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A deep-focus earthquake in seismology (also called a plutonic earthquake) is an earthquake with a hypocenter depth exceeding 300 km. They occur almost exclusively at convergent boundaries in association with subducted oceanic lithosphere .
In seismology, the depth of focus or focal depth is the depth at which an earthquake occurs. Earthquakes occurring at a depth of less than 70 km (43 mi) are classified as shallow-focus earthquakes, while those with a focal depth between 70 km (43 mi) and 300 km (190 mi) are commonly termed mid-focus or intermediate-depth earthquakes. [1]
Deep-focus earthquakes occur at a depth where the subducted lithosphere should no longer be brittle, due to the high temperature and pressure. A possible mechanism for the generation of deep-focus earthquakes is faulting caused by olivine undergoing a phase transition into a spinel structure. [22]
Hypocenter (Focus) and epicenter of an earthquake. An earthquake's hypocenter or focus is the position where the strain energy stored in the rock is first released, marking the point where the fault begins to rupture. [3] This occurs directly beneath the epicenter, at a distance known as the hypocentral depth or focal depth. [3]
A major earthquake measuring 7.4 hit Taiwan early Wednesday, killing 9 and injuring at least 1,000. A 7.4 earthquake is exponentially more destructive than the 4.8 quake that struck central New ...
Deep-focus earthquake, also called a plutonic earthquake, an earthquake with a depth exceeding 70 kilometres (43 mi). [5] Doublet earthquake, an earthquake that consists of at least two or more mainshocks of nearly identical magnitude, separated by a period of time. [6]
Friday morning's earthquake, an event more commonly associated with California, was the first many Northeasterners had ever felt.. The temblor, which measured 4.8 on the Richter scale, was ...
The magnitude of an earthquake is related to the total area of its fault rupture. [8] Most earthquakes are small, with rupture dimensions less than the depth of the focus so the rupture doesn't break the surface, but in high magnitude, destructive earthquakes, surface breaks are common. [8]