EARTHQUAKES |
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An earthquake is a sudden and sometimes catastrophic movement of a part of the Earth's surface. Earthquakes result from the dynamic release of elastic strain energy that radiates seismic waves. Earthquakes typically result from the movement of faults, planar zones of deformation within the Earth's upper crust. The word earthquake is also widely used to indicate the source region itself. The Earth's lithosphere is a patch work of plates in slow but constant motion (see plate tectonics). Earthquakes occur where the stress resulting from the differential motion of these plates exceeds the strength of the crust. The highest stress (and possible weakest zones) are most often found at the boundaries of the tectonic plates and hence these locations are where the majority of earthquakes occur. Events located at plate boundaries are called interplate earthquakes; the less frequent events that occur in the interior of the lithospheric plates are called intraplate earthquakes (see, for example, New Madrid Seismic Zone). Earthquakes related to plate tectonics are called tectonic earthquakes. Most earthquakes are tectonic, but they also occur in volcanic regions and as the result of a number of anthropogenic sources, such as reservoir induced seismicity, mining and the removal or injection of fluids into the crust. Seismic waves including some strong enough to be felt by humans can also be caused by explosions (chemical or nuclear), landslides, and collapse of old mine shafts, though these sources are not strictly earthquakes. These sources will also show a different seismogram than earthquakes
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INVESTMENT BANKING |
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Investment banks assist public and private corporations in raising funds in the capital markets (both equity and debt), as well as in providing strategic advisory services for mergers, acquisitions and other types of financial transactions. They also act as intermediaries in trading for clients. Investment banks differ from commercial banks, which take deposits and make commercial and retail loans. In recent years, however, the lines between the two types of structures have blurred, especially as commercial banks have offered more investment banking services. In the US, the Glass-Steagall Act, initially created in the wake of the Stock Market Crash of 1929, prohibited banks from both accepting deposits and underwriting securities; Glass-Steagall was repealed by the Gramm-Leach-Bliley Act in 1998. Investment banks may also differ from brokerages, which in general assist in the purchase and sale of stocks, bonds, and mutual funds. However some firms operate as both brokerages and investment banks; this includes some of the best known financial services firms in the world.
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