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Karst water tracing in some of the speleological features (caves and pits) in Dinaric karst area in Croatia
Published in A. Kranjc, Tracer Hydrology 97, 2020
Speleology has very important role in karst hydrogeology. Measuring of absolute neotectonic movements combined with explanations of speleogenesis and resolving of many karstification processes is possible in speleological features. Tectonic elements, invisible or “masked” on the surface (bedding, folds, faults, nappes, etc.), are resolved and documented by these neotectonic movements. Connection of speleological features (caves and pits) and karst ground water is even bigger. Flows which are directly measured and observed under ground are easier to understand than those which are only perceptive as “swallow hole - spring” phenomenon. Great number of underground connections were discovered only by injecting of special colors in swallow holes (ponors) and by registrating of color appearances in springs. The objective of speleohydrogeological researches that are conducted directly inside speleological features is comprehensive knowledge of speleological water channels, ground water flowing rules, amounts and directions of flows, chemical and bacteriological specialties of groundwater etc. Areas with differences in lithostratigraphic characteristics of primer rocks, in hydrogeological zoning, in speleomorphological types and hydrogeological functions of speleological features were selected.
Seismic ground motion parameters: An overview
Published in Edmund Booth, Seismic Design Practice into the Next Century, 1998
As earthquakes result from a sudden movement along a fault plane, the first undertaking in the field of anti-seismic protection is to identify such faults and to determine their potential in terms of magnitude. All branches of earth science need to be sollicited in order to succeed in doing this. Recent earthquakes such as El Asnam, in Algeria (1980), Coalinga (1983), Whittier Narrows (1987), and Northridge (1994), in California, and Armenia (1988) occurred on faults that had no visible expression at the surface. Thus the first lesson to be gained from this experience is the need to intensify multidisciplinary geological studies, including more particularly neotectonics, so as to identify these faults that lie concealed beneath sedimentary layers. Measurements of deformation rate using GPS techniques among others can be expected to improve seismic prevention in the not-too-distant future.
The tectonic history of Adelaide’s scarp-forming faults
Published in Australian Journal of Earth Sciences, 2019
The Adelaide Geosyncline (Preiss, 1987, 2000; Sprigg, 1952) is a complex of rift and sag basins that initiated at about 830 Ma; Table 1 shows a simplified stratigraphic summary for the Adelaide region. Extension of the Precambrian crust took place in at least five major rift episodes, each with its own locus, style, timing and extensional stress orientation. These rifting events established the long-standing weaknesses in the crust that persisted throughout every stage of the region’s subsequent tectonic history, and some may have even been inherited from structures in the Paleoproterozoic basement. The earliest rifting, of Willouran age, is recorded only by rift-valley sediments in the Flinders Ranges region several hundred kilometres north of Adelaide. This involved northeast–southwest extension accompanied by the intrusion of the 827 ± 6 Ma Gairdner Dolerite (Wingate, Campbell, Compston, & Gibson, 1998) and widespread extrusion of the Beda Basalt, Wooltana Volcanics and other equivalent mafic lavas. Subsequently, northwest-trending rift basins were filled with over 6 km of mixed clastic–carbonate–evaporite sediments, with minor continuing volcanism, e.g. the ca 800 Ma Rook Tuff. The Willouran Trough extended from the southern Flinders Ranges northwestward through the Willouran Ranges to the Peake and Denison ranges (Preiss, 1987, 2000). Significantly, these Willouran rifts did not affect the Adelaide region, which remained on the southwestern shoulder of these earliest extensional basins. This has important implications for the neotectonics, including seismicity, as the crust of the Flinders Ranges region has been more severely attenuated and weakened by this early deep fracturing and rifting than in the Mount Lofty Ranges.