1987 to process an unsteady temperature log of the 674 m deep submarine borehole BDP-98-2 (Akademichesky Ridge, Lake Baikal) and found it suitable to reconstruct the primary steady thermal gradient not disturbed by drilling. The steady gradient we derived using a special formalism, with reference to drilling conditions and measured thermal properties of sediments, was 63 mK/m, more than two times the unsteady gradient at different depths. Heat flow calculated with this gradient and a mean thermal conductivity of 1.1 W/(m·K) was 70 mW/m2, which is consistent with earlier geothermal data from the same area. Thus, the one-log procedure is a useful tool to predict the original undisturbed thermal gradients and estimate approximate heat flows if a single unsteady temperature log is available. 相似文献
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The characteristics of seismicity prior to the series of eight very strong earthquakes (M
w
= 7.0–9.0) in Northeast Japan are discussed. Ring seismicity structures that appeared prior to all eight events in two depth
ranges of 0–33 and 34–70 km are identified. The epicenters of the main shocks were located near areas of crossing or touching
of shallow and deep rings. It was shown that the sizes of shallow rings and threshold magnitudes corresponding to seismicity
rings grow with the energy of the main shocks. It was noted that the prognosis with respect to the place and magnitude of
the catastrophic earthquake on March 11, 2011, had been made before it based on the data obtained prior to July 1, 2009. Use
of the new data obtained prior to March 10, 2011, enabled us to specify this prognosis significantly. We obtained correlation
dependences of threshold magnitudes on the energy of the main shocks (with a high correlation coefficients). It was shown
that the duration of the period for seismicity rings to emerge in the considered region nearly did not depend on magnitude.
The nature of annular structures and the possibility of application of their parameters for prognosis of strong earthquakes
were discussed. 相似文献
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I. V. Lygin A. A. Bulychev D. A. Gilod T. B. Sokolova A. A. Fadeev 《Moscow University Geology Bulletin》2014,69(2):61-67
The scientific educational practice on gravimetry for the second-year students of the geophysical specialty in 2012–2013 was executed in Central Russia (Kaluga region, the Village of Aleksandrovka). It allowed us to provide an educational process with modern high-precision gravimeters and to fully preserve the curricula and to add elements of topography and geodesic practice. Over these 2 years reliable facts and data were received, which illustrated the possibilities of high-precision gravity measurements in studying the sedimentary cover features of a geological structure. 相似文献
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Based on the modified formalism of Dorogokupets and Oganov (2007), we calculated the equation of state for diamond, MgO, Ag, Al, Au, Cu, Mo, Nb, Pt, Ta, and W by simultaneous optimization of the data of shock-wave experiments and ultrasonic, X-ray diffraction, dilatometric, and thermochemical measurements in the temperature range from ~ 100 K to the melting points and pressures of up to several Mbar, depending on the material. The obtained room-temperature isotherms were adjusted with a shift of the R1 luminescence line of ruby, which was measured simultaneously with the unit cell parameters of metals in the helium and argon pressure media. The new ruby scale is expressed as P(GPa) = 1870?Δλ / λ0(1 + 6?Δλ / λ0). It can be used for correction of room-pressure isotherms of metals, diamond, and periclase. New simultaneous measurements of the volumes of Au, Pt, MgO, and B2-NaCl were used for interrelated test of obtained equations of state and calculation of the room-pressure isotherm for B2-NaCl. Therefore, the constructed equations of state for nine metals, diamond, periclase, and B2-NaCl can be considered self-consistent and consistent with the ruby scale and are close to a thermodynamic equilibrium. The calculated PVT relations can be used as self-consistent pressure scales in the study of the PVT properties of minerals using diamond anvil cell in a wide range of temperatures and pressures. 相似文献
80.
A.D. Duchkov L.S. Sokolova D.E. Ayunov O.N. Zlobina 《Russian Geology and Geophysics》2013,54(12):1522-1528
The thermal conductivity of rocks (λ) used previously to estimate heat flow in high-latitude Siberia was assumed to be λ = 1.8–2.0 W/(m?K), according to published evidence, but was almost never measured specially. We measured the thermal conductivity of core samples from boreholes drilled in the northeastern West Siberian Plate and in the Yenisei–Khatanga basin in the 1990s, using two advanced instruments: a comparator and a scanner of thermal conductivity. Altogether there were 305 samples of air-dry sediments (λd) from the 1100–4200 m interval of 23 holes, out of which 77 samples were then moistened (λw). The average thermal conductivities of rocks in dry and wet conditions were found to be λd = 1.9 ± 0.2 and λw = 2.6 ± 0.1 W/(m?K), respectively. Thus, the true thermal conductivity of sediments, which are saturated with water in this northern area, must be about 20–30% higher than that assumed in the previous heat flow determinations, and the latter are thus underestimated correspondingly. The updates to the thermal conductivity values imply major revision to the existing ideas of the thermal regime in the Siberian high latitudes. Such a serious revision of geothermal data will obviously require a large amount of additional experimental work. 相似文献