Observations and Theory of Microseisms
1951; American Meteorological Society; Linguagem: Inglês
10.1007/978-1-940033-70-9_107
Autores Tópico(s)Ultrasonics and Acoustic Wave Propagation
ResumoAs soon as fairly sensitive seismographs were available, it was found that the ground is never at rest. Various terms such as pulsations, pulsatory oscillations, microseismic movements, and microseisms were used to describe these continuous small movements which are not caused by earthquakes. Hecker, in 1906, divided the microseisms, as they are now usually called, into four groups: (1) those with periods of less than 4 sec, (2) those with periods of about 7 sec, (3) those with periods of about 30 sec, and (4) those with periods of about one minute and more. Later, additional types of microseisms were described. For a bibliography, see [4].
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