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A tectonic earthquake begins by an initial rupture at a point on the fault surface, a process known as nucleation. The scale of the nucleation zone is uncertain, with some evidence, such as the rupture dimensions of the smallest earthquakes, suggesting that it is smaller than 100 m while other evidence, such as a slow component revealed by low-frequency spectra of some earthquakes, suggest ...
In most earthquakes, the isoseismals define a single clear area of maximum intensity, which is known as the epicentral or meizoseismal area. [8] In some earthquakes, more than one maximum exists because of the effect of ground conditions or complexities in the rupture propagation, and other information is, therefore, required to identify the ...
The moment tensor solution is displayed graphically using a so-called beachball diagram. The pattern of energy radiated during an earthquake with a single direction of motion on a single fault plane may be modelled as a double couple, which is described mathematically as a special case of a second order tensor (similar to those for stress and strain) known as the moment tensor.
In seismology, an aftershock is a smaller earthquake that follows a larger earthquake, in the same area of the main shock, caused as the displaced crust adjusts to the effects of the main shock. Large earthquakes can have hundreds to thousands of instrumentally detectable aftershocks, which steadily decrease in magnitude and frequency according ...
This is backed up by evidence that the rupture of the 2001 Kunlun earthquake jumped more than 10 km across an extensional stepover. [3] The presence of stepovers during the rupture of strike-slip fault zones has been associated with the initiation of supershear propagation (propagation in excess of the S wave velocity) during earthquake rupture ...
[[Category:Earthquake templates]] to the <includeonly> section at the bottom of that page. Otherwise, add <noinclude>[[Category:Earthquake templates]]</noinclude> to the end of the template code, making sure it starts on the same line as the code's last character.
Evidence of rupture propagation at velocities greater than S wave velocities expected for the surrounding crust have been observed for several large earthquakes associated with strike-slip faults. During strike-slip, the main component of rupture propagation will be horizontal, in the direction of displacement, as a Mode II (in-plane) shear crack.
Typical values for P wave velocity in earthquakes are in the range 5 to 8 km/s. The precise speed varies according to the region of the Earth's interior, from less than 6 km/s in the Earth's crust to 13.5 km/s in the lower mantle, and 11 km/s through the inner core.