Stove process
The hearth process (also hearth process or hearth mechanism ) describes the sequence of events on which an earthquake is based. The beginning of the stove operation is as oven time (ger .: origin time indicated). The earthquake focus is located in the interior of the earth and encompasses the entire focus area involved, while the hypocenter describes the starting point of the rupture process (i.e. at the moment of the focus) and the epicenter denotes the point on the earth's surface that is vertically above it.
What happens at the hearth surface was first described in the early 20th century by the "elastic rebound theory" by the US geologist Harry Fielding Reid , which is still largely valid today:
Two blocks of crust (that can be relatively small fragments or entire lithospheric plates ) move against each other. Mechanical tension is built up in the contact area of the two blocks.
If the built-up tension exceeds the strength of the rock, fracture occurs, which is what constitutes the hearth process itself. In the process, the mechanical tension that has built up is discharged as the rock sections suddenly move against each other directly on the fracture surface, the hearth surface , thus creating a warp . The distance of the shift against each other is called the offset . This sudden movement triggers seismic waves that propagate radially from the fracture surface. An earthquake focus can only lie in the earth's crust , since only here is the rock brittle enough that it can break.
The propagation of the earthquake waves is influenced by the orientation of the focal area in the room, the duration and the rate of propagation of the fracture. This process and its chronological sequence represent the focus process. If the waves emanating (radiated) from an earthquake focus are recorded at a sufficient number of measuring stations in as many different azimuths as possible , the radiation characteristics of the quake can be determined from the waveform . The first use of the P-waves is usually used for this purpose. The evaluation of the seismic data results in the so-called hearth surface solution .
Individual evidence
- ^ Harry F. Reid: The elastic-rebound theory of earthquakes. University of California Publications. Bulletin of the Department of Geology. Vol. 6, 1911, pp. 413-444 ( HathiTrust ).