Ninth International Conference on Permafrost ... - IARC Research

Ni n t h In t e r n at i o n a l Co n f e r e n c e o n Pe r m a f r o s t06.5 m06.5 m0 100 200 300 m0 150 m 0 150 m024810MBedding rocks roof boundary(1, 2, 3 – different soils of terrace sediments)Figure 3. Georadar plot of diamond alluvial deposit from diamondfieldin Western Yakutia: a) radarogramm after preliminaryprocessing; b) radarogramm with picked geoelectric horizonscorresponding to different soils of terrace sediments.Figure 4. Radarogramm along coping of settling pound. Detectingseepage zone in the body of dam. 1: outline of deconsolidationsink; 2: seepage zone. On the right, road-covered wet mud withbroken stone. On the left, road after preparation.In December 2005 and February 2006, GPR seasonalsurveys were performed on a diamond alluvial depositduring winter frost penetration time. It appeared that, inDecember, the maximum frost penetration and summermaximum thaw depth rather precisely marked out, whichhas proved to be true by temperature observations. Furtherin January–February, during further freezing of a section,lithological borders, including the roof and bottom of theproductive horizon, distinctly stand out on the radarogramm,which proves to be true by the geological data on cores anddescription of a prospecting shaft. During processing, theaccount of a relief of a daytime surface has been carried out,and it has revealed confidently the bottom of the productivehorizon, to define its depth and thickness for the momentof the beginning dragging works. Consequently, it waspossible to predict the state of soils developed section (timeof thawing of productive horizon after filling dragging afoundation trench).ConclusionThe results presented in our work show that duringgeoradar survey, application of different types of preparationof studied surfaces (cleaning, filling, smoothing, wetting,etc.), as well as using and accounting seasonal- climatic andweather factors, allows productivity increase of GPR surveyin many cases.In spite of that, in a basis of georadar survey is differenceof rocks and soils in dielectric permittivity and electroconductivity, the basic character of georadar sections lays, asa rule, reflects mainly lithological boundaries (Finkelshtein etal. 1977, Vladov & Starovoitov 2005). Boundaries associatedwith the geocryological state frequently have a secondarycharacter and come to light on a radarogramm less precisely.In many cases, basic elements of geocryological structurecome to light more brightly during the periods which are notcorresponding seasonal geocryological state. In particular, itconcerns the boundary of maximal seasonal thawing duringintensive freezing.ReferencesFinkelshtein, M.I., Mendelson, V.L. & Kuteev, V.A. 1977.Radar-Location of Layered Terrestrial Covers.Moscow: Soviet Radio, 176 pp. (in Russian).Judge, A.S., Tucker, C.M., Pilon, J.A. & Moorman, B.J.1991. Remote Sensing of Permafrost by Ground-Penetrating Radar at Two Airports in Arctic Canada.Arctic 44 Supp. 1: 4-48.Velikin, S.A., Vladov, M.M. & Makcheeva, I.V. 2000.Application georadiolocation method for the study ofhydro units in permafrost conditions. In: Georadar inRussia-2000. Moscow, MGU: 36-38.Vladov, M.M. & Starovoitov, A.V. 2005. Introductionto georadiolocation. Moscow: MGU, 165 pp. (inRussian).330