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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Μορφοτεκτονική ανάλυση του ρήγματος Πεύκου Μεσσηνίας

Κουφόγιαννης, Ηλίας 02 April 2014 (has links)
Οι επαναλαμβανόμενες σεισμικές δονήσεις στη περιοχή, και ειδικότερα μετά τους σεισμούς στις 10/10/2001 (3,9 βαθμοί της κλίμακας Ρίχτερ) και στις 23/11/2011 (3,3 βαθμοί της κλίμακας Ρίχτερ), οι οποίοι προκάλεσαν εμφανείς ζημίες και οδήγησαν στο να κριθούν κτίρια της περιοχής ακατοίκητα, έγειραν το γεωλογικό ενδιαφέρον. Πιο συγκεκριμένα στόχος της παρούσας εργασίας είναι η χρήση μορφομετρικών δεικτών για τον υπολογισμό της ενεργότητας του ρήγματος. / Application of morphotectonic criteria for the qualitative and quantitative determination of the tectonic activity on the mountain range front segment, which is formed north – east of Arfara town, located in Messinia, southern – western part of Peloponnese.
2

Quaternary Geology and Tectonic Geomorphology of the Pocatello Valley Area, Idaho-Utah

Garr, John D. 01 May 1988 (has links)
Pocatello Valley in southeastern Idaho and northern Utah is a structural and topographic basin bounded on all sides by mountains composed of Paleozoic platform carbonates and elastics. In the late Pleistocene it contained pluvial Lake Utaho, which, prior to 1981, was considered to have been an arm of Lake Bonneville. This study corroborates the finding of Currey (1981) that the two lakes were separate. The Quaternary deposits examined in this study are divided into two broad groups: those that were deposited prior to the last pluvial lake cycle, and those that were deposited during and after the pluvial lake maximum, (since approximately 16 ka) when the area was occupied by Lake Utaho and Lake Bonneville. Pediment gravels, alluvial fans, piedmont colluvium, and talus comprise the older group: the younger deposits include stream channel deposits, lacustrine sediments, and loess. Quantitative front sinuosity height ratios) geomorphological techniques (mountain ratios and valley floor width-valley indicate that the bounding ranges on the east and west margins of Pocatello Valley are slightly to moderately active tectonically. Precise surveying of the Lake Utaho highstand shoreline revealed significant deviations from the smooth, isostatically rebounded shoreline elevation curve of Crittenden (1963). The greatest deflections occur where the sinuous shoreline crosses the more linear inferred range front faults at the base of Samaria Mountain, on the east margin of the valley. The deflections (as much as 6.4 m over a horizontal distance of 900 m) suggest that movement has occurred along the range front faults since the shorelines were created approximately 16 ka, but no fault scarps were formed. A buried colluvium estimated to be 95 ka + 15 ka that was exposed draped toward in a over the trench at the range the inferred fault, valley. There are front is monoclinally and dips as much as 49° no fractures in the colluvium, which suggests that, although relative movement between the mountain and valley blocks has occurred, the displacement has only warped the colluvium. This further suggests that any earthquakes accompanying the movements must have been below the magnitude threshold (ML 6.2-6.3) necessary for surface rupture.
3

Seismic Structure of the Western U.S. Mantle and Its Relation to Regional Tectonic and Magmatic Activity

Schmandt, Brandon, 1984- 09 1900 (has links)
xii, 95 p. : ill. (some col.) / Vigorous convective activity in the western U.S. mantle has long been inferred from the region's widespread intra-plate crustal deformation, volcanism, and high elevations, but the specific form of convective activity and the degree and nature of lithospheric involvement have been strongly debated. I design a seismic travel-time tomography method and implement it with seismic data from the EarthScope Transportable Array and complementary arrays to constrain three-dimensional seismic structure beneath the western U.S. Tomographic images of variations in compressional velocity, shear velocity, and the ratio of shear to compressional velocity in the western U.S. mantle to a depth of 1000 km are produced. Using these results I investigate mantle physical properties, Cenozoic subduction history, and the influence of small-scale lithospheric convection on regional tectonic and magmatic activity, with particular focus on southern California and the Pacific Northwest. This dissertation includes previously published co-authored material. Chapter II presents a travel-time tomography method I designed and first implemented with data from southern California and the surrounding southwestern U.S. The resulting images provide a new level of constraint on upper mantle seismic anomalies beneath the Transverse Ranges, southern Great Valley, Salton Trough, and southwestern Nevada volcanic field. Chapter III presents tomographic images of the western U.S. mantle, identifies upper mantle volumes where partial melt is probable, and discusses implications of the apparently widespread occurrence of gravitational instabilities of continental lithsophere and the complex geometry and buoyancy of subducted ocean lithosphere imaged beneath the western U.S. In Chapter IV, tomography images are used in conjunction with geologic constraints on major transitions in crustal deformation and magmatism to construct a model for Pacific Northwest evolution since the Cretaceous. Accretion in the Pacific Northwest at 55-50 Ma is suggested to stimulate roll-back of the flat subducting Farallon slab. This change in convergent margin structure is further suggested to drive the short-lived Challis magmatic trend and trigger the southward propagating Eocene-Oligocene transition from the Laramide orogeny to widespread crustal extension and ignimbrite magmatism. / Committee in charge: Eugene Humphreys, Chair; Douglas Toomey, Member; Emilie Hooft Toomey, Member; John Conery, Outside Member
4

Mapa geodynamických jevů v oblasti Nízkých Tater / Map of geodynamic phenomena in Lower Tatra area

Jackulíková, Denisa January 2017 (has links)
This investigative thesis provides an overview of the structural and kinematic formation of the Low Tatras in Slovakia. Numerous geological and geomorphological data from previous studies of the researched area were available. These were processed in a graphical user interface ArcMap to produce the Geodynamic map of Low Tatras at a scale of 1:200 000. By illustrating geodetic, geomorphologic, geophysical and other similar data on this map, it was possible to undertake a detailed analysis of the area and allow an assessment of the overall tectonic activity. This revealed two regions with higher than normal stress levels and therefore an associated increase in the risk of future seismic activity.

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