ROTAPHONE - a mechanical sensor system for measuring seismic ground motions and a method of seismic measurement using this system

ROTAPHONE - a mechanical sensor system for measuring seismic ground motions and a method of seismic measurement using this system

A measuring instrument, a combined seismic sensor system able to measure 6 components of seismic motion, i.e. 3 orthogonal translations components, 3 rotational components around the orthogonal axes  at a given measurement point. The instrument is suitable for measuring wave fields generated both by man-made sources (quarry blasts, a generator of rotational motions) and by natural sources (e.g. local earthquakes, rockbursts etc.).


The frame of the instrument is a solid rigid body adapted so that it can be easily attached to the ground motion of which is measured. Advantageously, it can have the shape of a disc or cylinder, for example. Typically, its dimensions are within decimetres to meters, usually within 1 m. Its weight enables easy transfer and manipulation and for that reason it is typically made of light metals (e.g. duralumin). Seismic sensors are mounted at various points on the frame and are of two types, vertical and horizontal, according to the seismic motion component they measure. The horizontal sensors have varying orientations so that it is possible to derive from them the waveform of two mutually perpendicular horizontal seismic components. The lowest number of sensors that need to be deployed on the frame for measuring three translational and three rotational components using a calibration based on the frame rigidity is 4 vertical sensors and 4 horizontal sensors. Nevertheless, it is advantageous to use a higher, even number of sensors that are arranged in parallel pairs.


The primary outputs of the seismic sensors are signals from vertical and horizontal sensors, e.g. geophones. The sensor outputs do not represent the real ground motion, however, because they are influenced by the frequency characteristics of the sensors. The goal is to measure the real ground motion in a certain frequency band. For that reason, the signals from the sensors are filtered with a band filter and are corrected with regard to the frequency characteristics.


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Poslední změna: 21. leden 2018 23:47 
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Univerzita Karlova

Ovocný trh 560/5

Praha 1, 116 36

Česká republika


Identifikátor datové schránky: piyj9b4

IČO: 00216208 

DIČ: CZ00216208


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