Comparative Measurements of Local Seismic Rotations by Three Independent Methods

0534817 - ÚSMH 2022 RIV CH eng J - Journal Article
Brokešová, J. - Málek, Jiří
Comparative Measurements of Local Seismic Rotations by Three Independent Methods.
Sensors. Roč. 20, č. 19 (2020), č. článku 5679. E-ISSN 1424-8220
R&D Projects: GA MŠMT(CZ) LTAUSA19083
Institutional support: RVO:67985891
Keywords : seismic rotation * rotational seismometer * Rotaphone * seismic array
OECD category: Geology
Impact factor: 3.576, year: 2020
Method of publishing: Open access
https://www.mdpi.com/1424-8220/20/19/5679

A comparative active experiment that is aimed at collocated measurement of seismic rotation rates along three orthogonal axes by means of three different methods is described. The rotation rates in a short-period range of 6-20 Hz were obtained using three different methods: the 6C Rotaphone sensor system developed by the authors, the commercial R-1 rotational sensor by Eentec, and a small-aperture array of twelve standard velocigraphs in a rectangular arrangement. Those three methods are compared and discussed in detail. A medium-size quarry blast was used as a seismic source. At a distance of approximately 240 m, the rotation rates reached an amplitude of the order of magnitude of 10(-4)-10(-5) rad/s. The array derived rotation rates displayed serious limitations, as clearly documented. The R-1 instruments have shown certain technical problems that partly limit their applicability. The measured rotation rates were compared to the relevant acceleration components according to rotation-to-translation relations. Out of all the three methods, the records best matching the acceleration components were made by Rotaphone. The experiment also revealed that rotation rates in the given short-period range noticeably changed over a distance as short as 2 m.
Permanent Link: http://hdl.handle.net/11104/0326944