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Petroleum Geological Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
The earth’s crust can be divided broadly into rigid and soft blocks. The rigid block is of relatively low mobility is called a ‘platform’, and a soft, mobile block is known a ‘geosyncline basin’. A platform is a part of land that is covered by sedimentary rock underlain by igneous and metamorphic basement rocks. Both igneous and metamorphic often crop out at the surface. A geosyncline basin is a large-scale depression in the earth’s crust. It is an open concave elongated trough (valley) on the earth’s surface. A platform block is unfit for petroleum, and the geosynclines basin is a favorable location for petroleum prospecting. A petroleum basin is a portion of a geosyncline basin. A petroleum basin is an open, shallow depression of greater width and length than depth and filled with sedimentary materals. Petroleum is generated and generally found in the sedimentary rock. Although sedimentary rock covers about 75% of the earth’s crust, not all regions of rock are suitable for oil and gas formation. Petroleum gas and oil fields are restricted to some selected areas of sedimentary rock in the form of land depressions or basins. Oil- and gas-bearing sediment basins are mostly located in the coastal and sea continental shelf area of the earth’s crust. Many off-shore petroleum fields are discovered and operated in these regions. A petroleum basin may be an oil-bearing or gas-bearing basin, or both oil and gas.
Subsidence above rock-salt cavities — Numerical and explicit evaluations
Published in M. Matos Fernandes, L. Ribeiro E Sousa, R.F. Azevedo, E.A. Vargas, Applications of Computational Mechanics in Geotechnical Engineering, 2020
J.E. Quintanilha de Menezes, D. Nguyen-Minh
Subsidence or vertical displacements can give rise to trough formation at the surface. Horizontal displacements can have serious consequences on existing surface structures. Usual empirical methods are incomplete for some situations as they only estimate subsidence values and not dangerous horizontal movements.
Theoretical analysis of ground deformation due to tunnelling through weak deposits of phosphatic chalk in area of the proposed Stonehenge tunnel
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2020
As can be seen in Figure 4 modelled settlement troughs do not follow Gaussian distribution as is the case with tunnelling in soft ground (O’Reilly and New, 1982) and was observed on Crossrail drive C310. Modeled troughs are narrower, deeper, and somewhat irregular in shape with smaller cross sectional areas than a trough of similar depth in soft ground. The shape of the settlement troughs are controlled by discontinuity spacing rather than particle interaction, as is the case with soft ground.
Cyclic tidalites and seismites at a submarine hydrothermal system for a 2450 Ma banded iron formation, Hamersley Basin, Western Australia
Published in Australian Journal of Earth Sciences, 2023
Both semidiurnal and diurnal tidal periods have been detected, with semidiurnal periods (12–12.5 h) dominant at most sites (‘semidiurnal’ and ‘diurnal’ refer to the lunar day, which is longer than the solar day, now being 24.8 h). Semidiurnal variations in submarine hydrothermal discharge and other factors occur at the crests of mid-ocean ridges and in backarc settings (Glasby & Kasahara, 2001). Schultz et al. (1992) identified predominantly semidiurnal periodicity in effluent discharge and temperature at the Juan de Fuca Ridge off northwest North America. Nishizawa et al. (1995) and Fujioka et al. (1997) found that cycles of hydrothermal upflow at the 200 m-diameter TAG (Trans-Atlantic Geotraverse) hydrothermal mound correlated with semidiurnal variations in tidal loading and earth tides. Observations of hydrothermal areas in the Mariana Trough in the western Pacific, the TAG area of the Mid-Atlantic Ridge and the Okinawa Trough in the East China Sea showed that low-frequency pressure pulses, suggesting hydrothermal upwelling, correlated with semidiurnal and diurnal tidal periods (Kasahara & Sato, 2001). At the Lucky Strike deep-sea vent on the Mid-Atlantic Ridge, hydrothermal discharge temperature records show semidiurnal frequencies (Barreyre et al., 2014). Additionally, prevailing semidiurnal and diurnal tidal bottom currents periodically advect non-buoyant effluent at the TAG hydrothermal mound (Kinoshita et al., 1998).
Variation analysis of multiple tsunami inundation models
Published in Coastal Engineering Journal, 2022
Yoshinori Shigihara, Kentaro Imai, Hiroyuki Iwase, Koji Kawasaki, Makoto Nemoto, Toshitaka Baba, Naotaka Yamamoto Chikasada, Yu Chida, Taro Arikawa
In the tsunami source model, there are 11 fault models that were developed for the Nankai Trough mega earthquake. Among them, we used Case 4, which has a large fault slip off the Shikoku region (see Figure 1 for details of the crustal deformation). Normally, for a magnitude 9 earthquake, the effects of dynamic fault rupture, that is, rupture speed and rise time, should be considered. For the sake of simplicity, we did not take them into account and set them so that the permanent displacement was reached the moment the earthquake occurred. The dataset contains crustal deformation (i.e. initial water surface level distribution) precomputed by the fault parameters of the earthquake. (The spatial grid spacing was computed at an 810 m resolution). We used these data as a basis for generating crustal deformation data for other spatial resolutions. The interpolation method used was arbitrary.
Framework for estimating the risk and resilience of road networks with bridges and embankments under both seismic and tsunami hazards
Published in Structure and Infrastructure Engineering, 2020
Hiroki Ishibashi, Mitsuyoshi Akiyama, Dan M. Frangopol, Shunichi Koshimura, Takayuki Kojima, Kengo Nanami
The next Nankai Trough earthquake is a concern in Japan. The occurrence probability within 30 years of the Nankai Trough earthquake has been estimated to range from 70 to 80% by the Headquarters for Earthquake Research Promotion (2013). It is expected that the damage to structures and the social impacts associated with the recovery process resulting from the ground motions and/or tsunamis caused by the Nankai Trough earthquake would be greater than those caused by the 2011 Great East Japan earthquake (Cabinet Office, Government of Japan, 2012a, 2012b; Central Disaster Management Council, 2003). Considering the damage due to recent large earthquakes and the anticipated Nankai Trough earthquake, disaster mitigation measures should be implemented based on not only reliability-based indicators that provide the safety level of individual structures but also social impacts, such as the economic loss, degradation of functionality and recovery time of road networks (Akiyama, Frangopol, Arai, & Koshimura, 2013).