PASSEQ 2006–2008: Passive seismic experiment in Trans-European Suture Zone     

M. Wilde-Piórko  W. H. Geissler  J. Plomerová  M. Grad  V. Babuška  E. Brückl  J. Cyziene  W. Czuba  R. England  E. Gaczyński  R. Gazdova  S. Gregersen  A. Guterch  W. Hanka  E. Hegedűs  B. Heuer  P. Jedlička  J. Lazauskiene  G. Randy Keller  R. Kind  K. Klinge  P. Kolinsky  K. Komminaho  E. Kozlovskaya  F. Krüger  T. Larsen  M. Majdański  J. Málek  G. Motuza  O. Novotný  R. Pietrasiak  Th. Plenefisch  B. Růžek  S. Sliaupa  P. Środa  M. Świeczak  T. Tiira  P. Voss  P. Wiejacz 《Studia Geophysica et Geodaetica》2008,52(3):439-448

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A Comparison of IRI-2016 foF2 Predictions with the Observations at Different Latitudes During Geomagnetic Storms     

Timoçin  E.  Ünal  İ.  Göker  Ü. D. 《Geomagnetism and Aeronomy》2018,58(7):846-856

Geomagnetism and Aeronomy - This study investigates the impacts of geomagnetic storms on the performance of the International Reference Ionosphere 2016 (IRI-2016) foF2 predictions at different...  相似文献   

Crustal and upper mantle velocity model along the DOBRE-4 profile from North Dobruja to the central region of the Ukrainian Shield: 2. geotectonic interpretation     

V. I. Starostenko  T. Janik  O. B. Gintov  D. V. Lysynchuk  P. Środa  W. Czuba  E. V. Kolomiyets  P. Aleksandrowski  V. D. Omelchenko  K. Komminaho  A. Guterch  T. Tiira  D. N. Gryn  O. V. Legostaeva  G. Thybo  A. V. Tolkunov 《Izvestiya Physics of the Solid Earth》2017,53(2):205-213

This part of the paper addresses the geotectonic interpretation of the velocity model obtained from the results of seismic studies under the DOBRE-4 project in Ukraine. The velocity field does not show distinct lateral changes from the Precambrian platform towards the younger tectonic structures in the southwest. Hence, based on the seismic data alone, it is not possible to recognize the tectonic units that are known on the surface. The Moho has an undulating pattern over an interval with a length of ~150 km. The amplitude of the undulations reaches 8 to 17 km. The similar wavelike behavior, although on a shorter spatial scale and lower amplitude, is also typical of the upper crust and upper mantle. The presence of several separate horizons in the folded crust revealed by the velocity model is consistent with the presence of the folded systems which have different extensions on the different depth levels in the Earth’s crust. This situation is believed to be typical of folding on the lithospheric scale and to reflect the rheological stratification of the crust. The DOBRE-4 velocity section of the crust and adjacent part of the mantle promotes a clearer view of the geodynamical model describing the formation of the southwestern part of East European Platform in the Early Precambrian from the plate’s tectonic standpoint.  相似文献   

Erratum to “Geophysics of sea ice in the Baltic Sea: A review” [Prog. Oceanogr. 80 (2009) 129-148]     

Timo Vihma  Jari Haapala 《Progress in Oceanography》2009,82(3):224

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Numerical modeling of rock failure under dynamic loading with polygonal elements     

Timo Saksala  Mahmood Jabareen 《国际地质力学数值与分析法杂志》2019,43(12):2056-2074

Polygonal finite elements are gaining an increasing attention in the computational mechanics literature, but their application in rock mechanics is very rare. This paper deals with numerical modeling of rock failure under dynamic loading based on polygonal finite elements. For this end, a damage-viscoplastic constitutive model for rock based on the Mohr-Coulomb criterion with the Rankine criterion as a tensile cutoff is employed and implemented with the polygonal finite element method. Moreover, the mineral mesostructure or rock is described by randomly mapping groups of polygonal elements representing the constituent minerals into a global mesh and assigning these groups with the corresponding mineral material properties. The performance of the polygonal elements is compared with that of the linear and quadratic triangular and bilinear quadrilateral elements in numerical simulations of controlled shear band formation under uniaxial compression and lateral splitting failure in the dogbone tension test. Numerical simulations of uniaxial tension and compression tests as well as dynamic Brazilian disc test under increasing loading rates demonstrate that the present approach predicts the correct failure modes as well as the dynamic increase in strength of rock.  相似文献   

Numerical modeling of adiabatic heat generation during rock fracture under dynamic loading     

Timo Saksala 《国际地质力学数值与分析法杂志》2019,43(9):1770-1783

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Resistance to the deinstitutionalization of a region: Borders,identity and activism in a municipality merger     

