On the effects of air pressure variations on radon exhalation into the atmosphere

A model is studied which claims to describe the effects of air pressure variations on the outflow of radon into the atmosphere from loose deposits that are treated as a porous medium having the gas dynamic properties described by Darcy’s law. It is shown that the model results are in satisfactory agreement with the experimental data acquired from a network for monitoring subsoil radon in the Petropavlovsk-Kamchatskii Geodynamic Site in 1997–2006. A technique has been developed for estimating the Darcy coefficient based on radon concentration data in loose deposits at various depths.     

The ecologo-geographical framework for the protection and recovery of taiga reindeer populations within the Konda river basin (Western Siberia)

The key aspects of reindeer ecology within the Konda river basin are considered. The study revealed the factors governing the characteristics of calving reindeer pastures determined by the structure of forest-bog landscapes of a different generalization level. A deficit of such pastures is regarded as the factor of differentiation of reindeer groups with respect to migrants and residents. It is shown that the individual geocomplexes have a multifunctional role. Of particular significance among them are the aufeis glades with outcrops of salt-saturated groundwater, and the dark-coniferous forests along river valleys rich in epiphytic lichens (beard lichens).     

Conflagration fires in taiga landscapes of Central Siberia

We examine the issues relating to the origin of conflagration fires, and the conditions for their emergence and occurrence in taiga landscapes of Central Siberia. We carry out an analysis of the natural-pyrological conditions of landscape where conflagration fires occur.     

Assessing the lightning-caused forest fire risks through the use of the GIS-oriented technology

The technology that has been developed for real-time analysis of the lightning-caused forest fire risks is discussed. Comparative estimates of the number and areas of such fires are obtained for Russia’s regions. The zone of localization of lightning-caused fires is identified through the use of the GIS capabilities.     

Variations in Ultrasonic Signal Spectra for Triaxial Testing of Rock Samples

Izvestiya, Physics of the Solid Earth - Abstract—Experiments on sandstone, basalt and granite were carried out on a controlled hydraulic press under triaxial loading conditions at confining...     

Trace Element Composition and Classification of the Chinga Iron Meteorite

A complete microelement analysis of the Chinga meteorite was performed, and the possibility of attributing it together with a number of other iron meteorites into the IVC subgroup, which is transition between IVA and IVB is proposed.     

Radiocarbon dates of late quaternary mammals in the Archangelsk Region and their contribution to reconstructions of the last glaciation in Eastern Europe

Twelve new AMS (Accelerator Mass Spectrometry) dates of large Quaternary mammal remains were reported: mammoth (Mammuthus primigenius, bison (Bison priscus), and musk ox (Ovibos pallantis) found in the Archangelsk Region. The absolute age of the identified samples varies from 46 000 to 22 000 calibrated years ago. These data suggest that a substantial part of the Archangelsk Region was not covered by ice during the indicated time interval.     

Limitations imposed by nonlinear phenomena on computation of acoustic paths

Approaches for estimating the influence of nonlinear effects on long-distance propagation of acoustic signals in an isothermal atmosphere are developed. It has been indicated that nonlinear effects can be ignored on paths up to 3000 km at beam angles smaller than 35° (nonlinear absorption). However, the spectrum will be pronouncedly distorted at these distances due to the generation of new harmonics (for initial Mach numbers about 10⁻⁴).     

Triggered and tectonic driven earthquakes in the Koyna–Warna region,western India

Two strong M?>?5.0 earthquakes within a span of six months occurred in a triggered seismicity environment in the Koyna–Warna region in western India in 2000. The region is experiencing continued seismicity since the last five decades indicating that this region is close to critical stresses and minor perturbations in the stresses due to reservoir loading and unloading can trigger earthquakes. In the present study we applied the technique developed for identification of prognostic anomalies for tectonic earthquakes to the Koyna–Warna catalogue prior to these two earthquakes with an aim to study the process of source preparation for triggered earthquakes. In case of tectonic earthquakes, unstable conditions in a source zone develop gradually leading to a metastable zone which shows variations in certain seismicity parameters known as prognostic anomalies. Our results indicate that the variations in seismicity parameters before the two strong earthquakes in the Koyna region have a pattern of prognostic anomalies typical of tectonic earthquakes. We conclude that initiation of failure in a metastable zone can be caused both, by external impacts, reservoir loading and unloading in our case, and internal processes of avalanche-like failure development.     

Nonlinear Ekman friction and asymmetry of cyclonic and anticyclonic coherent structures in geophysical flows

Doklady Earth Sciences -