Time filter

Source Type

Romanovsky V.E.,University of Alaska Fairbanks | Drozdov D.S.,Earth Cryosphere Institute | Oberman N.G.,MIRECO Mining Company | Malkova G.V.,Earth Cryosphere Institute | And 8 more authors.
Permafrost and Periglacial Processes

The results of the International Permafrost Association's International Polar Year Thermal State of Permafrost (TSP) project are presented based on field measurements from Russia during the IPY years (2007-09) and collected historical data. Most ground temperatures measured in existing and new boreholes show a substantial warming during the last 20 to 30 years. The magnitude of the warming varied with location, but was typically from 0.5°C to 2°C at the depth of zero annual amplitude. Thawing of Little Ice Age permafrost is ongoing at many locations. There are some indications that the late Holocene permafrost has begun to thaw at some undisturbed locations in northeastern Europe and northwest Siberia. Thawing of permafrost is most noticeable within the discontinuous permafrost domain. However, permafrost in Russia is also starting to thaw at some limited locations in the continuous permafrost zone. As a result, a northward displacement of the boundary between continuous and discontinuous permafrost zones was observed. This data set will serve as a baseline against which to measure changes of near-surface permafrost temperatures and permafrost boundaries, to validate climate model scenarios, and for temperature reanalysis. © 2010 John Wiley & Sons, Ltd. Source

Mindel I.G.,Institute of Environmental Geoscience | Sevosty'anov V.V.,Institute of Environmental Geoscience | Trifonov B.A.,Institute of Environmental Geoscience | Ragozin N.A.,Institute of Environmental Geoscience
Water Resources

Geological and geotechnical conditions in Imeretinskaya Depression, where Olympic Game facilities will be constructed, have some features not typical of other parts of the Great Sochi. These include the large thickness (up to 70-100 m) of Quaternary marine and alluvial deposits, overlying half-rocks and hard rocks, as well as a wide occurrence of soils of II-III and III category in terms of seismic properties. These factors, along with the high seismicity of the area, require one who determines the quantitative characteristics of seismic impacts, to take into account both the features of geological structure and properties of soils and the effect of both nearby and relatively remote earthquake sources on the magnitude and the frequency content of vibrations. Two geotechnically unfavorable sections within Imeretinskaya depression with poor data on the seismic properties of rocks throughout the depth of the Quaternary strata are used as examples to demonstrate the methodological approaches to evaluating the characteristics of seismic impacts. In conclusion, proposals regarding experimental verification of the obtained results are formulated and recommendations are given regarding the improvement of the properties of foundation soils on which earthquake induced accelerations under natural conditions reach 300-450 cm/s 2. © 2011 Pleiades Publishing, Ltd. Source

Discover hidden collaborations