Numerical simulation of the 30–45 ka debris avalanche flow of Montagne Pelée volcano,Martinique: from volcano flank collapse to submarine emplacement

Natural Hazards - In November 2015, China government announced that the national carbon emissions trading market is expected to start in 2017. Carbon emission trading system is a raising concern...     

Some possibilities of predicting radio wave absorption in the lower ionosphere

Summary An attempt is made to show possible ways of predicting radio wave absorption in the midlatitude lower ionosphere using relations between absorption and the intensity of solar ionizing radiation and/or common solar activity indices, and between absorption and f₀F2.

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aa mu nuau nu a¶rt;u ¶rt;um u u a mu ¶rt; nu u umum uuu uu (uu uu u¶rt;au amumu) u ¶rt; nu u f₀F2.

     

Consequences of transducer inductance for seismograph calibration

Summary The magnification achieved with the standard sine-wave method using seismometers with the calibration and signal coils tightly wound on the same coil former can be erroneous at high frequencies due to the mutual inductance between both coils. An attempt was made to eliminate this influence from the calibration data. The application of theoretical equations was tested with a short-period digital seismograph.

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ma¶rt;ama auau aa nu ¶rt;uu ¶rt;uu maauu m m m a u amma ua u a au u¶rt;mumu ¶rt; ua u auau am, u u a¶rt;m n¶rt;m umu. a ¶rt;aa nnma muam auau ¶rt;a. uu mmuu au u¶rt;a nu auauu mnu¶rt;u aa u anu.

     

Effects of the imf sector structure in the midlatitude troposphere and stratosphere

Summary The data on geopotential heights and temperatures at 7 pressure levels between 1000-10 hPa above Berlin(52.5 °N, 13.4 °E) are analysed for the winters of 1963–1973. No demonstrable effect of the interplanetary magnetic field sector boundary crossing (IMF SBC) is found in the lower and middle stratosphere, but there is a demonstrable effect in the middle troposphere at the 500 hPa level. This effect is less important than the IMF SBC effect in the tropospheric vorticity area index and seems to be of a different type.

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auum ¶rt;a nnmua m u mnam a 7 nm ¶rt;au ¶rt; 1000-10 a a¶rt; u(52,5 °.., 13,4 °.¶rt;.) ¶rt; u 1963–1973. ua ¶rt;aam m nu mau nam aum n( ) ¶rt;a amu u u ¶rt; mam, ma m a¶rt; ¶rt; mn a 500 a. mm m a, m u¶rt; na¶rt;u aumu am, u am m ¶rt; muna.

     

The relation between the heat flow field and the distribution ofP n -wave velocities for the European continent

Summary The dependence of P_n-wave velocities on the heat flow, temperature at the crustmantle boundary and the thickness of the Earth's crust in Europe was investigated in relation to the problem of lateral inhomogeneities in the upper mantle. A map was constructed of the distribution of P_n-wave velocities on the territory of Europe. The relations these investigations yielded, were compared with the results of laboratory experiments and all the results are discussed from the physical point of view. The conclusion drawn is that that temperature and pressure effect provide a sufficient explanation of the observed regional changes of P_n-wave velocities for the European continent.

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auum ¶rt;auu mu n¶rt; ¶rt; nmu uua (P_n) u mn nm, mnam a nmu amuu u m a mumuu n a u¶rt;aa u numa ¶rt;¶rt;m amuu. mumuu n a maa a uu m P_n- a nmu uua. u¶rt;u umam ¶rt;a mama aam u¶rt;au uuu m n¶rt; amuu u u ¶rt;au u mnam mmmm mama n¶rt;aa am. ¶rt;a ¶rt;, m ua uu m P_n- a n mum ¶rt;mam um uuu mnam u ¶rt;au a nmu uua.

     

Thermally driven hydromagnetic instabilities in a non-constantly stratified layer

Summary The convection in a rapidly rotating electrically conducting, fluid horizontal layer of non-constant stratification, permeated by an inhomogeneous magnetic field, is studied. In this connection, a temperature model of the layer is constructed, which creates a structure such that part of the layer is unstably and a part stably stratified. The results obtained are applied to the conditions in the fluid Earth's core.

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¶rt;m u m aa mn¶rt; u¶rt;uma , m um nm mamuuau u a¶rt;um ¶rt;¶rt; aum n. uaa nu m mna ¶rt; nu¶rt;um uu ma mm, nu m am mamuuum mau, a am — mau. mam unm ¶rt; aaua n, nu¶rt;u u¶rt; ¶rt; u.

     

Behaviour of quartz gravity meters under high frequency vertical motion

Summary Tests on the vertical vibrating table in the frequency range of70–110 Hz indicate that quartz gravity meters are10–100 times more sensitive at some frequencies than under low-frequency excitation. At high frequencies, the reading beam is at rest and deflected from the correct position. Slow fluctuations of amplitude and frequency near resonance could cause slow irregular motion of the beam with absence of low-frequency ground motion of sufficient intensity.

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unmauaum a mua um¶rt; ¶rt;uana amm 70–110u mam, m a m ammaaum 10–100 a mum nu uamm au. u amm au u a¶rt;um n m mu m nu. ¶rt; auauu anum¶rt; u amm au uu aa m am uamm u ua ¶rt;a mmmm uamm au n ¶rt;mam umumu.

     

The use of laboratory measurements of electric resistivity of rocks for evaluating the magnetotelluric method

Summary A profile model of electric resistivity as a function of depth was compiled, the initial parameters being the values of the electric resistivity determined experimentally for basaltic and eclogitic rocks from the Bohemian Massif. The curves of the apparent resistivity were computed for this model and the measure of information evaluated for the various model layers. The dominant influence of the subsurface layer was proved.     

On sweeping frequency impedance measurements

Summary The current spectral density I() dependence on the width of the frequency band and sweep period is studied. The relation between the required accuracy of measurement an the optional parameters of the sweeping process is formulated.