Microseismics
Microseismics is a geophysical term used to describe very weak seismic waves , the origin of which can only be researched statistically.
Microseismic phenomena are also known as ground unrest or seismic noise . They show up in the seismogram of an earthquake control station only as a fine, semi-regular tremor that can generally neither be assigned to a specific earthquake nor to an artificially generated earthquake (see seismic ). The term can be defined statistically and is also used as a counterpart to macroseismics .
Microseismics include ground vibrations caused by the railroad or heavy vehicles (in the city especially by the subway ), the long-range effect of the surf on the seashore and, in some cases, the earth's tides . Weak distant earthquakes or short-period swarms of earthquakes can also have an effect as a slight, pseudo-statistical tremor of the seismograph at a greater distance .
The seismic noise in the near field of the earthquake observatory is kept to a minimum due to the special selection made on a geologically stable subsurface, which can also be achieved by special vibration damping of the building.
From a statistical point of view, definitions of the term could be found by analyzing parameters such as amplitude and period characteristics. From the point of view of the scientific user , all phenomena can be counted in microseismics that are below the detection limit of earthquakes or cannot be assigned to such.
application
As part of the operation hamster data were microseismic vibrations caused by trucks -Transport to and from a NVA - ammunition depot goal intelligence investigations.