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Geological Structures
Published in F.G.H. Blyth, M. H. de Freitas, A Geology for Engineers, 2017
F.G.H. Blyth, M. H. de Freitas
Strike and dip are two fundamental conceptions in structural geology, and are the geologist’s method of defining the attitude of inclined strata. The information is placed on a map as a short arrow (dip arrow) with its tip at the point of observation, together with a number giving the angle of true dip (Fig. 12.1). For horizontal beds the symbol + is used, i.e. where the dip is zero.
Distribution of rocks at and below the surface
Published in A.C. McLean, C. D. Gribble, Geology for Civil Engineers, 2017
As with all structural surfaces, the orientation of a fault is expressed by its strike and dip. The displacement across a fault is called its slip, and the terms used to describe the components of slip (strike slip, dip slip and throw) are illustrated in Figure 4.18.
Stability assessment of tertiary stratified slope by using GIS and stereo-net
Published in Wang Sijing, Fu Bingjun, Li Zhongkui, st Century, 2020
Zhang Xiaobing, Teturo Esaki, Zhou Guoyun, Yasuhiro Mitani
known that most of slope failure patterns are plane slip along weak strata. The strike and dip of both rock strata and slope planes are the most fundamental element for plane slip slope failure. The stereo-net method is suitable to evaluate slope stability in this area.
Geochemical characteristics and structural setting of lithium–caesium–tantalum pegmatites of the Dorchap Dyke Swarm, northeast Victoria, Australia
Published in Australian Journal of Earth Sciences, 2023
B. R. Hines, D. Turnbull, L. Ashworth, S. McKnight
Structural measurements indicate a consistent northwest–southeast orientation of pegmatite dykes, with a mean strike of 125° (Figure 7a). Pegmatite dykes of the Dorchap Dyke Swarm are commonly steeply dipping (65–80°), although equally divided between northeast and southwest dip directions (Figure 7b). Dyke orientations demonstrate a strong structural control, with dyke orientations parallel to the fold axial planes and S1 cleavage of a northwest-trending shear system associated with tight, isoclinal folding of metasediments of the Omeo Metamorphic Complex, with several dykes demonstrating a northwest–southeast-trending (130–150°), possibly tectonic foliation within the pegmatite dyke itself (Figure 7b, c). Notably northeast-dipping dykes demonstrate a greater variation in strike and dip orientation (Figure 7b).
Stochastic source modeling and tsunami simulations of cascadia subduction earthquakes for Canadian Pacific coast
Published in Coastal Engineering Journal, 2022
The geometry of the CSZ is complex, being curved along the strike and becoming steeper along the dip, and cannot be represented by a collection of low spatial resolution sub-faults (e.g. several tens of kilometers, such as ComMIT/MOST model v. 1.7.0; Figure 4(a)). The Slab2 model for the CSZ can capture the complex geometry with variable strike and dip angles. The data are provided at grid points with 0.05° spatial resolution (4∼5 km). By limiting the sub-fault depths to 30 km, which is consistent with thermal studies of the CSZ (e.g. Fluck, Hyndman, and Wang 1997; Wang et al. 2003), a fault plane model for the CSZ, consisting of 7,452 sub-faults, is developed. Figure 5 shows the sub-faults together with depths, strike angles, and dip angles. Each sub-fault has a dimension of 5.6 km along the strike and 3.8 km along the dip. The spatial variations of the strike and dip angles show that the modeled fault plane is curved in a complex manner. These sub-faults are used as a basis to generate stochastic source models for the CSZ in Section 3.2.
The Cooper–Eromanga petroleum province, Australia
Published in Australian Journal of Earth Sciences, 2022
D. Kulikowski, K. Amrouch, K. Pokalai, S. I. Mackie, M. E. Gray, H. B. Burgin
Natural fractures can provide highly permeable pathways for hydrocarbon production if the local and regional fracture set geometries are known. The strike and dip angle of fracture sets are equally as important for optimising hydrocarbon recovery. Six regionally pervasive conjugate natural fracture sets (Figure 14a) are present in the Cooper–Eromanga basins (Kulikowski & Amrouch, 2017). The timing of their development, stratigraphic distribution and spatial intensity has been well constrained (Kulikowski, 2017; Kulikowski & Amrouch, 2017; Kulikowski, Cooke, et al., 2016). Extrapolation of wellbore-derived natural fractures and faults to the wider reservoir (Abul Khair et al., 2012, 2013, 2015; Backé et al., 2011; King et al., 2011; Kulikowski, Amrouch, and Burgin, 2018), suggests that upwards of 70% of wellbore fractures are represented in seismic curvature results.