Six-degree-of-freedom near-source seismic motions II: examples of real seismogram analysis and S-wave velocity retrieval

Brokešová, Johana; Málek, Jiří

doi:10.1007/s10950-015-9480-5

Cited by 21 publications

(11 citation statements)

References 31 publications

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“…The relation was confirmed with a simple geometrical consideration of motions [22,23]. The same results were found also in the seismic near field, where the spherical wave front was taken as a sufficient approximation [24,25]. This aspect of the measured oscillations leads to one of the reasons to study rotations--the phase velocity may be easily assessed in this way.…”

Section: Seismic Rotation In Various Continuum Modelssupporting

confidence: 68%

Measurement of Rotational Events in Regions Prone to Seismicity: A Review

Jaroszewicz¹,

Kurzych²,

Teisseyre³

et al. 2018

Geophysics

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On the basis of the explanation of rotational seismology as an area of study, a modern approach to the seismic rotation in various continuum models is summarized. The aim of this chapter is to formulate the fundamental requirements for rotational seismometer. Consequently, a review of all existing technologies of rotational seismometers including mechanical, electrochemical, magnetohydrodynamical, as well as optical type solutions is discussed. The analysis of their parameters that considers technical requirements enforced by rotational seismology has indicated an optical instrument using a Sagnac interferometer as the best solution. Fibre-Optic System for Rotational Events & phenomena Monitoring (FOSREM) with its main parameters and features is described as an example of such solution. Moreover, the example of rotational events recorded in Książ observatory, Poland, using mechanical rotational seismometers and FOSREM is presented. There are data for M = 3.8 earthquake near Jarocin, Poland on the 2012.01.06 at 15:37:56 at a distance of about 200 km from Książ. Although the used devices have totally different designs, the results obtained using FOSREM and the results calculated by mechanical devices show compatibility in rotational signals.

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Section: Seismic Rotation In Various Continuum Modelssupporting

confidence: 68%

Measurement of Rotational Events in Regions Prone to Seismicity: A Review

Jaroszewicz¹,

Kurzych²,

Teisseyre³

et al. 2018

Geophysics

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“…Some of the results of those tests are reported in the paper by Brokešová et al [ 27 ]. Besides several-months lasting measuring campaigns in the West Bohemia/Vogtland earthquake swarm region (Czech Republic) and in the active opening rift region of the Gulf of Corinth (Greece), it has been successfully applied since 2013 in a continuous monitoring in the vicinity of the Katla volcano, South Iceland [ 28 , 29 ]. Table 1 (middle) specifies the parameters of the instrument.…”

Section: Methods That Were Used To Determine Seismic Rotationmentioning

confidence: 99%

Comparative Measurements of Local Seismic Rotations by Three Independent Methods

Brokešová

Málek

2020

Sensors

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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.

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“…The Rotaphone (Brokesova and Malek, 2015) is an instrument that effectively estimates rotations by differencing pairs of closely spaced geophones, as shown in Appendix B's equation B-4. Figure 6b shows the instrument design.…”

Section: Rotaphonementioning

confidence: 99%

Recording active-seismic ground rotations using induction-coil magnetometers

et al. 2018

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Most of the current rotational sensing technology is not geared toward the recording of seismic rotations' amplitudes and frequencies. There are few instruments that are designed for rotational seismology, and the technology for building them is currently being developed. There are no mass industrial producers of seismic rotation sensors as there are for geophones, and only one current sensor model can be deployed on the ocean bottom. We reviewed some current rotationalseismic acquisition technologies, and developed a new method of recording rotations using an existing, robust and fielddeployable technology that had seen extensive use in large exploration surveys: induction-coil magnetometers. We conducted an active seismic experiment, in which we found that magnetometers could be used to record seismic rotations. We converted the magnetometer data to rotation-rate data, and validated them by comparing the waveforms and amplitudes with rotation rates recorded by electrokinetic rotation sensors.

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Six-degree-of-freedom near-source seismic motions II: examples of real seismogram analysis and S-wave velocity retrieval

Cited by 21 publications

References 31 publications

Measurement of Rotational Events in Regions Prone to Seismicity: A Review

Measurement of Rotational Events in Regions Prone to Seismicity: A Review

Comparative Measurements of Local Seismic Rotations by Three Independent Methods

Recording active-seismic ground rotations using induction-coil magnetometers

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