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In fluid dynamics, angle of attack (AOA, α, or ) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is moving. [1] Angle of attack is the angle between the body's reference line and the oncoming flow.
For shallow earthquakes – less than roughly 60 km deep – the surface waves are stronger, and may last several minutes; these carry most of the energy of the quake, and cause the most severe damage. An earthquake radiates energy in the form of different kinds of seismic waves, whose characteristics reflect the nature of both the rupture and ...
Earthquakes create distinct types of waves with different velocities. When recorded by a seismic observatory, their different travel times help scientists locate the quake's hypocenter. In geophysics, the refraction or reflection of seismic waves is used for research into Earth's internal structure. Scientists sometimes generate and measure ...
Moderately damaging earthquakes strike between New York and Wilmington, Delaware, about twice a century, the USGS said, and smaller earthquakes are felt in the region roughly every two to three years.
This is in contrast with the seismic magnitude usually reported for an earthquake. Magnitude scales measure the inherent force or strength of an earthquake – an event occurring at greater or lesser depth. (The "M w" scale is widely used.) The MM scale measures intensity of shaking, at any particular location, on the surface.
Fig.2 : Site effects in Mexico city: recordings from the 1985 earthquake. Seismic site effects have been first evidenced during the 1985 Mexico City earthquake. [4] The earthquake epicenter was located along the Pacific Coast (several hundreds kilometers from Mexico-City), the seismic shaking was however extremely strong leading to very large damages.
They can still propagate through the solid inner core: when a P wave strikes the boundary of molten and solid cores at an oblique angle, S waves will form and propagate in the solid medium. When these S waves hit the boundary again at an oblique angle, they will in turn create P waves that propagate through the liquid medium.
In a normal seismic hazard analyses intended for the public, that of a "maximum considered earthquake", or "maximum considered event" (MCE) for a specific area, is an earthquake that is expected to occur once in approximately 2,500 years; that is, it has a 2-percent probability of being exceeded in 50 years.