Kaj Zimmerbauer  Timo Suutari  Antti Saartenoja 《Geoforum》2012,43(6):1065-1075

Regions are contested processes in which various layers of borders become articulated, deconstructed and reconstructed by both activists and advocates. While many scholars currently tend to highlight the relational character of spaces, this study – acknowledging that seeing regions as relational or territorial is a highly contextual matter – emphasizes the territorial approach by stressing the multiple layers of borders and how they help to constitute and nurture regional identity. Focusing on deinstitutionalization of a region, it is argued here that regional restructuring can trigger activism, as proved by the activist movement at issue in the case study. This case study of a merger between two municipalities in Finland illustrates that when threatened with integration, (old) regions seem to be of especial importance as bordered territories of identification.  相似文献   

Modeling Fine‐Scale Geological Heterogeneity—Examples of Sand Lenses in Tills     

Timo Christian Kessler  Alessandro Comunian  Fabio Oriani  Philippe Renard  Bertel Nilsson  Knud Erik Klint  Poul Løgstrup Bjerg 《Ground water》2013,51(5):692-705

Sand lenses at various spatial scales are recognized to add heterogeneity to glacial sediments. They have high hydraulic conductivities relative to the surrounding till matrix and may affect the advective transport of water and contaminants in clayey till settings. Sand lenses were investigated on till outcrops producing binary images of geological cross‐sections capturing the size, shape and distribution of individual features. Sand lenses occur as elongated, anisotropic geobodies that vary in size and extent. Besides, sand lenses show strong non‐stationary patterns on section images that hamper subsequent simulation. Transition probability (TP) and multiple‐point statistics (MPS) were employed to simulate sand lens heterogeneity. We used one cross‐section to parameterize the spatial correlation and a second, parallel section as a reference: it allowed testing the quality of the simulations as a function of the amount of conditioning data under realistic conditions. The performance of the simulations was evaluated on the faithful reproduction of the specific geological structure caused by sand lenses. Multiple‐point statistics offer a better reproduction of sand lens geometry. However, two‐dimensional training images acquired by outcrop mapping are of limited use to generate three‐dimensional realizations with MPS. One can use a technique that consists in splitting the 3D domain into a set of slices in various directions that are sequentially simulated and reassembled into a 3D block. The identification of flow paths through a network of elongated sand lenses and the impact on the equivalent permeability in tills are essential to perform solute transport modeling in the low‐permeability sediments.  相似文献   

Foreword     

Matti Lepp?ranta  Timo Vihma  Huiding Wu 《极地研究(英文版)》2014,(4)

正Rapid changes of Arctic sea ice cover have been in the focus of the international climate research community in recent years.Quite a few of nations have completed a large number of related surveys and research projects in the Arctic Ocean.Up to now,China has performed six research cruises to the Arctic Ocean resulting in a significant volume of research output.Improved knowledge on the atmospheree-sea ice-ocean interactions in the Arctic is a  相似文献   

Deglaciation chronology of the Scandinavian Ice Sheet from the Lake Onega Basin to the Salpausselkä End Moraines     

Matti Saarnisto  Timo Saarinen 《Global and Planetary Change》2001,31(1-4)

Several long sediment cores (max. 12 m) from various parts (up to 150 km apart) of Lake Onega, Russian Karelia, have been studied for lithology, varve chronology and palaeomagnetism. The two longest varve records from the central basin contain 1300 varves. These indicate the length of the deglaciation period from these localities to the north of Lake Onega, where the drainage of glacial meltwaters was directed towards the White Sea and the deposition of varves in the Onega basin terminated. An estimate of the duration of deglaciation of the whole Onega basin is 1500 years. Natural remanent magnetization (NRM) is strong and stable in these sediments and accurately records changes in the Earth's magnetic field. A distinct change in the magnetic field, when the declination shifted from east to west by at least 60° in 350 varve years, is clearly identifiable in all cores. This palaeomagnetic feature was used for core to core correlation together with other variations in magnetic parameters and widely distributed lithological marker horizons. On the basis of the correlations between the cores and calibration of AMS radiocarbon dates from varves obtained from the northern archipelago of Lake Onega, the age of the westerly declination peak is dated to 13 090 cal. BP and accordingly the deglaciation of the Onega basin took place between 14 250 and 12 750±100 cal. BP. The westerly declination peak was also recognized earlier by Bakhmutov and Zagniy in the Helylä varved clay sequence near Sortavala on the northern shore of Lake Ladoga. Helylä is situated outside the Salpausselkä end moraines and the accumulation of varved clays continued there 1500 years after the declination peak, up until the drainage of the Baltic Ice Lake, which more or less coincides with the ice margin retreat from Salpausselkä II end moraine and the termination of the Younger Dryas event. The date thus arrived at for this event is 11 590±100 cal. BP, close to the recent results from Greenland ice cores and from varved lake sediments and tree rings from Central Europe. It is further suggested that the formation of the major Younger Dryas end moraines, the Finnish Salpausselkä I and Salpausselkä II and their correlatives in Russian Karelia, took place between 12 250 and 11 590 calendar years ago, clearly earlier than earlier estimated through correlation with the Swedish varve chronology.  相似文献