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Historical Note on Earthquakes
Published in Santiago Pujol, Ayhan Irfanoglu, Aishwarya Puranam, Drift-Driven Design of Buildings, 2022
Santiago Pujol, Ayhan Irfanoglu, Aishwarya Puranam
The shell of the earth, the crust, can be said to have two different thicknesses. Under the oceans, it is relatively thin. It varies in thickness from 5 to 8 km. Under the land masses, it is relatively thick. The thickness of the continental crust varies from 10 to 65 km. The eggshell analogy for the crust is not an exaggeration. It is paper thin compared with the radius of the earth, which is approximately 6,400 km. The total weight of the continental crust is less than 0.3% of the weight of the earth. Variations in the crust thickness are compensated by the weight of the water and the differences in the specific gravities of the crust under the oceans (3.0–3.1) and under the continents (2.7–2.8). If one thinks of the crust as virtually floating on the mantle, one is less likely to wonder why the earth does not wobble as it rotates about its axis. The weight of the crust plus the mantle has a reasonably uniform distribution over the globe.
Paths to the Energy Miracles
Published in H. B. Glushakow, Energy Miracles, 2022
Figure 125 is a diagram of the cross-sectional area of the Earth. The Earth’s crust is 35 km (21 miles) thick on average. At the boundary between crust and mantle, temperatures range from 500 to 1000°C (932 to 1864°F). At the deeper levels of the mantle bordering on the outer core, the temperature rises to 4000°C (7230°F).
Petroleum Geological Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
The earth’s crust is a thin layer of igneous, metamorphic and sedimentary rock covering the earth’s surface (already discussed). The earth’s crust can be divided into the continental (land) crust and the ocean crust. The oceanic crust consists of the sea bottom. Both crusts exhibit similarities as well as clear distinctions. The continental crust is lighter, lower-density and thicker than the ocean crust. The thickness of the continental crust varies from 20 to 70 km, whereas the thickness of the ocean crust is almost uniform and constant (8–10 km). The continental crust is made up of lighter minerals containing lighter elements such as silicon, aluminum and calcium; the ocean crust is predominantly made up of the heavier minerals containing heavier elements magnesium, iron and nickel. The ocean bottom crust is more active geologically. Underground geological phenomena are more pronounced in the ocean bottom than on land. Both types of crust are constantly being made and broken. However the continental crust is comparatively stable.
Propagation of Love-type wave in functionally graded pre-stressed magneto-visco-elastic fiber-reinforced composite structure
Published in Waves in Random and Complex Media, 2021
Pooja Singh, Amares Chattopadhyay, Abhishek Kumar Singh
Earthquake generally occurs when rock subterranean suddenly breaks and produces an enormous amount of energy in the Earth’s lithosphere leading to the generation of seismic waves. Lithosphere is a transition zone comprises of crust and upper part of the mantle where most of the geological phenomena such as earthquake, movement of tectonic plates and volcanic eruption take place, mechanical properties of which play a vital role for several geological reasons. When there is a sudden change in the physical properties of rock, seismic wave gets reflected and refracted through the boundaries and traces out different layers of the Earth’s interior. The study of Love wave is used for understanding the mechanism of earthquakes which produces horizontal motion to the ground and confined to the surface of the crust. Also, their propagation depends on the mechanism and magnitude of the earthquake, the epicenter distance and the structure of the Earth’s crust along the wave path. Jeffreys and Bullen [1] were analyzed the studies of Earth structure which is based on seismological observations.